wip: tests, clippy

Schema upgrades were buggy from 4->5 (the v5 would be skipped).  This
change also refactors the logic slightly so that future additions can
be clearer (no need to have if and else-if combinations).

.build.yml

@@ -0,0 +1,19 @@
+image: fedora/latest
+arch: x86_64
+artifacts:
+  - nostr-rs-relay/target/release/nostr-rs-relay
+environment:
+  RUST_LOG: debug
+packages:
+  - cargo
+  - sqlite-devel
+sources:
+  - https://git.sr.ht/~gheartsfield/nostr-rs-relay/
+shell: false
+tasks:
+  - build: |
+      cd nostr-rs-relay
+      cargo build --release
+  - test: |
+      cd nostr-rs-relay
+      cargo test --release

.cargo/config.toml

@@ -0,0 +1,2 @@
+[build]
+rustflags = ["--cfg", "tokio_unstable"]

.pre-commit-config.yaml

@@ -0,0 +1,16 @@
+# See https://pre-commit.com for more information
+# See https://pre-commit.com/hooks.html for more hooks
+repos:
+- repo: https://github.com/pre-commit/pre-commit-hooks
+  rev: v4.3.0
+  hooks:
+  - id: trailing-whitespace
+  - id: end-of-file-fixer
+  - id: check-yaml
+  - id: check-added-large-files
+- repo: https://github.com/doublify/pre-commit-rust
+  rev: v1.0
+  hooks:
+  - id: fmt
+  - id: cargo-check
+  - id: clippy

Cargo.toml

@@ -1,25 +1,38 @@
 [package]
 name = "nostr-rs-relay"
-version = "0.2.0"
+version = "0.6.2"
 edition = "2021"
 
 [dependencies]
-log = "^0.4"
-env_logger = "^0.9"
-tokio = { version = "^1.14", features = ["full"] }
-futures = "^0.3"
-futures-util = "^0.3"
-tokio-tungstenite = "^0.16"
-tungstenite = "^0.16"
-thiserror = "^1"
-uuid = { version = "^0.8", features = ["v4"] }
-config = { version = "0.11", features = ["toml"] }
-bitcoin_hashes = { version = "^0.9", features = ["serde"] }
-secp256k1 = { version = "^0.20", features = ["rand", "rand-std", "serde", "bitcoin_hashes"] }
-serde = { version = "^1.0", features = ["derive"] }
-serde_json = "^1.0"
-hex = "^0.4"
-rusqlite = "^0.26"
-lazy_static = "^1.4"
-governor = "^0.4"
-nonzero_ext = "^0.3"
+tracing = "0.1.36"
+tracing-subscriber = "0.2.0"
+tokio = { version = "1", features = ["full", "tracing", "signal"] }
+console-subscriber = "0.1.8"
+futures = "0.3"
+futures-util = "0.3"
+tokio-tungstenite = "0.17"
+tungstenite = "0.17"
+thiserror = "1"
+uuid = { version = "1.1.2", features = ["v4"] }
+config = { version = "0.12", features = ["toml"] }
+bitcoin_hashes = { version = "0.10", features = ["serde"] }
+secp256k1 = {version = "0.21", features = ["rand", "rand-std", "serde", "bitcoin_hashes"] }
+serde = { version = "1.0", features = ["derive"] }
+serde_json = {version = "1.0", features = ["preserve_order"]}
+hex = "0.4"
+rusqlite = { version = "0.26", features = ["limits","bundled"]}
+r2d2 = "0.8"
+r2d2_sqlite = "0.19"
+lazy_static = "1.4"
+governor = "0.4"
+nonzero_ext = "0.3"
+hyper = { version="0.14", features=["client", "server","http1","http2","tcp"] }
+hyper-tls = "0.5"
+http = { version = "0.2" }
+parse_duration = "2"
+rand = "0.8"
+const_format = "0.2.28"
+regex = "1"
+
+[dev-dependencies]
+anyhow = "1"

Dockerfile

@@ -1,4 +1,4 @@
-FROM rust:1.57 as builder
+FROM docker.io/library/rust:1.64.0@sha256:5cf09a76cb9baf4990d121221bbad64927cc5690ee54f246487e302ddc2ba300 as builder
 
 RUN USER=root cargo new --bin nostr-rs-relay
 WORKDIR ./nostr-rs-relay
@@ -12,12 +12,11 @@ COPY ./src ./src
 RUN rm ./target/release/deps/nostr*relay*
 RUN cargo build --release
 
-FROM debian:buster-slim
+FROM docker.io/library/debian:bullseye-20221004-slim@sha256:8b702518a671c926b5ece4efe386a476eb4777646a36d996d4bd50944f2f11a2
 ARG APP=/usr/src/app
 ARG APP_DATA=/usr/src/app/db
-
 RUN apt-get update \
-    && apt-get install -y ca-certificates tzdata sqlite3 \
+    && apt-get install -y ca-certificates tzdata sqlite3 libc6 \
     && rm -rf /var/lib/apt/lists/*
 
 EXPOSE 8080
@@ -35,9 +34,9 @@ COPY --from=builder /nostr-rs-relay/target/release/nostr-rs-relay ${APP}/nostr-r
 RUN chown -R $APP_USER:$APP_USER ${APP}
 
 USER $APP_USER
-WORKDIR ${APP_DATA}
+WORKDIR ${APP}
 
-ENV RUST_LOG=info
+ENV RUST_LOG=info,nostr_rs_relay=info
+ENV APP_DATA=${APP_DATA}
 
-
-CMD ["../nostr-rs-relay"]
+CMD ./nostr-rs-relay --db ${APP_DATA}

README.md

@@ -1,6 +1,6 @@
 # [nostr-rs-relay](https://git.sr.ht/~gheartsfield/nostr-rs-relay)
 
-This is a [nostr](https://github.com/fiatjaf/nostr) relay, written in
+This is a [nostr](https://github.com/nostr-protocol/nostr) relay, written in
 Rust.  It currently supports the entire relay protocol, and has a
 SQLite persistence layer.
 
@@ -8,19 +8,47 @@ The project master repository is available on
 [sourcehut](https://sr.ht/~gheartsfield/nostr-rs-relay/), and is
 mirrored on [GitHub](https://github.com/scsibug/nostr-rs-relay).
 
+[![builds.sr.ht status](https://builds.sr.ht/~gheartsfield/nostr-rs-relay/commits/master.svg)](https://builds.sr.ht/~gheartsfield/nostr-rs-relay/commits/master?)
+
+## Features
+
+[NIPs](https://github.com/nostr-protocol/nips) with a relay-specific implementation are listed here.
+
+- [x] NIP-01: [Basic protocol flow description](https://github.com/nostr-protocol/nips/blob/master/01.md)
+  * Core event model
+  * Hide old metadata events
+  * Id/Author prefix search
+- [x] NIP-02: [Contact List and Petnames](https://github.com/nostr-protocol/nips/blob/master/02.md)
+- [ ] NIP-03: [OpenTimestamps Attestations for Events](https://github.com/nostr-protocol/nips/blob/master/03.md)
+- [x] NIP-05: [Mapping Nostr keys to DNS-based internet identifiers](https://github.com/nostr-protocol/nips/blob/master/05.md)
+- [x] NIP-09: [Event Deletion](https://github.com/nostr-protocol/nips/blob/master/09.md)
+- [x] NIP-11: [Relay Information Document](https://github.com/nostr-protocol/nips/blob/master/11.md)
+- [x] NIP-12: [Generic Tag Queries](https://github.com/nostr-protocol/nips/blob/master/12.md)
+- [x] NIP-15: [End of Stored Events Notice](https://github.com/nostr-protocol/nips/blob/master/15.md)
+- [x] NIP-16: [Event Treatment](https://github.com/nostr-protocol/nips/blob/master/16.md)
+- [x] NIP-22: [Event `created_at` limits](https://github.com/nostr-protocol/nips/blob/master/22.md) (_future-dated events only_)
+
 ## Quick Start
 
-The provided `Dockerfile` will compile and build the server application.  Use a bind mount to store the SQLite database outside of the container image, and map the container's 8080 port to a host port (8090 in the example below).
+The provided `Dockerfile` will compile and build the server
+application.  Use a bind mount to store the SQLite database outside of
+the container image, and map the container's 8080 port to a host port
+(7000 in the example below).
 
 ```console
 $ docker build -t nostr-rs-relay .
-$ docker run -p 8090:8080 --mount src=$(pwd)/nostr_data,target=/usr/src/app/db,type=bind nostr-rs-relay
-[2021-12-12T04:20:47Z INFO  nostr_rs_relay] Listening on: 0.0.0.0:8080
-[2021-12-12T04:20:47Z INFO  nostr_rs_relay::db] Opened database for writing
-[2021-12-12T04:20:47Z INFO  nostr_rs_relay::db] init completed
+
+$ docker run -it -p 7000:8080 \
+  --mount src=$(pwd)/data,target=/usr/src/app/db,type=bind nostr-rs-relay
+
+[2021-12-31T19:58:31Z INFO  nostr_rs_relay] listening on: 0.0.0.0:8080
+[2021-12-31T19:58:31Z INFO  nostr_rs_relay::db] opened database "/usr/src/app/db/nostr.db" for writing
+[2021-12-31T19:58:31Z INFO  nostr_rs_relay::db] DB version = 2
 ```
 
-Use a `nostr` client such as [`noscl`](https://github.com/fiatjaf/noscl) to publish and query events.
+Use a `nostr` client such as
+[`noscl`](https://github.com/fiatjaf/noscl) to publish and query
+events.
 
 ```console
 $ noscl publish "hello world"
@@ -31,6 +59,40 @@ Text Note [81cf...2652] from 296a...9b92 5 seconds ago
   hello world
 ```
 
+A pre-built container is also available on DockerHub:
+https://hub.docker.com/r/scsibug/nostr-rs-relay
+
+## Configuration
+
+The sample [`config.toml`](config.toml) file demonstrates the
+configuration available to the relay.  This file is optional, but may
+be mounted into a docker container like so:
+
+```console
+$ docker run -it -p 7000:8080 \
+  --mount src=$(pwd)/config.toml,target=/usr/src/app/config.toml,type=bind \
+  --mount src=$(pwd)/data,target=/usr/src/app/db,type=bind \
+  nostr-rs-relay
+```
+
+Options include rate-limiting, event size limits, and network address
+settings.
+
+## Reverse Proxy Configuration
+
+For examples of putting the relay behind a reverse proxy (for TLS
+termination, load balancing, and other features), see [Reverse
+Proxy](reverse-proxy.md).
+
+## Dev Channel
+
+For development discussions, please feel free to use the [sourcehut
+mailing list](https://lists.sr.ht/~gheartsfield/nostr-rs-relay-devel).
+Or, drop by the [Nostr Telegram Channel](https://t.me/nostr_protocol).
+
+To chat about `nostr-rs-relay` on `nostr` itself; visit our channel on [anigma](https://anigma.io/) or another client that supports [NIP-28](https://github.com/nostr-protocol/nips/blob/master/28.md) chats:
+ * `2ad246a094fee48c6e455dd13d759d5f41b5a233120f5719d81ebc1935075194`
+
 License
 ---
 This project is MIT licensed.

config.toml

@@ -1,32 +1,111 @@
 # Nostr-rs-relay configuration
 
+[info]
+# The advertised URL for the Nostr websocket.
+relay_url = "wss://nostr.example.com/"
+
+# Relay information for clients.  Put your unique server name here.
+name = "nostr-rs-relay"
+
+# Description
+description = "A newly created nostr-rs-relay.\n\nCustomize this with your own info."
+
+# Administrative contact pubkey
+#pubkey = "0c2d168a4ae8ca58c9f1ab237b5df682599c6c7ab74307ea8b05684b60405d41"
+
+# Administrative contact URI
+#contact = "mailto:contact@example.com"
+
+[diagnostics]
+# Enable tokio tracing (for use with tokio-console)
+#tracing = true
+
+[database]
+# Directory for SQLite files.  Defaults to the current directory.  Can
+# also be specified (and overriden) with the "--db dirname" command
+# line option.
+data_directory = "."
+
+
+# Use an in-memory database instead of 'nostr.db'.
+# Caution; this will not survive a process restart!
+#in_memory = false
+
+# Database connection pool settings for subscribers:
+
+# Minimum number of SQLite reader connections
+#min_conn = 4
+
+# Maximum number of SQLite reader connections
+#max_conn = 128
+
 [network]
 # Bind to this network address
 address = "0.0.0.0"
+
 # Listen on this port
 port = 8080
 
 [options]
 # Reject events that have timestamps greater than this many seconds in
-# the future.  Defaults to rejecting anything greater than 30 minutes
-# from the current time.
-#reject_future_seconds = 1800
+# the future.  Recommended to reject anything greater than 30 minutes
+# from the current time, but the default is to allow any date.
+reject_future_seconds = 1800
 
 [limits]
 # Limit events created per second, averaged over one minute.  Must be
 # an integer.  If not set (or set to 0), defaults to unlimited.
-messages_per_sec = 0
+#messages_per_sec = 0
 
-# Maximum WebSocket message in bytes.  Defaults to 128k.
+# Limit the maximum size of an EVENT message.  Defaults to 128 KB.
+# Set to 0 for unlimited.
+#max_event_bytes = 131072
+
+# Maximum WebSocket message in bytes.  Defaults to 128 KB.
 #max_ws_message_bytes = 131072
 
-# Maximum WebSocket frame size in bytes.  Defaults to 128k.
+# Maximum WebSocket frame size in bytes.  Defaults to 128 KB.
 #max_ws_frame_bytes = 131072
 
 # Broadcast buffer size, in number of events.  This prevents slow
-# readers from consuming memory.  Defaults to 4096.
-#broadcast_buffer = 4096
+# readers from consuming memory.
+#broadcast_buffer = 16384
 
 # Event persistence buffer size, in number of events.  This provides
-# backpressure to senders if writes are slow.  Defaults to 16.
-#event_persist_buffer = 16
+# backpressure to senders if writes are slow.
+#event_persist_buffer = 4096
+
+[authorization]
+# Pubkey addresses in this array are whitelisted for event publishing.
+# Only valid events by these authors will be accepted, if the variable
+# is set.
+#pubkey_whitelist = [
+#  "35d26e4690cbe1a898af61cc3515661eb5fa763b57bd0b42e45099c8b32fd50f",
+#  "887645fef0ce0c3c1218d2f5d8e6132a19304cdc57cd20281d082f38cfea0072",
+#]
+
+[verified_users]
+# NIP-05 verification of users.  Can be "enabled" to require NIP-05
+# metadata for event authors, "passive" to perform validation but
+# never block publishing, or "disabled" to do nothing.
+#mode = "disabled"
+
+# Domain names that will be prevented from publishing events.
+#domain_blacklist = ["wellorder.net"]
+
+# Domain names that are allowed to publish events.  If defined, only
+# events NIP-05 verified authors at these domains are persisted.
+#domain_whitelist = ["example.com"]
+
+# Consider an pubkey "verified" if we have a successful validation
+# from the NIP-05 domain within this amount of time.  Note, if the
+# domain provides a successful response that omits the account,
+# verification is immediately revoked.
+#verify_expiration = "1 week"
+
+# How long to wait between verification attempts for a specific author.
+#verify_update_frequency = "24 hours"
+
+# How many consecutive failed checks before we give up on verifying
+# this author.
+#max_consecutive_failures = 20

docs/user-verification-nip05.md

@@ -0,0 +1,248 @@
+# Author Verification Design Document
+
+The relay will use NIP-05 DNS-based author verification to limit which
+authors can publish events to a relay.  This document describes how
+this feature will operate.
+
+## Considerations
+
+DNS-based author verification is designed to be deployed in relays that
+want to prevent spam, so there should be strong protections to prevent
+unauthorized authors from persisting data.  This includes data needed to
+verify new authors.
+
+There should be protections in place to ensure the relay cannot be
+used to spam or flood other webservers.  Additionally, there should be
+protections against server-side request forgery (SSRF).
+
+## Design Overview
+
+### Concepts
+
+All authors are initially "unverified".  Unverified authors that submit
+appropriate `NIP-05` metadata events become "candidates" for
+verification.  A candidate author becomes verified  when the relay
+inspects a kind `0` metadata event for the author with a `nip05` field,
+and follows the procedure in `NIP-05` to successfully associate the
+author with an internet identifier.
+
+The `NIP-05` procedure verifies an author for a fixed period of time,
+configurable by the relay operator.  If this "verification expiration
+time" (`verify_expiration`) is exceeded without being refreshed, they
+are once again unverified.
+
+Verified authors have their status regularly and automatically updated
+through scheduled polling to their verified domain, this process is
+"re-verification".  It is performed based on the configuration setting
+`verify_update_frequency`, which defines how long the relay waits
+between verification attempts (whether the result was success or
+failure).
+
+Authors may change their verification data (the internet identifier from
+`NIP-05`) with a new metadata event, which then requires
+re-verification.  Their old verification remains valid until
+expiration.
+
+Performing candidate author verification is a best-effort activity and
+may be significantly rate-limited to prevent relays being used to
+attack other hosts.  Candidate verification (untrusted authors) should
+never impact re-verification (trusted authors).
+
+## Operating Modes
+
+The relay may operate in one of three modes.  "Disabled" performs no
+validation activities, and will never permit or deny events based on
+an author's NIP-05 metadata.  "Passive" performs NIP-05 validation,
+but does not permit or deny events based on the validity or presence
+of NIP-05 metadata.  "Enabled" will require current and valid NIP-05
+metadata for any events to be persisted.  "Enabled" mode will
+additionally consider domain whitelist/blacklist configuration data to
+restrict which author's events are persisted.
+
+## Design Details
+
+### Data Storage
+
+Verification is stored in a dedicated table.  This tracks:
+
+* `nip05` identifier
+* most recent verification timestamp
+* most recent verification failure timestamp
+* reference to the metadata event (used for tracking `created_at` and
+  `pubkey`)
+
+### Event Handling
+
+All events are first validated to ensure the signature is valid.
+
+Incoming events of kind _other_ than metadata (kind `0`) submitted by
+clients will be evaluated as follows.
+
+* If the event's author has a current verification, the event is
+  persisted as normal.
+* If the event's author has either no verification, or the
+  verification is expired, the event is rejected.
+
+If the event is a metadata event, we handle it differently.
+
+We first determine the verification status of the event's pubkey.
+
+* If the event author is unverified, AND the event contains a `nip05`
+  key, we consider this a verification candidate.
+* If the event author is unverified, AND the event does not contain a
+  `nip05` key, this is not a candidate, and the event is dropped.
+
+* If the event author is verified, AND the event contains a `nip05`
+  key that is identical to the currently stored value, no special
+  action is needed.
+* If the event author is verified, AND the event contains a different
+  `nip05` than was previously verified, with a more recent timestamp,
+  we need to re-verify.
+* If the event author is verified, AND the event is missing a `nip05`
+  key, and the event timestamp is more recent than what was verified,
+  we do nothing.  The current verification will be allowed to expire.
+
+### Candidate Verification
+
+When a candidate verification is requested, a rate limit will be
+utilized.  If the rate limit is exceeded, new candidate verification
+requests will be dropped.  In practice, this is implemented by a
+size-limited channel that drops events that exceed a threshold.
+
+Candidates are never persisted in the database.
+
+### Re-Verification
+
+Re-verification is straightforward when there has been no change to
+the `nip05` key.  A new request to the `nip05` domain is performed,
+and if successful, the verification timestamp is updated to the
+current time.  If the request fails due to a timeout or server error,
+the failure timestamp is updated instead.
+
+When the the `nip05` key has changed and this event is more recent, we
+will create a new verification record, and delete all other records
+for the same name.
+
+Regarding creating new records vs. updating: We never update the event
+reference or `nip05` identifier in a verification record. Every update
+either reset the last failure or last success timestamp.
+
+### Determining Verification Status
+
+In determining if an event is from a verified author, the following
+procedure should be used:
+
+Join the verification table with the event table, to provide
+verification data alongside the event `created_at` and `pubkey`
+metadata.  Find the most recent verification record for the author,
+based on the `created_at` time.
+
+Reject the record if the success timestamp is not within our
+configured expiration time.
+
+Reject records with disallowed domains, based on any whitelists or
+blacklists in effect.
+
+If a result remains, the author is treated as verified.
+
+This does give a time window for authors transitioning their verified
+status between domains.  There may be a period of time in which there
+are multiple valid rows in the verification table for a given author.
+
+### Cleaning Up Inactive Verifications
+
+After a author verification has expired, we will continue to check for
+it to become valid again.  After a configurable number of attempts, we
+should simply forget it, and reclaim the space.
+
+### Addition of Domain Whitelist/Blacklist
+
+A set of whitelisted or blacklisted domains may be provided.  If both
+are provided, only the whitelist is used.  In this context, domains
+are either "allowed" (present on a whitelist and NOT present on a
+blacklist), or "denied" (NOT present on a whitelist and present on a
+blacklist).
+
+The processes outlined so far are modified in the presence of these
+options:
+
+* Only authors with allowed domains can become candidates for
+  verification.
+* Verification status queries additionally filter out any denied
+  domains.
+* Re-verification processes only proceed with allowed domains.
+
+### Integration
+
+We have an existing database writer thread, which receives events and
+attempts to persist them to disk.  Once validated and persisted, these
+events are broadcast to all subscribers.
+
+When verification is enabled, the writer must check to ensure a valid,
+unexpired verification record exists for the auther.  All metadata
+events (regardless of verification status) are forwarded to a verifier
+module.  If the verifier determines a new verification record is
+needed, it is also responsible for persisting and broadcasting the
+event, just as the database writer would have done.
+
+## Threat Scenarios
+
+Some of these mitigations are fully implemented, others are documented
+simply to demonstrate a mitigation is possible.
+
+### Domain Spamming
+
+*Threat*: A author with a high-volume of events creates a metadata event
+with a bogus domain, causing the relay to generate significant
+unwanted traffic to a target.
+
+*Mitigation*: Rate limiting for all candidate verification will limit
+external requests to a reasonable amount.  Currently, this is a simple
+delay that slows down the HTTP task.
+
+### Denial of Service for Legitimate Authors
+
+*Threat*: A author with a high-volume of events creates a metadata event
+with a domain that is invalid for them, _but which is used by other
+legitimate authors_.  This triggers rate-limiting against the legitimate
+domain, and blocks authors from updating their own metadata.
+
+*Mitigation*: Rate limiting should only apply to candidates, so any
+existing verified authors have priority for re-verification.  New
+authors will be affected, as we can not distinguish between the threat
+and a legitimate author. _(Unimplemented)_
+
+### Denial of Service by Consuming Storage
+
+*Threat*: A author creates a high volume of random metadata events with
+unique domains, in order to cause us to store large amounts of data
+for to-be-verified authors.
+
+*Mitigation*: No data is stored for candidate authors.  This makes it
+harder for new authors to become verified, but is effective at
+preventing this attack.
+
+### Metadata Replay for Verified Author
+
+*Threat*: Attacker replays out-of-date metadata event for a author, to
+cause a verification to fail.
+
+*Mitigation*: New metadata events have their signed timestamp compared
+against the signed timestamp of the event that has most recently
+verified them.  If the metadata event is older, it is discarded.
+
+### Server-Side Request Forgery via Metadata
+
+*Threat*: Attacker includes malicious data in the `nip05` event, which
+is used to generate HTTP requests against potentially internal
+resources.  Either leaking data, or invoking webservices beyond their
+own privileges.
+
+*Mitigation*: Consider detecting and dropping when the `nip05` field
+is an IP address.  Allow the relay operator to utilize the `blacklist`
+or `whitelist` to constrain hosts that will be contacted.  Most
+importantly, the verification process is hardcoded to only make
+requests to a known url path
+(`.well-known/nostr.json?name=<LOCAL_NAME>`).  The `<LOCAL_NAME>`
+component is restricted to a basic ASCII subset (preventing additional
+URL components).

mk-platform-agnostic-dockerfile.sh

@@ -0,0 +1,3 @@
+#!/usr/bin/env bash
+sed -E 's/@sha256:[[:alnum:]]+//g' Dockerfile > Dockerfile.any-platform
+echo "Created platform-agnostic Dockerfile in 'Dockerfile.any-platform'"

reverse-proxy.md

@@ -0,0 +1,92 @@
+# Reverse Proxy Setup Guide
+
+It is recommended to run `nostr-rs-relay` behind a reverse proxy such
+as `haproxy` or `nginx` to provide TLS termination.  Simple examples
+of `haproxy` and `nginx` configurations are documented here.
+
+## Minimal HAProxy Configuration
+
+Assumptions:
+
+* HAProxy version is `2.4.10` or greater (older versions not tested).
+* Hostname for the relay is `relay.example.com`.
+* Your relay should be available over wss://relay.example.com
+* Your (NIP-11) relay info page should be available on https://relay.example.com
+* SSL certificate is located in `/etc/certs/example.com.pem`.
+* Relay is running on port 8080.
+* Limit connections to 400 concurrent.
+* HSTS (HTTP Strict Transport Security) is desired.
+* Only TLS 1.2 or greater is allowed.
+
+```
+global
+    ssl-default-bind-ciphersuites TLS_AES_128_GCM_SHA256:TLS_AES_256_GCM_SHA384:TLS_CHACHA20_POLY1305_SHA256
+    ssl-default-bind-options prefer-client-ciphers no-sslv3 no-tlsv10 no-tlsv11 no-tls-tickets
+
+frontend fe_prod
+    mode    http
+    bind    :443 ssl crt /etc/certs/example.com.pem alpn h2,http/1.1
+    bind    :80
+    http-request set-header X-Forwarded-Proto https if { ssl_fc }
+    redirect scheme https code 301 if !{ ssl_fc }
+    acl host_relay hdr(host) -i relay.example.com
+    use_backend relay if host_relay
+    # HSTS (1 year)
+    http-response set-header Strict-Transport-Security max-age=31536000
+
+backend relay
+    mode http
+    timeout connect 5s
+    timeout client 50s
+    timeout server 50s
+    timeout tunnel 1h
+    timeout client-fin 30s
+    option tcp-check
+    default-server maxconn 400 check inter 20s fastinter 1s
+    server relay 127.0.0.1:8080
+```
+
+### HAProxy Notes
+
+You may experience WebSocket connection problems with Firefox if
+HTTP/2 is enabled, for older versions of HAProxy (2.3.x).  Either
+disable HTTP/2 (`h2`), or upgrade HAProxy.
+
+## Bare-bones Nginx Configuration
+
+Assumptions:
+
+* `Nginx` version is `1.18.0` (other versions not tested).
+* Hostname for the relay is `relay.example.com`.
+* SSL certificate and key are located at `/etc/letsencrypt/live/relay.example.com/`.
+* Relay is running on port `8080`.
+
+```
+http {
+    server {
+        listen 443 ssl;
+        server_name relay.example.com;
+        ssl_certificate /etc/letsencrypt/live/relay.example.com/fullchain.pem;
+        ssl_certificate_key /etc/letsencrypt/live/relay.example.com/privkey.pem;
+        ssl_protocols TLSv1 TLSv1.1 TLSv1.2;
+        ssl_ciphers HIGH:!aNULL:!MD5;
+        keepalive_timeout 70;
+
+        location / {
+            proxy_pass http://localhost:8080;
+            proxy_http_version 1.1;
+            proxy_set_header Upgrade $http_upgrade;
+            proxy_set_header Connection "Upgrade";
+            proxy_set_header Host $host;
+        }
+    }
+}
+```
+
+### Nginx Notes
+
+The above configuration was tested on `nginx` `1.18.0` was tested on `Ubuntu 20.04`.
+
+For help installing `nginx` on `Ubuntu`, see [this guide](https://www.digitalocean.com/community/tutorials/how-to-install-nginx-on-ubuntu-20-04).
+
+For guidance on using `letsencrypt` to obtain a cert on `Ubuntu`, including an `nginx` plugin, see [this post](https://www.digitalocean.com/community/tutorials/how-to-secure-nginx-with-let-s-encrypt-on-ubuntu-20-04).

rustfmt.toml

@@ -1 +1 @@
-edition = "2018"
+edition = "2021"

src/close.rs

@@ -1,9 +1,11 @@
 //! Subscription close request parsing
+//!
+//! Representation and parsing of `CLOSE` messages sent from clients.
 use crate::error::{Error, Result};
 use serde::{Deserialize, Serialize};
 
 /// Close command in network format
-#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
 pub struct CloseCmd {
     /// Protocol command, expected to always be "CLOSE".
     cmd: String,
@@ -11,8 +13,8 @@ pub struct CloseCmd {
     id: String,
 }
 
-/// Close command parsed
-#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
+/// Identifier of the subscription to be closed.
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
 pub struct Close {
     /// The subscription identifier being closed.
     pub id: String,
@@ -21,10 +23,10 @@ pub struct Close {
 impl From<CloseCmd> for Result<Close> {
     fn from(cc: CloseCmd) -> Result<Close> {
         // ensure command is correct
-        if cc.cmd != "CLOSE" {
-            Err(Error::CommandUnknownError)
-        } else {
+        if cc.cmd == "CLOSE" {
             Ok(Close { id: cc.id })
+        } else {
+            Err(Error::CommandUnknownError)
         }
     }
 }

src/config.rs

@@ -1,14 +1,29 @@
-use lazy_static::lazy_static;
-use log::*;
+//! Configuration file and settings management
+use config::{Config, ConfigError, File};
 use serde::{Deserialize, Serialize};
-use std::sync::RwLock;
+use std::time::Duration;
+use tracing::warn;
 
-// initialize a singleton default configuration
-lazy_static! {
-    pub static ref SETTINGS: RwLock<Settings> = RwLock::new(Settings::default());
+#[derive(Debug, Serialize, Deserialize, Clone)]
+#[allow(unused)]
+pub struct Info {
+    pub relay_url: Option<String>,
+    pub name: Option<String>,
+    pub description: Option<String>,
+    pub pubkey: Option<String>,
+    pub contact: Option<String>,
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Database {
+    pub data_directory: String,
+    pub in_memory: bool,
+    pub min_conn: u32,
+    pub max_conn: u32,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
 #[allow(unused)]
 pub struct Network {
     pub port: u16,
@@ -16,13 +31,13 @@ pub struct Network {
 }
 
 //
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 #[allow(unused)]
 pub struct Options {
     pub reject_future_seconds: Option<usize>, // if defined, reject any events with a timestamp more than X seconds in the future
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 #[allow(unused)]
 pub struct Retention {
     // TODO: implement
@@ -32,49 +47,143 @@ pub struct Retention {
     pub whitelist_addresses: Option<Vec<String>>, // whitelisted addresses (never delete)
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
 #[allow(unused)]
 pub struct Limits {
     pub messages_per_sec: Option<u32>, // Artificially slow down event writing to limit disk consumption (averaged over 1 minute)
-    pub max_event_bytes: Option<usize>,
+    pub max_event_bytes: Option<usize>, // Maximum size of an EVENT message
     pub max_ws_message_bytes: Option<usize>,
     pub max_ws_frame_bytes: Option<usize>,
     pub broadcast_buffer: usize, // events to buffer for subscribers (prevents slow readers from consuming memory)
     pub event_persist_buffer: usize, // events to buffer for database commits (block senders if database writes are too slow)
 }
 
-#[derive(Debug, Serialize, Deserialize)]
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Authorization {
+    pub pubkey_whitelist: Option<Vec<String>>, // If present, only allow these pubkeys to publish events
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Diagnostics {
+    pub tracing: bool, // enables tokio console-subscriber
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone, Copy)]
+#[serde(rename_all = "lowercase")]
+pub enum VerifiedUsersMode {
+    Enabled,
+    Passive,
+    Disabled,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct VerifiedUsers {
+    pub mode: VerifiedUsersMode, // Mode of operation: "enabled" (enforce) or "passive" (check only). If none, this is simply disabled.
+    pub domain_whitelist: Option<Vec<String>>, // If present, only allow verified users from these domains can publish events
+    pub domain_blacklist: Option<Vec<String>>, // If present, allow all verified users from any domain except these
+    pub verify_expiration: Option<String>, // how long a verification is cached for before no longer being used
+    pub verify_update_frequency: Option<String>, // how often to attempt to update verification
+    pub verify_expiration_duration: Option<Duration>, // internal result of parsing verify_expiration
+    pub verify_update_frequency_duration: Option<Duration>, // internal result of parsing verify_update_frequency
+    pub max_consecutive_failures: usize, // maximum number of verification failures in a row, before ceasing future checks
+}
+
+impl VerifiedUsers {
+    pub fn init(&mut self) {
+        self.verify_expiration_duration = self.verify_expiration_duration();
+        self.verify_update_frequency_duration = self.verify_update_duration();
+    }
+
+    #[must_use]
+    pub fn is_enabled(&self) -> bool {
+        self.mode == VerifiedUsersMode::Enabled
+    }
+
+    #[must_use]
+    pub fn is_active(&self) -> bool {
+        self.mode == VerifiedUsersMode::Enabled || self.mode == VerifiedUsersMode::Passive
+    }
+
+    #[must_use]
+    pub fn is_passive(&self) -> bool {
+        self.mode == VerifiedUsersMode::Passive
+    }
+
+    #[must_use]
+    pub fn verify_expiration_duration(&self) -> Option<Duration> {
+        self.verify_expiration
+            .as_ref()
+            .and_then(|x| parse_duration::parse(x).ok())
+    }
+
+    #[must_use]
+    pub fn verify_update_duration(&self) -> Option<Duration> {
+        self.verify_update_frequency
+            .as_ref()
+            .and_then(|x| parse_duration::parse(x).ok())
+    }
+
+    #[must_use]
+    pub fn is_valid(&self) -> bool {
+        self.verify_expiration_duration().is_some() && self.verify_update_duration().is_some()
+    }
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
 #[allow(unused)]
 pub struct Settings {
+    pub info: Info,
+    pub diagnostics: Diagnostics,
+    pub database: Database,
     pub network: Network,
     pub limits: Limits,
+    pub authorization: Authorization,
+    pub verified_users: VerifiedUsers,
     pub retention: Retention,
     pub options: Options,
 }
 
 impl Settings {
+    #[must_use]
     pub fn new() -> Self {
-        let d = Self::default();
+        let default_settings = Self::default();
         // attempt to construct settings with file
-        //        Self::new_from_default(&d).unwrap_or(d)
-        let from_file = Self::new_from_default(&d);
+        let from_file = Self::new_from_default(&default_settings);
         match from_file {
             Ok(f) => f,
             Err(e) => {
                 warn!("Error reading config file ({:?})", e);
-                d
+                default_settings
             }
         }
     }
 
-    fn new_from_default(default: &Settings) -> Result<Self, config::ConfigError> {
-        let config: config::Config = config::Config::new();
-        let settings: Settings = config
+    fn new_from_default(default: &Settings) -> Result<Self, ConfigError> {
+        let builder = Config::builder();
+        let config: Config = builder
             // use defaults
-            .with_merged(config::Config::try_from(default).unwrap())?
+            .add_source(Config::try_from(default)?)
             // override with file contents
-            .with_merged(config::File::with_name("config"))?
-            .try_into()?;
+            .add_source(File::with_name("config.toml"))
+            .build()?;
+        let mut settings: Settings = config.try_deserialize()?;
+        // ensure connection pool size is logical
+        assert!(
+            settings.database.min_conn <= settings.database.max_conn,
+            "Database min_conn setting ({}) cannot exceed max_conn ({})",
+            settings.database.min_conn,
+            settings.database.max_conn
+        );
+        // ensure durations parse
+        assert!(
+            settings.verified_users.is_valid(),
+            "VerifiedUsers time settings could not be parsed"
+        );
+        // initialize durations for verified users
+        settings.verified_users.init();
         Ok(settings)
     }
 }
@@ -82,6 +191,20 @@ impl Settings {
 impl Default for Settings {
     fn default() -> Self {
         Settings {
+            info: Info {
+                relay_url: None,
+                name: Some("Unnamed nostr-rs-relay".to_owned()),
+                description: None,
+                pubkey: None,
+                contact: None,
+            },
+            diagnostics: Diagnostics { tracing: false },
+            database: Database {
+                data_directory: ".".to_owned(),
+                in_memory: false,
+                min_conn: 4,
+                max_conn: 128,
+            },
             network: Network {
                 port: 8080,
                 address: "0.0.0.0".to_owned(),
@@ -91,8 +214,21 @@ impl Default for Settings {
                 max_event_bytes: Some(2 << 17),      // 128K
                 max_ws_message_bytes: Some(2 << 17), // 128K
                 max_ws_frame_bytes: Some(2 << 17),   // 128K
-                broadcast_buffer: 4096,
-                event_persist_buffer: 16,
+                broadcast_buffer: 16384,
+                event_persist_buffer: 4096,
+            },
+            authorization: Authorization {
+                pubkey_whitelist: None, // Allow any address to publish
+            },
+            verified_users: VerifiedUsers {
+                mode: VerifiedUsersMode::Disabled,
+                domain_whitelist: None,
+                domain_blacklist: None,
+                verify_expiration: Some("1 week".to_owned()),
+                verify_update_frequency: Some("1 day".to_owned()),
+                verify_expiration_duration: None,
+                verify_update_frequency_duration: None,
+                max_consecutive_failures: 20,
             },
             retention: Retention {
                 max_events: None,          // max events
@@ -101,7 +237,7 @@ impl Default for Settings {
                 whitelist_addresses: None, // whitelisted addresses (never delete)
             },
             options: Options {
-                reject_future_seconds: Some(30 * 60), // Reject events 30min in the future or greater
+                reject_future_seconds: None, // Reject events in the future if defined
             },
         }
     }

src/conn.rs

@@ -5,8 +5,8 @@ use crate::error::Result;
 use crate::event::Event;
 
 use crate::subscription::Subscription;
-use log::*;
 use std::collections::HashMap;
+use tracing::{debug, info};
 use uuid::Uuid;
 
 /// A subscription identifier has a maximum length
@@ -30,6 +30,7 @@ impl Default for ClientConn {
 
 impl ClientConn {
     /// Create a new, empty connection state.
+    #[must_use]
     pub fn new() -> Self {
         let client_id = Uuid::new_v4();
         ClientConn {
@@ -41,14 +42,16 @@ impl ClientConn {
 
     /// Get a short prefix of the client's unique identifier, suitable
     /// for logging.
+    #[must_use]
     pub fn get_client_prefix(&self) -> String {
         self.client_id.to_string().chars().take(8).collect()
     }
 
     /// Find all matching subscriptions.
+    #[must_use]
     pub fn get_matching_subscriptions(&self, e: &Event) -> Vec<&str> {
         let mut v: Vec<&str> = vec![];
-        for (id, sub) in self.subscriptions.iter() {
+        for (id, sub) in &self.subscriptions {
             if sub.interested_in_event(e) {
                 v.push(id);
             }
@@ -57,6 +60,10 @@ impl ClientConn {
     }
 
     /// Add a new subscription for this connection.
+    /// # Errors
+    ///
+    /// Will return `Err` if the client has too many subscriptions, or
+    /// if the provided name is excessively long.
     pub fn subscribe(&mut self, s: Subscription) -> Result<()> {
         let k = s.get_id();
         let sub_id_len = k.len();
@@ -91,12 +98,13 @@ impl ClientConn {
     }
 
     /// Remove the subscription for this connection.
-    pub fn unsubscribe(&mut self, c: Close) {
+    pub fn unsubscribe(&mut self, c: &Close) {
         // TODO: return notice if subscription did not exist.
         self.subscriptions.remove(&c.id);
         debug!(
-            "removed subscription, currently have {} active subs",
-            self.subscriptions.len()
+            "removed subscription, currently have {} active subs (cid={})",
+            self.subscriptions.len(),
+            self.client_id
         );
     }
 }

src/db.rs

@@ -1,136 +1,127 @@
 //! Event persistence and querying
-use crate::error::Result;
-use crate::event::Event;
+//use crate::config::SETTINGS;
+use crate::config::Settings;
+use crate::error::{Error, Result};
+use crate::event::{single_char_tagname, Event};
+use crate::hexrange::hex_range;
+use crate::hexrange::HexSearch;
+use crate::nip05;
+use crate::schema::{upgrade_db, STARTUP_SQL};
+use crate::subscription::ReqFilter;
 use crate::subscription::Subscription;
+use crate::utils::{is_hex, is_lower_hex};
 use governor::clock::Clock;
 use governor::{Quota, RateLimiter};
 use hex;
-use log::*;
+use r2d2;
+use r2d2_sqlite::SqliteConnectionManager;
 use rusqlite::params;
-use rusqlite::Connection;
+use rusqlite::types::ToSql;
 use rusqlite::OpenFlags;
-//use std::num::NonZeroU32;
-use crate::config::SETTINGS;
+use std::fmt::Write as _;
 use std::path::Path;
 use std::thread;
+use std::time::Duration;
+use std::time::Instant;
 use tokio::task;
+use tracing::{debug, info, trace, warn};
+
+pub type SqlitePool = r2d2::Pool<r2d2_sqlite::SqliteConnectionManager>;
+pub type PooledConnection = r2d2::PooledConnection<r2d2_sqlite::SqliteConnectionManager>;
+
+/// Events submitted from a client, with a return channel for notices
+pub struct SubmittedEvent {
+    pub event: Event,
+    pub notice_tx: tokio::sync::mpsc::Sender<String>,
+}
 
 /// Database file
-const DB_FILE: &str = "nostr.db";
+pub const DB_FILE: &str = "nostr.db";
 
-/// Startup DB Pragmas
-const STARTUP_SQL: &str = r##"
-PRAGMA main.synchronous=NORMAL;
-PRAGMA foreign_keys = ON;
-pragma mmap_size = 536870912; -- 512MB of mmap
-"##;
-
-/// Schema definition
-const INIT_SQL: &str = r##"
--- Database settings
-PRAGMA encoding = "UTF-8";
-PRAGMA journal_mode=WAL;
-PRAGMA main.synchronous=NORMAL;
-PRAGMA foreign_keys = ON;
-PRAGMA application_id = 1654008667;
-PRAGMA user_version = 2;
-
--- Event Table
-CREATE TABLE IF NOT EXISTS event (
-id INTEGER PRIMARY KEY,
-event_hash BLOB NOT NULL, -- 4-byte hash
-first_seen INTEGER NOT NULL, -- when the event was first seen (not authored!) (seconds since 1970)
-created_at INTEGER NOT NULL, -- when the event was authored
-author BLOB NOT NULL, -- author pubkey
-kind INTEGER NOT NULL, -- event kind
-hidden INTEGER, -- relevant for queries
-content TEXT NOT NULL -- serialized json of event object
-);
-
--- Event Indexes
-CREATE UNIQUE INDEX IF NOT EXISTS event_hash_index ON event(event_hash);
-CREATE INDEX IF NOT EXISTS created_at_index ON event(created_at);
-CREATE INDEX IF NOT EXISTS author_index ON event(author);
-CREATE INDEX IF NOT EXISTS kind_index ON event(kind);
-
--- Event References Table
-CREATE TABLE IF NOT EXISTS event_ref (
-id INTEGER PRIMARY KEY,
-event_id INTEGER NOT NULL, -- an event ID that contains an #e tag.
-referenced_event BLOB NOT NULL, -- the event that is referenced.
-FOREIGN KEY(event_id) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
-);
-
--- Event References Index
-CREATE INDEX IF NOT EXISTS event_ref_index ON event_ref(referenced_event);
-
--- Pubkey References Table
-CREATE TABLE IF NOT EXISTS pubkey_ref (
-id INTEGER PRIMARY KEY,
-event_id INTEGER NOT NULL, -- an event ID that contains an #p tag.
-referenced_pubkey BLOB NOT NULL, -- the pubkey that is referenced.
-FOREIGN KEY(event_id) REFERENCES event(id) ON UPDATE RESTRICT ON DELETE CASCADE
-);
-
--- Pubkey References Index
-CREATE INDEX IF NOT EXISTS pubkey_ref_index ON pubkey_ref(referenced_pubkey);
-"##;
-
-/// Upgrade DB to latest version, and execute pragma settings
-pub fn upgrade_db(conn: &mut Connection) -> Result<()> {
-    // check the version.
-    let curr_version = db_version(conn)?;
-    info!("DB version = {:?}", curr_version);
-
-    // initialize from scratch
-    if curr_version == 0 {
-        match conn.execute_batch(INIT_SQL) {
-            Ok(()) => info!("database pragma/schema initialized to v2, and ready"),
-            Err(err) => {
-                error!("update failed: {}", err);
-                panic!("database could not be initialized");
-            }
+/// Build a database connection pool.
+/// # Panics
+///
+/// Will panic if the pool could not be created.
+#[must_use]
+pub fn build_pool(
+    name: &str,
+    settings: &Settings,
+    flags: OpenFlags,
+    min_size: u32,
+    max_size: u32,
+    wait_for_db: bool,
+) -> SqlitePool {
+    let db_dir = &settings.database.data_directory;
+    let full_path = Path::new(db_dir).join(DB_FILE);
+    // small hack; if the database doesn't exist yet, that means the
+    // writer thread hasn't finished.  Give it a chance to work.  This
+    // is only an issue with the first time we run.
+    if !settings.database.in_memory {
+        while !full_path.exists() && wait_for_db {
+            debug!("Database reader pool is waiting on the database to be created...");
+            thread::sleep(Duration::from_millis(500));
         }
-    } else if curr_version == 1 {
-        // only change is adding a hidden column to events.
-        let upgrade_sql = r##"
-ALTER TABLE event ADD hidden INTEGER;
-UPDATE event SET hidden=FALSE;
-PRAGMA user_version = 2;
-"##;
-        match conn.execute_batch(upgrade_sql) {
-            Ok(()) => info!("database schema upgraded v1 -> v2"),
-            Err(err) => {
-                error!("update failed: {}", err);
-                panic!("database could not be upgraded");
-            }
-        }
-    } else if curr_version == 2 {
-        debug!("Database version was already current");
-    } else if curr_version > 2 {
-        panic!("Database version is newer than supported by this executable");
     }
-    // Setup PRAGMA
-    conn.execute_batch(STARTUP_SQL)?;
-    Ok(())
+    let manager = if settings.database.in_memory {
+        SqliteConnectionManager::memory()
+            .with_flags(flags)
+            .with_init(|c| c.execute_batch(STARTUP_SQL))
+    } else {
+        SqliteConnectionManager::file(&full_path)
+            .with_flags(flags)
+            .with_init(|c| c.execute_batch(STARTUP_SQL))
+    };
+    let pool: SqlitePool = r2d2::Pool::builder()
+        .test_on_check_out(true) // no noticeable performance hit
+        .min_idle(Some(min_size))
+        .max_size(max_size)
+        .build(manager)
+        .unwrap();
+    info!(
+        "Built a connection pool {:?} (min={}, max={})",
+        name, min_size, max_size
+    );
+    pool
 }
 
 /// Spawn a database writer that persists events to the SQLite store.
 pub async fn db_writer(
-    mut event_rx: tokio::sync::mpsc::Receiver<Event>,
+    settings: Settings,
+    mut event_rx: tokio::sync::mpsc::Receiver<SubmittedEvent>,
     bcast_tx: tokio::sync::broadcast::Sender<Event>,
+    metadata_tx: tokio::sync::broadcast::Sender<Event>,
     mut shutdown: tokio::sync::broadcast::Receiver<()>,
 ) -> tokio::task::JoinHandle<Result<()>> {
+    // are we performing NIP-05 checking?
+    let nip05_active = settings.verified_users.is_active();
+    // are we requriing NIP-05 user verification?
+    let nip05_enabled = settings.verified_users.is_enabled();
+
     task::spawn_blocking(move || {
-        let mut conn = Connection::open_with_flags(
-            Path::new(DB_FILE),
+        let db_dir = &settings.database.data_directory;
+        let full_path = Path::new(db_dir).join(DB_FILE);
+        // create a connection pool
+        let pool = build_pool(
+            "event writer",
+            &settings,
             OpenFlags::SQLITE_OPEN_READ_WRITE | OpenFlags::SQLITE_OPEN_CREATE,
-        )?;
-        info!("opened database for writing");
-        upgrade_db(&mut conn)?;
+            1,
+            4,
+            false,
+        );
+        if settings.database.in_memory {
+            info!("using in-memory database, this will not persist a restart!");
+        } else {
+            info!("opened database {:?} for writing", full_path);
+        }
+        upgrade_db(&mut pool.get()?)?;
+
+        // Make a copy of the whitelist
+        let whitelist = &settings.authorization.pubkey_whitelist.clone();
+
         // get rate limit settings
-        let config = SETTINGS.read().unwrap();
-        let rps_setting = config.limits.messages_per_sec;
+        let rps_setting = settings.limits.messages_per_sec;
+        let mut most_recent_rate_limit = Instant::now();
         let mut lim_opt = None;
         let clock = governor::clock::QuantaClock::default();
         if let Some(rps) = rps_setting {
@@ -141,7 +132,7 @@ pub async fn db_writer(
             }
         }
         loop {
-            if let Ok(_) = shutdown.try_recv() {
+            if shutdown.try_recv().is_ok() {
                 info!("shutting down database writer");
                 break;
             }
@@ -152,47 +143,143 @@ pub async fn db_writer(
                 break;
             }
             let mut event_write = false;
-            let event = next_event.unwrap();
-            match write_event(&mut conn, &event) {
-                Ok(updated) => {
-                    if updated == 0 {
-                        debug!("ignoring duplicate event");
-                    } else {
-                        info!("persisted event: {}", event.get_event_id_prefix());
-                        event_write = true;
-                        // send this out to all clients
-                        bcast_tx.send(event.clone()).ok();
-                    }
-                }
-                Err(err) => {
-                    warn!("event insert failed: {}", err);
+            let subm_event = next_event.unwrap();
+            let event = subm_event.event;
+            let notice_tx = subm_event.notice_tx;
+            // check if this event is authorized.
+            if let Some(allowed_addrs) = whitelist {
+                // if the event address is not in allowed_addrs.
+                if !allowed_addrs.contains(&event.pubkey) {
+                    info!(
+                        "Rejecting event {}, unauthorized author",
+                        event.get_event_id_prefix()
+                    );
+                    notice_tx
+                        .try_send("pubkey is not allowed to publish to this relay".to_owned())
+                        .ok();
+                    continue;
                 }
             }
+
+            // send any metadata events to the NIP-05 verifier
+            if nip05_active && event.is_kind_metadata() {
+                // we are sending this prior to even deciding if we
+                // persist it.  this allows the nip05 module to
+                // inspect it, update if necessary, or persist a new
+                // event and broadcast it itself.
+                metadata_tx.send(event.clone()).ok();
+            }
+
+            // check for  NIP-05 verification
+            if nip05_enabled {
+                match nip05::query_latest_user_verification(pool.get()?, event.pubkey.to_owned()) {
+                    Ok(uv) => {
+                        if uv.is_valid(&settings.verified_users) {
+                            info!(
+                                "new event from verified author ({:?},{:?})",
+                                uv.name.to_string(),
+                                event.get_author_prefix()
+                            );
+                        } else {
+                            info!("rejecting event, author ({:?} / {:?}) verification invalid (expired/wrong domain)",
+                                  uv.name.to_string(),
+                                  event.get_author_prefix()
+                            );
+                            notice_tx
+                                .try_send(
+                                    "NIP-05 verification is no longer valid (expired/wrong domain)"
+                                        .to_owned(),
+                                )
+                                .ok();
+                            continue;
+                        }
+                    }
+                    Err(Error::SqlError(rusqlite::Error::QueryReturnedNoRows)) => {
+                        debug!(
+                            "no verification records found for pubkey: {:?}",
+                            event.get_author_prefix()
+                        );
+                        notice_tx
+                            .try_send("NIP-05 verification needed to publish events".to_owned())
+                            .ok();
+                        continue;
+                    }
+                    Err(e) => {
+                        warn!("checking nip05 verification status failed: {:?}", e);
+                        continue;
+                    }
+                }
+            }
+            // TODO: cache recent list of authors to remove a DB call.
+            let start = Instant::now();
+            if event.kind >= 20000 && event.kind < 30000 {
+                info!(
+                    "published ephemeral event {:?} from {:?} in {:?}",
+                    event.get_event_id_prefix(),
+                    event.get_author_prefix(),
+                    start.elapsed()
+                );
+                bcast_tx.send(event.clone()).ok();
+                event_write = true
+            } else {
+                match write_event(&mut pool.get()?, &event) {
+                    Ok(updated) => {
+                        if updated == 0 {
+                            trace!("ignoring duplicate or deleted event");
+                        } else {
+                            info!(
+                                "persisted event {:?} from {:?} in {:?}",
+                                event.get_event_id_prefix(),
+                                event.get_author_prefix(),
+                                start.elapsed()
+                            );
+                            event_write = true;
+                            // send this out to all clients
+                            bcast_tx.send(event.clone()).ok();
+                        }
+                    }
+                    Err(err) => {
+                        warn!("event insert failed: {:?}", err);
+                        notice_tx
+                            .try_send(
+                                "relay experienced an error trying to publish the latest event"
+                                    .to_owned(),
+                            )
+                            .ok();
+                    }
+                }
+            }
+
             // use rate limit, if defined, and if an event was actually written.
             if event_write {
                 if let Some(ref lim) = lim_opt {
                     if let Err(n) = lim.check() {
-                        info!("Rate limiting event creation");
-                        thread::sleep(n.wait_time_from(clock.now()));
+                        let wait_for = n.wait_time_from(clock.now());
+                        // check if we have recently logged rate
+                        // limits, but print out a message only once
+                        // per second.
+                        if most_recent_rate_limit.elapsed().as_secs() > 10 {
+                            warn!(
+                                "rate limit reached for event creation (sleep for {:?}) (suppressing future messages for 10 seconds)",
+                                wait_for
+                            );
+                            // reset last rate limit message
+                            most_recent_rate_limit = Instant::now();
+                        }
+                        // block event writes, allowing them to queue up
+                        thread::sleep(wait_for);
                         continue;
                     }
                 }
             }
         }
-        conn.close().ok();
         info!("database connection closed");
         Ok(())
     })
 }
 
-pub fn db_version(conn: &mut Connection) -> Result<usize> {
-    let query = "PRAGMA user_version;";
-    let curr_version = conn.query_row(query, [], |row| row.get(0))?;
-    Ok(curr_version)
-}
-
-/// Persist an event to the database.
-pub fn write_event(conn: &mut Connection, e: &Event) -> Result<usize> {
+/// Persist an event to the database, returning rows added.
+pub fn write_event(conn: &mut PooledConnection, e: &Event) -> Result<usize> {
     // start transaction
     let tx = conn.transaction()?;
     // get relevant fields from event and convert to blobs.
@@ -200,65 +287,111 @@ pub fn write_event(conn: &mut Connection, e: &Event) -> Result<usize> {
     let pubkey_blob = hex::decode(&e.pubkey).ok();
     let event_str = serde_json::to_string(&e).ok();
     // ignore if the event hash is a duplicate.
-    let ins_count = tx.execute(
+    let mut ins_count = tx.execute(
         "INSERT OR IGNORE INTO event (event_hash, created_at, kind, author, content, first_seen, hidden) VALUES (?1, ?2, ?3, ?4, ?5, strftime('%s','now'), FALSE);",
         params![id_blob, e.created_at, e.kind, pubkey_blob, event_str]
     )?;
     if ins_count == 0 {
         // if the event was a duplicate, no need to insert event or
-        // pubkey references.
+        // pubkey references.  This will abort the txn.
         return Ok(ins_count);
     }
     // remember primary key of the event most recently inserted.
     let ev_id = tx.last_insert_rowid();
-    // add all event tags into the event_ref table
-    let etags = e.get_event_tags();
-    if !etags.is_empty() {
-        for etag in etags.iter() {
-            tx.execute(
-                "INSERT OR IGNORE INTO event_ref (event_id, referenced_event) VALUES (?1, ?2)",
-                params![ev_id, hex::decode(&etag).ok()],
-            )?;
+    // add all tags to the tag table
+    for tag in e.tags.iter() {
+        // ensure we have 2 values.
+        if tag.len() >= 2 {
+            let tagname = &tag[0];
+            let tagval = &tag[1];
+            // only single-char tags are searchable
+            let tagchar_opt = single_char_tagname(tagname);
+            match &tagchar_opt {
+                Some(_) => {
+                    // if tagvalue is lowercase hex;
+                    if is_lower_hex(tagval) && (tagval.len() % 2 == 0) {
+                        tx.execute(
+			    "INSERT OR IGNORE INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3)",
+			    params![ev_id, &tagname, hex::decode(&tagval).ok()],
+			)?;
+                    } else {
+                        tx.execute(
+                            "INSERT OR IGNORE INTO tag (event_id, name, value) VALUES (?1, ?2, ?3)",
+                            params![ev_id, &tagname, &tagval],
+                        )?;
+                    }
+                }
+                None => {}
+            }
         }
     }
-    // add all event tags into the pubkey_ref table
-    let ptags = e.get_pubkey_tags();
-    if !ptags.is_empty() {
-        for ptag in ptags.iter() {
-            tx.execute(
-                "INSERT OR IGNORE INTO pubkey_ref (event_id, referenced_pubkey) VALUES (?1, ?2)",
-                params![ev_id, hex::decode(&ptag).ok()],
-            )?;
-        }
-    }
-    // if this event is for a metadata update, hide every other kind=0
-    // event from the same author that was issued earlier than this.
-    if e.kind == 0 {
+    // if this event is replaceable update, hide every other replaceable
+    // event with the same kind from the same author that was issued
+    // earlier than this.
+    if e.kind == 0 || e.kind == 3 || (e.kind >= 10000 && e.kind < 20000) {
         let update_count = tx.execute(
-            "UPDATE event SET hidden=TRUE WHERE id!=? AND kind=0 AND author=? AND created_at <= ? and hidden!=TRUE",
-            params![ev_id, hex::decode(&e.pubkey).ok(), e.created_at],
+            "UPDATE event SET hidden=TRUE WHERE id!=? AND kind=? AND author=? AND created_at <= ? and hidden!=TRUE",
+            params![ev_id, e.kind, hex::decode(&e.pubkey).ok(), e.created_at],
         )?;
         if update_count > 0 {
-            info!("hid {} older metadata events", update_count);
+            info!(
+                "hid {} older replaceable kind {} events for author: {:?}",
+                update_count,
+                e.kind,
+                e.get_author_prefix()
+            );
         }
     }
-    // if this event is for a contact update, hide every other kind=3
-    // event from the same author that was issued earlier than this.
-    if e.kind == 3 {
-        let update_count = tx.execute(
-            "UPDATE event SET hidden=TRUE WHERE id!=? AND kind=3 AND author=? AND created_at <= ? and hidden!=TRUE",
-            params![ev_id, hex::decode(&e.pubkey).ok(), e.created_at],
-        )?;
-        if update_count > 0 {
-            info!("hid {} older contact events", update_count);
+    // if this event is a deletion, hide the referenced events from the same author.
+    if e.kind == 5 {
+        let event_candidates = e.tag_values_by_name("e");
+        // first parameter will be author
+        let mut params: Vec<Box<dyn ToSql>> = vec![Box::new(hex::decode(&e.pubkey)?)];
+        event_candidates
+            .iter()
+            .filter(|x| is_hex(x) && x.len() == 64)
+            .filter_map(|x| hex::decode(x).ok())
+            .for_each(|x| params.push(Box::new(x)));
+        let query = format!(
+            "UPDATE event SET hidden=TRUE WHERE kind!=5 AND author=? AND event_hash IN ({})",
+            repeat_vars(params.len() - 1)
+        );
+        let mut stmt = tx.prepare(&query)?;
+        let update_count = stmt.execute(rusqlite::params_from_iter(params))?;
+        info!(
+            "hid {} deleted events for author {:?}",
+            update_count,
+            e.get_author_prefix()
+        );
+    } else {
+        // check if a deletion has already been recorded for this event.
+        // Only relevant for non-deletion events
+        let del_count = tx.query_row(
+	    "SELECT e.id FROM event e LEFT JOIN tag t ON e.id=t.event_id WHERE e.author=? AND t.name='e' AND e.kind=5 AND t.value_hex=? LIMIT 1;",
+	    params![pubkey_blob, id_blob], |row| row.get::<usize, usize>(0));
+        // check if a the query returned a result, meaning we should
+        // hid the current event
+        if del_count.ok().is_some() {
+            // a deletion already existed, mark original event as hidden.
+            info!(
+                "hid event: {:?} due to existing deletion by author: {:?}",
+                e.get_event_id_prefix(),
+                e.get_author_prefix()
+            );
+            let _update_count =
+                tx.execute("UPDATE event SET hidden=TRUE WHERE id=?", params![ev_id])?;
+            // event was deleted, so let caller know nothing new
+            // arrived, preventing this from being sent to active
+            // subscriptions
+            ins_count = 0;
         }
     }
     tx.commit()?;
     Ok(ins_count)
 }
 
-/// Event resulting from a specific subscription request
-#[derive(PartialEq, Debug, Clone)]
+/// Serialized event associated with a specific subscription request.
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub struct QueryResult {
     /// Subscription identifier
     pub sub_id: String,
@@ -266,99 +399,176 @@ pub struct QueryResult {
     pub event: String,
 }
 
-/// Check if a string contains only hex characters.
-fn is_hex(s: &str) -> bool {
-    s.chars().all(|x| char::is_ascii_hexdigit(&x))
+/// Produce a arbitrary list of '?' parameters.
+fn repeat_vars(count: usize) -> String {
+    if count == 0 {
+        return "".to_owned();
+    }
+    let mut s = "?,".repeat(count);
+    // Remove trailing comma
+    s.pop();
+    s
 }
 
-/// Create a dynamic SQL query string from a subscription.
-fn query_from_sub(sub: &Subscription) -> String {
+/// Create a dynamic SQL subquery and params from a subscription filter.
+fn query_from_filter(f: &ReqFilter) -> (String, Vec<Box<dyn ToSql>>) {
     // build a dynamic SQL query.  all user-input is either an integer
     // (sqli-safe), or a string that is filtered to only contain
-    // hexadecimal characters.
-    let mut query =
-        "SELECT DISTINCT(e.content) FROM event e LEFT JOIN event_ref er ON e.id=er.event_id LEFT JOIN pubkey_ref pr ON e.id=pr.event_id "
-            .to_owned();
-    // for every filter in the subscription, generate a where clause
-    let mut filter_clauses: Vec<String> = Vec::new();
+    // hexadecimal characters.  Strings that require escaping (tag
+    // names/values) use parameters.
+
+    // if the filter is malformed, don't return anything.
+    if f.force_no_match {
+        let empty_query =
+            "SELECT DISTINCT(e.content), e.created_at FROM event e WHERE 1=0".to_owned();
+        // query parameters for SQLite
+        let empty_params: Vec<Box<dyn ToSql>> = vec![];
+        return (empty_query, empty_params);
+    }
+
+    let mut query = "SELECT DISTINCT(e.content), e.created_at FROM event e  ".to_owned();
+    // query parameters for SQLite
+    let mut params: Vec<Box<dyn ToSql>> = vec![];
+
+    // individual filter components (single conditions such as an author or event ID)
+    let mut filter_components: Vec<String> = Vec::new();
+    // Query for "authors", allowing prefix matches
+    if let Some(authvec) = &f.authors {
+        // take each author and convert to a hexsearch
+        let mut auth_searches: Vec<String> = vec![];
+        for auth in authvec {
+            match hex_range(auth) {
+                Some(HexSearch::Exact(ex)) => {
+                    auth_searches.push("author=?".to_owned());
+                    params.push(Box::new(ex));
+                }
+                Some(HexSearch::Range(lower, upper)) => {
+                    auth_searches.push("(author>? AND author<?)".to_owned());
+                    params.push(Box::new(lower));
+                    params.push(Box::new(upper));
+                }
+                Some(HexSearch::LowerOnly(lower)) => {
+                    auth_searches.push("author>?".to_owned());
+                    params.push(Box::new(lower));
+                }
+                None => {
+                    info!("Could not parse hex range from author {:?}", auth);
+                }
+            }
+        }
+        let authors_clause = format!("({})", auth_searches.join(" OR "));
+        filter_components.push(authors_clause);
+    }
+    // Query for Kind
+    if let Some(ks) = &f.kinds {
+        // kind is number, no escaping needed
+        let str_kinds: Vec<String> = ks.iter().map(|x| x.to_string()).collect();
+        let kind_clause = format!("kind IN ({})", str_kinds.join(", "));
+        filter_components.push(kind_clause);
+    }
+    // Query for event, allowing prefix matches
+    if let Some(idvec) = &f.ids {
+        // take each author and convert to a hexsearch
+        let mut id_searches: Vec<String> = vec![];
+        for id in idvec {
+            match hex_range(id) {
+                Some(HexSearch::Exact(ex)) => {
+                    id_searches.push("event_hash=?".to_owned());
+                    params.push(Box::new(ex));
+                }
+                Some(HexSearch::Range(lower, upper)) => {
+                    id_searches.push("(event_hash>? AND event_hash<?)".to_owned());
+                    params.push(Box::new(lower));
+                    params.push(Box::new(upper));
+                }
+                Some(HexSearch::LowerOnly(lower)) => {
+                    id_searches.push("event_hash>?".to_owned());
+                    params.push(Box::new(lower));
+                }
+                None => {
+                    info!("Could not parse hex range from id {:?}", id);
+                }
+            }
+        }
+        let id_clause = format!("({})", id_searches.join(" OR "));
+        filter_components.push(id_clause);
+    }
+    // Query for tags
+    if let Some(map) = &f.tags {
+        for (key, val) in map.iter() {
+            let mut str_vals: Vec<Box<dyn ToSql>> = vec![];
+            let mut blob_vals: Vec<Box<dyn ToSql>> = vec![];
+            for v in val {
+                if (v.len() % 2 == 0) && is_lower_hex(v) {
+                    if let Ok(h) = hex::decode(&v) {
+                        blob_vals.push(Box::new(h));
+                    }
+                } else {
+                    str_vals.push(Box::new(v.to_owned()));
+                }
+            }
+            // create clauses with "?" params for each tag value being searched
+            let str_clause = format!("value IN ({})", repeat_vars(str_vals.len()));
+            let blob_clause = format!("value_hex IN ({})", repeat_vars(blob_vals.len()));
+            // find evidence of the target tag name/value existing for this event.
+            let tag_clause = format!("e.id IN (SELECT e.id FROM event e LEFT JOIN tag t on e.id=t.event_id WHERE hidden!=TRUE and (name=? AND ({} OR {})))", str_clause, blob_clause);
+            // add the tag name as the first parameter
+            params.push(Box::new(key.to_string()));
+            // add all tag values that are plain strings as params
+            params.append(&mut str_vals);
+            // add all tag values that are blobs as params
+            params.append(&mut blob_vals);
+            filter_components.push(tag_clause);
+        }
+    }
+    // Query for timestamp
+    if f.since.is_some() {
+        let created_clause = format!("created_at > {}", f.since.unwrap());
+        filter_components.push(created_clause);
+    }
+    // Query for timestamp
+    if f.until.is_some() {
+        let until_clause = format!("created_at < {}", f.until.unwrap());
+        filter_components.push(until_clause);
+    }
+    // never display hidden events
+    query.push_str(" WHERE hidden!=TRUE");
+    // build filter component conditions
+    if !filter_components.is_empty() {
+        query.push_str(" AND ");
+        query.push_str(&filter_components.join(" AND "));
+    }
+    // Apply per-filter limit to this subquery.
+    // The use of a LIMIT implies a DESC order, to capture only the most recent events.
+    if let Some(lim) = f.limit {
+        let _ = write!(query, " ORDER BY e.created_at DESC LIMIT {}", lim);
+    } else {
+        query.push_str(" ORDER BY e.created_at ASC")
+    }
+    (query, params)
+}
+
+/// Create a dynamic SQL query string and params from a subscription.
+fn query_from_sub(sub: &Subscription) -> (String, Vec<Box<dyn ToSql>>) {
+    // build a dynamic SQL query for an entire subscription, based on
+    // SQL subqueries for filters.
+    let mut subqueries: Vec<String> = Vec::new();
+    // subquery params
+    let mut params: Vec<Box<dyn ToSql>> = vec![];
+    // for every filter in the subscription, generate a subquery
     for f in sub.filters.iter() {
-        // individual filter components
-        let mut filter_components: Vec<String> = Vec::new();
-        // Query for "authors"
-        if f.authors.is_some() {
-            let authors_escaped: Vec<String> = f
-                .authors
-                .as_ref()
-                .unwrap()
-                .iter()
-                .filter(|&x| is_hex(x))
-                .map(|x| format!("x'{}'", x))
-                .collect();
-            let authors_clause = format!("author IN ({})", authors_escaped.join(", "));
-            filter_components.push(authors_clause);
-        }
-        // Query for Kind
-        if f.kind.is_some() {
-            // kind is number, no escaping needed
-            let kind_clause = format!("kind = {}", f.kind.unwrap());
-            filter_components.push(kind_clause);
-        }
-        // Query for event
-        if f.id.is_some() {
-            let id_str = f.id.as_ref().unwrap();
-            if is_hex(id_str) {
-                let id_clause = format!("event_hash = x'{}'", id_str);
-                filter_components.push(id_clause);
-            }
-        }
-        // Query for referenced event
-        if f.event.is_some() {
-            let ev_str = f.event.as_ref().unwrap();
-            if is_hex(ev_str) {
-                let ev_clause = format!("referenced_event = x'{}'", ev_str);
-                filter_components.push(ev_clause);
-            }
-        }
-        // Query for referenced pet name pubkey
-        if f.pubkey.is_some() {
-            let pet_str = f.pubkey.as_ref().unwrap();
-            if is_hex(pet_str) {
-                let pet_clause = format!("referenced_pubkey = x'{}'", pet_str);
-                filter_components.push(pet_clause);
-            }
-        }
-        // Query for timestamp
-        if f.since.is_some() {
-            let created_clause = format!("created_at > {}", f.since.unwrap());
-            filter_components.push(created_clause);
-        }
-        // Query for timestamp
-        if f.until.is_some() {
-            let until_clause = format!("created_at < {}", f.until.unwrap());
-            filter_components.push(until_clause);
-        }
-
-        // combine all clauses, and add to filter_clauses
-        if !filter_components.is_empty() {
-            let mut fc = "( ".to_owned();
-            fc.push_str(&filter_components.join(" AND "));
-            fc.push_str(" )");
-            filter_clauses.push(fc);
-        } else {
-            // never display hidden events
-            filter_clauses.push("hidden!=FALSE".to_owned());
-        }
+        let (f_subquery, mut f_params) = query_from_filter(f);
+        subqueries.push(f_subquery);
+        params.append(&mut f_params);
     }
-
-    // combine all filters with OR clauses, if any exist
-    if !filter_clauses.is_empty() {
-        query.push_str(" WHERE ");
-        query.push_str(&filter_clauses.join(" OR "));
-    }
-    // add order clause
-    query.push_str(" ORDER BY created_at ASC");
-    debug!("query string: {}", query);
-    query
+    // encapsulate subqueries into select statements
+    let subqueries_selects: Vec<String> = subqueries
+        .iter()
+        .map(|s| format!("SELECT content, created_at FROM ({})", s))
+        .collect();
+    let query: String = subqueries_selects.join(" UNION ");
+    debug!("final query string: {}", query);
+    (query, params)
 }
 
 /// Perform a database query using a subscription.
@@ -369,35 +579,68 @@ fn query_from_sub(sub: &Subscription) -> String {
 /// query is immediately aborted.
 pub async fn db_query(
     sub: Subscription,
+    client_id: String,
+    pool: SqlitePool,
     query_tx: tokio::sync::mpsc::Sender<QueryResult>,
     mut abandon_query_rx: tokio::sync::oneshot::Receiver<()>,
 ) {
     task::spawn_blocking(move || {
-        let conn =
-            Connection::open_with_flags(Path::new(DB_FILE), OpenFlags::SQLITE_OPEN_READ_ONLY)
-                .unwrap();
-        debug!("opened database for reading");
         debug!("going to query for: {:?}", sub);
+        let mut row_count: usize = 0;
+        let start = Instant::now();
         // generate SQL query
-        let q = query_from_sub(&sub);
-        // execute the query
-        let mut stmt = conn.prepare(&q).unwrap();
-        let mut event_rows = stmt.query([]).unwrap();
-        while let Some(row) = event_rows.next().unwrap() {
-            // check if this is still active (we could do this every N rows)
-            if abandon_query_rx.try_recv().is_ok() {
-                debug!("query aborted");
-                return;
+        let (q, p) = query_from_sub(&sub);
+        debug!("SQL generated in {:?}", start.elapsed());
+        // show pool stats
+        debug!("DB pool stats: {:?}", pool.state());
+        let start = Instant::now();
+        if let Ok(conn) = pool.get() {
+            // execute the query. Don't cache, since queries vary so much.
+            let mut stmt = conn.prepare(&q)?;
+            let mut event_rows = stmt.query(rusqlite::params_from_iter(p))?;
+            let mut first_result = true;
+            while let Some(row) = event_rows.next()? {
+                if first_result {
+                    debug!(
+                        "time to first result: {:?} (cid={}, sub={:?})",
+                        start.elapsed(),
+                        client_id,
+                        sub.id
+                    );
+                    first_result = false;
+                }
+                // check if this is still active
+                // TODO:  check every N rows
+                if abandon_query_rx.try_recv().is_ok() {
+                    debug!("query aborted (sub={:?})", sub.id);
+                    return Ok(());
+                }
+                row_count += 1;
+                let event_json = row.get(0)?;
+                query_tx
+                    .blocking_send(QueryResult {
+                        sub_id: sub.get_id(),
+                        event: event_json,
+                    })
+                    .ok();
             }
-            // TODO: check before unwrapping
-            let event_json = row.get(0).unwrap();
             query_tx
                 .blocking_send(QueryResult {
                     sub_id: sub.get_id(),
-                    event: event_json,
+                    event: "EOSE".to_string(),
                 })
                 .ok();
+            debug!(
+                "query completed ({} rows) in {:?} (cid={}, sub={:?})",
+                row_count,
+                start.elapsed(),
+                client_id,
+                sub.id
+            );
+        } else {
+            warn!("Could not get a database connection for querying");
         }
-        debug!("query completed");
+        let ok: Result<()> = Ok(());
+        ok
     });
 }

src/delegation.rs

@@ -0,0 +1,410 @@
+//! Event parsing and validation
+use crate::error::Error;
+use crate::error::Result;
+use crate::event::Event;
+use bitcoin_hashes::{sha256, Hash};
+use lazy_static::lazy_static;
+use regex::Regex;
+use secp256k1::{schnorr, Secp256k1, VerifyOnly, XOnlyPublicKey};
+use serde::{Deserialize, Serialize};
+use std::str::FromStr;
+use tracing::{debug, info};
+
+// This handles everything related to delegation, in particular the
+// condition/rune parsing and logic.
+
+// Conditions are poorly specified, so we will implement the minimum
+// necessary for now.
+
+// fields MUST be either "kind" or "created_at".
+// operators supported are ">", "<", "=", "!".
+// no operations on 'content' are supported.
+
+// this allows constraints for:
+// valid date ranges (valid from X->Y dates).
+// specific kinds (publish kind=1,5)
+// kind ranges (publish ephemeral events, kind>19999&kind<30001)
+
+// for more complex scenarios (allow delegatee to publish ephemeral
+// AND replacement events), it may be necessary to generate and use
+// different condition strings, since we do not support grouping or
+// "OR" logic.
+
+// using serde_urldecode, we can get a serde data format from the
+// condition string.  We will then map that with a deserializer that
+// maps to a ConditionQuery.
+
+lazy_static! {
+    /// Secp256k1 verification instance.
+    pub static ref SECP: Secp256k1<VerifyOnly> = Secp256k1::verification_only();
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
+pub enum Field {
+    Kind,
+    CreatedAt,
+}
+
+impl FromStr for Field {
+    type Err = Error;
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        if value == "kind" {
+            Ok(Field::Kind)
+        } else if value == "created_at" {
+            Ok(Field::CreatedAt)
+        } else {
+            Err(Error::DelegationParseError)
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
+pub enum Operator {
+    LessThan,
+    GreaterThan,
+    Equals,
+    NotEquals,
+}
+impl FromStr for Operator {
+    type Err = Error;
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        if value == "<" {
+            Ok(Operator::LessThan)
+        } else if value == ">" {
+            Ok(Operator::GreaterThan)
+        } else if value == "=" {
+            Ok(Operator::Equals)
+        } else if value == "!" {
+            Ok(Operator::NotEquals)
+        } else {
+            Err(Error::DelegationParseError)
+        }
+    }
+}
+
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
+pub struct ConditionQuery {
+    pub(crate) conditions: Vec<Condition>,
+}
+
+impl ConditionQuery {
+    pub fn allows_event(&self, _event: &Event) -> bool {
+        // check each condition, to ensure that the event complies with the restriction.
+
+        false
+    }
+}
+
+// Verify that the delegator approved the delegation; return a ConditionQuery if so.
+pub fn validate_delegation(
+    delegator: &str,
+    delegatee: &str,
+    cond_query: &str,
+    sigstr: &str,
+) -> Option<ConditionQuery> {
+    // form the token
+    let tok = format!("nostr:delegation:{}:{}", delegatee, cond_query);
+    // form SHA256 hash
+    let digest: sha256::Hash = sha256::Hash::hash(tok.as_bytes());
+    let sig = schnorr::Signature::from_str(sigstr).unwrap();
+    if let Ok(msg) = secp256k1::Message::from_slice(digest.as_ref()) {
+        if let Ok(pubkey) = XOnlyPublicKey::from_str(delegator) {
+            let verify = SECP.verify_schnorr(&sig, &msg, &pubkey);
+            if verify.is_ok() {
+                // return the parsed condition query
+                cond_query.parse::<ConditionQuery>().ok()
+            } else {
+                debug!("client sent an delegation signature that did not validate");
+                None
+            }
+        } else {
+            debug!("client sent malformed delegation pubkey");
+            None
+        }
+    } else {
+        info!("error converting delegation digest to secp256k1 message");
+        None
+    }
+}
+
+/// Parsed delegation condition
+/// see https://github.com/nostr-protocol/nips/pull/28#pullrequestreview-1084903800
+/// An example complex condition would be:  kind=1,2,3&created_at<1665265999
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
+pub struct Condition {
+    pub(crate) field: Field,
+    pub(crate) operator: Operator,
+    pub(crate) values: Vec<u64>,
+}
+
+impl Condition {
+    /// Check if this condition allows the given event to be delegated
+    pub fn allows_event(&self, event: &Event) -> bool {
+        // determine what the right-hand side of the operator is
+        let resolved_field = match &self.field {
+            Field::Kind => event.kind,
+            Field::CreatedAt => event.created_at,
+        };
+        match &self.operator {
+            Operator::LessThan => {
+                // the less-than operator is only valid for single values.
+                if self.values.len() == 1 {
+                    if let Some(v) = self.values.first() {
+                        return resolved_field < *v;
+                    }
+                }
+            }
+            Operator::GreaterThan => {
+                // the greater-than operator is only valid for single values.
+                if self.values.len() == 1 {
+                    if let Some(v) = self.values.first() {
+                        return resolved_field > *v;
+                    }
+                }
+            }
+            Operator::Equals => {
+                // equals is interpreted as "must be equal to at least one provided value"
+                return self.values.iter().any(|&x| resolved_field == x);
+            }
+            Operator::NotEquals => {
+                // not-equals is interpreted as "must not be equal to any provided value"
+                // this is the one case where an empty list of values could be allowed; even though it is a pointless restriction.
+                return self.values.iter().all(|&x| resolved_field != x);
+            }
+        }
+        false
+    }
+}
+
+fn str_to_condition(cs: &str) -> Option<Condition> {
+    // a condition is a string (alphanum+underscore), an operator (<>=!), and values (num+comma)
+    lazy_static! {
+        static ref RE: Regex = Regex::new("([[:word:]]+)([<>=!]+)([,[[:digit:]]]*)").unwrap();
+    }
+    // match against the regex
+    let caps = RE.captures(cs)?;
+    let field = caps.get(1)?.as_str().parse::<Field>().ok()?;
+    let operator = caps.get(2)?.as_str().parse::<Operator>().ok()?;
+    // values are just comma separated numbers, but all must be parsed
+    let rawvals = caps.get(3)?.as_str();
+    let values = rawvals
+        .split_terminator(',')
+        .map(|n| n.parse::<u64>().ok())
+        .collect::<Option<Vec<_>>>()?;
+    // convert field string into Field
+    Some(Condition {
+        field,
+        operator,
+        values,
+    })
+}
+
+/// Parse a condition query from a string slice
+impl FromStr for ConditionQuery {
+    type Err = Error;
+    fn from_str(value: &str) -> Result<Self, Self::Err> {
+        // split the string with '&'
+        let mut conditions = vec![];
+        let condstrs = value.split_terminator('&');
+        // parse each individual condition
+        for c in condstrs {
+            conditions.push(str_to_condition(c).ok_or(Error::DelegationParseError)?);
+        }
+        Ok(ConditionQuery { conditions })
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    // parse condition strings
+    #[test]
+    fn parse_empty() -> Result<()> {
+        // given an empty condition query, produce an empty vector
+        let empty_cq = ConditionQuery { conditions: vec![] };
+        let parsed = "".parse::<ConditionQuery>()?;
+        assert_eq!(parsed, empty_cq);
+        Ok(())
+    }
+
+    // parse field 'kind'
+    #[test]
+    fn test_kind_field_parse() -> Result<()> {
+        let field = "kind".parse::<Field>()?;
+        assert_eq!(field, Field::Kind);
+        Ok(())
+    }
+    // parse field 'created_at'
+    #[test]
+    fn test_created_at_field_parse() -> Result<()> {
+        let field = "created_at".parse::<Field>()?;
+        assert_eq!(field, Field::CreatedAt);
+        Ok(())
+    }
+    // parse unknown field
+    #[test]
+    fn unknown_field_parse() {
+        let field = "unk".parse::<Field>();
+        assert!(field.is_err());
+    }
+
+    // parse a full conditional query with an empty array
+    #[test]
+    fn parse_kind_equals_empty() -> Result<()> {
+        // given an empty condition query, produce an empty vector
+        let kind_cq = ConditionQuery {
+            conditions: vec![Condition {
+                field: Field::Kind,
+                operator: Operator::Equals,
+                values: vec![],
+            }],
+        };
+        let parsed = "kind=".parse::<ConditionQuery>()?;
+        assert_eq!(parsed, kind_cq);
+        Ok(())
+    }
+    // parse a full conditional query with a single value
+    #[test]
+    fn parse_kind_equals_singleval() -> Result<()> {
+        // given an empty condition query, produce an empty vector
+        let kind_cq = ConditionQuery {
+            conditions: vec![Condition {
+                field: Field::Kind,
+                operator: Operator::Equals,
+                values: vec![1],
+            }],
+        };
+        let parsed = "kind=1".parse::<ConditionQuery>()?;
+        assert_eq!(parsed, kind_cq);
+        Ok(())
+    }
+    // parse a full conditional query with multiple values
+    #[test]
+    fn parse_kind_equals_multival() -> Result<()> {
+        // given an empty condition query, produce an empty vector
+        let kind_cq = ConditionQuery {
+            conditions: vec![Condition {
+                field: Field::Kind,
+                operator: Operator::Equals,
+                values: vec![1, 2, 4],
+            }],
+        };
+        let parsed = "kind=1,2,4".parse::<ConditionQuery>()?;
+        assert_eq!(parsed, kind_cq);
+        Ok(())
+    }
+    // parse multiple conditions
+    #[test]
+    fn parse_multi_conditions() -> Result<()> {
+        // given an empty condition query, produce an empty vector
+        let cq = ConditionQuery {
+            conditions: vec![
+                Condition {
+                    field: Field::Kind,
+                    operator: Operator::GreaterThan,
+                    values: vec![10000],
+                },
+                Condition {
+                    field: Field::Kind,
+                    operator: Operator::LessThan,
+                    values: vec![20000],
+                },
+                Condition {
+                    field: Field::Kind,
+                    operator: Operator::NotEquals,
+                    values: vec![10001],
+                },
+                Condition {
+                    field: Field::CreatedAt,
+                    operator: Operator::LessThan,
+                    values: vec![1665867123],
+                },
+            ],
+        };
+        let parsed =
+            "kind>10000&kind<20000&kind!10001&created_at<1665867123".parse::<ConditionQuery>()?;
+        assert_eq!(parsed, cq);
+        Ok(())
+    }
+    fn simple_event() -> Event {
+        Event {
+            id: "0".to_owned(),
+            pubkey: "0".to_owned(),
+            created_at: 0,
+            kind: 0,
+            tags: vec![],
+            content: "".to_owned(),
+            sig: "0".to_owned(),
+            tagidx: None,
+        }
+    }
+    // Check for condition logic on event w/ empty values
+    #[test]
+    fn condition_with_empty_values() {
+        let mut c = Condition {
+            field: Field::Kind,
+            operator: Operator::GreaterThan,
+            values: vec![],
+        };
+        let e = simple_event();
+        assert!(!c.allows_event(&e));
+        c.operator = Operator::LessThan;
+        assert!(!c.allows_event(&e));
+        c.operator = Operator::Equals;
+        assert!(!c.allows_event(&e));
+        // Not Equals applied to an empty list *is* allowed
+        // (pointless, but logically valid).
+        c.operator = Operator::NotEquals;
+        assert!(c.allows_event(&e));
+    }
+
+    // Check for condition logic on event w/ single value
+    #[test]
+    fn condition_kind_gt_event_single() {
+        let c = Condition {
+            field: Field::Kind,
+            operator: Operator::GreaterThan,
+            values: vec![10],
+        };
+        let mut e = simple_event();
+        // kind is not greater than 10, not allowed
+        e.kind = 1;
+        assert!(!c.allows_event(&e));
+        // kind is greater than 10, allowed
+        e.kind = 100;
+        assert!(c.allows_event(&e));
+        // kind is 10, not allowed
+        e.kind = 10;
+        assert!(!c.allows_event(&e));
+    }
+    // Check for condition logic on event w/ multi values
+    #[test]
+    fn condition_with_multi_values() {
+        let mut c = Condition {
+            field: Field::Kind,
+            operator: Operator::Equals,
+            values: vec![0, 10, 20],
+        };
+        let mut e = simple_event();
+        // Allow if event kind is in list for Equals
+        e.kind = 10;
+        assert!(c.allows_event(&e));
+        // Deny if event kind is not in list for Equals
+        e.kind = 11;
+        assert!(!c.allows_event(&e));
+        // Deny if event kind is in list for NotEquals
+        e.kind = 10;
+        c.operator = Operator::NotEquals;
+        assert!(!c.allows_event(&e));
+        // Allow if event kind is not in list for NotEquals
+        e.kind = 99;
+        c.operator = Operator::NotEquals;
+        assert!(c.allows_event(&e));
+        // Always deny if GreaterThan/LessThan for a list
+        c.operator = Operator::LessThan;
+        assert!(!c.allows_event(&e));
+        c.operator = Operator::GreaterThan;
+        assert!(!c.allows_event(&e));
+    }
+}

src/error.rs

@@ -21,6 +21,8 @@ pub enum Error {
     CloseParseFailed,
     #[error("Event validation failed")]
     EventInvalid,
+    #[error("Event too large")]
+    EventMaxLengthError(usize),
     #[error("Subscription identifier max length exceeded")]
     SubIdMaxLengthError,
     #[error("Maximum concurrent subscription count reached")]
@@ -36,6 +38,53 @@ pub enum Error {
     SqlError(rusqlite::Error),
     #[error("Config error")]
     ConfigError(config::ConfigError),
+    #[error("Data directory does not exist")]
+    DatabaseDirError,
+    #[error("Database Connection Pool Error")]
+    DatabasePoolError(r2d2::Error),
+    #[error("Custom Error : {0}")]
+    CustomError(String),
+    #[error("Task join error")]
+    JoinError,
+    #[error("Hyper Client error")]
+    HyperError(hyper::Error),
+    #[error("Hex encoding error")]
+    HexError(hex::FromHexError),
+    #[error("Delegation parse error")]
+    DelegationParseError,
+    #[error("Unknown/Undocumented")]
+    UnknownError,
+}
+
+//impl From<Box<dyn std::error::Error>> for Error {
+//    fn from(e: Box<dyn std::error::Error>) -> Self {
+//        Error::CustomError("error".to_owned())
+//    }
+//}
+
+impl From<hex::FromHexError> for Error {
+    fn from(h: hex::FromHexError) -> Self {
+        Error::HexError(h)
+    }
+}
+
+impl From<hyper::Error> for Error {
+    fn from(h: hyper::Error) -> Self {
+        Error::HyperError(h)
+    }
+}
+
+impl From<r2d2::Error> for Error {
+    fn from(d: r2d2::Error) -> Self {
+        Error::DatabasePoolError(d)
+    }
+}
+
+impl From<tokio::task::JoinError> for Error {
+    /// Wrap SQL error
+    fn from(_j: tokio::task::JoinError) -> Self {
+        Error::JoinError
+    }
 }
 
 impl From<rusqlite::Error> for Error {

src/event.rs

@@ -1,25 +1,34 @@
 //! Event parsing and validation
-use crate::config;
+use crate::delegation::validate_delegation;
 use crate::error::Error::*;
 use crate::error::Result;
+use crate::nip05;
+use crate::utils::unix_time;
 use bitcoin_hashes::{sha256, Hash};
-use log::*;
-use secp256k1::{schnorrsig, Secp256k1};
+use lazy_static::lazy_static;
+use secp256k1::{schnorr, Secp256k1, VerifyOnly, XOnlyPublicKey};
 use serde::{Deserialize, Deserializer, Serialize};
 use serde_json::value::Value;
 use serde_json::Number;
+use std::collections::HashMap;
+use std::collections::HashSet;
 use std::str::FromStr;
-use std::time::SystemTime;
+use tracing::{debug, info};
 
-/// Event command in network format
-#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
+lazy_static! {
+    /// Secp256k1 verification instance.
+    pub static ref SECP: Secp256k1<VerifyOnly> = Secp256k1::verification_only();
+}
+
+/// Event command in network format.
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
 pub struct EventCmd {
     cmd: String, // expecting static "EVENT"
     event: Event,
 }
 
-/// Event parsed
-#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
+/// Parsed nostr event.
+#[derive(Serialize, Deserialize, PartialEq, Eq, Debug, Clone)]
 pub struct Event {
     pub id: String,
     pub(crate) pubkey: String,
@@ -30,6 +39,9 @@ pub struct Event {
     pub(crate) tags: Vec<Vec<String>>,
     pub(crate) content: String,
     pub(crate) sig: String,
+    // Optimization for tag search, built on demand.
+    #[serde(skip)]
+    pub(crate) tagidx: Option<HashMap<char, HashSet<String>>>,
 }
 
 /// Simple tag type for array of array of strings.
@@ -41,7 +53,26 @@ where
     D: Deserializer<'de>,
 {
     let opt = Option::deserialize(deserializer)?;
-    Ok(opt.unwrap_or_else(Vec::new))
+    Ok(opt.unwrap_or_default())
+}
+
+/// Attempt to form a single-char tag name.
+pub fn single_char_tagname(tagname: &str) -> Option<char> {
+    // We return the tag character if and only if the tagname consists
+    // of a single char.
+    let mut tagnamechars = tagname.chars();
+    let firstchar = tagnamechars.next();
+    match firstchar {
+        Some(_) => {
+            // check second char
+            if tagnamechars.next().is_none() {
+                firstchar
+            } else {
+                None
+            }
+        }
+        None => None,
+    }
 }
 
 /// Convert network event to parsed/validated event.
@@ -51,45 +82,125 @@ impl From<EventCmd> for Result<Event> {
         if ec.cmd != "EVENT" {
             Err(CommandUnknownError)
         } else if ec.event.is_valid() {
-            Ok(ec.event)
+            let mut e = ec.event;
+            e.build_index();
+            Ok(e)
         } else {
             Err(EventInvalid)
         }
     }
 }
 
-/// Seconds since 1970
-fn unix_time() -> u64 {
-    SystemTime::now()
-        .duration_since(SystemTime::UNIX_EPOCH)
-        .map(|x| x.as_secs())
-        .unwrap_or(0)
-}
-
 impl Event {
+    pub fn is_kind_metadata(&self) -> bool {
+        self.kind == 0
+    }
+
+    /// Pull a NIP-05 Name out of the event, if one exists
+    pub fn get_nip05_addr(&self) -> Option<nip05::Nip05Name> {
+        if self.is_kind_metadata() {
+            // very quick check if we should attempt to parse this json
+            if self.content.contains("\"nip05\"") {
+                // Parse into JSON
+                let md_parsed: Value = serde_json::from_str(&self.content).ok()?;
+                let md_map = md_parsed.as_object()?;
+                let nip05_str = md_map.get("nip05")?.as_str()?;
+                return nip05::Nip05Name::try_from(nip05_str).ok();
+            }
+        }
+        None
+    }
+
+    // is this event delegated (properly)?
+    // does the signature match, and are conditions valid?
+    // if so, return an alternate author for the event
+    pub fn delegated_author(&self) -> Option<String> {
+        // is there a delegation tag?
+        let delegation_tag = self.tag_values_by_name("delegation");
+        // delegation tags should have exactly 3 elements after the name (pubkey, condition, sig)
+        // the event is signed by the delagatee
+        let delegatee = &self.pubkey;
+        // the delegation tag references the claimed delagator
+        let delegator = delegation_tag.get(0)?;
+        let querystr = delegation_tag.get(1)?;
+        let sig = delegation_tag.get(2)?;
+        // pass into the validate_delegation
+        if let Some(cond_query) = validate_delegation(delegator, delegatee, querystr, sig) {
+            // check if this condition query would allow this event.
+            if cond_query.allows_event(self) {
+                Some(delegator.into())
+            } else {
+                None
+            }
+        } else {
+            None
+        }
+    }
+
+    /// Build an event tag index
+    fn build_index(&mut self) {
+        // if there are no tags; just leave the index as None
+        if self.tags.is_empty() {
+            return;
+        }
+        // otherwise, build an index
+        let mut idx: HashMap<char, HashSet<String>> = HashMap::new();
+        // iterate over tags that have at least 2 elements
+        for t in self.tags.iter().filter(|x| x.len() > 1) {
+            let tagname = t.get(0).unwrap();
+            let tagnamechar_opt = single_char_tagname(tagname);
+            if tagnamechar_opt.is_none() {
+                continue;
+            }
+            let tagnamechar = tagnamechar_opt.unwrap();
+            let tagval = t.get(1).unwrap();
+            // ensure a vector exists for this tag
+            idx.entry(tagnamechar).or_insert_with(HashSet::new);
+            // get the tag vec and insert entry
+            let idx_tag_vec = idx.get_mut(&tagnamechar).expect("could not get tag vector");
+            idx_tag_vec.insert(tagval.clone());
+        }
+        // save the tag structure
+        self.tagidx = Some(idx);
+    }
+
     /// Create a short event identifier, suitable for logging.
     pub fn get_event_id_prefix(&self) -> String {
         self.id.chars().take(8).collect()
     }
+    pub fn get_author_prefix(&self) -> String {
+        self.pubkey.chars().take(8).collect()
+    }
 
-    /// Check if this event has a valid signature.
-    fn is_valid(&self) -> bool {
-        // TODO: return a Result with a reason for invalid events
-        // don't bother to validate an event with a timestamp in the distant future.
-        let config = config::SETTINGS.read().unwrap();
-        let max_future_sec = config.options.reject_future_seconds;
-        if let Some(allowable_future) = max_future_sec {
+    /// Retrieve tag values
+    pub fn tag_values_by_name(&self, tag_name: &str) -> Vec<String> {
+        self.tags
+            .iter()
+            .filter(|x| x.len() > 1)
+            .filter(|x| x.get(0).unwrap() == tag_name)
+            .map(|x| x.get(1).unwrap().to_owned())
+            .collect()
+    }
+
+    pub fn is_valid_timestamp(&self, reject_future_seconds: Option<usize>) -> bool {
+        if let Some(allowable_future) = reject_future_seconds {
             let curr_time = unix_time();
             // calculate difference, plus how far future we allow
             if curr_time + (allowable_future as u64) < self.created_at {
                 let delta = self.created_at - curr_time;
                 debug!(
-                    "Event is too far in the future ({} seconds), rejecting",
+                    "event is too far in the future ({} seconds), rejecting",
                     delta
                 );
                 return false;
             }
         }
+        true
+    }
+
+    /// Check if this event has a valid signature.
+    fn is_valid(&self) -> bool {
+        // TODO: return a Result with a reason for invalid events
         // validation is performed by:
         // * parsing JSON string into event fields
         // * create an array:
@@ -97,7 +208,7 @@ impl Event {
         // * serialize with no spaces/newlines
         let c_opt = self.to_canonical();
         if c_opt.is_none() {
-            info!("event could not be canonicalized");
+            debug!("event could not be canonicalized");
             return false;
         }
         let c = c_opt.unwrap();
@@ -106,15 +217,23 @@ impl Event {
         let hex_digest = format!("{:x}", digest);
         // * ensure the id matches the computed sha256sum.
         if self.id != hex_digest {
+            debug!("event id does not match digest");
             return false;
         }
         // * validate the message digest (sig) using the pubkey & computed sha256 message hash.
-        let secp = Secp256k1::new();
-        let sig = schnorrsig::Signature::from_str(&self.sig).unwrap();
-        let message = secp256k1::Message::from(digest);
-        let pubkey = schnorrsig::PublicKey::from_str(&self.pubkey).unwrap();
-        let verify = secp.schnorrsig_verify(&sig, &message, &pubkey);
-        matches!(verify, Ok(()))
+        let sig = schnorr::Signature::from_str(&self.sig).unwrap();
+        if let Ok(msg) = secp256k1::Message::from_slice(digest.as_ref()) {
+            if let Ok(pubkey) = XOnlyPublicKey::from_str(&self.pubkey) {
+                let verify = SECP.verify_schnorr(&sig, &msg, &pubkey);
+                matches!(verify, Ok(()))
+            } else {
+                debug!("client sent malformed pubkey");
+                false
+            }
+        } else {
+            info!("error converting digest to secp256k1 message");
+            false
+        }
     }
 
     /// Convert event to canonical representation for signing.
@@ -154,36 +273,19 @@ impl Event {
         serde_json::Value::Array(tags)
     }
 
-    /// Get a list of event tags.
-    pub fn get_event_tags(&self) -> Vec<&str> {
-        let mut etags = vec![];
-        for t in self.tags.iter() {
-            if t.len() >= 2 && t.get(0).unwrap() == "e" {
-                etags.push(&t.get(1).unwrap()[..]);
-            }
+    /// Determine if the given tag and value set intersect with tags in this event.
+    pub fn generic_tag_val_intersect(&self, tagname: char, check: &HashSet<String>) -> bool {
+        match &self.tagidx {
+            // check if this is indexable tagname
+            Some(idx) => match idx.get(&tagname) {
+                Some(valset) => {
+                    let common = valset.intersection(check);
+                    common.count() > 0
+                }
+                None => false,
+            },
+            None => false,
         }
-        etags
-    }
-
-    /// Get a list of pubkey/petname tags.
-    pub fn get_pubkey_tags(&self) -> Vec<&str> {
-        let mut ptags = vec![];
-        for t in self.tags.iter() {
-            if t.len() >= 2 && t.get(0).unwrap() == "p" {
-                ptags.push(&t.get(1).unwrap()[..]);
-            }
-        }
-        ptags
-    }
-
-    /// Check if a given event is referenced in an event tag.
-    pub fn event_tag_match(&self, eventid: &str) -> bool {
-        self.get_event_tags().contains(&eventid)
-    }
-
-    /// Check if a given event is referenced in an event tag.
-    pub fn pubkey_tag_match(&self, pubkey: &str) -> bool {
-        self.get_pubkey_tags().contains(&pubkey)
     }
 }
 
@@ -199,6 +301,7 @@ mod tests {
             tags: vec![],
             content: "".to_owned(),
             sig: "0".to_owned(),
+            tagidx: None,
         }
     }
 
@@ -219,18 +322,24 @@ mod tests {
     }
 
     #[test]
-    fn empty_event_tag_match() -> Result<()> {
+    fn empty_event_tag_match() {
         let event = simple_event();
-        assert!(!event.event_tag_match("foo"));
-        Ok(())
+        assert!(!event
+            .generic_tag_val_intersect('e', &HashSet::from(["foo".to_owned(), "bar".to_owned()])));
     }
 
     #[test]
-    fn single_event_tag_match() -> Result<()> {
+    fn single_event_tag_match() {
         let mut event = simple_event();
         event.tags = vec![vec!["e".to_owned(), "foo".to_owned()]];
-        assert!(event.event_tag_match("foo"));
-        Ok(())
+        event.build_index();
+        assert_eq!(
+            event.generic_tag_val_intersect(
+                'e',
+                &HashSet::from(["foo".to_owned(), "bar".to_owned()])
+            ),
+            true
+        );
     }
 
     #[test]
@@ -273,12 +382,65 @@ mod tests {
             tags: vec![],
             content: "this is a test".to_owned(),
             sig: "abcde".to_owned(),
+            tagidx: None,
         };
         let c = e.to_canonical();
         let expected = Some(r#"[0,"012345",501234,1,[],"this is a test"]"#.to_owned());
         assert_eq!(c, expected);
     }
 
+    #[test]
+    fn event_tag_select() {
+        let e = Event {
+            id: "999".to_owned(),
+            pubkey: "012345".to_owned(),
+            created_at: 501234,
+            kind: 1,
+            tags: vec![
+                vec!["j".to_owned(), "abc".to_owned()],
+                vec!["e".to_owned(), "foo".to_owned()],
+                vec!["e".to_owned(), "bar".to_owned()],
+                vec!["e".to_owned(), "baz".to_owned()],
+                vec![
+                    "p".to_owned(),
+                    "aaaa".to_owned(),
+                    "ws://example.com".to_owned(),
+                ],
+            ],
+            content: "this is a test".to_owned(),
+            sig: "abcde".to_owned(),
+            tagidx: None,
+        };
+        let v = e.tag_values_by_name("e");
+        assert_eq!(v, vec!["foo", "bar", "baz"]);
+    }
+
+    #[test]
+    fn event_no_tag_select() {
+        let e = Event {
+            id: "999".to_owned(),
+            pubkey: "012345".to_owned(),
+            created_at: 501234,
+            kind: 1,
+            tags: vec![
+                vec!["j".to_owned(), "abc".to_owned()],
+                vec!["e".to_owned(), "foo".to_owned()],
+                vec!["e".to_owned(), "baz".to_owned()],
+                vec![
+                    "p".to_owned(),
+                    "aaaa".to_owned(),
+                    "ws://example.com".to_owned(),
+                ],
+            ],
+            content: "this is a test".to_owned(),
+            sig: "abcde".to_owned(),
+            tagidx: None,
+        };
+        let v = e.tag_values_by_name("x");
+        // asking for tags that don't exist just returns zero-length vector
+        assert_eq!(v.len(), 0);
+    }
+
     #[test]
     fn event_canonical_with_tags() {
         let e = Event {
@@ -296,6 +458,7 @@ mod tests {
             ],
             content: "this is a test".to_owned(),
             sig: "abcde".to_owned(),
+            tagidx: None,
         };
         let c = e.to_canonical();
         let expected_json = r###"[0,"012345",501234,1,[["#e","aoeu"],["#p","aaaa","ws://example.com"]],"this is a test"]"###;

src/hexrange.rs

@@ -0,0 +1,158 @@
+//! Utilities for searching hexadecimal
+use crate::utils::is_hex;
+use hex;
+
+/// Types of hexadecimal queries.
+#[derive(PartialEq, Eq, Debug, Clone)]
+pub enum HexSearch {
+    // when no range is needed, exact 32-byte
+    Exact(Vec<u8>),
+    // lower (inclusive) and upper range (exclusive)
+    Range(Vec<u8>, Vec<u8>),
+    // lower bound only, upper bound is MAX inclusive
+    LowerOnly(Vec<u8>),
+}
+
+/// Check if a string contains only f chars
+fn is_all_fs(s: &str) -> bool {
+    s.chars().all(|x| x == 'f' || x == 'F')
+}
+
+/// Find the next hex sequence greater than the argument.
+pub fn hex_range(s: &str) -> Option<HexSearch> {
+    // handle special cases
+    if !is_hex(s) || s.len() > 64 {
+        return None;
+    }
+    if s.len() == 64 {
+        return Some(HexSearch::Exact(hex::decode(s).ok()?));
+    }
+    // if s is odd, add a zero
+    let mut hash_base = s.to_owned();
+    let mut odd = hash_base.len() % 2 != 0;
+    if odd {
+        // extend the string to make it even
+        hash_base.push('0');
+    }
+    let base = hex::decode(hash_base).ok()?;
+    // check for all ff's
+    if is_all_fs(s) {
+        // there is no higher bound, we only want to search for blobs greater than this.
+        return Some(HexSearch::LowerOnly(base));
+    }
+
+    // return a range
+    let mut upper = base.clone();
+    let mut byte_len = upper.len();
+
+    // for odd strings, we made them longer, but we want to increment the upper char (+16).
+    // we know we can do this without overflowing because we explicitly set the bottom half to 0's.
+    while byte_len > 0 {
+        byte_len -= 1;
+        // check if byte can be incremented, or if we need to carry.
+        let b = upper[byte_len];
+        if b == u8::MAX {
+            // reset and carry
+            upper[byte_len] = 0;
+        } else if odd {
+            // check if first char in this byte is NOT 'f'
+            if b < 240 {
+                upper[byte_len] = b + 16; // bump up the first character in this byte
+                                          // increment done, stop iterating through the vec
+                break;
+            }
+            // if it is 'f', reset the byte to 0 and do a carry
+            // reset and carry
+            upper[byte_len] = 0;
+            // done with odd logic, so don't repeat this
+            odd = false;
+        } else {
+            // bump up the first character in this byte
+            upper[byte_len] = b + 1;
+            // increment done, stop iterating
+            break;
+        }
+    }
+    Some(HexSearch::Range(base, upper))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use crate::error::Result;
+
+    #[test]
+    fn hex_range_exact() -> Result<()> {
+        let hex = "abcdef00abcdef00abcdef00abcdef00abcdef00abcdef00abcdef00abcdef00";
+        let r = hex_range(hex);
+        assert_eq!(
+            r,
+            Some(HexSearch::Exact(hex::decode(hex).expect("invalid hex")))
+        );
+        Ok(())
+    }
+    #[test]
+    fn hex_full_range() -> Result<()> {
+        let hex = "aaaa";
+        let hex_upper = "aaab";
+        let r = hex_range(hex);
+        assert_eq!(
+            r,
+            Some(HexSearch::Range(
+                hex::decode(hex).expect("invalid hex"),
+                hex::decode(hex_upper).expect("invalid hex")
+            ))
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn hex_full_range_odd() -> Result<()> {
+        let r = hex_range("abc");
+        assert_eq!(
+            r,
+            Some(HexSearch::Range(
+                hex::decode("abc0").expect("invalid hex"),
+                hex::decode("abd0").expect("invalid hex")
+            ))
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn hex_full_range_odd_end_f() -> Result<()> {
+        let r = hex_range("abf");
+        assert_eq!(
+            r,
+            Some(HexSearch::Range(
+                hex::decode("abf0").expect("invalid hex"),
+                hex::decode("ac00").expect("invalid hex")
+            ))
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn hex_no_upper() -> Result<()> {
+        let r = hex_range("ffff");
+        assert_eq!(
+            r,
+            Some(HexSearch::LowerOnly(
+                hex::decode("ffff").expect("invalid hex")
+            ))
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn hex_no_upper_odd() -> Result<()> {
+        let r = hex_range("fff");
+        assert_eq!(
+            r,
+            Some(HexSearch::LowerOnly(
+                hex::decode("fff0").expect("invalid hex")
+            ))
+        );
+        Ok(())
+    }
+}

src/info.rs

@@ -0,0 +1,43 @@
+//! Relay metadata using NIP-11
+/// Relay Info
+use crate::config;
+use serde::{Deserialize, Serialize};
+
+pub const CARGO_PKG_VERSION: Option<&'static str> = option_env!("CARGO_PKG_VERSION");
+
+#[derive(Debug, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct RelayInfo {
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub id: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub name: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub description: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub pubkey: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub contact: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub supported_nips: Option<Vec<i64>>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub software: Option<String>,
+    #[serde(skip_serializing_if = "Option::is_none")]
+    pub version: Option<String>,
+}
+
+/// Convert an Info configuration into public Relay Info
+impl From<config::Info> for RelayInfo {
+    fn from(i: config::Info) -> Self {
+        RelayInfo {
+            id: i.relay_url,
+            name: i.name,
+            description: i.description,
+            pubkey: i.pubkey,
+            contact: i.contact,
+            supported_nips: Some(vec![1, 2, 9, 11, 12, 15, 16, 22]),
+            software: Some("https://git.sr.ht/~gheartsfield/nostr-rs-relay".to_owned()),
+            version: CARGO_PKG_VERSION.map(|x| x.to_owned()),
+        }
+    }
+}

src/lib.rs

@@ -2,7 +2,14 @@ pub mod close;
 pub mod config;
 pub mod conn;
 pub mod db;
+pub mod delegation;
 pub mod error;
 pub mod event;
-pub mod protostream;
+pub mod hexrange;
+pub mod info;
+pub mod nip05;
+pub mod schema;
 pub mod subscription;
+pub mod utils;
+// Public API for creating relays programatically
+pub mod server;

src/main.rs

@@ -1,248 +1,51 @@
 //! Server process
-use futures::SinkExt;
-use futures::StreamExt;
-use log::*;
-use nostr_rs_relay::close::Close;
+
 use nostr_rs_relay::config;
-use nostr_rs_relay::conn;
-use nostr_rs_relay::db;
-use nostr_rs_relay::error::{Error, Result};
-use nostr_rs_relay::event::Event;
-use nostr_rs_relay::protostream;
-use nostr_rs_relay::protostream::NostrMessage::*;
-use nostr_rs_relay::protostream::NostrResponse::*;
-use std::collections::HashMap;
-use tokio::net::{TcpListener, TcpStream};
-use tokio::runtime::Builder;
-use tokio::sync::broadcast;
-use tokio::sync::broadcast::{Receiver, Sender};
-use tokio::sync::mpsc;
-use tokio::sync::oneshot;
-use tungstenite::protocol::WebSocketConfig;
+use nostr_rs_relay::server::start_server;
+use std::env;
+use std::sync::mpsc as syncmpsc;
+use std::sync::mpsc::{Receiver as MpscReceiver, Sender as MpscSender};
+use std::thread;
+use tracing::info;
+
+use console_subscriber::ConsoleLayer;
+
+/// Return a requested DB name from command line arguments.
+fn db_from_args(args: &[String]) -> Option<String> {
+    if args.len() == 3 && args.get(1) == Some(&"--db".to_owned()) {
+        return args.get(2).map(std::clone::Clone::clone);
+    }
+    None
+}
 
 /// Start running a Nostr relay server.
-fn main() -> Result<(), Error> {
-    // setup logger
-    let _ = env_logger::try_init();
-    {
-        let mut settings = config::SETTINGS.write().unwrap();
-        // replace default settings with those read from config.toml
-        let c = config::Settings::new();
-        *settings = c;
-    }
-    let config = config::SETTINGS.read().unwrap();
-    debug!("config: {:?}", config);
-    let addr = format!("{}:{}", config.network.address.trim(), config.network.port);
-    // configure tokio runtime
-    let rt = Builder::new_multi_thread()
-        .enable_all()
-        .thread_name("tokio-ws")
-        .build()
-        .unwrap();
-    // start tokio
-    rt.block_on(async {
-        let settings = config::SETTINGS.read().unwrap();
-        let listener = TcpListener::bind(&addr).await.expect("Failed to bind");
-        info!("listening on: {}", addr);
-        // all client-submitted valid events are broadcast to every
-        // other client on this channel.  This should be large enough
-        // to accomodate slower readers (messages are dropped if
-        // clients can not keep up).
-        let (bcast_tx, _) = broadcast::channel::<Event>(settings.limits.broadcast_buffer);
-        // validated events that need to be persisted are sent to the
-        // database on via this channel.
-        let (event_tx, event_rx) = mpsc::channel::<Event>(settings.limits.event_persist_buffer);
-        // establish a channel for letting all threads now about a
-        // requested server shutdown.
-        let (invoke_shutdown, _) = broadcast::channel::<()>(1);
-        let ctrl_c_shutdown = invoke_shutdown.clone();
-        // listen for ctrl-c interruupts
-        tokio::spawn(async move {
-            tokio::signal::ctrl_c().await.unwrap();
-            info!("shutting down due to SIGINT");
-            ctrl_c_shutdown.send(()).ok();
-        });
-        // start the database writer thread.  Give it a channel for
-        // writing events, and for publishing events that have been
-        // written (to all connected clients).
-        db::db_writer(event_rx, bcast_tx.clone(), invoke_shutdown.subscribe()).await;
+fn main() {
+    // setup tracing
+    let _trace_sub = tracing_subscriber::fmt::try_init();
+    info!("Starting up from main");
+    // get database directory from args
+    let args: Vec<String> = env::args().collect();
+    let db_dir: Option<String> = db_from_args(&args);
+    // configure settings from config.toml
+    // replace default settings with those read from config.toml
+    let mut settings = config::Settings::new();
 
-        // track unique client connection count
-        let mut client_accept_count: usize = 0;
-        let mut stop_listening = invoke_shutdown.subscribe();
-        // handle new client connection requests, or SIGINT signals.
-        loop {
-            tokio::select! {
-                _ = stop_listening.recv() => {
-                    break;
-                }
-                Ok((stream, _)) = listener.accept() => {
-                    client_accept_count += 1;
-                    info!("creating new connection for client #{}",client_accept_count);
-                    tokio::spawn(nostr_server(
-                        stream,
-                        bcast_tx.clone(),
-                        event_tx.clone(),
-                        invoke_shutdown.subscribe(),
-                    ));
-                }
-            }
-        }
+    if settings.diagnostics.tracing {
+        // enable tracing with tokio-console
+        ConsoleLayer::builder().with_default_env().init();
+    }
+
+    // update with database location
+    if let Some(db) = db_dir {
+        settings.database.data_directory = db;
+    }
+    let (_, ctrl_rx): (MpscSender<()>, MpscReceiver<()>) = syncmpsc::channel();
+    // run this in a new thread
+    let handle = thread::spawn(|| {
+        // we should have a 'control plane' channel to monitor and bump the server.
+        // this will let us do stuff like clear the database, shutdown, etc.
+        let _svr = start_server(settings, ctrl_rx);
     });
-    Ok(())
-}
-
-/// Handle new client connections.  This runs through an event loop
-/// for all client communication.
-async fn nostr_server(
-    stream: TcpStream,
-    broadcast: Sender<Event>,
-    event_tx: tokio::sync::mpsc::Sender<Event>,
-    mut shutdown: Receiver<()>,
-) {
-    // get a broadcast channel for clients to communicate on
-    let mut bcast_rx = broadcast.subscribe();
-    let mut config = WebSocketConfig::default();
-    {
-        let settings = config::SETTINGS.read().unwrap();
-        config.max_message_size = settings.limits.max_ws_message_bytes;
-        config.max_frame_size = settings.limits.max_ws_frame_bytes;
-    }
-    // upgrade the TCP connection to WebSocket
-    let conn = tokio_tungstenite::accept_async_with_config(stream, Some(config)).await;
-    let ws_stream = conn.expect("websocket handshake error");
-    // wrap websocket into a stream & sink of Nostr protocol messages
-    let mut nostr_stream = protostream::wrap_ws_in_nostr(ws_stream);
-    // Track internal client state
-    let mut conn = conn::ClientConn::new();
-    let cid = conn.get_client_prefix();
-    // Create a channel for receiving query results from the database.
-    // we will send out the tx handle to any query we generate.
-    let (query_tx, mut query_rx) = mpsc::channel::<db::QueryResult>(256);
-    // maintain a hashmap of a oneshot channel for active subscriptions.
-    // when these subscriptions are cancelled, make a message
-    // available to the executing query so it knows to stop.
-    //let (abandon_query_tx, _) = oneshot::channel::<()>();
-    let mut running_queries: HashMap<String, oneshot::Sender<()>> = HashMap::new();
-    // for stats, keep track of how many events the client published,
-    // and how many it received from queries.
-    let mut client_published_event_count: usize = 0;
-    let mut client_received_event_count: usize = 0;
-    info!("new connection for client: {}", cid);
-    loop {
-        tokio::select! {
-            _ = shutdown.recv() => {
-                // server shutting down, exit loop
-                break;
-            },
-            Some(query_result) = query_rx.recv() => {
-                // database informed us of a query result we asked for
-                let res = EventRes(query_result.sub_id,query_result.event);
-                client_received_event_count += 1;
-                nostr_stream.send(res).await.ok();
-            },
-            Ok(global_event) = bcast_rx.recv() => {
-                // an event has been broadcast to all clients
-                // first check if there is a subscription for this event.
-                let matching_subs = conn.get_matching_subscriptions(&global_event);
-                for s in matching_subs {
-                    // TODO: serialize at broadcast time, instead of
-                    // once for each consumer.
-                    if let Ok(event_str) = serde_json::to_string(&global_event) {
-                        debug!("sub match: client: {}, sub: {}, event: {}",
-                               cid, s,
-                               global_event.get_event_id_prefix());
-                        // create an event response and send it
-                        let res = EventRes(s.to_owned(),event_str);
-                        nostr_stream.send(res).await.ok();
-                    } else {
-                        warn!("could not convert event to string");
-                    }
-                }
-            },
-            // check if this client has a subscription
-            proto_next = nostr_stream.next() => {
-                match proto_next {
-                    Some(Ok(EventMsg(ec))) => {
-                        // An EventCmd needs to be validated to be converted into an Event
-                        // handle each type of message
-                        let parsed : Result<Event> = Result::<Event>::from(ec);
-                        match parsed {
-                            Ok(e) => {
-                                let id_prefix:String = e.id.chars().take(8).collect();
-                                debug!("successfully parsed/validated event: {} from client: {}", id_prefix, cid);
-                                // Write this to the database
-                                event_tx.send(e.clone()).await.ok();
-                                client_published_event_count += 1;
-                            },
-                            Err(_) => {
-                                info!("client {} sent an invalid event", cid);
-                                nostr_stream.send(NoticeRes("event was invalid".to_owned())).await.ok();
-                            }
-                        }
-                    },
-                    Some(Ok(SubMsg(s))) => {
-                        debug!("client {} requesting a subscription", cid);
-                        // subscription handling consists of:
-                        // * registering the subscription so future events can be matched
-                        // * making a channel to cancel to request later
-                        // * sending a request for a SQL query
-                        let (abandon_query_tx, abandon_query_rx) = oneshot::channel::<()>();
-                        match conn.subscribe(s.clone()) {
-                            Ok(()) => {
-                                running_queries.insert(s.id.to_owned(), abandon_query_tx);
-                                // start a database query
-                                db::db_query(s, query_tx.clone(), abandon_query_rx).await;
-                            },
-                            Err(e) => {
-                                info!("Subscription error: {}", e);
-                                nostr_stream.send(NoticeRes(format!("{}",e))).await.ok();
-
-                            }
-                        }
-                    },
-                    Some(Ok(CloseMsg(cc))) => {
-                        // closing a request simply removes the subscription.
-                        let parsed : Result<Close> = Result::<Close>::from(cc);
-                        match parsed {
-                            Ok(c) => {
-                                // check if a query is currently
-                                // running, and remove it if so.
-                                let stop_tx = running_queries.remove(&c.id);
-                                if let Some(tx) = stop_tx {
-                                    tx.send(()).ok();
-                                }
-                                // stop checking new events against
-                                // the subscription
-                                conn.unsubscribe(c);
-                            },
-                            Err(_) => {
-                                info!("invalid command ignored");
-
-                            }
-                        }
-                    },
-                    None => {
-                        debug!("normal websocket close from client: {}",cid);
-                        break;
-                    },
-                    Some(Err(Error::ConnError)) => {
-                        debug!("got connection close/error, disconnecting client: {}",cid);
-                        break;
-                    }
-                    Some(Err(e)) => {
-                        info!("got non-fatal error from client: {}, error: {:?}", cid, e);
-                    },
-                }
-            },
-        }
-    }
-    // connection cleanup - ensure any still running queries are terminated.
-    for (_, stop_tx) in running_queries.into_iter() {
-        stop_tx.send(()).ok();
-    }
-    info!(
-        "stopping connection for client: {} (client sent {} event(s), received {})",
-        cid, client_published_event_count, client_received_event_count
-    );
+    // block on nostr thread to finish.
+    handle.join().unwrap();
 }

src/nip05.rs

@@ -0,0 +1,824 @@
+//! User verification using NIP-05 names
+//!
+//! NIP-05 defines a mechanism for authors to associate an internet
+//! address with their public key, in metadata events.  This module
+//! consumes a stream of metadata events, and keeps a database table
+//! updated with the current NIP-05 verification status.
+use crate::config::VerifiedUsers;
+use crate::db;
+use crate::error::{Error, Result};
+use crate::event::Event;
+use crate::utils::unix_time;
+use hyper::body::HttpBody;
+use hyper::client::connect::HttpConnector;
+use hyper::Client;
+use hyper_tls::HttpsConnector;
+use rand::Rng;
+use rusqlite::params;
+use std::time::Duration;
+use std::time::Instant;
+use std::time::SystemTime;
+use tokio::time::Interval;
+use tracing::{debug, info, warn};
+
+/// NIP-05 verifier state
+pub struct Verifier {
+    /// Metadata events for us to inspect
+    metadata_rx: tokio::sync::broadcast::Receiver<Event>,
+    /// Newly validated events get written and then broadcast on this channel to subscribers
+    event_tx: tokio::sync::broadcast::Sender<Event>,
+    /// SQLite read query pool
+    read_pool: db::SqlitePool,
+    /// SQLite write query pool
+    write_pool: db::SqlitePool,
+    /// Settings
+    settings: crate::config::Settings,
+    /// HTTP client
+    client: hyper::Client<HttpsConnector<HttpConnector>, hyper::Body>,
+    /// After all accounts are updated, wait this long before checking again.
+    wait_after_finish: Duration,
+    /// Minimum amount of time between HTTP queries
+    http_wait_duration: Duration,
+    /// Interval for updating verification records
+    reverify_interval: Interval,
+}
+
+/// A NIP-05 identifier is a local part and domain.
+#[derive(PartialEq, Eq, Debug, Clone)]
+pub struct Nip05Name {
+    local: String,
+    domain: String,
+}
+
+impl Nip05Name {
+    /// Does this name represent the entire domain?
+    pub fn is_domain_only(&self) -> bool {
+        self.local == "_"
+    }
+
+    /// Determine the URL to query for verification
+    fn to_url(&self) -> Option<http::Uri> {
+        format!(
+            "https://{}/.well-known/nostr.json?name={}",
+            self.domain, self.local
+        )
+        .parse::<http::Uri>()
+        .ok()
+    }
+}
+
+// Parsing Nip05Names from strings
+impl std::convert::TryFrom<&str> for Nip05Name {
+    type Error = Error;
+    fn try_from(inet: &str) -> Result<Self, Self::Error> {
+        // break full name at the @ boundary.
+        let components: Vec<&str> = inet.split('@').collect();
+        if components.len() != 2 {
+            Err(Error::CustomError("too many/few components".to_owned()))
+        } else {
+            // check if local name is valid
+            let local = components[0];
+            let domain = components[1];
+            if local
+                .chars()
+                .all(|x| x.is_alphanumeric() || x == '_' || x == '-' || x == '.')
+            {
+                if domain
+                    .chars()
+                    .all(|x| x.is_alphanumeric() || x == '-' || x == '.')
+                {
+                    Ok(Nip05Name {
+                        local: local.to_owned(),
+                        domain: domain.to_owned(),
+                    })
+                } else {
+                    Err(Error::CustomError(
+                        "invalid character in domain part".to_owned(),
+                    ))
+                }
+            } else {
+                Err(Error::CustomError(
+                    "invalid character in local part".to_owned(),
+                ))
+            }
+        }
+    }
+}
+
+impl std::fmt::Display for Nip05Name {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(f, "{}@{}", self.local, self.domain)
+    }
+}
+
+// Current time, with a slight foward jitter in seconds
+fn now_jitter(sec: u64) -> u64 {
+    // random time between now, and 10min in future.
+    let mut rng = rand::thread_rng();
+    let jitter_amount = rng.gen_range(0..sec);
+    let now = unix_time();
+    now.saturating_add(jitter_amount)
+}
+
+/// Check if the specified username and address are present and match in this response body
+fn body_contains_user(username: &str, address: &str, bytes: hyper::body::Bytes) -> Result<bool> {
+    // convert the body into json
+    let body: serde_json::Value = serde_json::from_slice(&bytes)?;
+    // ensure we have a names object.
+    let names_map = body
+        .as_object()
+        .and_then(|x| x.get("names"))
+        .and_then(|x| x.as_object())
+        .ok_or_else(|| Error::CustomError("not a map".to_owned()))?;
+    // get the pubkey for the requested user
+    let check_name = names_map.get(username).and_then(|x| x.as_str());
+    // ensure the address is a match
+    Ok(check_name.map(|x| x == address).unwrap_or(false))
+}
+
+impl Verifier {
+    pub fn new(
+        metadata_rx: tokio::sync::broadcast::Receiver<Event>,
+        event_tx: tokio::sync::broadcast::Sender<Event>,
+        settings: crate::config::Settings,
+    ) -> Result<Self> {
+        info!("creating NIP-05 verifier");
+        // build a database connection for reading and writing.
+        let write_pool = db::build_pool(
+            "nip05 writer",
+            &settings,
+            rusqlite::OpenFlags::SQLITE_OPEN_READ_WRITE,
+            1,    // min conns
+            4,    // max conns
+            true, // wait for DB
+        );
+        let read_pool = db::build_pool(
+            "nip05 reader",
+            &settings,
+            rusqlite::OpenFlags::SQLITE_OPEN_READ_ONLY,
+            1,    // min conns
+            8,    // max conns
+            true, // wait for DB
+        );
+        // setup hyper client
+        let https = HttpsConnector::new();
+        let client = Client::builder().build::<_, hyper::Body>(https);
+
+        // After all accounts have been re-verified, don't check again
+        // for this long.
+        let wait_after_finish = Duration::from_secs(60 * 10);
+        // when we have an active queue of accounts to validate, we
+        // will wait this duration between HTTP requests.
+        let http_wait_duration = Duration::from_secs(1);
+        // setup initial interval for re-verification.  If we find
+        // there is no work to be done, it will be reset to a longer
+        // duration.
+        let reverify_interval = tokio::time::interval(http_wait_duration);
+        Ok(Verifier {
+            metadata_rx,
+            event_tx,
+            read_pool,
+            write_pool,
+            settings,
+            client,
+            wait_after_finish,
+            http_wait_duration,
+            reverify_interval,
+        })
+    }
+
+    /// Perform web verification against a NIP-05 name and address.
+    pub async fn get_web_verification(
+        &mut self,
+        nip: &Nip05Name,
+        pubkey: &str,
+    ) -> UserWebVerificationStatus {
+        self.get_web_verification_res(nip, pubkey)
+            .await
+            .unwrap_or(UserWebVerificationStatus::Unknown)
+    }
+
+    /// Perform web verification against an `Event` (must be metadata).
+    pub async fn get_web_verification_from_event(
+        &mut self,
+        e: &Event,
+    ) -> UserWebVerificationStatus {
+        let nip_parse = e.get_nip05_addr();
+        if let Some(nip) = nip_parse {
+            self.get_web_verification_res(&nip, &e.pubkey)
+                .await
+                .unwrap_or(UserWebVerificationStatus::Unknown)
+        } else {
+            UserWebVerificationStatus::Unknown
+        }
+    }
+
+    /// Perform web verification, with a `Result` return.
+    async fn get_web_verification_res(
+        &mut self,
+        nip: &Nip05Name,
+        pubkey: &str,
+    ) -> Result<UserWebVerificationStatus> {
+        // determine if this domain should be checked
+        if !is_domain_allowed(
+            &nip.domain,
+            &self.settings.verified_users.domain_whitelist,
+            &self.settings.verified_users.domain_blacklist,
+        ) {
+            return Ok(UserWebVerificationStatus::DomainNotAllowed);
+        }
+        let url = nip
+            .to_url()
+            .ok_or_else(|| Error::CustomError("invalid NIP-05 URL".to_owned()))?;
+        let req = hyper::Request::builder()
+            .method(hyper::Method::GET)
+            .uri(url)
+            .header("Accept", "application/json")
+            .header(
+                "User-Agent",
+                format!(
+                    "nostr-rs-relay/{} NIP-05 Verifier",
+                    crate::info::CARGO_PKG_VERSION.unwrap()
+                ),
+            )
+            .body(hyper::Body::empty())
+            .expect("request builder");
+
+        let response_fut = self.client.request(req);
+
+        // HTTP request with timeout
+        match tokio::time::timeout(Duration::from_secs(5), response_fut).await {
+            Ok(response_res) => {
+                // limit size of verification document to 1MB.
+                const MAX_ALLOWED_RESPONSE_SIZE: u64 = 1024 * 1024;
+                let response = response_res?;
+                // determine content length from response
+                let response_content_length = match response.body().size_hint().upper() {
+                    Some(v) => v,
+                    None => MAX_ALLOWED_RESPONSE_SIZE + 1, // reject missing content length
+                };
+                // TODO: test how hyper handles the client providing an inaccurate content-length.
+                if response_content_length <= MAX_ALLOWED_RESPONSE_SIZE {
+                    let (parts, body) = response.into_parts();
+                    // TODO: consider redirects
+                    if parts.status == http::StatusCode::OK {
+                        // parse body, determine if the username / key / address is present
+                        let body_bytes = hyper::body::to_bytes(body).await?;
+                        let body_matches = body_contains_user(&nip.local, pubkey, body_bytes)?;
+                        if body_matches {
+                            return Ok(UserWebVerificationStatus::Verified);
+                        }
+                        // successful response, parsed as a nip-05
+                        // document, but this name/pubkey was not
+                        // present.
+                        return Ok(UserWebVerificationStatus::Unverified);
+                    }
+                } else {
+                    info!(
+                        "content length missing or exceeded limits for account: {:?}",
+                        nip.to_string()
+                    );
+                }
+            }
+            Err(_) => {
+                info!("timeout verifying account {:?}", nip);
+                return Ok(UserWebVerificationStatus::Unknown);
+            }
+        }
+        Ok(UserWebVerificationStatus::Unknown)
+    }
+
+    /// Perform NIP-05 verifier tasks.
+    pub async fn run(&mut self) {
+        // use this to schedule periodic re-validation tasks
+        // run a loop, restarting on failure
+        loop {
+            let res = self.run_internal().await;
+            if let Err(e) = res {
+                info!("error in verifier: {:?}", e);
+            }
+        }
+    }
+
+    /// Internal select loop for performing verification
+    async fn run_internal(&mut self) -> Result<()> {
+        tokio::select! {
+            m = self.metadata_rx.recv() => {
+                match m {
+                    Ok(e) => {
+                        if let Some(naddr) = e.get_nip05_addr() {
+                            info!("got metadata event for ({:?},{:?})", naddr.to_string() ,e.get_author_prefix());
+                            // Process a new author, checking if they are verified:
+                            let check_verified = get_latest_user_verification(self.read_pool.get().expect("could not get connection"), &e.pubkey).await;
+                            // ensure the event we got is more recent than the one we have, otherwise we can ignore it.
+                            if let Ok(last_check) = check_verified {
+                                if e.created_at <= last_check.event_created {
+                                    // this metadata is from the same author as an existing verification.
+                                    // it is older than what we have, so we can ignore it.
+                                    debug!("received older metadata event for author {:?}", e.get_author_prefix());
+                                    return Ok(());
+                                }
+                            }
+                            // old, or no existing record for this user.  In either case, we just create a new one.
+                            let start = Instant::now();
+                            let v = self.get_web_verification_from_event(&e).await;
+                            info!(
+                                "checked name {:?}, result: {:?}, in: {:?}",
+                                naddr.to_string(),
+                                v,
+                                start.elapsed()
+                            );
+                            // sleep to limit how frequently we make HTTP requests for new metadata events.  This should limit us to 4 req/sec.
+                            tokio::time::sleep(Duration::from_millis(250)).await;
+                            // if this user was verified, we need to write the
+                            // record, persist the event, and broadcast.
+                            if let UserWebVerificationStatus::Verified = v {
+                                self.create_new_verified_user(&naddr.to_string(), &e).await?;
+                            }
+                        }
+                    },
+                    Err(tokio::sync::broadcast::error::RecvError::Lagged(c)) => {
+                        warn!("incoming metadata events overwhelmed buffer, {} events dropped",c);
+                    }
+                    Err(tokio::sync::broadcast::error::RecvError::Closed) => {
+                        info!("metadata broadcast channel closed");
+                    }
+                }
+            },
+            _ = self.reverify_interval.tick() => {
+                // check and see if there is an old account that needs
+                // to be reverified
+                self.do_reverify().await?;
+            },
+        }
+        Ok(())
+    }
+
+    /// Reverify the oldest user verification record.
+    async fn do_reverify(&mut self) -> Result<()> {
+        let reverify_setting = self
+            .settings
+            .verified_users
+            .verify_update_frequency_duration;
+        let max_failures = self.settings.verified_users.max_consecutive_failures;
+        // get from settings, but default to 6hrs between re-checking an account
+        let reverify_dur = reverify_setting.unwrap_or_else(|| Duration::from_secs(60 * 60 * 6));
+        // find all verification records that have success or failure OLDER than the reverify_dur.
+        let now = SystemTime::now();
+        let earliest = now - reverify_dur;
+        let earliest_epoch = earliest
+            .duration_since(SystemTime::UNIX_EPOCH)
+            .map(|x| x.as_secs())
+            .unwrap_or(0);
+        let vr = get_oldest_user_verification(self.read_pool.get()?, earliest_epoch).await;
+        match vr {
+            Ok(ref v) => {
+                let new_status = self.get_web_verification(&v.name, &v.address).await;
+                match new_status {
+                    UserWebVerificationStatus::Verified => {
+                        // freshly verified account, update the
+                        // timestamp.
+                        self.update_verification_record(self.write_pool.get()?, v)
+                            .await?;
+                    }
+                    UserWebVerificationStatus::DomainNotAllowed
+                    | UserWebVerificationStatus::Unknown => {
+                        // server may be offline, or temporarily
+                        // blocked by the config file.  Note the
+                        // failure so we can process something
+                        // else.
+
+                        // have we had enough failures to give up?
+                        if v.failure_count >= max_failures as u64 {
+                            info!(
+                                "giving up on verifying {:?} after {} failures",
+                                v.name, v.failure_count
+                            );
+                            self.delete_verification_record(self.write_pool.get()?, v)
+                                .await?;
+                        } else {
+                            // record normal failure, incrementing failure count
+                            self.fail_verification_record(self.write_pool.get()?, v)
+                                .await?;
+                        }
+                    }
+                    UserWebVerificationStatus::Unverified => {
+                        // domain has removed the verification, drop
+                        // the record on our side.
+                        self.delete_verification_record(self.write_pool.get()?, v)
+                            .await?;
+                    }
+                }
+            }
+            Err(Error::SqlError(rusqlite::Error::QueryReturnedNoRows)) => {
+                // No users need verification.  Reset the interval to
+                // the next verification attempt.
+                let start = tokio::time::Instant::now() + self.wait_after_finish;
+                self.reverify_interval = tokio::time::interval_at(start, self.http_wait_duration);
+            }
+            Err(ref e) => {
+                warn!(
+                    "Error when checking for NIP-05 verification records: {:?}",
+                    e
+                );
+            }
+        }
+        Ok(())
+    }
+
+    /// Reset the verification timestamp on a VerificationRecord
+    pub async fn update_verification_record(
+        &mut self,
+        mut conn: db::PooledConnection,
+        vr: &VerificationRecord,
+    ) -> Result<()> {
+        let vr_id = vr.rowid;
+        let vr_str = vr.to_string();
+        tokio::task::spawn_blocking(move || {
+            // add some jitter to the verification to prevent everything from stacking up together.
+            let verif_time = now_jitter(600);
+            let tx = conn.transaction()?;
+            {
+                // update verification time and reset any failure count
+                let query =
+                    "UPDATE user_verification SET verified_at=?, failure_count=0 WHERE id=?";
+                let mut stmt = tx.prepare(query)?;
+                stmt.execute(params![verif_time, vr_id])?;
+            }
+            tx.commit()?;
+            info!("verification updated for {}", vr_str);
+            let ok: Result<()> = Ok(());
+            ok
+        })
+        .await?
+    }
+    /// Reset the failure timestamp on a VerificationRecord
+    pub async fn fail_verification_record(
+        &mut self,
+        mut conn: db::PooledConnection,
+        vr: &VerificationRecord,
+    ) -> Result<()> {
+        let vr_id = vr.rowid;
+        let vr_str = vr.to_string();
+        let fail_count = vr.failure_count.saturating_add(1);
+        tokio::task::spawn_blocking(move || {
+            // add some jitter to the verification to prevent everything from stacking up together.
+            let fail_time = now_jitter(600);
+            let tx = conn.transaction()?;
+            {
+                let query = "UPDATE user_verification SET failed_at=?, failure_count=? WHERE id=?";
+                let mut stmt = tx.prepare(query)?;
+                stmt.execute(params![fail_time, fail_count, vr_id])?;
+            }
+            tx.commit()?;
+            info!("verification failed for {}", vr_str);
+            let ok: Result<()> = Ok(());
+            ok
+        })
+        .await?
+    }
+    /// Delete a VerificationRecord that is no longer valid
+    pub async fn delete_verification_record(
+        &mut self,
+        mut conn: db::PooledConnection,
+        vr: &VerificationRecord,
+    ) -> Result<()> {
+        let vr_id = vr.rowid;
+        let vr_str = vr.to_string();
+        tokio::task::spawn_blocking(move || {
+            let tx = conn.transaction()?;
+            {
+                let query = "DELETE FROM user_verification WHERE id=?;";
+                let mut stmt = tx.prepare(query)?;
+                stmt.execute(params![vr_id])?;
+            }
+            tx.commit()?;
+            info!("verification rescinded for {}", vr_str);
+            let ok: Result<()> = Ok(());
+            ok
+        })
+        .await?
+    }
+
+    /// Persist an event, create a verification record, and broadcast.
+    // TODO: have more event-writing logic handled in the db module.
+    // Right now, these events avoid the rate limit.  That is
+    // acceptable since as soon as the user is registered, this path
+    // is no longer used.
+    // TODO: refactor these into spawn_blocking
+    // calls to get them off the async executors.
+    async fn create_new_verified_user(&mut self, name: &str, event: &Event) -> Result<()> {
+        let start = Instant::now();
+        // we should only do this if we are enabled.  if we are
+        // disabled/passive, the event has already been persisted.
+        let should_write_event = self.settings.verified_users.is_enabled();
+        if should_write_event {
+            match db::write_event(&mut self.write_pool.get()?, event) {
+                Ok(updated) => {
+                    if updated != 0 {
+                        info!(
+                            "persisted event: {:?} in {:?}",
+                            event.get_event_id_prefix(),
+                            start.elapsed()
+                        );
+                        self.event_tx.send(event.clone()).ok();
+                    }
+                }
+                Err(err) => {
+                    warn!("event insert failed: {:?}", err);
+                    if let Error::SqlError(r) = err {
+                        warn!("because: : {:?}", r);
+                    }
+                }
+            }
+        }
+        // write the verification record
+        save_verification_record(self.write_pool.get()?, event, name).await?;
+        Ok(())
+    }
+}
+
+/// Result of checking user's verification status against DNS/HTTP.
+#[derive(PartialEq, Eq, Debug, Clone)]
+pub enum UserWebVerificationStatus {
+    Verified,         // user is verified, as of now.
+    DomainNotAllowed, // domain blacklist or whitelist denied us from attempting a verification
+    Unknown,          // user's status could not be determined (timeout, server error)
+    Unverified,       // user's status is not verified (successful check, name / addr do not match)
+}
+
+/// A NIP-05 verification record.
+#[derive(PartialEq, Eq, Debug, Clone)]
+// Basic information for a verification event.  Gives us all we need to assert a NIP-05 address is good.
+pub struct VerificationRecord {
+    pub rowid: u64,                // database row for this verification event
+    pub name: Nip05Name,           // address being verified
+    pub address: String,           // pubkey
+    pub event: String,             // event ID hash providing the verification
+    pub event_created: u64,        // when the metadata event was published
+    pub last_success: Option<u64>, // the most recent time a verification was provided.  None if verification under this name has never succeeded.
+    pub last_failure: Option<u64>, // the most recent time verification was attempted, but could not be completed.
+    pub failure_count: u64,        // how many consecutive failures have been observed.
+}
+
+/// Check with settings to determine if a given domain is allowed to
+/// publish.
+pub fn is_domain_allowed(
+    domain: &str,
+    whitelist: &Option<Vec<String>>,
+    blacklist: &Option<Vec<String>>,
+) -> bool {
+    // if there is a whitelist, domain must be present in it.
+    if let Some(wl) = whitelist {
+        // workaround for Vec contains not accepting &str
+        return wl.iter().any(|x| x == domain);
+    }
+    // otherwise, check that user is not in the blacklist
+    if let Some(bl) = blacklist {
+        return !bl.iter().any(|x| x == domain);
+    }
+    true
+}
+
+impl VerificationRecord {
+    /// Check if the record is recent enough to be considered valid,
+    /// and the domain is allowed.
+    pub fn is_valid(&self, verified_users_settings: &VerifiedUsers) -> bool {
+        //let settings = SETTINGS.read().unwrap();
+        // how long a verification record is good for
+        let nip05_expiration = &verified_users_settings.verify_expiration_duration;
+        if let Some(e) = nip05_expiration {
+            if !self.is_current(e) {
+                return false;
+            }
+        }
+        // check domains
+        is_domain_allowed(
+            &self.name.domain,
+            &verified_users_settings.domain_whitelist,
+            &verified_users_settings.domain_blacklist,
+        )
+    }
+
+    /// Check if this record has been validated since the given
+    /// duration.
+    fn is_current(&self, d: &Duration) -> bool {
+        match self.last_success {
+            Some(s) => {
+                // current time - duration
+                let now = SystemTime::now();
+                let cutoff = now - *d;
+                let cutoff_epoch = cutoff
+                    .duration_since(SystemTime::UNIX_EPOCH)
+                    .map(|x| x.as_secs())
+                    .unwrap_or(0);
+                s > cutoff_epoch
+            }
+            None => false,
+        }
+    }
+}
+
+impl std::fmt::Display for VerificationRecord {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        write!(
+            f,
+            "({:?},{:?})",
+            self.name.to_string(),
+            self.address.chars().take(8).collect::<String>()
+        )
+    }
+}
+
+/// Create a new verification record based on an event
+pub async fn save_verification_record(
+    mut conn: db::PooledConnection,
+    event: &Event,
+    name: &str,
+) -> Result<()> {
+    let e = hex::decode(&event.id).ok();
+    let n = name.to_owned();
+    let a_prefix = event.get_author_prefix();
+    tokio::task::spawn_blocking(move || {
+        let tx = conn.transaction()?;
+        {
+            // if we create a /new/ one, we should get rid of any old ones.  or group the new ones by name and only consider the latest.
+            let query = "INSERT INTO user_verification (metadata_event, name, verified_at) VALUES ((SELECT id from event WHERE event_hash=?), ?, strftime('%s','now'));";
+            let mut stmt = tx.prepare(query)?;
+            stmt.execute(params![e, n])?;
+            // get the row ID
+            let v_id = tx.last_insert_rowid();
+            // delete everything else by this name
+            let del_query = "DELETE FROM user_verification WHERE name = ? AND id != ?;";
+            let mut del_stmt = tx.prepare(del_query)?;
+            let count = del_stmt.execute(params![n,v_id])?;
+            if count > 0 {
+                info!("removed {} old verification records for ({:?},{:?})", count, n, a_prefix);
+            }
+        }
+        tx.commit()?;
+        info!("saved new verification record for ({:?},{:?})", n, a_prefix);
+        let ok: Result<()> = Ok(());
+        ok
+    }).await?
+}
+
+/// Retrieve the most recent verification record for a given pubkey (async).
+pub async fn get_latest_user_verification(
+    conn: db::PooledConnection,
+    pubkey: &str,
+) -> Result<VerificationRecord> {
+    let p = pubkey.to_owned();
+    tokio::task::spawn_blocking(move || query_latest_user_verification(conn, p)).await?
+}
+
+/// Query database for the latest verification record for a given pubkey.
+pub fn query_latest_user_verification(
+    mut conn: db::PooledConnection,
+    pubkey: String,
+) -> Result<VerificationRecord> {
+    let tx = conn.transaction()?;
+    let query = "SELECT v.id, v.name, e.event_hash, e.created_at, v.verified_at, v.failed_at, v.failure_count FROM user_verification v LEFT JOIN event e ON e.id=v.metadata_event WHERE e.author=? ORDER BY e.created_at DESC, v.verified_at DESC, v.failed_at DESC LIMIT 1;";
+    let mut stmt = tx.prepare_cached(query)?;
+    let fields = stmt.query_row(params![hex::decode(&pubkey).ok()], |r| {
+        let rowid: u64 = r.get(0)?;
+        let rowname: String = r.get(1)?;
+        let eventid: Vec<u8> = r.get(2)?;
+        let created_at: u64 = r.get(3)?;
+        // create a tuple since we can't throw non-rusqlite errors in this closure
+        Ok((
+            rowid,
+            rowname,
+            eventid,
+            created_at,
+            r.get(4).ok(),
+            r.get(5).ok(),
+            r.get(6)?,
+        ))
+    })?;
+    Ok(VerificationRecord {
+        rowid: fields.0,
+        name: Nip05Name::try_from(&fields.1[..])?,
+        address: pubkey,
+        event: hex::encode(fields.2),
+        event_created: fields.3,
+        last_success: fields.4,
+        last_failure: fields.5,
+        failure_count: fields.6,
+    })
+}
+
+/// Retrieve the oldest user verification (async)
+pub async fn get_oldest_user_verification(
+    conn: db::PooledConnection,
+    earliest: u64,
+) -> Result<VerificationRecord> {
+    tokio::task::spawn_blocking(move || query_oldest_user_verification(conn, earliest)).await?
+}
+
+pub fn query_oldest_user_verification(
+    mut conn: db::PooledConnection,
+    earliest: u64,
+) -> Result<VerificationRecord> {
+    let tx = conn.transaction()?;
+    let query = "SELECT v.id, v.name, e.event_hash, e.author, e.created_at, v.verified_at, v.failed_at, v.failure_count FROM user_verification v LEFT JOIN event e ON e.id=v.metadata_event WHERE (v.verified_at < ? OR v.verified_at IS NULL) AND (v.failed_at < ? OR v.failed_at IS NULL) ORDER BY v.verified_at ASC, v.failed_at ASC LIMIT 1;";
+    let mut stmt = tx.prepare_cached(query)?;
+    let fields = stmt.query_row(params![earliest, earliest], |r| {
+        let rowid: u64 = r.get(0)?;
+        let rowname: String = r.get(1)?;
+        let eventid: Vec<u8> = r.get(2)?;
+        let pubkey: Vec<u8> = r.get(3)?;
+        let created_at: u64 = r.get(4)?;
+        // create a tuple since we can't throw non-rusqlite errors in this closure
+        Ok((
+            rowid,
+            rowname,
+            eventid,
+            pubkey,
+            created_at,
+            r.get(5).ok(),
+            r.get(6).ok(),
+            r.get(7)?,
+        ))
+    })?;
+    let vr = VerificationRecord {
+        rowid: fields.0,
+        name: Nip05Name::try_from(&fields.1[..])?,
+        address: hex::encode(fields.3),
+        event: hex::encode(fields.2),
+        event_created: fields.4,
+        last_success: fields.5,
+        last_failure: fields.6,
+        failure_count: fields.7,
+    };
+    Ok(vr)
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn local_from_inet() {
+        let addr = "bob@example.com";
+        let parsed = Nip05Name::try_from(addr);
+        assert!(!parsed.is_err());
+        let v = parsed.unwrap();
+        assert_eq!(v.local, "bob");
+        assert_eq!(v.domain, "example.com");
+    }
+
+    #[test]
+    fn not_enough_sep() {
+        let addr = "bob_example.com";
+        let parsed = Nip05Name::try_from(addr);
+        assert!(parsed.is_err());
+    }
+
+    #[test]
+    fn too_many_sep() {
+        let addr = "foo@bob@example.com";
+        let parsed = Nip05Name::try_from(addr);
+        assert!(parsed.is_err());
+    }
+
+    #[test]
+    fn invalid_local_name() {
+        // non-permitted ascii chars
+        assert!(Nip05Name::try_from("foo!@example.com").is_err());
+        assert!(Nip05Name::try_from("foo @example.com").is_err());
+        assert!(Nip05Name::try_from(" foo@example.com").is_err());
+        assert!(Nip05Name::try_from("f oo@example.com").is_err());
+        assert!(Nip05Name::try_from("foo<@example.com").is_err());
+        // unicode dash
+        assert!(Nip05Name::try_from("foo‐bar@example.com").is_err());
+        // emoji
+        assert!(Nip05Name::try_from("foo😭bar@example.com").is_err());
+    }
+    #[test]
+    fn invalid_domain_name() {
+        // non-permitted ascii chars
+        assert!(Nip05Name::try_from("foo@examp!e.com").is_err());
+        assert!(Nip05Name::try_from("foo@ example.com").is_err());
+        assert!(Nip05Name::try_from("foo@exa mple.com").is_err());
+        assert!(Nip05Name::try_from("foo@example .com").is_err());
+        assert!(Nip05Name::try_from("foo@exa<mple.com").is_err());
+        // unicode dash
+        assert!(Nip05Name::try_from("foobar@exa‐mple.com").is_err());
+        // emoji
+        assert!(Nip05Name::try_from("foobar@ex😭ample.com").is_err());
+    }
+
+    #[test]
+    fn to_url() {
+        let nip = Nip05Name::try_from("foobar@example.com").unwrap();
+        assert_eq!(
+            nip.to_url(),
+            Some(
+                "https://example.com/.well-known/nostr.json?name=foobar"
+                    .parse()
+                    .unwrap()
+            )
+        );
+    }
+}

src/protostream.rs

@@ -1,122 +0,0 @@
-//! Nostr protocol layered over WebSocket
-use crate::close::CloseCmd;
-use crate::error::{Error, Result};
-use crate::event::EventCmd;
-use crate::subscription::Subscription;
-use core::pin::Pin;
-use futures::sink::Sink;
-use futures::stream::Stream;
-use futures::task::Context;
-use futures::task::Poll;
-use log::*;
-use serde::{Deserialize, Serialize};
-use tokio::net::TcpStream;
-use tokio_tungstenite::WebSocketStream;
-use tungstenite::error::Error as WsError;
-use tungstenite::protocol::Message;
-
-/// Nostr protocol messages from a client
-#[derive(Deserialize, Serialize, Clone, PartialEq, Debug)]
-#[serde(untagged)]
-pub enum NostrMessage {
-    /// An `EVENT` message
-    EventMsg(EventCmd),
-    /// A `REQ` message
-    SubMsg(Subscription),
-    /// A `CLOSE` message
-    CloseMsg(CloseCmd),
-}
-
-/// Nostr protocol messages from a relay/server
-#[derive(Deserialize, Serialize, Clone, PartialEq, Debug)]
-pub enum NostrResponse {
-    /// A `NOTICE` response
-    NoticeRes(String),
-    /// An `EVENT` response, composed of the subscription identifier,
-    /// and serialized event JSON
-    EventRes(String, String),
-}
-
-/// A Nostr protocol stream is layered on top of a Websocket stream.
-pub struct NostrStream {
-    ws_stream: WebSocketStream<TcpStream>,
-}
-
-/// Given a websocket, return a protocol stream wrapper.
-pub fn wrap_ws_in_nostr(ws: WebSocketStream<TcpStream>) -> NostrStream {
-    NostrStream { ws_stream: ws }
-}
-
-/// Implement the [`Stream`] interface to produce Nostr messages.
-impl Stream for NostrStream {
-    type Item = Result<NostrMessage>;
-    fn poll_next(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Option<Self::Item>> {
-        /// Convert Message to NostrMessage
-        fn convert(msg: String) -> Result<NostrMessage> {
-            debug!("raw msg: {}", msg);
-            let event_size = msg.len();
-            debug!("event size is {} bytes", event_size);
-            let parsed_res: Result<NostrMessage> = serde_json::from_str(&msg).map_err(|e| e.into());
-            match parsed_res {
-                Ok(m) => Ok(m),
-                Err(e) => {
-                    debug!("proto parse error: {:?}", e);
-                    Err(Error::ProtoParseError)
-                }
-            }
-        }
-        match Pin::new(&mut self.ws_stream).poll_next(cx) {
-            Poll::Pending => Poll::Pending,
-            Poll::Ready(None) => Poll::Ready(None),
-            Poll::Ready(Some(v)) => match v {
-                Ok(Message::Text(vs)) => Poll::Ready(Some(convert(vs))),
-                Ok(Message::Binary(_)) => Poll::Ready(Some(Err(Error::ProtoParseError))),
-                Ok(Message::Pong(_)) | Ok(Message::Ping(_)) => Poll::Pending,
-                Ok(Message::Close(_)) => Poll::Ready(None),
-                Err(WsError::AlreadyClosed) | Err(WsError::ConnectionClosed) => Poll::Ready(None),
-                Err(_) => Poll::Ready(Some(Err(Error::ConnError))),
-            },
-        }
-    }
-}
-
-/// Implement the [`Sink`] interface to produce Nostr responses.
-impl Sink<NostrResponse> for NostrStream {
-    type Error = Error;
-
-    fn poll_ready(mut self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        // map the error type
-        match Pin::new(&mut self.ws_stream).poll_ready(cx) {
-            Poll::Ready(Ok(())) => Poll::Ready(Ok(())),
-            Poll::Ready(Err(_)) => Poll::Ready(Err(Error::ConnWriteError)),
-            Poll::Pending => Poll::Pending,
-        }
-    }
-
-    fn start_send(mut self: Pin<&mut Self>, item: NostrResponse) -> Result<(), Self::Error> {
-        // TODO: do real escaping for these - at least on NOTICE,
-        // which surely has some problems if arbitrary text is sent.
-        let send_str = match item {
-            NostrResponse::NoticeRes(msg) => {
-                let s = msg.replace("\"", "");
-                format!("[\"NOTICE\",\"{}\"]", s)
-            }
-            NostrResponse::EventRes(sub, eventstr) => {
-                let subesc = sub.replace("\"", "");
-                format!("[\"EVENT\",\"{}\",{}]", subesc, eventstr)
-            }
-        };
-        match Pin::new(&mut self.ws_stream).start_send(Message::Text(send_str)) {
-            Ok(()) => Ok(()),
-            Err(_) => Err(Error::ConnWriteError),
-        }
-    }
-
-    fn poll_flush(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        Poll::Ready(Ok(()))
-    }
-
-    fn poll_close(self: Pin<&mut Self>, _: &mut Context<'_>) -> Poll<Result<(), Self::Error>> {
-        Poll::Ready(Ok(()))
-    }
-}

src/schema.rs

@@ -0,0 +1,373 @@
+//! Database schema and migrations
+use crate::db::PooledConnection;
+use crate::error::Result;
+use crate::event::{single_char_tagname, Event};
+use crate::utils::is_lower_hex;
+use const_format::formatcp;
+use rusqlite::limits::Limit;
+use rusqlite::params;
+use rusqlite::Connection;
+use std::cmp::Ordering;
+use std::time::Instant;
+use tracing::{debug, error, info};
+
+/// Startup DB Pragmas
+pub const STARTUP_SQL: &str = r##"
+PRAGMA main.synchronous=NORMAL;
+PRAGMA foreign_keys = ON;
+PRAGMA journal_size_limit=32768;
+pragma mmap_size = 536870912; -- 512MB of mmap
+"##;
+
+/// Latest database version
+pub const DB_VERSION: usize = 7;
+
+/// Schema definition
+const INIT_SQL: &str = formatcp!(
+    r##"
+-- Database settings
+PRAGMA encoding = "UTF-8";
+PRAGMA journal_mode=WAL;
+PRAGMA main.synchronous=NORMAL;
+PRAGMA foreign_keys = ON;
+PRAGMA application_id = 1654008667;
+PRAGMA user_version = {};
+
+-- Event Table
+CREATE TABLE IF NOT EXISTS event (
+id INTEGER PRIMARY KEY,
+event_hash BLOB NOT NULL, -- 4-byte hash
+first_seen INTEGER NOT NULL, -- when the event was first seen (not authored!) (seconds since 1970)
+created_at INTEGER NOT NULL, -- when the event was authored
+author BLOB NOT NULL, -- author pubkey
+delegator BLOB, -- delegator pubkey (NIP-26)
+kind INTEGER NOT NULL, -- event kind
+hidden INTEGER, -- relevant for queries
+content TEXT NOT NULL -- serialized json of event object
+);
+
+-- Event Indexes
+CREATE UNIQUE INDEX IF NOT EXISTS event_hash_index ON event(event_hash);
+CREATE INDEX IF NOT EXISTS created_at_index ON event(created_at);
+CREATE INDEX IF NOT EXISTS author_index ON event(author);
+CREATE INDEX IF NOT EXISTS kind_index ON event(kind);
+
+-- Tag Table
+-- Tag values are stored as either a BLOB (if they come in as a
+-- hex-string), or TEXT otherwise.
+-- This means that searches need to select the appropriate column.
+CREATE TABLE IF NOT EXISTS tag (
+id INTEGER PRIMARY KEY,
+event_id INTEGER NOT NULL, -- an event ID that contains a tag.
+name TEXT, -- the tag name ("p", "e", whatever)
+value TEXT, -- the tag value, if not hex.
+value_hex BLOB, -- the tag value, if it can be interpreted as a lowercase hex string.
+FOREIGN KEY(event_id) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
+);
+CREATE INDEX IF NOT EXISTS tag_val_index ON tag(value);
+CREATE INDEX IF NOT EXISTS tag_val_hex_index ON tag(value_hex);
+
+-- NIP-05 User Validation
+CREATE TABLE IF NOT EXISTS user_verification (
+id INTEGER PRIMARY KEY,
+metadata_event INTEGER NOT NULL, -- the metadata event used for this validation.
+name TEXT NOT NULL, -- the nip05 field value (user@domain).
+verified_at INTEGER, -- timestamp this author/nip05 was most recently verified.
+failed_at INTEGER, -- timestamp a verification attempt failed (host down).
+failure_count INTEGER DEFAULT 0, -- number of consecutive failures.
+FOREIGN KEY(metadata_event) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
+);
+CREATE INDEX IF NOT EXISTS user_verification_name_index ON user_verification(name);
+CREATE INDEX IF NOT EXISTS user_verification_event_index ON user_verification(metadata_event);
+"##,
+    DB_VERSION
+);
+
+/// Determine the current application database schema version.
+pub fn curr_db_version(conn: &mut Connection) -> Result<usize> {
+    let query = "PRAGMA user_version;";
+    let curr_version = conn.query_row(query, [], |row| row.get(0))?;
+    Ok(curr_version)
+}
+
+fn mig_init(conn: &mut PooledConnection) -> Result<usize> {
+    match conn.execute_batch(INIT_SQL) {
+        Ok(()) => {
+            info!(
+                "database pragma/schema initialized to v{}, and ready",
+                DB_VERSION
+            );
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be initialized");
+        }
+    }
+    Ok(DB_VERSION)
+}
+
+/// Upgrade DB to latest version, and execute pragma settings
+pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
+    // check the version.
+    let mut curr_version = curr_db_version(conn)?;
+    info!("DB version = {:?}", curr_version);
+
+    debug!(
+        "SQLite max query parameters: {}",
+        conn.limit(Limit::SQLITE_LIMIT_VARIABLE_NUMBER)
+    );
+    debug!(
+        "SQLite max table/blob/text length: {} MB",
+        (conn.limit(Limit::SQLITE_LIMIT_LENGTH) as f64 / (1024 * 1024) as f64).floor()
+    );
+    debug!(
+        "SQLite max SQL length: {} MB",
+        (conn.limit(Limit::SQLITE_LIMIT_SQL_LENGTH) as f64 / (1024 * 1024) as f64).floor()
+    );
+
+    match curr_version.cmp(&DB_VERSION) {
+        // Database is new or not current
+        Ordering::Less => {
+            // initialize from scratch
+            if curr_version == 0 {
+                curr_version = mig_init(conn)?;
+            }
+            // for initialized but out-of-date schemas, proceed to
+            // upgrade sequentially until we are current.
+            if curr_version == 1 {
+                curr_version = mig_1_to_2(conn)?;
+            }
+
+            if curr_version == 2 {
+                curr_version = mig_2_to_3(conn)?;
+            }
+
+            if curr_version == 3 {
+                curr_version = mig_3_to_4(conn)?;
+            }
+
+            if curr_version == 4 {
+                curr_version = mig_4_to_5(conn)?;
+            }
+
+            if curr_version == 5 {
+                curr_version = mig_5_to_6(conn)?;
+            }
+            if curr_version == 6 {
+                curr_version = mig_6_to_7(conn)?;
+            }
+            if curr_version == DB_VERSION {
+                info!(
+                    "All migration scripts completed successfully.  Welcome to v{}.",
+                    DB_VERSION
+                );
+            }
+        }
+        // Database is current, all is good
+        Ordering::Equal => {
+            debug!("Database version was already current (v{})", DB_VERSION);
+        }
+        // Database is newer than what this code understands, abort
+        Ordering::Greater => {
+            panic!(
+                "Database version is newer than supported by this executable (v{} > v{})",
+                curr_version, DB_VERSION
+            );
+        }
+    }
+
+    // Setup PRAGMA
+    conn.execute_batch(STARTUP_SQL)?;
+    debug!("SQLite PRAGMA startup completed");
+    Ok(())
+}
+
+//// Migration Scripts
+
+fn mig_1_to_2(conn: &mut PooledConnection) -> Result<usize> {
+    // only change is adding a hidden column to events.
+    let upgrade_sql = r##"
+ALTER TABLE event ADD hidden INTEGER;
+UPDATE event SET hidden=FALSE;
+PRAGMA user_version = 2;
+"##;
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v1 -> v2");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    Ok(2)
+}
+
+fn mig_2_to_3(conn: &mut PooledConnection) -> Result<usize> {
+    // this version lacks the tag column
+    info!("database schema needs update from 2->3");
+    let upgrade_sql = r##"
+CREATE TABLE IF NOT EXISTS tag (
+id INTEGER PRIMARY KEY,
+event_id INTEGER NOT NULL, -- an event ID that contains a tag.
+name TEXT, -- the tag name ("p", "e", whatever)
+value TEXT, -- the tag value, if not hex.
+value_hex BLOB, -- the tag value, if it can be interpreted as a hex string.
+FOREIGN KEY(event_id) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
+);
+PRAGMA user_version = 3;
+"##;
+    // TODO: load existing refs into tag table
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v2 -> v3");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    // iterate over every event/pubkey tag
+    let tx = conn.transaction()?;
+    {
+        let mut stmt = tx.prepare("select event_id, \"e\", lower(hex(referenced_event)) from event_ref union select event_id, \"p\", lower(hex(referenced_pubkey)) from pubkey_ref;")?;
+        let mut tag_rows = stmt.query([])?;
+        while let Some(row) = tag_rows.next()? {
+            // we want to capture the event_id that had the tag, the tag name, and the tag hex value.
+            let event_id: u64 = row.get(0)?;
+            let tag_name: String = row.get(1)?;
+            let tag_value: String = row.get(2)?;
+            // this will leave behind p/e tags that were non-hex, but they are invalid anyways.
+            if is_lower_hex(&tag_value) {
+                tx.execute(
+                    "INSERT INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3);",
+                    params![event_id, tag_name, hex::decode(&tag_value).ok()],
+                )?;
+            }
+        }
+    }
+    info!("Updated tag values");
+    tx.commit()?;
+    Ok(3)
+}
+
+fn mig_3_to_4(conn: &mut PooledConnection) -> Result<usize> {
+    info!("database schema needs update from 3->4");
+    let upgrade_sql = r##"
+-- incoming metadata events with nip05
+CREATE TABLE IF NOT EXISTS user_verification (
+id INTEGER PRIMARY KEY,
+metadata_event INTEGER NOT NULL, -- the metadata event used for this validation.
+name TEXT NOT NULL, -- the nip05 field value (user@domain).
+verified_at INTEGER, -- timestamp this author/nip05 was most recently verified.
+failed_at INTEGER, -- timestamp a verification attempt failed (host down).
+failure_count INTEGER DEFAULT 0, -- number of consecutive failures.
+FOREIGN KEY(metadata_event) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
+);
+CREATE INDEX IF NOT EXISTS user_verification_name_index ON user_verification(name);
+CREATE INDEX IF NOT EXISTS user_verification_event_index ON user_verification(metadata_event);
+PRAGMA user_version = 4;
+"##;
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v3 -> v4");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    Ok(4)
+}
+
+fn mig_4_to_5(conn: &mut PooledConnection) -> Result<usize> {
+    info!("database schema needs update from 4->5");
+    let upgrade_sql = r##"
+DROP TABLE IF EXISTS event_ref;
+DROP TABLE IF EXISTS pubkey_ref;
+PRAGMA user_version=5;
+"##;
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v4 -> v5");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    Ok(5)
+}
+
+fn mig_5_to_6(conn: &mut PooledConnection) -> Result<usize> {
+    info!("database schema needs update from 5->6");
+    // We need to rebuild the tags table.  iterate through the
+    // event table.  build event from json, insert tags into a
+    // fresh tag table.  This was needed due to a logic error in
+    // how hex-like tags got indexed.
+    let start = Instant::now();
+    let tx = conn.transaction()?;
+    {
+        // Clear out table
+        tx.execute("DELETE FROM tag;", [])?;
+        let mut stmt = tx.prepare("select id, content from event order by id;")?;
+        let mut tag_rows = stmt.query([])?;
+        while let Some(row) = tag_rows.next()? {
+            // we want to capture the event_id that had the tag, the tag name, and the tag hex value.
+            let event_id: u64 = row.get(0)?;
+            let event_json: String = row.get(1)?;
+            let event: Event = serde_json::from_str(&event_json)?;
+            // look at each event, and each tag, creating new tag entries if appropriate.
+            for t in event.tags.iter().filter(|x| x.len() > 1) {
+                let tagname = t.get(0).unwrap();
+                let tagnamechar_opt = single_char_tagname(tagname);
+                if tagnamechar_opt.is_none() {
+                    continue;
+                }
+                // safe because len was > 1
+                let tagval = t.get(1).unwrap();
+                // insert as BLOB if we can restore it losslessly.
+                // this means it needs to be even length and lowercase.
+                if (tagval.len() % 2 == 0) && is_lower_hex(tagval) {
+                    tx.execute(
+                        "INSERT INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3);",
+                        params![event_id, tagname, hex::decode(&tagval).ok()],
+                    )?;
+                } else {
+                    // otherwise, insert as text
+                    tx.execute(
+                        "INSERT INTO tag (event_id, name, value) VALUES (?1, ?2, ?3);",
+                        params![event_id, tagname, &tagval],
+                    )?;
+                }
+            }
+        }
+        tx.execute("PRAGMA user_version = 6;", [])?;
+    }
+    tx.commit()?;
+    info!("database schema upgraded v5 -> v6 in {:?}", start.elapsed());
+    // vacuum after large table modification
+    let start = Instant::now();
+    conn.execute("VACUUM;", [])?;
+    info!("vacuumed DB after tags rebuild in {:?}", start.elapsed());
+    Ok(6)
+}
+
+fn mig_6_to_7(conn: &mut PooledConnection) -> Result<usize> {
+    info!("database schema needs update from 6->7");
+    // only change is adding a hidden column to events.
+    let upgrade_sql = r##"
+ALTER TABLE event ADD delegator BLOB;
+PRAGMA user_version = 7;
+"##;
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v6 -> v7");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    Ok(7)
+}

src/server.rs

@@ -0,0 +1,621 @@
+//! Server process
+use crate::close::Close;
+use crate::close::CloseCmd;
+use crate::config::{Settings, VerifiedUsersMode};
+use crate::conn;
+use crate::db;
+use crate::db::SubmittedEvent;
+use crate::error::{Error, Result};
+use crate::event::Event;
+use crate::event::EventCmd;
+use crate::info::RelayInfo;
+use crate::nip05;
+use crate::subscription::Subscription;
+use futures::SinkExt;
+use futures::StreamExt;
+use hyper::header::ACCEPT;
+use hyper::service::{make_service_fn, service_fn};
+use hyper::upgrade::Upgraded;
+use hyper::{
+    header, server::conn::AddrStream, upgrade, Body, Request, Response, Server, StatusCode,
+};
+use serde::{Deserialize, Serialize};
+use serde_json::json;
+use std::collections::HashMap;
+use std::convert::Infallible;
+use std::net::SocketAddr;
+use std::path::Path;
+use std::sync::mpsc::Receiver as MpscReceiver;
+use std::time::Duration;
+use std::time::Instant;
+use tokio::runtime::Builder;
+use tokio::sync::broadcast::{self, Receiver, Sender};
+use tokio::sync::mpsc;
+use tokio::sync::oneshot;
+use tokio_tungstenite::WebSocketStream;
+use tracing::*;
+use tungstenite::error::CapacityError::MessageTooLong;
+use tungstenite::error::Error as WsError;
+use tungstenite::handshake;
+use tungstenite::protocol::Message;
+use tungstenite::protocol::WebSocketConfig;
+
+/// Handle arbitrary HTTP requests, including for WebSocket upgrades.
+async fn handle_web_request(
+    mut request: Request<Body>,
+    pool: db::SqlitePool,
+    settings: Settings,
+    remote_addr: SocketAddr,
+    broadcast: Sender<Event>,
+    event_tx: tokio::sync::mpsc::Sender<SubmittedEvent>,
+    shutdown: Receiver<()>,
+) -> Result<Response<Body>, Infallible> {
+    match (
+        request.uri().path(),
+        request.headers().contains_key(header::UPGRADE),
+    ) {
+        // Request for / as websocket
+        ("/", true) => {
+            trace!("websocket with upgrade request");
+            //assume request is a handshake, so create the handshake response
+            let response = match handshake::server::create_response_with_body(&request, || {
+                Body::empty()
+            }) {
+                Ok(response) => {
+                    //in case the handshake response creation succeeds,
+                    //spawn a task to handle the websocket connection
+                    tokio::spawn(async move {
+                        //using the hyper feature of upgrading a connection
+                        match upgrade::on(&mut request).await {
+                            //if successfully upgraded
+                            Ok(upgraded) => {
+                                // set WebSocket configuration options
+                                let config = WebSocketConfig {
+                                    max_message_size: settings.limits.max_ws_message_bytes,
+                                    max_frame_size: settings.limits.max_ws_frame_bytes,
+                                    ..Default::default()
+                                };
+                                //create a websocket stream from the upgraded object
+                                let ws_stream = WebSocketStream::from_raw_socket(
+                                    //pass the upgraded object
+                                    //as the base layer stream of the Websocket
+                                    upgraded,
+                                    tokio_tungstenite::tungstenite::protocol::Role::Server,
+                                    Some(config),
+                                )
+                                .await;
+
+                                tokio::spawn(nostr_server(
+                                    pool, settings, ws_stream, broadcast, event_tx, shutdown,
+                                ));
+                            }
+                            Err(e) => println!(
+                                "error when trying to upgrade connection \
+                                 from address {} to websocket connection. \
+                                 Error is: {}",
+                                remote_addr, e
+                            ),
+                        }
+                    });
+                    //return the response to the handshake request
+                    response
+                }
+                Err(error) => {
+                    warn!("websocket response failed");
+                    let mut res =
+                        Response::new(Body::from(format!("Failed to create websocket: {}", error)));
+                    *res.status_mut() = StatusCode::BAD_REQUEST;
+                    return Ok(res);
+                }
+            };
+            Ok::<_, Infallible>(response)
+        }
+        // Request for Relay info
+        ("/", false) => {
+            // handle request at root with no upgrade header
+            // Check if this is a nostr server info request
+            let accept_header = &request.headers().get(ACCEPT);
+            // check if application/nostr+json is included
+            if let Some(media_types) = accept_header {
+                if let Ok(mt_str) = media_types.to_str() {
+                    if mt_str.contains("application/nostr+json") {
+                        // build a relay info response
+                        debug!("Responding to server info request");
+                        let rinfo = RelayInfo::from(settings.info);
+                        let b = Body::from(serde_json::to_string_pretty(&rinfo).unwrap());
+                        return Ok(Response::builder()
+                            .status(200)
+                            .header("Content-Type", "application/nostr+json")
+                            .header("Access-Control-Allow-Origin", "*")
+                            .body(b)
+                            .unwrap());
+                    }
+                }
+            }
+            Ok(Response::builder()
+                .status(200)
+                .header("Content-Type", "text/plain")
+                .body(Body::from("Please use a Nostr client to connect."))
+                .unwrap())
+        }
+        (_, _) => {
+            //handle any other url
+            Ok(Response::builder()
+                .status(StatusCode::NOT_FOUND)
+                .body(Body::from("Nothing here."))
+                .unwrap())
+        }
+    }
+}
+
+// return on a control-c or internally requested shutdown signal
+async fn ctrl_c_or_signal(mut shutdown_signal: Receiver<()>) {
+    let mut term_signal = tokio::signal::unix::signal(tokio::signal::unix::SignalKind::terminate())
+        .expect("could not define signal");
+    loop {
+        tokio::select! {
+            _ = shutdown_signal.recv() => {
+            info!("Shutting down webserver as requested");
+                    // server shutting down, exit loop
+                    break;
+                },
+            _ = tokio::signal::ctrl_c() => {
+            info!("Shutting down webserver due to SIGINT");
+                    break;
+            },
+        _ = term_signal.recv() => {
+        info!("Shutting down webserver due to SIGTERM");
+        break;
+        },
+
+        }
+    }
+}
+
+/// Start running a Nostr relay server.
+pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result<(), Error> {
+    trace!("Config: {:?}", settings);
+    // do some config validation.
+    if !Path::new(&settings.database.data_directory).is_dir() {
+        error!("Database directory does not exist");
+        return Err(Error::DatabaseDirError);
+    }
+    let addr = format!(
+        "{}:{}",
+        settings.network.address.trim(),
+        settings.network.port
+    );
+    let socket_addr = addr.parse().expect("listening address not valid");
+    // address whitelisting settings
+    if let Some(addr_whitelist) = &settings.authorization.pubkey_whitelist {
+        info!(
+            "Event publishing restricted to {} pubkey(s)",
+            addr_whitelist.len()
+        );
+    }
+    // check if NIP-05 enforced user verification is on
+    if settings.verified_users.is_active() {
+        info!(
+            "NIP-05 user verification mode:{:?}",
+            settings.verified_users.mode
+        );
+        if let Some(d) = settings.verified_users.verify_update_duration() {
+            info!("NIP-05 check user verification every:   {:?}", d);
+        }
+        if let Some(d) = settings.verified_users.verify_expiration_duration() {
+            info!("NIP-05 user verification expires after: {:?}", d);
+        }
+        if let Some(wl) = &settings.verified_users.domain_whitelist {
+            info!("NIP-05 domain whitelist: {:?}", wl);
+        }
+        if let Some(bl) = &settings.verified_users.domain_blacklist {
+            info!("NIP-05 domain blacklist: {:?}", bl);
+        }
+    }
+    // configure tokio runtime
+    let rt = Builder::new_multi_thread()
+        .enable_all()
+        .thread_name("tokio-ws")
+        .build()
+        .unwrap();
+    // start tokio
+    rt.block_on(async {
+        let broadcast_buffer_limit = settings.limits.broadcast_buffer;
+        let persist_buffer_limit = settings.limits.event_persist_buffer;
+        let verified_users_active = settings.verified_users.is_active();
+        let db_min_conn = settings.database.min_conn;
+        let db_max_conn = settings.database.max_conn;
+        let settings = settings.clone();
+        info!("listening on: {}", socket_addr);
+        // all client-submitted valid events are broadcast to every
+        // other client on this channel.  This should be large enough
+        // to accomodate slower readers (messages are dropped if
+        // clients can not keep up).
+        let (bcast_tx, _) = broadcast::channel::<Event>(broadcast_buffer_limit);
+        // validated events that need to be persisted are sent to the
+        // database on via this channel.
+        let (event_tx, event_rx) = mpsc::channel::<SubmittedEvent>(persist_buffer_limit);
+        // establish a channel for letting all threads now about a
+        // requested server shutdown.
+        let (invoke_shutdown, shutdown_listen) = broadcast::channel::<()>(1);
+        // create a channel for sending any new metadata event.  These
+        // will get processed relatively slowly (a potentially
+        // multi-second blocking HTTP call) on a single thread, so we
+        // buffer requests on the channel.  No harm in dropping events
+        // here, since we are protecting against DoS.  This can make
+        // it difficult to setup initial metadata in bulk, since
+        // overwhelming this will drop events and won't register
+        // metadata events.
+        let (metadata_tx, metadata_rx) = broadcast::channel::<Event>(4096);
+        // start the database writer thread.  Give it a channel for
+        // writing events, and for publishing events that have been
+        // written (to all connected clients).
+        db::db_writer(
+            settings.clone(),
+            event_rx,
+            bcast_tx.clone(),
+            metadata_tx.clone(),
+            shutdown_listen,
+        )
+        .await;
+        info!("db writer created");
+
+        // create a nip-05 verifier thread; if enabled.
+        if settings.verified_users.mode != VerifiedUsersMode::Disabled {
+            let verifier_opt =
+                nip05::Verifier::new(metadata_rx, bcast_tx.clone(), settings.clone());
+            if let Ok(mut v) = verifier_opt {
+                if verified_users_active {
+                    tokio::task::spawn(async move {
+                        info!("starting up NIP-05 verifier...");
+                        v.run().await;
+                    });
+                }
+            }
+        }
+        // listen for (external to tokio) shutdown request
+        let controlled_shutdown = invoke_shutdown.clone();
+        tokio::spawn(async move {
+            info!("control message listener started");
+            match shutdown_rx.recv() {
+                Ok(()) => {
+                    info!("control message requesting shutdown");
+                    controlled_shutdown.send(()).ok();
+                }
+                Err(std::sync::mpsc::RecvError) => {
+                    debug!("shutdown requestor is disconnected");
+                }
+            };
+        });
+        // listen for ctrl-c interruupts
+        let ctrl_c_shutdown = invoke_shutdown.clone();
+        // listener for webserver shutdown
+        let webserver_shutdown_listen = invoke_shutdown.subscribe();
+
+        tokio::spawn(async move {
+            tokio::signal::ctrl_c().await.unwrap();
+            info!("shutting down due to SIGINT (main)");
+            ctrl_c_shutdown.send(()).ok();
+        });
+        // build a connection pool for sqlite connections
+        let pool = db::build_pool(
+            "client query",
+            &settings,
+            rusqlite::OpenFlags::SQLITE_OPEN_READ_ONLY
+                | rusqlite::OpenFlags::SQLITE_OPEN_SHARED_CACHE,
+            db_min_conn,
+            db_max_conn,
+            true,
+        );
+        // A `Service` is needed for every connection, so this
+        // creates one from our `handle_request` function.
+        let make_svc = make_service_fn(|conn: &AddrStream| {
+            let svc_pool = pool.clone();
+            let remote_addr = conn.remote_addr();
+            let bcast = bcast_tx.clone();
+            let event = event_tx.clone();
+            let stop = invoke_shutdown.clone();
+            let settings = settings.clone();
+            async move {
+                // service_fn converts our function into a `Service`
+                Ok::<_, Infallible>(service_fn(move |request: Request<Body>| {
+                    handle_web_request(
+                        request,
+                        svc_pool.clone(),
+                        settings.clone(),
+                        remote_addr,
+                        bcast.clone(),
+                        event.clone(),
+                        stop.subscribe(),
+                    )
+                }))
+            }
+        });
+        let server = Server::bind(&socket_addr)
+            .serve(make_svc)
+            .with_graceful_shutdown(ctrl_c_or_signal(webserver_shutdown_listen));
+        // run hyper in this thread.  This is why the thread does not return.
+        if let Err(e) = server.await {
+            eprintln!("server error: {}", e);
+        }
+    });
+    Ok(())
+}
+
+/// Nostr protocol messages from a client
+#[derive(Deserialize, Serialize, Clone, PartialEq, Eq, Debug)]
+#[serde(untagged)]
+pub enum NostrMessage {
+    /// An `EVENT` message
+    EventMsg(EventCmd),
+    /// A `REQ` message
+    SubMsg(Subscription),
+    /// A `CLOSE` message
+    CloseMsg(CloseCmd),
+}
+
+/// Convert Message to NostrMessage
+fn convert_to_msg(msg: String, max_bytes: Option<usize>) -> Result<NostrMessage> {
+    let parsed_res: Result<NostrMessage> = serde_json::from_str(&msg).map_err(|e| e.into());
+    match parsed_res {
+        Ok(m) => {
+            if let NostrMessage::EventMsg(_) = m {
+                if let Some(max_size) = max_bytes {
+                    // check length, ensure that some max size is set.
+                    if msg.len() > max_size && max_size > 0 {
+                        return Err(Error::EventMaxLengthError(msg.len()));
+                    }
+                }
+            }
+            Ok(m)
+        }
+        Err(e) => {
+            debug!("proto parse error: {:?}", e);
+            debug!("parse error on message: {}", msg.trim());
+            Err(Error::ProtoParseError)
+        }
+    }
+}
+
+/// Turn a string into a NOTICE message ready to send over a WebSocket
+fn make_notice_message(msg: &str) -> Message {
+    Message::text(json!(["NOTICE", msg]).to_string())
+}
+
+/// Handle new client connections.  This runs through an event loop
+/// for all client communication.
+async fn nostr_server(
+    pool: db::SqlitePool,
+    settings: Settings,
+    mut ws_stream: WebSocketStream<Upgraded>,
+    broadcast: Sender<Event>,
+    event_tx: mpsc::Sender<SubmittedEvent>,
+    mut shutdown: Receiver<()>,
+) {
+    // get a broadcast channel for clients to communicate on
+    let mut bcast_rx = broadcast.subscribe();
+    // Track internal client state
+    let mut conn = conn::ClientConn::new();
+    let cid = conn.get_client_prefix();
+    // Create a channel for receiving query results from the database.
+    // we will send out the tx handle to any query we generate.
+    let (query_tx, mut query_rx) = mpsc::channel::<db::QueryResult>(256);
+    // Create channel for receiving NOTICEs
+    let (notice_tx, mut notice_rx) = mpsc::channel::<String>(32);
+
+    // last time this client sent data (message, ping, etc.)
+    let mut last_message_time = Instant::now();
+
+    // ping interval (every 5 minutes)
+    let default_ping_dur = Duration::from_secs(300);
+
+    // disconnect after 20 minutes without a ping response or event.
+    let max_quiet_time = Duration::from_secs(60 * 20);
+
+    let start = tokio::time::Instant::now() + default_ping_dur;
+    let mut ping_interval = tokio::time::interval_at(start, default_ping_dur);
+
+    // maintain a hashmap of a oneshot channel for active subscriptions.
+    // when these subscriptions are cancelled, make a message
+    // available to the executing query so it knows to stop.
+    let mut running_queries: HashMap<String, oneshot::Sender<()>> = HashMap::new();
+
+    // for stats, keep track of how many events the client published,
+    // and how many it received from queries.
+    let mut client_published_event_count: usize = 0;
+    let mut client_received_event_count: usize = 0;
+    info!("new connection for client: {:?}", cid);
+    loop {
+        tokio::select! {
+            _ = shutdown.recv() => {
+        info!("Shutting client connection down due to shutdown: {:?}", cid);
+                // server shutting down, exit loop
+                break;
+            },
+            _ = ping_interval.tick() => {
+                // check how long since we talked to client
+                // if it has been too long, disconnect
+                if last_message_time.elapsed() > max_quiet_time {
+                    debug!("ending connection due to lack of client ping response");
+                    break;
+                }
+                // Send a ping
+                ws_stream.send(Message::Ping(Vec::new())).await.ok();
+            },
+            Some(notice_msg) = notice_rx.recv() => {
+                ws_stream.send(make_notice_message(&notice_msg)).await.ok();
+            },
+            Some(query_result) = query_rx.recv() => {
+                // database informed us of a query result we asked for
+                let subesc = query_result.sub_id.replace('"', "");
+                if query_result.event == "EOSE" {
+                    let send_str = format!("[\"EOSE\",\"{}\"]", subesc);
+                    ws_stream.send(Message::Text(send_str)).await.ok();
+                } else {
+                    client_received_event_count += 1;
+                    // send a result
+                    let send_str = format!("[\"EVENT\",\"{}\",{}]", subesc, &query_result.event);
+                    ws_stream.send(Message::Text(send_str)).await.ok();
+                }
+            },
+            // TODO: consider logging the LaggedRecv error
+            Ok(global_event) = bcast_rx.recv() => {
+                // an event has been broadcast to all clients
+                // first check if there is a subscription for this event.
+                let matching_subs = conn.get_matching_subscriptions(&global_event);
+                for s in matching_subs {
+                    // TODO: serialize at broadcast time, instead of
+                    // once for each consumer.
+                    if let Ok(event_str) = serde_json::to_string(&global_event) {
+                        debug!("sub match for client: {:?}, sub: {:?}, event: {:?}",
+                               cid, s,
+                               global_event.get_event_id_prefix());
+                        // create an event response and send it
+                        let subesc = s.replace('"', "");
+                        ws_stream.send(Message::Text(format!("[\"EVENT\",\"{}\",{}]", subesc, event_str))).await.ok();
+                    } else {
+                        warn!("could not serialize event: {:?}", global_event.get_event_id_prefix());
+                    }
+                }
+            },
+            ws_next = ws_stream.next() => {
+                // update most recent message time for client
+                last_message_time = Instant::now();
+                // Consume text messages from the client, parse into Nostr messages.
+                let nostr_msg = match ws_next {
+                    Some(Ok(Message::Text(m))) => {
+                        convert_to_msg(m,settings.limits.max_event_bytes)
+                    },
+            Some(Ok(Message::Binary(_))) => {
+            ws_stream.send(
+                make_notice_message("binary messages are not accepted")).await.ok();
+                        continue;
+                    },
+                    Some(Ok(Message::Ping(_) | Message::Pong(_))) => {
+                        // get a ping/pong, ignore.  tungstenite will
+                        // send responses automatically.
+                        continue;
+                    },
+            Some(Err(WsError::Capacity(MessageTooLong{size, max_size}))) => {
+            ws_stream.send(
+                make_notice_message(
+                &format!("message too large ({} > {})",size, max_size))).await.ok();
+                        continue;
+            },
+                    None |
+            Some(Ok(Message::Close(_)) |
+             Err(WsError::AlreadyClosed | WsError::ConnectionClosed |
+                 WsError::Protocol(tungstenite::error::ProtocolError::ResetWithoutClosingHandshake)))
+                        => {
+                        debug!("websocket close from client: {:?}",cid);
+                        break;
+                    },
+                    Some(Err(WsError::Io(e))) => {
+                        // IO errors are considered fatal
+                        warn!("IO error (client: {:?}): {:?}", cid, e);
+                        break;
+                    }
+                    x => {
+                        // default condition on error is to close the client connection
+                        info!("unknown error (client: {:?}): {:?} (closing conn)", cid, x);
+                        break;
+                    }
+                };
+
+                // convert ws_next into proto_next
+                match nostr_msg {
+                    Ok(NostrMessage::EventMsg(ec)) => {
+                        // An EventCmd needs to be validated to be converted into an Event
+                        // handle each type of message
+                        let parsed : Result<Event> = Result::<Event>::from(ec);
+                        match parsed {
+                            Ok(e) => {
+                                let id_prefix:String = e.id.chars().take(8).collect();
+                                debug!("successfully parsed/validated event: {:?} from client: {:?}", id_prefix, cid);
+                                // check if the event is too far in the future.
+                                if e.is_valid_timestamp(settings.options.reject_future_seconds) {
+                                    // Write this to the database.
+                                    let submit_event = SubmittedEvent { event: e.clone(), notice_tx: notice_tx.clone() };
+                                    event_tx.send(submit_event).await.ok();
+                                    client_published_event_count += 1;
+                } else {
+                    info!("client {:?} sent a far future-dated event", cid);
+                    if let Some(fut_sec) = settings.options.reject_future_seconds {
+                    ws_stream.send(make_notice_message(&format!("The event created_at field is out of the acceptable range (+{}sec) for this relay and was not stored.",fut_sec))).await.ok();
+                    }
+                }
+                            },
+                            Err(_) => {
+                                info!("client {:?} sent an invalid event", cid);
+                                ws_stream.send(make_notice_message("event was invalid")).await.ok();
+                            }
+                        }
+                    },
+                    Ok(NostrMessage::SubMsg(s)) => {
+                        debug!("client {} requesting a subscription", cid);
+                        // subscription handling consists of:
+                        // * registering the subscription so future events can be matched
+                        // * making a channel to cancel to request later
+                        // * sending a request for a SQL query
+                        let (abandon_query_tx, abandon_query_rx) = oneshot::channel::<()>();
+                        match conn.subscribe(s.clone()) {
+                            Ok(()) => {
+                                // when we insert, if there was a previous query running with the same name, cancel it.
+                                if let Some(previous_query) = running_queries.insert(s.id.to_owned(), abandon_query_tx) {
+                                    previous_query.send(()).ok();
+                                }
+                                // start a database query
+                                db::db_query(s, cid.to_owned(), pool.clone(), query_tx.clone(), abandon_query_rx).await;
+                            },
+                            Err(e) => {
+                                info!("Subscription error: {}", e);
+                                ws_stream.send(make_notice_message(&e.to_string())).await.ok();
+                            }
+                        }
+                    },
+                    Ok(NostrMessage::CloseMsg(cc)) => {
+                        // closing a request simply removes the subscription.
+                        let parsed : Result<Close> = Result::<Close>::from(cc);
+            if let Ok(c) = parsed {
+                                // check if a query is currently
+                                // running, and remove it if so.
+                                let stop_tx = running_queries.remove(&c.id);
+                                if let Some(tx) = stop_tx {
+                                    tx.send(()).ok();
+                                }
+                                // stop checking new events against
+                                // the subscription
+                                conn.unsubscribe(&c);
+                            } else {
+                                info!("invalid command ignored");
+                                ws_stream.send(make_notice_message("could not parse command")).await.ok();
+                            }
+                    },
+                    Err(Error::ConnError) => {
+                        debug!("got connection close/error, disconnecting client: {:?}",cid);
+                        break;
+                    }
+                    Err(Error::EventMaxLengthError(s)) => {
+                        info!("client {:?} sent event larger ({} bytes) than max size", cid, s);
+                        ws_stream.send(make_notice_message("event exceeded max size")).await.ok();
+                    },
+                    Err(Error::ProtoParseError) => {
+                        info!("client {:?} sent event that could not be parsed", cid);
+                        ws_stream.send(make_notice_message("could not parse command")).await.ok();
+                    },
+                    Err(e) => {
+                        info!("got non-fatal error from client: {:?}, error: {:?}", cid, e);
+                    },
+                }
+            },
+        }
+    }
+    // connection cleanup - ensure any still running queries are terminated.
+    for (_, stop_tx) in running_queries {
+        stop_tx.send(()).ok();
+    }
+    info!(
+        "stopping connection for client: {:?} (client sent {} event(s), received {})",
+        cid, client_published_event_count, client_received_event_count
+    );
+}

src/subscription.rs

@@ -1,10 +1,14 @@
 //! Subscription and filter parsing
 use crate::error::Result;
 use crate::event::Event;
+use serde::de::Unexpected;
 use serde::{Deserialize, Deserializer, Serialize};
+use serde_json::Value;
+use std::collections::HashMap;
+use std::collections::HashSet;
 
 /// Subscription identifier and set of request filters
-#[derive(Serialize, PartialEq, Debug, Clone)]
+#[derive(Serialize, PartialEq, Eq, Debug, Clone)]
 pub struct Subscription {
     pub id: String,
     pub filters: Vec<ReqFilter>,
@@ -15,24 +19,108 @@ pub struct Subscription {
 /// Corresponds to client-provided subscription request elements.  Any
 /// element can be present if it should be used in filtering, or
 /// absent ([`None`]) if it should be ignored.
-#[derive(Serialize, Deserialize, PartialEq, Debug, Clone)]
+#[derive(Serialize, PartialEq, Eq, Debug, Clone)]
 pub struct ReqFilter {
-    /// Event hash
-    pub id: Option<String>,
-    /// Event kind
-    pub kind: Option<u64>,
-    /// Referenced event hash
-    #[serde(rename = "#e")]
-    pub event: Option<String>,
-    /// Referenced public key for a petname
-    #[serde(rename = "#p")]
-    pub pubkey: Option<String>,
+    /// Event hashes
+    pub ids: Option<Vec<String>>,
+    /// Event kinds
+    pub kinds: Option<Vec<u64>>,
     /// Events published after this time
     pub since: Option<u64>,
     /// Events published before this time
     pub until: Option<u64>,
     /// List of author public keys
     pub authors: Option<Vec<String>>,
+    /// Limit number of results
+    pub limit: Option<u64>,
+    /// Set of tags
+    #[serde(skip)]
+    pub tags: Option<HashMap<char, HashSet<String>>>,
+    /// Force no matches due to malformed data
+    pub force_no_match: bool,
+}
+
+impl<'de> Deserialize<'de> for ReqFilter {
+    fn deserialize<D>(deserializer: D) -> Result<ReqFilter, D::Error>
+    where
+        D: Deserializer<'de>,
+    {
+        let received: Value = Deserialize::deserialize(deserializer)?;
+        let filter = received.as_object().ok_or_else(|| {
+            serde::de::Error::invalid_type(
+                Unexpected::Other("reqfilter is not an object"),
+                &"a json object",
+            )
+        })?;
+        let mut rf = ReqFilter {
+            ids: None,
+            kinds: None,
+            since: None,
+            until: None,
+            authors: None,
+            limit: None,
+            tags: None,
+            force_no_match: false,
+        };
+        let mut ts = None;
+        // iterate through each key, and assign values that exist
+        for (key, val) in filter.into_iter() {
+            // ids
+            if key == "ids" {
+                rf.ids = Deserialize::deserialize(val).ok();
+            } else if key == "kinds" {
+                rf.kinds = Deserialize::deserialize(val).ok();
+            } else if key == "since" {
+                rf.since = Deserialize::deserialize(val).ok();
+            } else if key == "until" {
+                rf.until = Deserialize::deserialize(val).ok();
+            } else if key == "limit" {
+                rf.limit = Deserialize::deserialize(val).ok();
+            } else if key == "authors" {
+                rf.authors = Deserialize::deserialize(val).ok();
+            } else if key.starts_with('#') && key.len() > 1 && val.is_array() {
+                if let Some(tag_search) = tag_search_char_from_filter(key) {
+                    if ts.is_none() {
+                        // Initialize the tag if necessary
+                        ts = Some(HashMap::new());
+                    }
+                    if let Some(m) = ts.as_mut() {
+                        let tag_vals: Option<Vec<String>> = Deserialize::deserialize(val).ok();
+                        if let Some(v) = tag_vals {
+                            let hs = HashSet::from_iter(v.into_iter());
+                            m.insert(tag_search.to_owned(), hs);
+                        }
+                    };
+                } else {
+                    // tag search that is multi-character, don't add to subscription
+                    rf.force_no_match = true;
+                    continue;
+                }
+            }
+        }
+        rf.tags = ts;
+        Ok(rf)
+    }
+}
+
+/// Attempt to form a single-char identifier from a tag search filter
+fn tag_search_char_from_filter(tagname: &str) -> Option<char> {
+    let tagname_nohash = &tagname[1..];
+    // We return the tag character if and only if the tagname consists
+    // of a single char.
+    let mut tagnamechars = tagname_nohash.chars();
+    let firstchar = tagnamechars.next();
+    match firstchar {
+        Some(_) => {
+            // check second char
+            if tagnamechars.next().is_none() {
+                firstchar
+            } else {
+                None
+            }
+        }
+        None => None,
+    }
 }
 
 impl<'de> Deserialize<'de> for Subscription {
@@ -42,7 +130,7 @@ impl<'de> Deserialize<'de> for Subscription {
     where
         D: Deserializer<'de>,
     {
-        let mut v: serde_json::Value = Deserialize::deserialize(deserializer)?;
+        let mut v: Value = Deserialize::deserialize(deserializer)?;
         // this shoud be a 3-or-more element array.
         // verify the first element is a String, REQ
         // get the subscription from the second element.
@@ -77,6 +165,7 @@ impl<'de> Deserialize<'de> for Subscription {
         for fv in i {
             let f: ReqFilter = serde_json::from_value(fv.take())
                 .map_err(|_| serde::de::Error::custom("could not parse filter"))?;
+            // create indexes
             filters.push(f);
         }
         Ok(Subscription {
@@ -103,46 +192,65 @@ impl Subscription {
     }
 }
 
-impl ReqFilter {
-    /// Check for a match within the authors list.
-    // TODO: Ambiguity; what if the array is empty?  Should we
-    // consider that the same as null?
-    fn authors_match(&self, event: &Event) -> bool {
-        self.authors
-            .as_ref()
-            .map(|vs| vs.contains(&event.pubkey.to_owned()))
-            .unwrap_or(true)
+fn prefix_match(prefixes: &[String], target: &str) -> bool {
+    for prefix in prefixes {
+        if target.starts_with(prefix) {
+            return true;
+        }
     }
-    /// Check if this filter either matches, or does not care about the event tags.
-    fn event_match(&self, event: &Event) -> bool {
-        self.event
+    // none matched
+    false
+}
+
+impl ReqFilter {
+    fn ids_match(&self, event: &Event) -> bool {
+        self.ids
             .as_ref()
-            .map(|t| event.event_tag_match(t))
+            .map(|vs| prefix_match(vs, &event.id))
             .unwrap_or(true)
     }
 
-    /// Check if this filter either matches, or does not care about
-    /// the pubkey/petname tags.
-    fn pubkey_match(&self, event: &Event) -> bool {
-        self.pubkey
+    fn authors_match(&self, event: &Event) -> bool {
+        self.authors
             .as_ref()
-            .map(|t| event.pubkey_tag_match(t))
+            .map(|vs| prefix_match(vs, &event.pubkey))
             .unwrap_or(true)
     }
 
+    fn tag_match(&self, event: &Event) -> bool {
+        // get the hashset from the filter.
+        if let Some(map) = &self.tags {
+            for (key, val) in map.iter() {
+                let tag_match = event.generic_tag_val_intersect(*key, val);
+                // if there is no match for this tag, the match fails.
+                if !tag_match {
+                    return false;
+                }
+                // if there was a match, we move on to the next one.
+            }
+        }
+        // if the tag map is empty, the match succeeds (there was no filter)
+        true
+    }
+
     /// Check if this filter either matches, or does not care about the kind.
     fn kind_match(&self, kind: u64) -> bool {
-        self.kind.map(|v| v == kind).unwrap_or(true)
+        self.kinds
+            .as_ref()
+            .map(|ks| ks.contains(&kind))
+            .unwrap_or(true)
     }
 
     /// Determine if all populated fields in this filter match the provided event.
     pub fn interested_in_event(&self, event: &Event) -> bool {
-        self.id.as_ref().map(|v| v == &event.id).unwrap_or(true)
+        //        self.id.as_ref().map(|v| v == &event.id).unwrap_or(true)
+        self.ids_match(event)
             && self.since.map(|t| event.created_at > t).unwrap_or(true)
+            && self.until.map(|t| event.created_at < t).unwrap_or(true)
             && self.kind_match(event.kind)
             && self.authors_match(event)
-            && self.pubkey_match(event)
-            && self.event_match(event)
+            && self.tag_match(event)
+            && !self.force_no_match
     }
 }
 
@@ -173,27 +281,66 @@ mod tests {
     }
 
     #[test]
-    fn invalid_filter() {
-        // unrecognized field in filter
-        let raw_json = "[\"REQ\",\"some-id\",{\"foo\": 3}]";
-        assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
+    fn legacy_filter() {
+        // legacy field in filter
+        let raw_json = "[\"REQ\",\"some-id\",{\"kind\": 3}]";
+        assert!(serde_json::from_str::<Subscription>(raw_json).is_ok());
     }
 
     #[test]
     fn author_filter() -> Result<()> {
-        let raw_json = "[\"REQ\",\"some-id\",{\"author\": \"test-author-id\"}]";
+        let raw_json = r#"["REQ","some-id",{"authors": ["test-author-id"]}]"#;
         let s: Subscription = serde_json::from_str(raw_json)?;
         assert_eq!(s.id, "some-id");
         assert_eq!(s.filters.len(), 1);
         let first_filter = s.filters.get(0).unwrap();
-        assert_eq!(first_filter.author, Some("test-author-id".to_owned()));
+        assert_eq!(
+            first_filter.authors,
+            Some(vec!("test-author-id".to_owned()))
+        );
+        Ok(())
+    }
+
+    #[test]
+    fn interest_author_prefix_match() -> Result<()> {
+        // subscription with a filter for ID
+        let s: Subscription = serde_json::from_str(r#"["REQ","xyz",{"authors": ["abc"]}]"#)?;
+        let e = Event {
+            id: "foo".to_owned(),
+            pubkey: "abcd".to_owned(),
+            created_at: 0,
+            kind: 0,
+            tags: Vec::new(),
+            content: "".to_owned(),
+            sig: "".to_owned(),
+            tagidx: None,
+        };
+        assert!(s.interested_in_event(&e));
+        Ok(())
+    }
+
+    #[test]
+    fn interest_id_prefix_match() -> Result<()> {
+        // subscription with a filter for ID
+        let s: Subscription = serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"]}]"#)?;
+        let e = Event {
+            id: "abcd".to_owned(),
+            pubkey: "".to_owned(),
+            created_at: 0,
+            kind: 0,
+            tags: Vec::new(),
+            content: "".to_owned(),
+            sig: "".to_owned(),
+            tagidx: None,
+        };
+        assert!(s.interested_in_event(&e));
         Ok(())
     }
 
     #[test]
     fn interest_id_nomatch() -> Result<()> {
         // subscription with a filter for ID
-        let s: Subscription = serde_json::from_str(r#"["REQ","xyz",{"id":"abc"}]"#)?;
+        let s: Subscription = serde_json::from_str(r#"["REQ","xyz",{"ids": ["xyz"]}]"#)?;
         let e = Event {
             id: "abcde".to_owned(),
             pubkey: "".to_owned(),
@@ -202,15 +349,17 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), false);
+        assert!(!s.interested_in_event(&e));
         Ok(())
     }
 
     #[test]
-    fn interest_time_and_id() -> Result<()> {
+    fn interest_until() -> Result<()> {
         // subscription with a filter for ID and time
-        let s: Subscription = serde_json::from_str(r#"["REQ","xyz",{"id":"abc", "since": 1000}]"#)?;
+        let s: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "until": 1000}]"#)?;
         let e = Event {
             id: "abc".to_owned(),
             pubkey: "".to_owned(),
@@ -219,8 +368,53 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), false);
+        assert!(s.interested_in_event(&e));
+        Ok(())
+    }
+
+    #[test]
+    fn interest_range() -> Result<()> {
+        // subscription with a filter for ID and time
+        let s_in: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 100, "until": 200}]"#)?;
+        let s_before: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 100, "until": 140}]"#)?;
+        let s_after: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 160, "until": 200}]"#)?;
+        let e = Event {
+            id: "abc".to_owned(),
+            pubkey: "".to_owned(),
+            created_at: 150,
+            kind: 0,
+            tags: Vec::new(),
+            content: "".to_owned(),
+            sig: "".to_owned(),
+            tagidx: None,
+        };
+        assert!(s_in.interested_in_event(&e));
+        assert!(!s_before.interested_in_event(&e));
+        assert!(!s_after.interested_in_event(&e));
+        Ok(())
+    }
+
+    #[test]
+    fn interest_time_and_id() -> Result<()> {
+        // subscription with a filter for ID and time
+        let s: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 1000}]"#)?;
+        let e = Event {
+            id: "abc".to_owned(),
+            pubkey: "".to_owned(),
+            created_at: 50,
+            kind: 0,
+            tags: Vec::new(),
+            content: "".to_owned(),
+            sig: "".to_owned(),
+            tagidx: None,
+        };
+        assert!(!s.interested_in_event(&e));
         Ok(())
     }
 
@@ -236,8 +430,9 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), true);
+        assert!(s.interested_in_event(&e));
         Ok(())
     }
 
@@ -253,8 +448,9 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), true);
+        assert!(s.interested_in_event(&e));
         Ok(())
     }
 
@@ -270,12 +466,13 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), true);
+        assert!(s.interested_in_event(&e));
         Ok(())
     }
-    #[test]
 
+    #[test]
     fn authors_multi_pubkey() -> Result<()> {
         // check for any of a set of authors, against the pubkey
         let s: Subscription = serde_json::from_str(r#"["REQ","xyz",{"authors":["abc", "bcd"]}]"#)?;
@@ -287,8 +484,9 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), true);
+        assert!(s.interested_in_event(&e));
         Ok(())
     }
 
@@ -304,8 +502,9 @@ mod tests {
             tags: Vec::new(),
             content: "".to_owned(),
             sig: "".to_owned(),
+            tagidx: None,
         };
-        assert_eq!(s.interested_in_event(&e), false);
+        assert!(!s.interested_in_event(&e));
         Ok(())
     }
 }

src/utils.rs

@@ -0,0 +1,33 @@
+//! Common utility functions
+use std::time::SystemTime;
+
+/// Seconds since 1970.
+pub fn unix_time() -> u64 {
+    SystemTime::now()
+        .duration_since(SystemTime::UNIX_EPOCH)
+        .map(|x| x.as_secs())
+        .unwrap_or(0)
+}
+
+/// Check if a string contains only hex characters.
+pub fn is_hex(s: &str) -> bool {
+    s.chars().all(|x| char::is_ascii_hexdigit(&x))
+}
+
+/// Check if a string contains only lower-case hex chars.
+pub fn is_lower_hex(s: &str) -> bool {
+    s.chars().all(|x| {
+        (char::is_ascii_lowercase(&x) || char::is_ascii_digit(&x)) && char::is_ascii_hexdigit(&x)
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn lower_hex() {
+        let hexstr = "abcd0123";
+        assert_eq!(is_lower_hex(hexstr), true);
+    }
+}

tests/common/mod.rs

@@ -0,0 +1,110 @@
+use anyhow::{anyhow, Result};
+use nostr_rs_relay::config;
+use nostr_rs_relay::server::start_server;
+//use http::{Request, Response};
+use hyper::{Client, StatusCode, Uri};
+use std::net::TcpListener;
+use std::sync::atomic::{AtomicU16, Ordering};
+use std::sync::mpsc as syncmpsc;
+use std::sync::mpsc::{Receiver as MpscReceiver, Sender as MpscSender};
+use std::thread;
+use std::thread::JoinHandle;
+use std::time::Duration;
+use tracing::{debug, info};
+
+pub struct Relay {
+    pub port: u16,
+    pub handle: JoinHandle<()>,
+    pub shutdown_tx: MpscSender<()>,
+}
+
+pub fn start_relay() -> Result<Relay> {
+    // setup tracing
+    let _trace_sub = tracing_subscriber::fmt::try_init();
+    info!("Starting a new relay");
+    // replace default settings
+    let mut settings = config::Settings::default();
+    // identify open port
+    info!("Checking for address...");
+    let port = get_available_port().unwrap();
+    info!("Found open port: {}", port);
+    // bind to local interface only
+    settings.network.address = "127.0.0.1".to_owned();
+    settings.network.port = port;
+    // create an in-memory DB with multiple readers
+    settings.database.in_memory = true;
+    settings.database.min_conn = 4;
+    settings.database.max_conn = 8;
+    let (shutdown_tx, shutdown_rx): (MpscSender<()>, MpscReceiver<()>) = syncmpsc::channel();
+    let handle = thread::spawn(|| {
+        // server will block the thread it is run on.
+        let _ = start_server(settings, shutdown_rx);
+    });
+    // how do we know the relay has finished starting up?
+    Ok(Relay {
+        port,
+        handle,
+        shutdown_tx,
+    })
+}
+
+// check if the server is healthy via HTTP request
+async fn server_ready(relay: &Relay) -> Result<bool> {
+    let uri: String = format!("http://127.0.0.1:{}/", relay.port);
+    let client = Client::new();
+    let uri: Uri = uri.parse().unwrap();
+    let res = client.get(uri).await?;
+    Ok(res.status() == StatusCode::OK)
+}
+
+pub async fn wait_for_healthy_relay(relay: &Relay) -> Result<()> {
+    // TODO: maximum time to wait for server to become healthy.
+    // give it a little time to start up before we start polling
+    tokio::time::sleep(Duration::from_millis(10)).await;
+    loop {
+        let server_check = server_ready(relay).await;
+        match server_check {
+            Ok(true) => {
+                // server responded with 200-OK.
+                break;
+            }
+            Ok(false) => {
+                // server responded with an error, we're done.
+                return Err(anyhow!("Got non-200-OK from relay"));
+            }
+            Err(_) => {
+                // server is not yet ready, probably connection refused...
+                debug!("Relay not ready, will try again...");
+                tokio::time::sleep(Duration::from_millis(10)).await;
+            }
+        }
+    }
+    info!("relay is ready");
+    Ok(())
+    // simple message sent to web browsers
+    //let mut request = Request::builder()
+    //    .uri("https://www.rust-lang.org/")
+    //    .header("User-Agent", "my-awesome-agent/1.0");
+}
+
+// from https://elliotekj.com/posts/2017/07/25/find-available-tcp-port-rust/
+// This needed some modification; if multiple tasks all ask for open ports, they will tend to get the same one.
+// instead we should try to try these incrementally/globally.
+
+static PORT_COUNTER: AtomicU16 = AtomicU16::new(4030);
+
+fn get_available_port() -> Option<u16> {
+    let startsearch = PORT_COUNTER.fetch_add(10, Ordering::SeqCst);
+    if startsearch >= 20000 {
+        // wrap around
+        PORT_COUNTER.store(4030, Ordering::Relaxed);
+    }
+    (startsearch..20000).find(|port| port_is_available(*port))
+}
+pub fn port_is_available(port: u16) -> bool {
+    info!("checking on port {}", port);
+    match TcpListener::bind(("127.0.0.1", port)) {
+        Ok(_) => true,
+        Err(_) => false,
+    }
+}

tests/integration_test.rs

@@ -0,0 +1,47 @@
+use anyhow::Result;
+
+use std::thread;
+use std::time::Duration;
+
+mod common;
+
+#[tokio::test]
+async fn start_and_stop() -> Result<()> {
+    // this will be the common pattern for acquiring a new relay:
+    // start a fresh relay, on a port to-be-provided back to us:
+    let relay = common::start_relay()?;
+    // wait for the relay's webserver to start up and deliver a page:
+    common::wait_for_healthy_relay(&relay).await?;
+    let port = relay.port;
+    // just make sure we can startup and shut down.
+    // if we send a shutdown message before the server is listening,
+    // we will get a SendError.  Keep sending until someone is
+    // listening.
+    loop {
+        let shutdown_res = relay.shutdown_tx.send(());
+        match shutdown_res {
+            Ok(()) => {
+                break;
+            }
+            Err(_) => {
+                thread::sleep(Duration::from_millis(100));
+            }
+        }
+    }
+    // wait for relay to shutdown
+    let thread_join = relay.handle.join();
+    assert!(thread_join.is_ok());
+    // assert that port is now available.
+    assert!(common::port_is_available(port));
+    Ok(())
+}
+
+#[tokio::test]
+async fn relay_home_page() -> Result<()> {
+    // get a relay and wait for startup...
+    let relay = common::start_relay()?;
+    common::wait_for_healthy_relay(&relay).await?;
+    // tell relay to shutdown
+    let _res = relay.shutdown_tx.send(());
+    Ok(())
+}