build: bump version to 0.8.3

Updating anyhow v1.0.68 -> v1.0.69
Updating axum v0.6.4 -> v0.6.6
Updating cxx v1.0.89 -> v1.0.90
Updating cxx-build v1.0.89 -> v1.0.90
Updating cxxbridge-flags v1.0.89 -> v1.0.90
Updating cxxbridge-macro v1.0.89 -> v1.0.90
Adding hermit-abi v0.3.1
Updating is-terminal v0.4.2 -> v0.4.3
Updating pest v2.5.4 -> v2.5.5
Updating pest_derive v2.5.4 -> v2.5.5
Updating pest_generator v2.5.4 -> v2.5.5
Updating pest_meta v2.5.4 -> v2.5.5
Updating proc-macro2 v1.0.50 -> v1.0.51
Updating raw-cpuid v10.6.0 -> v10.6.1
Updating rustix v0.36.7 -> v0.36.8
Updating serde_json v1.0.91 -> v1.0.93
Updating signal-hook-registry v1.4.0 -> v1.4.1
Updating thread_local v1.1.4 -> v1.1.7
Updating tinyvec_macros v0.1.0 -> v0.1.1
Updating tokio-native-tls v0.3.0 -> v0.3.1
Updating tokio-util v0.7.4 -> v0.7.7

.build.yml

@@ -7,6 +7,7 @@ environment:
 packages:
   - cargo
   - sqlite-devel
+  - protobuf-compiler
 sources:
   - https://git.sr.ht/~gheartsfield/nostr-rs-relay/
 shell: false

.github/workflows/ci.yml

@@ -0,0 +1,39 @@
+name: Test and build
+
+on:
+  push:
+    branches:
+      - master
+
+jobs:
+  test_nostr-rs-relay:
+    runs-on: ubuntu-latest
+    steps:
+      - uses: actions/checkout@v2
+
+      - name: Update local toolchain
+        run: |
+          sudo apt-get install -y protobuf-compiler
+          rustup update
+          rustup component add clippy
+          rustup install nightly
+
+      - name: Toolchain info
+        run: |
+          cargo --version --verbose
+          rustc --version
+          cargo clippy --version
+
+      # - name: Lint
+      #   run: |
+      #     cargo fmt -- --check
+      #     cargo clippy -- -D warnings
+
+      - name: Test
+        run: |
+          cargo check
+          cargo test --all
+
+      - name: Build
+        run: |
+          cargo build --release --locked

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "nostr-rs-relay"
-version = "0.7.16"
+version = "0.8.3"
 edition = "2021"
 authors = ["Greg Heartsfield <scsibug@imap.cc>"]
 description = "A relay implementation for the Nostr protocol"
@@ -12,9 +12,12 @@ keywords = ["nostr", "server"]
 categories = ["network-programming", "web-programming"]
 
 [dependencies]
+clap = { version = "4.0.32", features = ["env", "default", "derive"]}
 tracing = "0.1.36"
 tracing-subscriber = "0.2.0"
 tokio = { version = "1", features = ["full", "tracing", "signal"] }
+prost = "0.11"
+tonic = "0.8.3"
 console-subscriber = "0.1.8"
 futures = "0.3"
 futures-util = "0.3"
@@ -41,6 +44,16 @@ parse_duration = "2"
 rand = "0.8"
 const_format = "0.2.28"
 regex = "1"
+async-trait = "0.1.60"
+async-std = "1.12.0"
+sqlx = { version ="0.6.2", features=["runtime-tokio-rustls", "postgres", "chrono"]}
+chrono = "0.4.23"
+prometheus = "0.13.3"
+indicatif = "0.17.3"
+bech32 = "0.9.1"
 
 [dev-dependencies]
 anyhow = "1"
+
+[build-dependencies]
+tonic-build = { version="0.8.3", features = ["prost"] }

Dockerfile

@@ -1,5 +1,7 @@
-FROM docker.io/library/rust:1.66.0 as builder
-
+FROM docker.io/library/rust:1-bookworm as builder
+RUN apt-get update \
+    && apt-get install -y cmake protobuf-compiler \
+    && rm -rf /var/lib/apt/lists/*
 RUN USER=root cargo install cargo-auditable
 RUN USER=root cargo new --bin nostr-rs-relay
 WORKDIR ./nostr-rs-relay
@@ -12,6 +14,8 @@ RUN rm src/*.rs
 
 # copy project source code
 COPY ./src ./src
+COPY ./proto ./proto
+COPY ./build.rs ./build.rs
 
 # build auditable release using locked deps
 RUN rm ./target/release/deps/nostr*relay*

README.md

@@ -2,7 +2,8 @@
 
 This is a [nostr](https://github.com/nostr-protocol/nostr) relay,
 written in Rust.  It currently supports the entire relay protocol, and
-persists data with SQLite.
+persists data with SQLite.  There is experimental support for
+Postgresql.
 
 The project master repository is available on
 [sourcehut](https://sr.ht/~gheartsfield/nostr-rs-relay/), and is
@@ -10,6 +11,9 @@ 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?)
 
+![Github CI](https://github.com/schlunsen/nostr-rs-relay/actions/workflows/ci.yml/badge.svg)
+
+
 ## Features
 
 [NIPs](https://github.com/nostr-protocol/nips) with a relay-specific implementation are listed here.
@@ -30,6 +34,7 @@ mirrored on [GitHub](https://github.com/scsibug/nostr-rs-relay).
 - [x] NIP-22: [Event `created_at` limits](https://github.com/nostr-protocol/nips/blob/master/22.md) (_future-dated events only_)
 - [ ] NIP-26: [Event Delegation](https://github.com/nostr-protocol/nips/blob/master/26.md) (_implemented, but currently disabled_)
 - [x] NIP-28: [Public Chat](https://github.com/nostr-protocol/nips/blob/master/28.md)
+- [x] NIP-33: [Parameterized Replaceable Events](https://github.com/nostr-protocol/nips/blob/master/33.md)
 
 ## Quick Start
 
@@ -148,3 +153,8 @@ To chat about `nostr-rs-relay` on `nostr` itself; visit our channel on [anigma](
 License
 ---
 This project is MIT licensed.
+
+External Documentation and Links
+---
+
+* [BlockChainCaffe's Nostr Relay Setup Guide](https://github.com/BlockChainCaffe/Nostr-Relay-Setup-Guide)

build.rs

@@ -0,0 +1,4 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tonic_build::compile_protos("proto/nauthz.proto")?;
+    Ok(())
+}

config.toml

@@ -18,16 +18,20 @@ description = "A newly created nostr-rs-relay.\n\nCustomize this with your own i
 
 [diagnostics]
 # Enable tokio tracing (for use with tokio-console)
-#tracing = true
+#tracing = false
 
 [database]
+# Database engine (sqlite/postgres).  Defaults to sqlite.
+# Support for postgres is currently experimental.
+#engine = "sqlite"
+
 # Directory for SQLite files.  Defaults to the current directory.  Can
 # also be specified (and overriden) with the "--db dirname" command
 # line option.
-data_directory = "."
-
+#data_directory = "."
 
 # Use an in-memory database instead of 'nostr.db'.
+# Requires sqlite engine.
 # Caution; this will not survive a process restart!
 #in_memory = false
 
@@ -40,6 +44,20 @@ data_directory = "."
 # to approx the number of cores.
 #max_conn = 8
 
+# Database connection string.  Required for postgres; not used for
+# sqlite.
+#connection = "postgresql://postgres:nostr@localhost:7500/nostr"
+
+[grpc]
+# gRPC interfaces for externalized decisions and other extensions to
+# functionality.
+#
+# Events can be authorized through an external service, by providing
+# the URL below.  In the event the server is not accessible, events
+# will be permitted.  The protobuf3 schema used is available in
+# `proto/nauthz.proto`.
+# event_authorization_server = "http://[::1]:50051"
+
 [network]
 # Bind to this network address
 address = "0.0.0.0"
@@ -63,13 +81,18 @@ 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.  Note:
+# an integer.  If not set (or set to 0), there is no limit.  Note:
 # this is for the server as a whole, not per-connection.
-# messages_per_sec = 0
+#
+# Limiting event creation is highly recommended if your relay is
+# public!
+#
+#messages_per_sec = 5
 
-# Limit client subscriptions created per second, averaged over one
-# minute.  Must be an integer.  If not set (or set to 0), defaults to
-# unlimited.
+# Limit client subscriptions created, averaged over one minute.  Must
+# be an integer.  If not set (or set to 0), defaults to unlimited.
+# Strongly recommended to set this to a low value such as 10 to ensure
+# fair service.
 #subscriptions_per_min = 0
 
 # UNIMPLEMENTED...

docs/database-maintenance.md

@@ -7,7 +7,7 @@ intervention.  For heavily trafficked relays, there are a number of
 steps that the operator may need to take to maintain performance and
 limit disk usage.
 
-This maintenance guide is current as of version `0.7.14`.  Future
+This maintenance guide is current as of version `0.8.2`.  Future
 versions may incorporate and automate some of these steps.
 
 ## Backing Up the Database
@@ -22,7 +22,7 @@ dated file, and then compress to minimize size:
 
 ```console
 BACKUP_FILE=/var/backups/nostr/`date +%Y%m%d_%H%M`.db
-sqlite3 -readonly /apps/nostr-relay/nostr.db ".backup $BACKUP_FILE
+sqlite3 -readonly /apps/nostr-relay/nostr.db ".backup $BACKUP_FILE"
 sqlite3 $BACKUP_FILE "vacuum;"
 bzip2 -9 $BACKUP_FILE
 ```
@@ -43,18 +43,15 @@ vacuum;
 
 ## Clearing Hidden Events
 
-When events are deleted, either through deletion events, metadata or
-follower updates, or a replaceable event kind, the event is not
-actually removed from the database.  Instead, a flag `HIDDEN` is set
-to true for the event, which excludes it from search results.  The
-original intent was to ensure that subsequent rebroadcasts of the
-event would be easily detected as having been deleted, and would not
-need to be stored again.  In practice, this decision causes excessive
-growth of the `tags` table, since all the previous followers are
-retained for those `HIDDEN` events.
+When events are deleted, the event is not actually removed from the
+database.  Instead, a flag `HIDDEN` is set to true for the event,
+which excludes it from search results.  High volume replacements from
+profile or other replaceable events are deleted, not hidden, in the
+current version of the relay.
 
-The `event` and especially the `tag` table can be significantly
-reduced in size by running these commands:
+In the current version, removing hidden events should not result in
+significant space savings, but it can still be used if there is no
+desire to hold on to events that can never be re-broadcast.
 
 ```console
 PRAGMA foreign_keys = ON;

docs/grpc-extensions.md

@@ -0,0 +1,79 @@
+# gRPC Extensions Design Document
+
+The relay will be extensible through gRPC endpoints, definable in the
+main configuration file.  These will allow external programs to host
+logic for deciding things such as, should this event be persisted,
+should this connection be allowed, and should this subscription
+request be registered.  The primary goal is allow for relay operator
+specific functionality that allows them to serve smaller communities
+and reduce spam and abuse.
+
+This will likely evolve substantially, the first goal is to get a
+basic one-way service that lets an externalized program decide on
+event persistance.  This does not represent the final state of gRPC
+extensibility in `nostr-rs-relay`.
+
+## Considerations
+
+Write event latency must not be significantly affected.  However, the
+primary reason we are implementing this is spam/abuse protection, so
+we are willing to tolerate some increase in latency if that protects
+us against outages!
+
+The interface should provide enough information to make simple
+decisions, without burdening the relay to do extra queries.  The
+decision endpoint will be mostly responsible for maintaining state and
+gathering additional details.
+
+## Design Overview
+
+A gRPC server may be defined in the `config.toml` file.  If it exists,
+the relay will attempt to connect to it and send a message for each
+`EVENT` command submitted by clients.  If a successful response is
+returned indicating the event is permitted, the relay continues
+processing the event as normal.  All existing whitelist, blacklist,
+and `NIP-05` validation checks are still performed and MAY still
+result in the event being rejected.  If a successful response is
+returned indicated the decision is anything other than permit, then
+the relay MUST reject the event, and return a command result to the
+user (using `NIP-20`) indicating the event was blocked (optionally
+providing a message).
+
+In the event there is an error in the gRPC interface, event processing
+proceeds as if gRPC was disabled (fail open).  This allows gRPC
+servers to be deployed with minimal chance of causing a full relay
+outage.
+
+## Design Details
+
+Currently one procedure call is supported, `EventAdmit`, in the
+`Authorization` service.  It accepts the following data in order to
+support authorization decisions:
+
+- The event itself
+- The client IP that submitted the event
+- The client's HTTP origin header, if one exists
+- The client's HTTP user agent header, if one exists
+- The public key of the client, if `NIP-42` authentication was
+  performed (not supported in the relay yet!)
+- The `NIP-05` associated with the event's public key, if it is known
+  to the relay
+
+A server providing authorization decisions will return the following:
+
+- A decision to permit or deny the event
+- An optional message that explains why the event was denied, to be
+  transmitted to the client
+
+## Security Issues
+
+There is little attempt to secure this interface, since it is intended
+for use processes running on the same host.  It is recommended to
+ensure that the gRPC server providing the API is not exposed to the
+public Internet.  Authorization server implementations should have
+their own security reviews performed.
+
+A slow gRPC server could cause availability issues for event
+processing, since this is performed on a single thread.  Avoid any
+expensive or long-running processes that could result from submitted
+events, since any client can initiate a gRPC call to the service.

nauthz_server_example/Cargo.toml

@@ -0,0 +1,13 @@
+[package]
+name = "nauthz-server"
+version = "0.1.0"
+edition = "2021"
+
+[dependencies]
+# Common dependencies
+tokio = { version = "1.0", features = ["rt-multi-thread", "macros"] }
+prost = "0.11"
+tonic = "0.8.3"
+
+[build-dependencies]
+tonic-build = { version="0.8.3", features = ["prost"] }

nauthz_server_example/build.rs

@@ -0,0 +1,4 @@
+fn main() -> Result<(), Box<dyn std::error::Error>> {
+    tonic_build::compile_protos("../proto/nauthz.proto")?;
+    Ok(())
+}

nauthz_server_example/src/main.rs

@@ -0,0 +1,61 @@
+use tonic::{transport::Server, Request, Response, Status};
+
+use nauthz_grpc::authorization_server::{Authorization, AuthorizationServer};
+use nauthz_grpc::{EventReply, EventRequest, Decision};
+
+pub mod nauthz_grpc {
+    tonic::include_proto!("nauthz");
+}
+
+#[derive(Default)]
+pub struct EventAuthz {
+    allowed_kinds: Vec<u64>,
+}
+
+#[tonic::async_trait]
+impl Authorization for EventAuthz {
+
+    async fn event_admit(
+        &self,
+        request: Request<EventRequest>,
+    ) -> Result<Response<EventReply>, Status> {
+        let reply;
+        let req = request.into_inner();
+        let event = req.event.unwrap();
+        let content_prefix:String = event.content.chars().take(40).collect();
+        println!("recvd event, [kind={}, origin={:?}, nip05_domain={:?}, tag_count={}, content_sample={:?}]",
+                 event.kind, req.origin, req.nip05.map(|x| x.domain), event.tags.len(), content_prefix);
+        // Permit any event with a whitelisted kind
+        if self.allowed_kinds.contains(&event.kind) {
+            println!("This looks fine! (kind={})",event.kind);
+            reply = nauthz_grpc::EventReply {
+                decision: Decision::Permit as i32,
+                message: None
+            };
+        } else {
+            println!("Blocked! (kind={})",event.kind);
+            reply = nauthz_grpc::EventReply {
+                decision: Decision::Deny as i32,
+                message: Some(format!("kind {} not permitted", event.kind)),
+            };
+        }
+        Ok(Response::new(reply))
+    }
+}
+
+#[tokio::main]
+async fn main() -> Result<(), Box<dyn std::error::Error>> {
+    let addr = "[::1]:50051".parse().unwrap();
+
+    // A simple authorization engine that allows kinds 0-3
+    let checker = EventAuthz {
+        allowed_kinds: vec![0,1,2,3],
+    };
+    println!("EventAuthz Server listening on {}", addr);
+    // Start serving
+    Server::builder()
+        .add_service(AuthorizationServer::new(checker))
+        .serve(addr)
+        .await?;
+    Ok(())
+}

proto/nauthz.proto

@@ -0,0 +1,60 @@
+syntax = "proto3";
+
+// Nostr Authorization Services
+package nauthz;
+
+// Authorization for actions against a relay
+service Authorization {
+  // Determine if an event should be admitted to the relay
+  rpc EventAdmit(EventRequest) returns (EventReply) {}
+}
+
+message Event {
+  bytes id = 1;                // 32-byte SHA256 hash of serialized event
+  bytes pubkey = 2;            // 32-byte public key of event creator
+  fixed64 created_at = 3;      // UNIX timestamp provided by event creator
+  uint64 kind = 4;             // event kind
+  string content = 5;          // arbitrary event contents
+  repeated TagEntry tags = 6;  // event tag array
+  bytes sig = 7;               // 32-byte signature of the event id
+  // Individual values for a single tag
+  message TagEntry {
+    repeated string values = 1;
+  }
+}
+
+// Event data and metadata for authorization decisions
+message EventRequest {
+  Event event =
+      1;  // the event to be admitted for further relay processing
+  optional string ip_addr =
+      2;  // IP address of the client that submitted the event
+  optional string origin =
+      3;  // HTTP origin header from the client, if one exists
+  optional string user_agent =
+      4;  // HTTP user-agent header from the client, if one exists
+  optional bytes auth_pubkey =
+      5;  // the public key associated with a NIP-42 AUTH'd session, if
+          // authentication occurred
+  optional Nip05Name nip05 =
+      6; // NIP-05 address associated with the event pubkey, if it is
+         // known and has been validated by the relay
+  // A NIP_05 verification record
+  message Nip05Name {
+    string local = 1;
+    string domain = 2;
+  }
+}
+
+// A permit or deny decision
+enum Decision {
+  DECISION_UNSPECIFIED = 0;
+  DECISION_PERMIT = 1; // Admit this event for further processing
+  DECISION_DENY = 2; // Deny persisting or propagating this event
+}
+
+// Response to a event authorization request
+message EventReply {
+  Decision decision = 1;       // decision to enforce
+  optional string message = 2; // informative message for the client
+}

reverse-proxy.md

@@ -68,13 +68,32 @@ http {
         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;
+        ssl_protocols TLSv1.3 TLSv1.2;
+        ssl_prefer_server_ciphers on;
+        ssl_ecdh_curve secp521r1:secp384r1;
+        ssl_ciphers EECDH+AESGCM:EECDH+AES256;
+
+        # Optional Diffie-Helmann parameters
+        # Generate with openssl dhparam -out /etc/ssl/certs/dhparam.pem 4096
+        #ssl_dhparam /etc/ssl/certs/dhparam.pem;
+
+        ssl_session_cache shared:TLS:2m;
+        ssl_buffer_size 4k;
+
+        # OCSP stapling
+        ssl_stapling on;
+        ssl_stapling_verify on;
+        resolver 1.1.1.1 1.0.0.1 [2606:4700:4700::1111] [2606:4700:4700::1001]; # Cloudflare
+
+        # Set HSTS to 365 days
+        add_header Strict-Transport-Security 'max-age=31536000; includeSubDomains; preload' always;
         keepalive_timeout 70;
 
         location / {
             proxy_pass http://localhost:8080;
             proxy_http_version 1.1;
+            proxy_read_timeout 1d;
+            proxy_send_timeout 1d;
             proxy_set_header Upgrade $http_upgrade;
             proxy_set_header Connection "Upgrade";
             proxy_set_header Host $host;

src/bin/bulkloader.rs

@@ -0,0 +1,175 @@
+use std::io;
+use std::path::Path;
+use nostr_rs_relay::utils::is_lower_hex;
+use tracing::info;
+use nostr_rs_relay::config;
+use nostr_rs_relay::event::{Event,single_char_tagname};
+use nostr_rs_relay::error::{Error, Result};
+use nostr_rs_relay::repo::sqlite::{PooledConnection, build_pool};
+use nostr_rs_relay::repo::sqlite_migration::{curr_db_version, DB_VERSION};
+use rusqlite::{OpenFlags, Transaction};
+use std::sync::mpsc;
+use std::thread;
+use rusqlite::params;
+
+/// Bulk load JSONL data from STDIN to the database specified in config.toml (or ./nostr.db as a default).
+/// The database must already exist, this will not create a new one.
+/// Tested against schema v13.
+
+pub fn main() -> Result<()> {
+    let _trace_sub = tracing_subscriber::fmt::try_init();
+    println!("Nostr-rs-relay Bulk Loader");
+    // check for a database file, or create one.
+    let settings = config::Settings::new(&None);
+    if !Path::new(&settings.database.data_directory).is_dir() {
+        info!("Database directory does not exist");
+        return Err(Error::DatabaseDirError);
+    }
+    // Get a database pool
+    let pool = build_pool("bulk-loader", &settings, OpenFlags::SQLITE_OPEN_READ_WRITE | OpenFlags::SQLITE_OPEN_CREATE, 1,4,false);
+    {
+	// check for database schema version
+	let mut conn: PooledConnection = pool.get()?;
+	let version = curr_db_version(&mut conn)?;
+	info!("current version is: {:?}", version);
+	// ensure the schema version is current.
+	if version != DB_VERSION {
+	    info!("version is not current, exiting");
+	    panic!("cannot write to schema other than v{DB_VERSION}");
+	}
+    }
+    // this channel will contain parsed events ready to be inserted
+    let (event_tx, event_rx) = mpsc::sync_channel(100_000);
+    // Thread for reading events
+    let _stdin_reader_handler = thread::spawn(move || {
+	let stdin = io::stdin();
+	for readline in stdin.lines() {
+	    if let Ok(line) = readline {
+		// try to parse a nostr event
+		let eres: Result<Event, serde_json::Error> = serde_json::from_str(&line);
+		if let Ok(mut e) = eres {
+		    if let Ok(()) = e.validate() {
+			e.build_index();
+			//debug!("Event: {:?}", e);
+			event_tx.send(Some(e)).ok();
+		    } else {
+			info!("could not validate event");
+		    }
+		} else {
+		    info!("error reading event: {:?}", eres);
+		}
+	    } else {
+		// error reading
+		info!("error reading: {:?}", readline);
+	    }
+	}
+	info!("finished parsing events");
+	event_tx.send(None).ok();
+	let ok: Result<()> = Ok(());
+        ok
+    });
+    let mut conn: PooledConnection = pool.get()?;
+    let mut events_read = 0;
+    let event_batch_size =50_000;
+    let mut new_events = 0;
+    let mut has_more_events = true;
+    while has_more_events {
+	// begin a transaction
+	let tx = conn.transaction()?;
+	// read in batch_size events and commit
+	for _ in 0..event_batch_size {
+	    match event_rx.recv() {
+		Ok(Some(e)) => {
+		    events_read += 1;
+		    // ignore ephemeral events
+		    if !(e.kind >= 20000 && e.kind < 30000) {
+			match write_event(&tx, e) {
+			    Ok(c) => {
+				new_events += c;
+			    },
+			    Err(e) => {
+				info!("error inserting event: {:?}", e);
+			    }
+			}
+		    }
+		},
+		Ok(None) => {
+		    // signal that the sender will never produce more
+		    // events
+		    has_more_events=false;
+		    break;
+		},
+		Err(_) => {
+		    info!("sender is closed");
+		    // sender is done
+		}
+	    }
+	}
+	info!("committed {} events...", new_events);
+	tx.commit()?;
+	conn.execute_batch("pragma wal_checkpoint(truncate)")?;
+
+    }
+    info!("processed {} events", events_read);
+    info!("stored {} new events", new_events);
+    // get a connection for writing events
+    // read standard in.
+    info!("finished reading input");
+    Ok(())
+}
+
+/// Write an event and update the tag table.
+/// Assumes the event has its index built.
+fn write_event(tx: &Transaction, e: Event) -> Result<usize> {
+    let id_blob = hex::decode(&e.id).ok();
+    let pubkey_blob: Option<Vec<u8>> = hex::decode(&e.pubkey).ok();
+    let delegator_blob: Option<Vec<u8>> = e.delegated_by.as_ref().and_then(|d| hex::decode(d).ok());
+    let event_str = serde_json::to_string(&e).ok();
+    // ignore if the event hash is a duplicate.
+    let ins_count = tx.execute(
+	"INSERT OR IGNORE INTO event (event_hash, created_at, kind, author, delegated_by, content, first_seen, hidden) VALUES (?1, ?2, ?3, ?4, ?5, ?6, strftime('%s','now'), FALSE);",
+	params![id_blob, e.created_at, e.kind, pubkey_blob, delegator_blob, event_str]
+    )?;
+    if ins_count == 0 {
+	return Ok(0);
+    }
+    // we want to capture the event_id that had the tag, the tag name, and the tag hex value.
+    let event_id = tx.last_insert_rowid();
+    // look at each event, and each tag, creating new tag entries if appropriate.
+    for t in e.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],
+            )?;
+        }
+    }
+    if e.is_replaceable() {
+	//let query = "SELECT id FROM event WHERE kind=? AND author=? ORDER BY created_at DESC LIMIT 1;";
+	//let count: usize = tx.query_row(query, params![e.kind, pubkey_blob], |row| row.get(0))?;
+	//info!("found {} rows that /would/ be preserved", count);
+	match tx.execute(
+	    "DELETE FROM event WHERE kind=? and author=? and id NOT IN (SELECT id FROM event WHERE kind=? AND author=? ORDER BY created_at DESC LIMIT 1);",
+	    params![e.kind, pubkey_blob, e.kind, pubkey_blob],
+	) {
+	    Ok(_) => {},
+	    Err(x) => {info!("error deleting replaceable event: {:?}",x);}
+	}
+    }
+    Ok(ins_count)
+}

src/cli.rs

@@ -0,0 +1,20 @@
+use clap::Parser;
+
+#[derive(Parser)]
+#[command(about = "A nostr relay written in Rust", author = env!("CARGO_PKG_AUTHORS"), version = env!("CARGO_PKG_VERSION"))]
+pub struct CLIArgs {
+    #[arg(
+        short,
+        long,
+        help = "Use the <directory> as the location of the database",
+        required = false,
+    )]
+    pub db: Option<String>,
+    #[arg(
+        short,
+        long,
+        help = "Use the <file name> as the location of the config file",
+        required = false,
+    )]
+    pub config: Option<String>,
+}

src/config.rs

@@ -18,9 +18,17 @@ pub struct Info {
 #[allow(unused)]
 pub struct Database {
     pub data_directory: String,
+    pub engine: String,
     pub in_memory: bool,
     pub min_conn: u32,
     pub max_conn: u32,
+    pub connection: String,
+}
+
+#[derive(Debug, Clone, Serialize, Deserialize)]
+#[allow(unused)]
+pub struct Grpc {
+    pub event_admission_server: Option<String>,
 }
 
 #[derive(Debug, Clone, Serialize, Deserialize)]
@@ -143,6 +151,7 @@ pub struct Settings {
     pub info: Info,
     pub diagnostics: Diagnostics,
     pub database: Database,
+    pub grpc: Grpc,
     pub network: Network,
     pub limits: Limits,
     pub authorization: Authorization,
@@ -153,10 +162,10 @@ pub struct Settings {
 
 impl Settings {
     #[must_use]
-    pub fn new() -> Self {
+    pub fn new(config_file_name: &Option<String>) -> Self {
         let default_settings = Self::default();
         // attempt to construct settings with file
-        let from_file = Self::new_from_default(&default_settings);
+        let from_file = Self::new_from_default(&default_settings, config_file_name);
         match from_file {
             Ok(f) => f,
             Err(e) => {
@@ -166,13 +175,19 @@ impl Settings {
         }
     }
 
-    fn new_from_default(default: &Settings) -> Result<Self, ConfigError> {
+
+    fn new_from_default(default: &Settings, config_file_name: &Option<String>) -> Result<Self, ConfigError> {
+        let default_config_file_name = "config.toml".to_string();
+        let config: &String = match config_file_name {
+            Some(value) => value,
+            None => &default_config_file_name
+        };
         let builder = Config::builder();
         let config: Config = builder
-            // use defaults
+        // use defaults
             .add_source(Config::try_from(default)?)
-            // override with file contents
-            .add_source(File::with_name("config.toml"))
+        // override with file contents
+            .add_source(File::with_name(config))
             .build()?;
         let mut settings: Settings = config.try_deserialize()?;
         // ensure connection pool size is logical
@@ -206,9 +221,14 @@ impl Default for Settings {
             diagnostics: Diagnostics { tracing: false },
             database: Database {
                 data_directory: ".".to_owned(),
+                engine: "sqlite".to_owned(),
                 in_memory: false,
                 min_conn: 4,
                 max_conn: 8,
+		connection: "".to_owned(),
+            },
+            grpc: Grpc {
+                event_admission_server: None,
             },
             network: Network {
                 port: 8080,

src/conn.rs

@@ -14,7 +14,7 @@ const MAX_SUBSCRIPTION_ID_LEN: usize = 256;
 /// State for a client connection
 pub struct ClientConn {
     /// Client IP (either from socket, or configured proxy header
-    client_ip: String,
+    client_ip_addr: String,
     /// Unique client identifier generated at connection time
     client_id: Uuid,
     /// The current set of active client subscriptions
@@ -32,22 +32,22 @@ impl Default for ClientConn {
 impl ClientConn {
     /// Create a new, empty connection state.
     #[must_use]
-    pub fn new(client_ip: String) -> Self {
+    pub fn new(client_ip_addr: String) -> Self {
         let client_id = Uuid::new_v4();
         ClientConn {
-            client_ip,
+            client_ip_addr,
             client_id,
             subscriptions: HashMap::new(),
             max_subs: 32,
         }
     }
 
-    pub fn subscriptions(&self) -> &HashMap<String, Subscription> {
+    #[must_use] pub fn subscriptions(&self) -> &HashMap<String, Subscription> {
         &self.subscriptions
     }
 
     /// Check if the given subscription already exists
-    pub fn has_subscription(&self, sub: &Subscription) -> bool {
+    #[must_use] pub fn has_subscription(&self, sub: &Subscription) -> bool {
         self.subscriptions.values().any(|x| x == sub)
     }
 
@@ -60,7 +60,7 @@ impl ClientConn {
 
     #[must_use]
     pub fn ip(&self) -> &str {
-        &self.client_ip
+        &self.client_ip_addr
     }
 
     /// Add a new subscription for this connection.

src/delegation.rs

@@ -84,7 +84,7 @@ pub struct ConditionQuery {
 }
 
 impl ConditionQuery {
-    pub fn allows_event(&self, event: &Event) -> bool {
+    #[must_use] pub fn allows_event(&self, event: &Event) -> bool {
         // check each condition, to ensure that the event complies
         // with the restriction.
         for c in &self.conditions {
@@ -101,14 +101,14 @@ impl ConditionQuery {
 }
 
 // Verify that the delegator approved the delegation; return a ConditionQuery if so.
-pub fn validate_delegation(
+#[must_use] 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);
+    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();
@@ -133,8 +133,8 @@ pub fn validate_delegation(
 }
 
 /// 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
+/// 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 field: Field,
@@ -144,7 +144,7 @@ pub struct Condition {
 
 impl Condition {
     /// Check if this condition allows the given event to be delegated
-    pub fn allows_event(&self, event: &Event) -> bool {
+    #[must_use] 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,
@@ -323,7 +323,7 @@ mod tests {
                 Condition {
                     field: Field::CreatedAt,
                     operator: Operator::LessThan,
-                    values: vec![1665867123],
+                    values: vec![1_665_867_123],
                 },
             ],
         };

src/error.rs

@@ -48,6 +48,10 @@ pub enum Error {
     DatabaseDirError,
     #[error("Database Connection Pool Error")]
     DatabasePoolError(r2d2::Error),
+    #[error("SQL error")]
+    SqlxError(sqlx::Error),
+    #[error("Database Connection Pool Error")]
+    SqlxDatabasePoolError(sqlx::Error),
     #[error("Custom Error : {0}")]
     CustomError(String),
     #[error("Task join error")]
@@ -58,6 +62,12 @@ pub enum Error {
     HexError(hex::FromHexError),
     #[error("Delegation parse error")]
     DelegationParseError,
+    #[error("Channel closed error")]
+    ChannelClosed,
+    #[error("Authz error")]
+    AuthzError,
+    #[error("Tonic GRPC error")]
+    TonicError(tonic::Status),
     #[error("Unknown/Undocumented")]
     UnknownError,
 }
@@ -100,6 +110,12 @@ impl From<rusqlite::Error> for Error {
     }
 }
 
+impl From<sqlx::Error> for Error {
+    fn from(d: sqlx::Error) -> Self {
+        Error::SqlxDatabasePoolError(d)
+    }
+}
+
 impl From<serde_json::Error> for Error {
     /// Wrap JSON error
     fn from(r: serde_json::Error) -> Self {
@@ -120,3 +136,10 @@ impl From<config::ConfigError> for Error {
         Error::ConfigError(r)
     }
 }
+
+impl From<tonic::Status> for Error {
+    /// Wrap Config error
+    fn from(r: tonic::Status) -> Self {
+        Error::TonicError(r)
+    }
+}

src/event.rs

@@ -1,6 +1,6 @@
 //! Event parsing and validation
 use crate::delegation::validate_delegation;
-use crate::error::Error::*;
+use crate::error::Error::{CommandUnknownError, EventCouldNotCanonicalize, EventInvalidId, EventInvalidSignature, EventMalformedPubkey};
 use crate::error::Result;
 use crate::nip05;
 use crate::utils::unix_time;
@@ -28,7 +28,7 @@ pub struct EventCmd {
 }
 
 impl EventCmd {
-    pub fn event_id(&self) -> &str {
+    #[must_use] pub fn event_id(&self) -> &str {
         &self.event.id
     }
 }
@@ -65,7 +65,7 @@ where
 }
 
 /// Attempt to form a single-char tag name.
-pub fn single_char_tagname(tagname: &str) -> Option<char> {
+#[must_use] 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();
@@ -87,22 +87,22 @@ pub fn single_char_tagname(tagname: &str) -> Option<char> {
 impl From<EventCmd> for Result<Event> {
     fn from(ec: EventCmd) -> Result<Event> {
         // ensure command is correct
-        if ec.cmd != "EVENT" {
-            Err(CommandUnknownError)
-        } else {
+        if ec.cmd == "EVENT" {
             ec.event.validate().map(|_| {
                 let mut e = ec.event;
                 e.build_index();
                 e.update_delegation();
                 e
             })
+        } else {
+            Err(CommandUnknownError)
         }
     }
 }
 
 impl Event {
     #[cfg(test)]
-    pub fn simple_event() -> Event {
+    #[must_use] pub fn simple_event() -> Event {
         Event {
             id: "0".to_owned(),
             pubkey: "0".to_owned(),
@@ -116,12 +116,49 @@ impl Event {
         }
     }
 
-    pub fn is_kind_metadata(&self) -> bool {
+    #[must_use] pub fn is_kind_metadata(&self) -> bool {
         self.kind == 0
     }
 
+    /// Should this event be persisted?
+    #[must_use] pub fn is_ephemeral(&self) -> bool {
+        self.kind >= 20000 && self.kind < 30000
+    }
+
+    /// Should this event be replaced with newer timestamps from same author?
+    #[must_use] pub fn is_replaceable(&self) -> bool {
+        self.kind == 0 || self.kind == 3 || self.kind == 41 || (self.kind >= 10000 && self.kind < 20000)
+    }
+
+    /// Should this event be replaced with newer timestamps from same author, for distinct `d` tag values?
+    #[must_use] pub fn is_param_replaceable(&self) -> bool {
+        self.kind >= 30000 && self.kind < 40000
+    }
+
+    /// What is the replaceable `d` tag value?
+
+    /// Should this event be replaced with newer timestamps from same author, for distinct `d` tag values?
+    #[must_use] pub fn distinct_param(&self) -> Option<String> {
+        if self.is_param_replaceable() {
+            let default = "".to_string();
+            let dvals:Vec<&String> = self.tags
+                .iter()
+                .filter(|x| !x.is_empty())
+                .filter(|x| x.get(0).unwrap() == "d")
+                .map(|x| x.get(1).unwrap_or(&default)).take(1)
+                .collect();
+            let dval_first = dvals.get(0);
+            match dval_first {
+                Some(_) => {dval_first.map(|x| x.to_string())},
+                None => Some(default)
+            }
+        } else {
+            None
+        }
+    }
+
     /// Pull a NIP-05 Name out of the event, if one exists
-    pub fn get_nip05_addr(&self) -> Option<nip05::Nip05Name> {
+    #[must_use] 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\"") {
@@ -138,7 +175,7 @@ impl Event {
     // 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> {
+    #[must_use] pub fn delegated_author(&self) -> Option<String> {
         // is there a delegation tag?
         let delegation_tag: Vec<String> = self
             .tags
@@ -146,8 +183,7 @@ impl Event {
             .filter(|x| x.len() == 4)
             .filter(|x| x.get(0).unwrap() == "delegation")
             .take(1)
-            .next()?
-            .to_vec(); // get first tag
+            .next()?.clone(); // get first tag
 
         //let delegation_tag = self.tag_values_by_name("delegation");
         // delegation tags should have exactly 3 elements after the name (pubkey, condition, sig)
@@ -176,11 +212,11 @@ impl Event {
     }
 
     /// Update delegation status
-    fn update_delegation(&mut self) {
+    pub fn update_delegation(&mut self) {
         self.delegated_by = self.delegated_author();
     }
     /// Build an event tag index
-    fn build_index(&mut self) {
+    pub fn build_index(&mut self) {
         // if there are no tags; just leave the index as None
         if self.tags.is_empty() {
             return;
@@ -207,24 +243,24 @@ impl Event {
     }
 
     /// Create a short event identifier, suitable for logging.
-    pub fn get_event_id_prefix(&self) -> String {
+    #[must_use] pub fn get_event_id_prefix(&self) -> String {
         self.id.chars().take(8).collect()
     }
-    pub fn get_author_prefix(&self) -> String {
+    #[must_use] pub fn get_author_prefix(&self) -> String {
         self.pubkey.chars().take(8).collect()
     }
 
     /// Retrieve tag initial values across all tags matching the name
-    pub fn tag_values_by_name(&self, tag_name: &str) -> Vec<String> {
+    #[must_use] 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())
+            .map(|x| x.get(1).unwrap().clone())
             .collect()
     }
 
-    pub fn is_valid_timestamp(&self, reject_future_seconds: Option<usize>) -> bool {
+    #[must_use] 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
@@ -256,7 +292,7 @@ impl Event {
         let c = c_opt.unwrap();
         // * compute the sha256sum.
         let digest: sha256::Hash = sha256::Hash::hash(c.as_bytes());
-        let hex_digest = format!("{:x}", digest);
+        let hex_digest = format!("{digest:x}");
         // * ensure the id matches the computed sha256sum.
         if self.id != hex_digest {
             debug!("event id does not match digest");
@@ -286,7 +322,7 @@ impl Event {
         let id = Number::from(0_u64);
         c.push(serde_json::Value::Number(id));
         // public key
-        c.push(Value::String(self.pubkey.to_owned()));
+        c.push(Value::String(self.pubkey.clone()));
         // creation time
         let created_at = Number::from(self.created_at);
         c.push(serde_json::Value::Number(created_at));
@@ -296,7 +332,7 @@ impl Event {
         // tags
         c.push(self.tags_to_canonical());
         // content
-        c.push(Value::String(self.content.to_owned()));
+        c.push(Value::String(self.content.clone()));
         serde_json::to_string(&Value::Array(c)).ok()
     }
 
@@ -304,11 +340,11 @@ impl Event {
     fn tags_to_canonical(&self) -> Value {
         let mut tags = Vec::<Value>::new();
         // iterate over self tags,
-        for t in self.tags.iter() {
+        for t in &self.tags {
             // each tag is a vec of strings
             let mut a = Vec::<Value>::new();
             for v in t.iter() {
-                a.push(serde_json::Value::String(v.to_owned()));
+                a.push(serde_json::Value::String(v.clone()));
             }
             tags.push(serde_json::Value::Array(a));
         }
@@ -316,7 +352,7 @@ impl Event {
     }
 
     /// 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 {
+    #[must_use] 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) {
@@ -355,7 +391,7 @@ mod tests {
     fn empty_event_tag_match() {
         let event = Event::simple_event();
         assert!(!event
-            .generic_tag_val_intersect('e', &HashSet::from(["foo".to_owned(), "bar".to_owned()])));
+                .generic_tag_val_intersect('e', &HashSet::from(["foo".to_owned(), "bar".to_owned()])));
     }
 
     #[test]
@@ -408,7 +444,7 @@ mod tests {
             id: "999".to_owned(),
             pubkey: "012345".to_owned(),
             delegated_by: None,
-            created_at: 501234,
+            created_at: 501_234,
             kind: 1,
             tags: vec![],
             content: "this is a test".to_owned(),
@@ -426,7 +462,7 @@ mod tests {
             id: "999".to_owned(),
             pubkey: "012345".to_owned(),
             delegated_by: None,
-            created_at: 501234,
+            created_at: 501_234,
             kind: 1,
             tags: vec![
                 vec!["j".to_owned(), "abc".to_owned()],
@@ -453,7 +489,7 @@ mod tests {
             id: "999".to_owned(),
             pubkey: "012345".to_owned(),
             delegated_by: None,
-            created_at: 501234,
+            created_at: 501_234,
             kind: 1,
             tags: vec![
                 vec!["j".to_owned(), "abc".to_owned()],
@@ -480,7 +516,7 @@ mod tests {
             id: "999".to_owned(),
             pubkey: "012345".to_owned(),
             delegated_by: None,
-            created_at: 501234,
+            created_at: 501_234,
             kind: 1,
             tags: vec![
                 vec!["#e".to_owned(), "aoeu".to_owned()],
@@ -499,4 +535,123 @@ mod tests {
         let expected = Some(expected_json.to_owned());
         assert_eq!(c, expected);
     }
+
+    #[test]
+    fn ephemeral_event() {
+        let mut event = Event::simple_event();
+        event.kind=20000;
+        assert!(event.is_ephemeral());
+        event.kind=29999;
+        assert!(event.is_ephemeral());
+        event.kind=30000;
+        assert!(!event.is_ephemeral());
+        event.kind=19999;
+        assert!(!event.is_ephemeral());
+    }
+
+    #[test]
+    fn replaceable_event() {
+        let mut event = Event::simple_event();
+        event.kind=0;
+        assert!(event.is_replaceable());
+        event.kind=3;
+        assert!(event.is_replaceable());
+        event.kind=10000;
+        assert!(event.is_replaceable());
+        event.kind=19999;
+        assert!(event.is_replaceable());
+        event.kind=20000;
+        assert!(!event.is_replaceable());
+    }
+
+    #[test]
+    fn param_replaceable_event() {
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        assert!(event.is_param_replaceable());
+        event.kind = 39999;
+        assert!(event.is_param_replaceable());
+        event.kind = 29999;
+        assert!(!event.is_param_replaceable());
+        event.kind = 40000;
+        assert!(!event.is_param_replaceable());
+    }
+
+    #[test]
+    fn param_replaceable_value_case_1() {
+        // NIP case #1: "tags":[["d",""]]
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        event.tags = vec![
+            vec!["d".to_owned(), "".to_owned()]];
+        assert_eq!(event.distinct_param(), Some("".to_string()));
+    }
+
+    #[test]
+    fn param_replaceable_value_case_2() {
+        // NIP case #2: "tags":[]: implicit d tag with empty value
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        assert_eq!(event.distinct_param(), Some("".to_string()));
+    }
+
+    #[test]
+    fn param_replaceable_value_case_3() {
+        // NIP case #3: "tags":[["d"]]: implicit empty value ""
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        event.tags = vec![
+            vec!["d".to_owned()]];
+        assert_eq!(event.distinct_param(), Some("".to_string()));
+    }
+
+    #[test]
+    fn param_replaceable_value_case_4() {
+        // NIP case #4: "tags":[["d",""],["d","not empty"]]: only first d tag is considered
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        event.tags = vec![
+            vec!["d".to_owned(), "".to_string()],
+            vec!["d".to_owned(), "not empty".to_string()]
+        ];
+        assert_eq!(event.distinct_param(), Some("".to_string()));
+    }
+
+    #[test]
+    fn param_replaceable_value_case_4b() {
+        // Variation of #4 with
+        // NIP case #4: "tags":[["d","not empty"],["d",""]]: only first d tag is considered
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        event.tags = vec![
+            vec!["d".to_owned(), "not empty".to_string()],
+            vec!["d".to_owned(), "".to_string()]
+        ];
+        assert_eq!(event.distinct_param(), Some("not empty".to_string()));
+    }
+
+    #[test]
+    fn param_replaceable_value_case_5() {
+        // NIP case #5: "tags":[["d"],["d","some value"]]: only first d tag is considered
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        event.tags = vec![
+            vec!["d".to_owned()],
+            vec!["d".to_owned(), "second value".to_string()],
+            vec!["d".to_owned(), "third value".to_string()]
+        ];
+        assert_eq!(event.distinct_param(), Some("".to_string()));
+    }
+
+    #[test]
+    fn param_replaceable_value_case_6() {
+        // NIP case #6: "tags":[["e"]]: same as no tags
+        let mut event = Event::simple_event();
+        event.kind = 30000;
+        event.tags = vec![
+            vec!["e".to_owned()],
+        ];
+        assert_eq!(event.distinct_param(), Some("".to_string()));
+    }
+
 }

src/hexrange.rs

@@ -1,5 +1,5 @@
 //! Utilities for searching hexadecimal
-use crate::utils::is_hex;
+use crate::utils::{is_hex};
 use hex;
 
 /// Types of hexadecimal queries.
@@ -19,16 +19,15 @@ fn is_all_fs(s: &str) -> bool {
 }
 
 /// 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 {
+#[must_use] pub fn hex_range(s: &str) -> Option<HexSearch> {
+    let mut hash_base = s.to_owned();
+    if !is_hex(&hash_base) || hash_base.len() > 64 {
         return None;
     }
-    if s.len() == 64 {
-        return Some(HexSearch::Exact(hex::decode(s).ok()?));
+    if hash_base.len() == 64 {
+        return Some(HexSearch::Exact(hex::decode(&hash_base).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
@@ -57,8 +56,9 @@ pub fn hex_range(s: &str) -> Option<HexSearch> {
         } 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
+		// bump up the first character in this byte
+                upper[byte_len] = b + 16;
+		// increment done, stop iterating through the vec
                 break;
             }
             // if it is 'f', reset the byte to 0 and do a carry

src/info.rs

@@ -35,9 +35,9 @@ impl From<config::Info> for RelayInfo {
             description: i.description,
             pubkey: i.pubkey,
             contact: i.contact,
-            supported_nips: Some(vec![1, 2, 9, 11, 12, 15, 16, 20, 22]),
+            supported_nips: Some(vec![1, 2, 9, 11, 12, 15, 16, 20, 22, 33]),
             software: Some("https://git.sr.ht/~gheartsfield/nostr-rs-relay".to_owned()),
-            version: CARGO_PKG_VERSION.map(|x| x.to_owned()),
+            version: CARGO_PKG_VERSION.map(std::borrow::ToOwned::to_owned),
         }
     }
 }

src/lib.rs

@@ -1,3 +1,4 @@
+pub mod cli;
 pub mod close;
 pub mod config;
 pub mod conn;
@@ -8,8 +9,9 @@ pub mod event;
 pub mod hexrange;
 pub mod info;
 pub mod nip05;
+pub mod nauthz;
 pub mod notice;
-pub mod schema;
+pub mod repo;
 pub mod subscription;
 pub mod utils;
 // Public API for creating relays programatically

src/main.rs

@@ -1,77 +1,51 @@
 //! Server process
-
+use clap::Parser;
+use nostr_rs_relay::cli::CLIArgs;
 use nostr_rs_relay::config;
 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
-}
-
-fn print_version() {
-    println!("{} v{}", env!("CARGO_PKG_NAME"), env!("CARGO_PKG_VERSION"));
-}
-
-fn print_help() {
-    println!("Usage: nostr-rs-relay [OPTION]...\n");
-    println!("Options:");
-    println!("  --help              Show this help message and exit");
-    println!("  --version           Show version information and exit");
-    println!("  --db <directory>    Use the <directory> as the location of the database");
-}
-
 /// Start running a Nostr relay server.
 fn main() {
+    let args = CLIArgs::parse();
+
+    // get config file name from args
+    let config_file_arg = args.config;
+
+    // configure settings from the config file (defaults to config.toml)
+    // replace default settings with those read from the config file
+    let mut settings = config::Settings::new(&config_file_arg);
+
     // 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 help_flag: bool = args.contains(&"--help".to_owned());
-    // if --help flag was passed, display help and exit
-    if help_flag {
-        print_help();
-        return;
-    }
-
-    let version_flag: bool = args.contains(&"--version".to_owned());
-    // if --version flag was passed, display version and exit
-    if version_flag {
-        print_version();
-        return;
-    }
-
-    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();
-
     if settings.diagnostics.tracing {
         // enable tracing with tokio-console
         ConsoleLayer::builder().with_default_env().init();
+    } else {
+        // standard logging
+        tracing_subscriber::fmt::try_init().unwrap();
     }
-    // update with database location
-    if let Some(db) = db_dir {
-        settings.database.data_directory = db;
-    }
+    info!("Starting up from main");
 
+    // get database directory from args
+    let db_dir_arg = args.db;
+
+    // update with database location from args, if provided
+    if let Some(db_dir) = db_dir_arg {
+        settings.database.data_directory = db_dir;
+    }
+    // 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.; for now all this does is initiate shutdown if
+    // `()` is sent.  This will change in the future, this is just a
+    // stopgap to shutdown the relay when it is used as a library.
     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);
+    let handle = thread::spawn(move || {
+        let _svr = start_server(&settings, ctrl_rx);
     });
     // block on nostr thread to finish.
     handle.join().unwrap();

src/nauthz.rs

@@ -0,0 +1,110 @@
+use crate::error::{Error, Result};
+use crate::{event::Event, nip05::Nip05Name};
+use nauthz_grpc::authorization_client::AuthorizationClient;
+use nauthz_grpc::event::TagEntry;
+use nauthz_grpc::{Decision, Event as GrpcEvent, EventReply, EventRequest};
+use tracing::{info, warn};
+
+pub mod nauthz_grpc {
+    tonic::include_proto!("nauthz");
+}
+
+// A decision for the DB to act upon
+pub trait AuthzDecision: Send + Sync {
+    fn permitted(&self) -> bool;
+    fn message(&self) -> Option<String>;
+}
+
+impl AuthzDecision for EventReply {
+    fn permitted(&self) -> bool {
+        self.decision == Decision::Permit as i32
+    }
+    fn message(&self) -> Option<String> {
+        self.message.clone()
+    }
+}
+
+// A connection to an event admission GRPC server
+pub struct EventAuthzService {
+    server_addr: String,
+    conn: Option<AuthorizationClient<tonic::transport::Channel>>,
+}
+
+// conversion of Nip05Names into GRPC type
+impl std::convert::From<Nip05Name> for nauthz_grpc::event_request::Nip05Name {
+    fn from(value: Nip05Name) -> Self {
+        nauthz_grpc::event_request::Nip05Name {
+            local: value.local.clone(),
+            domain: value.domain.clone(),
+        }
+    }
+}
+
+// conversion of event tags into gprc struct
+fn tags_to_protobuf(tags: &Vec<Vec<String>>) -> Vec<TagEntry> {
+    tags.iter()
+        .map(|x| TagEntry { values: x.clone() })
+        .collect()
+}
+
+impl EventAuthzService {
+    pub async fn connect(server_addr: &str) -> EventAuthzService {
+        let mut eas = EventAuthzService {
+            server_addr: server_addr.to_string(),
+            conn: None,
+        };
+        eas.ready_connection().await;
+        eas
+    }
+
+    pub async fn ready_connection(self: &mut Self) {
+        if self.conn.is_none() {
+            let client = AuthorizationClient::connect(self.server_addr.to_string()).await;
+            if let Err(ref msg) = client {
+                warn!("could not connect to nostr authz GRPC server: {:?}", msg);
+            } else {
+                info!("connected to nostr authorization GRPC server");
+            }
+            self.conn = client.ok();
+        }
+    }
+
+    pub async fn admit_event(
+        self: &mut Self,
+        event: &Event,
+        ip: &str,
+        origin: Option<String>,
+        user_agent: Option<String>,
+        nip05: Option<Nip05Name>,
+    ) -> Result<Box<dyn AuthzDecision>> {
+        self.ready_connection().await;
+        let id_blob = hex::decode(&event.id)?;
+        let pubkey_blob = hex::decode(&event.pubkey)?;
+        let sig_blob = hex::decode(&event.sig)?;
+        if let Some(ref mut c) = self.conn {
+            let gevent = GrpcEvent {
+                id: id_blob,
+                pubkey: pubkey_blob,
+                sig: sig_blob,
+                created_at: event.created_at,
+                kind: event.kind,
+                content: event.content.clone(),
+                tags: tags_to_protobuf(&event.tags),
+            };
+            let svr_res = c
+                .event_admit(EventRequest {
+                    event: Some(gevent),
+                    ip_addr: Some(ip.to_string()),
+                    origin,
+                    user_agent,
+                    auth_pubkey: None,
+                    nip05: nip05.map(|x| nauthz_grpc::event_request::Nip05Name::from(x)),
+                })
+                .await?;
+            let reply = svr_res.into_inner();
+            return Ok(Box::new(reply));
+        } else {
+            return Err(Error::AuthzError);
+        }
+    }
+}

src/nip05.rs

@@ -5,16 +5,14 @@
 //! 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 crate::repo::NostrRepo;
+use std::sync::Arc;
 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;
@@ -23,14 +21,12 @@ use tracing::{debug, info, warn};
 
 /// NIP-05 verifier state
 pub struct Verifier {
+    /// Repository for saving/retrieving events and records
+    repo: Arc<dyn NostrRepo>,
     /// 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
@@ -46,13 +42,13 @@ pub struct Verifier {
 /// A NIP-05 identifier is a local part and domain.
 #[derive(PartialEq, Eq, Debug, Clone)]
 pub struct Nip05Name {
-    local: String,
-    domain: String,
+    pub local: String,
+    pub domain: String,
 }
 
 impl Nip05Name {
     /// Does this name represent the entire domain?
-    pub fn is_domain_only(&self) -> bool {
+    #[must_use] pub fn is_domain_only(&self) -> bool {
         self.local == "_"
     }
 
@@ -62,8 +58,8 @@ impl Nip05Name {
             "https://{}/.well-known/nostr.json?name={}",
             self.domain, self.local
         )
-        .parse::<http::Uri>()
-        .ok()
+            .parse::<http::Uri>()
+            .ok()
     }
 }
 
@@ -73,16 +69,11 @@ impl std::convert::TryFrom<&str> for Nip05Name {
     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 {
+        if components.len() == 2 {
             // 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 local.chars().all(|x| x.is_alphanumeric() || x == '_' || x == '-' || x == '.') {
                 if domain
                     .chars()
                     .all(|x| x.is_alphanumeric() || x == '-' || x == '.')
@@ -101,6 +92,8 @@ impl std::convert::TryFrom<&str> for Nip05Name {
                     "invalid character in local part".to_owned(),
                 ))
             }
+        } else {
+            Err(Error::CustomError("too many/few components".to_owned()))
         }
     }
 }
@@ -111,55 +104,30 @@ impl std::fmt::Display for Nip05Name {
     }
 }
 
-// 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> {
+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)?;
+    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())
+        .and_then(serde_json::Value::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());
+    let check_name = names_map.get(username).and_then(serde_json::Value::as_str);
     // ensure the address is a match
-    Ok(check_name.map(|x| x == address).unwrap_or(false))
+    Ok(check_name.map_or(false, |x| x == address))
 }
 
 impl Verifier {
     pub fn new(
+        repo: Arc<dyn NostrRepo>,
         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);
@@ -175,10 +143,9 @@ impl Verifier {
         // duration.
         let reverify_interval = tokio::time::interval(http_wait_duration);
         Ok(Verifier {
+            repo,
             metadata_rx,
             event_tx,
-            read_pool,
-            write_pool,
             settings,
             client,
             wait_after_finish,
@@ -246,44 +213,40 @@ impl Verifier {
 
         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);
+        if let Ok(response_res) = tokio::time::timeout(Duration::from_secs(5), response_fut).await {
+            // 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);
                     }
-                } else {
-                    info!(
-                        "content length missing or exceeded limits for account: {:?}",
-                        nip.to_string()
-                    );
+                    // 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);
-            }
+        } else {
+            info!("timeout verifying account {:?}", nip);
+            return Ok(UserWebVerificationStatus::Unknown);
         }
         Ok(UserWebVerificationStatus::Unknown)
     }
@@ -294,8 +257,15 @@ impl Verifier {
         // run a loop, restarting on failure
         loop {
             let res = self.run_internal().await;
-            if let Err(e) = res {
+            match res {
+                Err(Error::ChannelClosed) => {
+                    // channel was closed, we are shutting down
+                    return;
+                },
+                Err(e) => {
                 info!("error in verifier: {:?}", e);
+                },
+                _ => {}
             }
         }
     }
@@ -309,7 +279,7 @@ impl Verifier {
                         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;
+                            let check_verified = self.repo.get_latest_user_verification(&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 {
@@ -342,6 +312,7 @@ impl Verifier {
                     }
                     Err(tokio::sync::broadcast::error::RecvError::Closed) => {
                         info!("metadata broadcast channel closed");
+                        return Err(Error::ChannelClosed);
                     }
                 }
             },
@@ -370,7 +341,7 @@ impl Verifier {
             .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;
+        let vr = self.repo.get_oldest_user_verification(earliest_epoch).await;
         match vr {
             Ok(ref v) => {
                 let new_status = self.get_web_verification(&v.name, &v.address).await;
@@ -378,34 +349,37 @@ impl Verifier {
                     UserWebVerificationStatus::Verified => {
                         // freshly verified account, update the
                         // timestamp.
-                        self.update_verification_record(self.write_pool.get()?, v)
+                        self.repo.update_verification_timestamp(v.rowid)
                             .await?;
+                        info!("verification updated for {}", v.to_string());
+
                     }
                     UserWebVerificationStatus::DomainNotAllowed
-                    | UserWebVerificationStatus::Unknown => {
-                        // server may be offline, or temporarily
-                        // blocked by the config file.  Note the
-                        // failure so we can process something
-                        // else.
+			| 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?;
-                        }
-                    }
+                            // 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.repo.delete_verification(v.rowid)
+                                    .await?;
+                            } else {
+				// record normal failure, incrementing failure count
+				info!("verification failed for {}", v.to_string());
+				self.repo.fail_verification(v.rowid).await?;
+                            }
+			}
                     UserWebVerificationStatus::Unverified => {
                         // domain has removed the verification, drop
                         // the record on our side.
-                        self.delete_verification_record(self.write_pool.get()?, v)
+                        info!("verification rescinded for {}", v.to_string());
+                        self.repo.delete_verification(v.rowid)
                             .await?;
                     }
                 }
@@ -426,80 +400,6 @@ impl Verifier {
         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
@@ -513,7 +413,7 @@ impl Verifier {
         // 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) {
+            match self.repo.write_event(event).await {
                 Ok(updated) => {
                     if updated != 0 {
                         info!(
@@ -533,7 +433,7 @@ impl Verifier {
             }
         }
         // write the verification record
-        save_verification_record(self.write_pool.get()?, event, name).await?;
+        self.repo.create_verification_record(&event.id, name).await?;
         Ok(())
     }
 }
@@ -563,7 +463,7 @@ pub struct VerificationRecord {
 
 /// Check with settings to determine if a given domain is allowed to
 /// publish.
-pub fn is_domain_allowed(
+#[must_use] pub fn is_domain_allowed(
     domain: &str,
     whitelist: &Option<Vec<String>>,
     blacklist: &Option<Vec<String>>,
@@ -583,7 +483,7 @@ pub fn is_domain_allowed(
 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 {
+    #[must_use] 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;
@@ -630,130 +530,6 @@ impl std::fmt::Display for VerificationRecord {
     }
 }
 
-/// 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 INNER 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::*;
@@ -762,7 +538,7 @@ mod tests {
     fn local_from_inet() {
         let addr = "bob@example.com";
         let parsed = Nip05Name::try_from(addr);
-        assert!(!parsed.is_err());
+        assert!(parsed.is_ok());
         let v = parsed.unwrap();
         assert_eq!(v.local, "bob");
         assert_eq!(v.domain, "example.com");

src/notice.rs

@@ -19,18 +19,14 @@ pub enum Notice {
 }
 
 impl EventResultStatus {
-    pub fn to_bool(&self) -> bool {
+    #[must_use] pub fn to_bool(&self) -> bool {
         match self {
-            Self::Saved => true,
-            Self::Duplicate => true,
-            Self::Invalid => false,
-            Self::Blocked => false,
-            Self::RateLimited => false,
-            Self::Error => false,
+            Self::Duplicate | Self::Saved => true,
+            Self::Invalid |Self::Blocked | Self::RateLimited | Self::Error => false,
         }
     }
 
-    pub fn prefix(&self) -> &'static str {
+    #[must_use] pub fn prefix(&self) -> &'static str {
         match self {
             Self::Saved => "saved",
             Self::Duplicate => "duplicate",
@@ -47,7 +43,7 @@ impl Notice {
     //    Notice::err_msg(format!("{}", err), id)
     //}
 
-    pub fn message(msg: String) -> Notice {
+    #[must_use] pub fn message(msg: String) -> Notice {
         Notice::Message(msg)
     }
 
@@ -56,27 +52,27 @@ impl Notice {
         Notice::EventResult(EventResult { id, msg, status })
     }
 
-    pub fn invalid(id: String, msg: &str) -> Notice {
+    #[must_use] pub fn invalid(id: String, msg: &str) -> Notice {
         Notice::prefixed(id, msg, EventResultStatus::Invalid)
     }
 
-    pub fn blocked(id: String, msg: &str) -> Notice {
+    #[must_use] pub fn blocked(id: String, msg: &str) -> Notice {
         Notice::prefixed(id, msg, EventResultStatus::Blocked)
     }
 
-    pub fn rate_limited(id: String, msg: &str) -> Notice {
+    #[must_use] pub fn rate_limited(id: String, msg: &str) -> Notice {
         Notice::prefixed(id, msg, EventResultStatus::RateLimited)
     }
 
-    pub fn duplicate(id: String) -> Notice {
+    #[must_use] pub fn duplicate(id: String) -> Notice {
         Notice::prefixed(id, "", EventResultStatus::Duplicate)
     }
 
-    pub fn error(id: String, msg: &str) -> Notice {
+    #[must_use] pub fn error(id: String, msg: &str) -> Notice {
         Notice::prefixed(id, msg, EventResultStatus::Error)
     }
 
-    pub fn saved(id: String) -> Notice {
+    #[must_use] pub fn saved(id: String) -> Notice {
         Notice::EventResult(EventResult {
             id,
             msg: "".into(),

src/repo/mod.rs

@@ -0,0 +1,69 @@
+use crate::db::QueryResult;
+use crate::error::Result;
+use crate::event::Event;
+use crate::nip05::VerificationRecord;
+use crate::subscription::Subscription;
+use crate::utils::unix_time;
+use async_trait::async_trait;
+use rand::Rng;
+
+pub mod sqlite;
+pub mod sqlite_migration;
+pub mod postgres;
+pub mod postgres_migration;
+
+#[async_trait]
+pub trait NostrRepo: Send + Sync {
+    /// Start the repository (any initialization or maintenance tasks can be kicked off here)
+    async fn start(&self) -> Result<()>;
+
+    /// Run migrations and return current version
+    async fn migrate_up(&self) -> Result<usize>;
+
+    /// Persist event to database
+    async fn write_event(&self, e: &Event) -> Result<u64>;
+
+    /// Perform a database query using a subscription.
+    ///
+    /// The [`Subscription`] is converted into a SQL query.  Each result
+    /// is published on the `query_tx` channel as it is returned.  If a
+    /// message becomes available on the `abandon_query_rx` channel, the
+    /// query is immediately aborted.
+    async fn query_subscription(
+        &self,
+        sub: Subscription,
+        client_id: String,
+        query_tx: tokio::sync::mpsc::Sender<QueryResult>,
+        mut abandon_query_rx: tokio::sync::oneshot::Receiver<()>,
+    ) -> Result<()>;
+
+    /// Perform normal maintenance
+    async fn optimize_db(&self) -> Result<()>;
+
+    /// Create a new verification record connected to a specific event
+    async fn create_verification_record(&self, event_id: &str, name: &str) -> Result<()>;
+
+    /// Update verification timestamp
+    async fn update_verification_timestamp(&self, id: u64) -> Result<()>;
+
+    /// Update verification record as failed
+    async fn fail_verification(&self, id: u64) -> Result<()>;
+
+    /// Delete verification record
+    async fn delete_verification(&self, id: u64) -> Result<()>;
+
+    /// Get the latest verification record for a given pubkey.
+    async fn get_latest_user_verification(&self, pub_key: &str) -> Result<VerificationRecord>;
+
+    /// Get oldest verification before timestamp
+    async fn get_oldest_user_verification(&self, before: u64) -> Result<VerificationRecord>;
+}
+
+// Current time, with a slight forward jitter in seconds
+pub(crate) 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)
+}

src/repo/postgres.rs

@@ -0,0 +1,741 @@
+use crate::db::QueryResult;
+use crate::error::Result;
+use crate::event::{single_char_tagname, Event};
+use crate::nip05::{Nip05Name, VerificationRecord};
+use crate::repo::{now_jitter, NostrRepo};
+use crate::subscription::{ReqFilter, Subscription};
+use async_std::stream::StreamExt;
+use async_trait::async_trait;
+use chrono::{DateTime, TimeZone, Utc};
+use sqlx::postgres::PgRow;
+use sqlx::{Error, Execute, FromRow, Postgres, QueryBuilder, Row};
+use std::time::{Duration, Instant};
+use sqlx::Error::RowNotFound;
+
+use crate::hexrange::{hex_range, HexSearch};
+use crate::repo::postgres_migration::run_migrations;
+use crate::server::NostrMetrics;
+use crate::utils::{is_hex, is_lower_hex};
+use tokio::sync::mpsc::Sender;
+use tokio::sync::oneshot::Receiver;
+use tracing::log::trace;
+use tracing::{debug, error, info};
+use crate::error;
+
+pub type PostgresPool = sqlx::pool::Pool<Postgres>;
+
+pub struct PostgresRepo {
+    conn: PostgresPool,
+    metrics: NostrMetrics,
+}
+
+impl PostgresRepo {
+    pub fn new(c: PostgresPool, m: NostrMetrics) -> PostgresRepo {
+        PostgresRepo {
+            conn: c,
+            metrics: m,
+        }
+    }
+}
+
+#[async_trait]
+impl NostrRepo for PostgresRepo {
+
+    async fn start(&self) -> Result<()> {
+	info!("not implemented");
+	Ok(())
+    }
+
+    async fn migrate_up(&self) -> Result<usize> {
+        Ok(run_migrations(&self.conn).await?)
+    }
+
+    async fn write_event(&self, e: &Event) -> Result<u64> {
+        // start transaction
+        let mut tx = self.conn.begin().await?;
+        let start = Instant::now();
+
+        // get relevant fields from event and convert to blobs.
+        let id_blob = hex::decode(&e.id).ok();
+        let pubkey_blob: Option<Vec<u8>> = hex::decode(&e.pubkey).ok();
+        let delegator_blob: Option<Vec<u8>> =
+            e.delegated_by.as_ref().and_then(|d| hex::decode(d).ok());
+        let event_str = serde_json::to_string(&e).unwrap();
+
+        // determine if this event would be shadowed by an existing
+        // replaceable event or parameterized replaceable event.
+        if e.is_replaceable() {
+            let repl_count = sqlx::query(
+                "SELECT e.id FROM event e WHERE e.pub_key=? AND e.kind=? AND e.created_at >= ? LIMIT 1;")
+                .bind(&pubkey_blob)
+                .bind(e.kind as i64)
+                .bind(Utc.timestamp_opt(e.created_at as i64, 0).unwrap())
+                .fetch_optional(&mut tx)
+                .await?;
+            if repl_count.is_some() {
+                return Ok(0);
+            }
+        }
+        if let Some(d_tag) = e.distinct_param() {
+            let repl_count:i64 = if is_lower_hex(&d_tag) && (d_tag.len() % 2 == 0) {
+                sqlx::query_scalar(
+                    "SELECT count(*) AS count FROM event e LEFT JOIN tag t ON e.id=t.event_id WHERE e.pub_key=$1 AND e.kind=$2 AND t.name='d' AND t.value_hex=$3 AND e.created_at >= $4 LIMIT 1;")
+                    .bind(hex::decode(&e.pubkey).ok())
+                    .bind(e.kind as i64)
+                    .bind(hex::decode(d_tag).ok())
+                    .bind(Utc.timestamp_opt(e.created_at as i64, 0).unwrap())
+                    .fetch_one(&mut tx)
+                    .await?
+            } else {
+                sqlx::query_scalar(
+                    "SELECT count(*) AS count FROM event e LEFT JOIN tag t ON e.id=t.event_id WHERE e.pub_key=$1 AND e.kind=$2 AND t.name='d' AND t.value=$3 AND e.created_at >= $4 LIMIT 1;")
+                    .bind(hex::decode(&e.pubkey).ok())
+                    .bind(e.kind as i64)
+                    .bind(d_tag.as_bytes())
+                    .bind(Utc.timestamp_opt(e.created_at as i64, 0).unwrap())
+                    .fetch_one(&mut tx)
+                    .await?
+            };
+            // if any rows were returned, then some newer event with
+            // the same author/kind/tag value exist, and we can ignore
+            // this event.
+            if repl_count > 0 {
+                return Ok(0)
+            }
+        }
+        // ignore if the event hash is a duplicate.
+        let mut ins_count = sqlx::query(
+            r#"INSERT INTO "event"
+(id, pub_key, created_at, kind, "content", delegated_by)
+VALUES($1, $2, $3, $4, $5, $6)
+ON CONFLICT (id) DO NOTHING"#,
+        )
+            .bind(&id_blob)
+            .bind(&pubkey_blob)
+            .bind(Utc.timestamp_opt(e.created_at as i64, 0).unwrap())
+            .bind(e.kind as i64)
+            .bind(event_str.into_bytes())
+            .bind(delegator_blob)
+            .execute(&mut tx)
+            .await?
+            .rows_affected();
+
+        if ins_count == 0 {
+            // if the event was a duplicate, no need to insert event or
+            // pubkey references.  This will abort the txn.
+            return Ok(0);
+        }
+
+        // add all tags to the tag table
+        for tag in e.tags.iter() {
+            // ensure we have 2 values.
+            if tag.len() >= 2 {
+                let tag_name = &tag[0];
+                let tag_val = &tag[1];
+                // only single-char tags are searchable
+                let tag_char_opt = single_char_tagname(tag_name);
+                let query = "INSERT INTO tag (event_id, \"name\", value) VALUES($1, $2, $3) \
+                    ON CONFLICT (event_id, \"name\", value) DO NOTHING";
+                match &tag_char_opt {
+                    Some(_) => {
+                        // if tag value is lowercase hex;
+                        if is_lower_hex(tag_val) && (tag_val.len() % 2 == 0) {
+                            sqlx::query(query)
+                                .bind(&id_blob)
+                                .bind(tag_name)
+                                .bind(hex::decode(tag_val).ok())
+                                .execute(&mut tx)
+                                .await?;
+                        } else {
+                            sqlx::query(query)
+                                .bind(&id_blob)
+                                .bind(tag_name)
+                                .bind(tag_val.as_bytes())
+                                .execute(&mut tx)
+                                .await?;
+                        }
+                    }
+                    None => {}
+                }
+            }
+        }
+        if e.is_replaceable() {
+            let update_count = sqlx::query("DELETE FROM \"event\" WHERE kind=$1 and pub_key = $2 and id not in (select id from \"event\" where kind=$1 and pub_key=$2 order by created_at desc limit 1);")
+                .bind(e.kind as i64)
+                .bind(hex::decode(&e.pubkey).ok())
+                .execute(&mut tx)
+                .await?.rows_affected();
+            if update_count > 0 {
+                info!(
+                    "hid {} older replaceable kind {} events for author: {:?}",
+                    update_count,
+                    e.kind,
+                    e.get_author_prefix()
+                );
+            }
+        }
+        // parameterized replaceable events
+        // check for parameterized replaceable events that would be hidden; don't insert these either.
+        if let Some(d_tag) = e.distinct_param() {
+            let update_count = if is_lower_hex(&d_tag) && (d_tag.len() % 2 == 0) {
+                sqlx::query("DELETE FROM event WHERE kind=$1 AND pub_key=$2 AND id IN (SELECT e.id FROM event e LEFT JOIN tag t ON e.id=t.event_id WHERE e.kind=$1 AND e.pub_key=$2 AND t.name='d' AND t.value_hex=$3 ORDER BY created_at DESC OFFSET 1);")
+                    .bind(e.kind as i64)
+                    .bind(hex::decode(&e.pubkey).ok())
+                    .bind(hex::decode(d_tag).ok())
+                    .execute(&mut tx)
+                    .await?.rows_affected()
+            } else {
+                sqlx::query("DELETE FROM event WHERE kind=$1 AND pub_key=$2 AND id IN (SELECT e.id FROM event e LEFT JOIN tag t ON e.id=t.event_id WHERE e.kind=$1 AND e.pub_key=$2 AND t.name='d' AND t.value=$3 ORDER BY created_at DESC OFFSET 1);")
+                    .bind(e.kind as i64)
+                    .bind(hex::decode(&e.pubkey).ok())
+                    .bind(d_tag.as_bytes())
+                    .execute(&mut tx)
+                    .await?.rows_affected()
+            };
+            if update_count > 0 {
+                info!(
+                    "removed {} older parameterized replaceable kind {} events for author: {:?}",
+                    update_count,
+                    e.kind,
+                    e.get_author_prefix()
+                );
+            }
+        }
+        // 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");
+            let pub_keys: Vec<Vec<u8>> = event_candidates
+                .iter()
+                .filter(|x| is_hex(x) && x.len() == 64)
+                .filter_map(|x| hex::decode(x).ok())
+                .collect();
+
+            let mut builder = QueryBuilder::new(
+                "UPDATE \"event\" SET hidden = 1::bit(1) WHERE kind != 5 AND pub_key = ",
+            );
+            builder.push_bind(hex::decode(&e.pubkey).ok());
+            builder.push(" AND id IN (");
+
+            let mut sep = builder.separated(", ");
+            for pk in pub_keys {
+                sep.push_bind(pk);
+            }
+            sep.push_unseparated(")");
+
+            let update_count = builder.build().execute(&mut tx).await?.rows_affected();
+            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 = sqlx::query(
+                "SELECT e.id FROM \"event\" e \
+            LEFT JOIN tag t ON e.id = t.event_id \
+            WHERE e.pub_key = $1 AND t.\"name\" = 'e' AND e.kind = 5 AND t.value = $2 LIMIT 1",
+            )
+                .bind(&pubkey_blob)
+                .bind(&id_blob)
+                .fetch_optional(&mut tx)
+                .await?;
+
+            // check if a the query returned a result, meaning we should
+            // hid the current event
+            if del_count.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()
+                );
+                sqlx::query("UPDATE \"event\" SET hidden = 1::bit(1) WHERE id = $1")
+                    .bind(&id_blob)
+                    .execute(&mut tx)
+                    .await?;
+                // event was deleted, so let caller know nothing new
+                // arrived, preventing this from being sent to active
+                // subscriptions
+                ins_count = 0;
+            }
+        }
+        tx.commit().await?;
+        self.metrics
+            .write_events
+            .observe(start.elapsed().as_secs_f64());
+        Ok(ins_count)
+    }
+
+    async fn query_subscription(
+        &self,
+        sub: Subscription,
+        client_id: String,
+        query_tx: Sender<QueryResult>,
+        mut abandon_query_rx: Receiver<()>,
+    ) -> Result<()> {
+        let start = Instant::now();
+        let mut row_count: usize = 0;
+        let metrics = &self.metrics;
+
+        for filter in sub.filters.iter() {
+            let start = Instant::now();
+            // generate SQL query
+            let q_filter = query_from_filter(filter);
+            if q_filter.is_none() {
+                debug!("Failed to generate query!");
+                continue;
+            }
+
+            debug!("SQL generated in {:?}", start.elapsed());
+
+            // cutoff for displaying slow queries
+            let slow_cutoff = Duration::from_millis(2000);
+
+            // any client that doesn't cause us to generate new rows in 5
+            // seconds gets dropped.
+            let abort_cutoff = Duration::from_secs(5);
+
+            let start = Instant::now();
+            let mut slow_first_event;
+            let mut last_successful_send = Instant::now();
+
+            // execute the query. Don't cache, since queries vary so much.
+            let mut q_filter = q_filter.unwrap();
+            let q_build = q_filter.build();
+            let sql = q_build.sql();
+            let mut results = q_build.fetch(&self.conn);
+
+            let mut first_result = true;
+            while let Some(row) = results.next().await {
+                if let Err(e) = row {
+                    error!("Query failed: {} {} {:?}", e, sql, filter);
+                    break;
+                }
+                let first_event_elapsed = start.elapsed();
+                slow_first_event = first_event_elapsed >= slow_cutoff;
+                if first_result {
+                    debug!(
+                        "first result in {:?} (cid: {}, sub: {:?})",
+                        first_event_elapsed, client_id, sub.id
+                    );
+                    first_result = false;
+                }
+
+                // logging for slow queries; show sub and SQL.
+                // to reduce logging; only show 1/16th of clients (leading 0)
+                if slow_first_event && client_id.starts_with("00") {
+                    debug!(
+                        "query req (slow): {:?} (cid: {}, sub: {:?})",
+                        &sub, client_id, sub.id
+                    );
+                } else {
+                    trace!(
+                        "query req: {:?} (cid: {}, sub: {:?})",
+                        &sub,
+                        client_id,
+                        sub.id
+                    );
+                }
+
+                // check if this is still active; every 100 rows
+                if row_count % 100 == 0 && abandon_query_rx.try_recv().is_ok() {
+                    debug!("query cancelled by client (cid: {}, sub: {:?})", client_id, sub.id);
+                    return Ok(());
+                }
+
+                row_count += 1;
+                let event_json: Vec<u8> = row.unwrap().get(0);
+                loop {
+                    if query_tx.capacity() != 0 {
+                        // we have capacity to add another item
+                        break;
+                    } else {
+                        // the queue is full
+                        trace!("db reader thread is stalled");
+                        if last_successful_send + abort_cutoff < Instant::now() {
+                            // the queue has been full for too long, abort
+                            info!("aborting database query due to slow client");
+                            metrics.query_aborts.with_label_values(&["slowclient"]).inc();
+                            return Ok(());
+                        }
+                        // give the queue a chance to clear before trying again
+                        async_std::task::sleep(Duration::from_millis(100)).await;
+                    }
+                }
+
+                // TODO: we could use try_send, but we'd have to juggle
+                // getting the query result back as part of the error
+                // result.
+                query_tx
+                    .send(QueryResult {
+                        sub_id: sub.get_id(),
+                        event: String::from_utf8(event_json).unwrap(),
+                    })
+                    .await
+                    .ok();
+                last_successful_send = Instant::now();
+            }
+        }
+        query_tx
+            .send(QueryResult {
+                sub_id: sub.get_id(),
+                event: "EOSE".to_string(),
+            })
+            .await
+            .ok();
+        self.metrics
+            .query_sub
+            .observe(start.elapsed().as_secs_f64());
+        debug!(
+            "query completed in {:?} (cid: {}, sub: {:?}, db_time: {:?}, rows: {})",
+            start.elapsed(),
+            client_id,
+            sub.id,
+            start.elapsed(),
+            row_count
+        );
+        Ok(())
+    }
+
+    async fn optimize_db(&self) -> Result<()> {
+        // Not implemented
+        Ok(())
+    }
+
+    async fn create_verification_record(&self, event_id: &str, name: &str) -> Result<()> {
+        let mut tx = self.conn.begin().await?;
+
+        sqlx::query("DELETE FROM user_verification WHERE \"name\" = $1")
+            .bind(name)
+            .execute(&mut tx)
+            .await?;
+
+        sqlx::query("INSERT INTO user_verification (event_id, \"name\", verified_at) VALUES ($1, $2, now())")
+            .bind(hex::decode(event_id).ok())
+            .bind(name)
+            .execute(&mut tx)
+            .await?;
+
+        tx.commit().await?;
+        info!("saved new verification record for ({:?})", name);
+        Ok(())
+    }
+
+    async fn update_verification_timestamp(&self, id: u64) -> Result<()> {
+        // add some jitter to the verification to prevent everything from stacking up together.
+        let verify_time = now_jitter(600);
+
+        // update verification time and reset any failure count
+        sqlx::query(
+            "UPDATE user_verification SET verified_at = $1, fail_count = 0 WHERE id = $2",
+        )
+            .bind(Utc.timestamp_opt(verify_time as i64, 0).unwrap())
+            .bind(id as i64)
+            .execute(&self.conn)
+            .await?;
+
+        info!("verification updated for {}", id);
+        Ok(())
+    }
+
+    async fn fail_verification(&self, id: u64) -> Result<()> {
+        sqlx::query("UPDATE user_verification SET failed_at = now(), fail_count = fail_count + 1 WHERE id = $1")
+            .bind(id as i64)
+            .execute(&self.conn)
+            .await?;
+        Ok(())
+    }
+
+    async fn delete_verification(&self, id: u64) -> Result<()> {
+        sqlx::query("DELETE FROM user_verification WHERE id = $1")
+            .bind(id as i64)
+            .execute(&self.conn)
+            .await?;
+        Ok(())
+    }
+
+    async fn get_latest_user_verification(&self, pub_key: &str) -> Result<VerificationRecord> {
+        let query = r#"SELECT
+            v.id,
+            v."name",
+            e.id as event_id,
+            e.pub_key,
+            e.created_at,
+            v.verified_at,
+            v.failed_at,
+            v.fail_count
+            FROM user_verification v
+            LEFT JOIN "event" e ON e.id = v.event_id
+            WHERE e.pub_key = $1
+            ORDER BY e.created_at DESC, v.verified_at DESC, v.failed_at DESC
+            LIMIT 1"#;
+        sqlx::query_as::<_, VerificationRecord>(query)
+            .bind(hex::decode(pub_key).ok())
+            .fetch_optional(&self.conn)
+            .await?
+            .ok_or(error::Error::SqlxError(RowNotFound))
+    }
+
+    async fn get_oldest_user_verification(&self, before: u64) -> Result<VerificationRecord> {
+        let query = r#"SELECT
+            v.id,
+            v."name",
+            e.id as event_id,
+            e.pub_key,
+            e.created_at,
+            v.verified_at,
+            v.failed_at,
+            v.fail_count
+            FROM user_verification v
+            LEFT JOIN "event" e ON e.id = v.event_id
+                WHERE (v.verified_at < $1 OR v.verified_at IS NULL)
+                AND (v.failed_at < $1 OR v.failed_at IS NULL)
+            ORDER BY v.verified_at ASC, v.failed_at ASC
+            LIMIT 1"#;
+        sqlx::query_as::<_, VerificationRecord>(query)
+            .bind(Utc.timestamp_opt(before as i64, 0).unwrap())
+            .fetch_optional(&self.conn)
+            .await?
+            .ok_or(error::Error::SqlxError(RowNotFound))
+    }
+}
+
+/// Create a dynamic SQL query and params from a subscription filter.
+fn query_from_filter(f: &ReqFilter) -> Option<QueryBuilder<Postgres>> {
+    // if the filter is malformed, don't return anything.
+    if f.force_no_match {
+        return None;
+    }
+
+    let mut query = QueryBuilder::new("SELECT e.\"content\", e.created_at FROM \"event\" e WHERE ");
+
+    let mut push_and = false;
+    // Query for "authors", allowing prefix matches
+    if let Some(auth_vec) = &f.authors {
+        // filter out non-hex values
+        let auth_vec: Vec<&String> = auth_vec.iter().filter(|a| is_hex(a)).collect();
+
+        if !auth_vec.is_empty() {
+            query.push("(");
+
+            // shortcut authors into "IN" query
+            let any_is_range = auth_vec.iter().any(|pk| pk.len() != 64);
+            if !any_is_range {
+                query.push("e.pub_key in (");
+                let mut pk_sep = query.separated(", ");
+                for pk in auth_vec.iter() {
+                    pk_sep.push_bind(hex::decode(pk).ok());
+                }
+                query.push(") OR e.delegated_by in (");
+                let mut pk_delegated_sep = query.separated(", ");
+                for pk in auth_vec.iter() {
+                    pk_delegated_sep.push_bind(hex::decode(pk).ok());
+                }
+                query.push(")");
+                push_and = true;
+            } else {
+                let mut range_authors = query.separated(" OR ");
+                for auth in auth_vec {
+                    match hex_range(auth) {
+                        Some(HexSearch::Exact(ex)) => {
+                            range_authors
+                                .push("(e.pub_key = ")
+                                .push_bind_unseparated(ex.clone())
+                                .push_unseparated(" OR e.delegated_by = ")
+                                .push_bind_unseparated(ex)
+                                .push_unseparated(")");
+                        }
+                        Some(HexSearch::Range(lower, upper)) => {
+                            range_authors
+                                .push("((e.pub_key > ")
+                                .push_bind_unseparated(lower.clone())
+                                .push_unseparated(" AND e.pub_key < ")
+                                .push_bind_unseparated(upper.clone())
+                                .push_unseparated(") OR (e.delegated_by > ")
+                                .push_bind_unseparated(lower)
+                                .push_unseparated(" AND e.delegated_by < ")
+                                .push_bind_unseparated(upper)
+                                .push_unseparated("))");
+                        }
+                        Some(HexSearch::LowerOnly(lower)) => {
+                            range_authors
+                                .push("(e.pub_key > ")
+                                .push_bind_unseparated(lower.clone())
+                                .push_unseparated(" OR e.delegated_by > ")
+                                .push_bind_unseparated(lower)
+                                .push_unseparated(")");
+                        }
+                        None => {
+                            info!("Could not parse hex range from author {:?}", auth);
+                        }
+                    }
+                    push_and = true;
+                }
+            }
+            query.push(")");
+        }
+    }
+
+    // Query for Kind
+    if let Some(ks) = &f.kinds {
+        if !ks.is_empty() {
+            if push_and {
+                query.push(" AND ");
+            }
+            push_and = true;
+
+            query.push("e.kind in (");
+            let mut list_query = query.separated(", ");
+            for k in ks.iter() {
+                list_query.push_bind(*k as i64);
+            }
+            query.push(")");
+        }
+    }
+
+    // Query for event, allowing prefix matches
+    if let Some(id_vec) = &f.ids {
+        // filter out non-hex values
+        let id_vec: Vec<&String> = id_vec.iter().filter(|a| is_hex(a)).collect();
+
+        if !id_vec.is_empty() {
+            if push_and {
+                query.push(" AND (");
+            } else {
+                query.push("(");
+            }
+            push_and = true;
+
+            // shortcut ids into "IN" query
+            let any_is_range = id_vec.iter().any(|pk| pk.len() != 64);
+            if !any_is_range {
+                query.push("id in (");
+                let mut sep = query.separated(", ");
+                for id in id_vec.iter() {
+                    sep.push_bind(hex::decode(id).ok());
+                }
+                query.push(")");
+            } else {
+                // take each author and convert to a hex search
+                let mut id_query = query.separated(" OR ");
+                for id in id_vec {
+                    match hex_range(id) {
+                        Some(HexSearch::Exact(ex)) => {
+                            id_query
+                                .push("(id = ")
+                                .push_bind_unseparated(ex)
+                                .push_unseparated(")");
+                        }
+                        Some(HexSearch::Range(lower, upper)) => {
+                            id_query
+                                .push("(id > ")
+                                .push_bind_unseparated(lower)
+                                .push_unseparated(" AND id < ")
+                                .push_bind_unseparated(upper)
+                                .push_unseparated(")");
+                        }
+                        Some(HexSearch::LowerOnly(lower)) => {
+                            id_query
+                                .push("(id > ")
+                                .push_bind_unseparated(lower)
+                                .push_unseparated(")");
+                        }
+                        None => {
+                            info!("Could not parse hex range from id {:?}", id);
+                        }
+                    }
+                }
+            }
+
+            query.push(")");
+        }
+    }
+
+    // Query for tags
+    if let Some(map) = &f.tags {
+        if !map.is_empty() {
+            if push_and {
+                query.push(" AND ");
+            }
+            push_and = true;
+
+            for (key, val) in map.iter() {
+                query.push("e.id IN (SELECT ee.id FROM \"event\" ee LEFT JOIN tag t on ee.id = t.event_id WHERE ee.hidden != 1::bit(1) and (t.\"name\" = ")
+                    .push_bind(key.to_string())
+                    .push(" AND (value in (");
+
+                // plain value match first
+                let mut tag_query = query.separated(", ");
+                for v in val.iter() {
+                    if (v.len() % 2 != 0) && !is_lower_hex(v) {
+                        tag_query.push_bind(v.as_bytes());
+                    } else {
+                        tag_query.push_bind(hex::decode(v).ok());
+                    }
+                }
+                query.push("))))");
+            }
+        }
+    }
+
+    // Query for timestamp
+    if f.since.is_some() {
+        if push_and {
+            query.push(" AND ");
+        }
+        push_and = true;
+        query
+            .push("e.created_at > ")
+            .push_bind(Utc.timestamp_opt(f.since.unwrap() as i64, 0).unwrap());
+    }
+
+    // Query for timestamp
+    if f.until.is_some() {
+        if push_and {
+            query.push(" AND ");
+        }
+        push_and = true;
+        query
+            .push("e.created_at < ")
+            .push_bind(Utc.timestamp_opt(f.until.unwrap() as i64, 0).unwrap());
+    }
+
+    // never display hidden events
+    if push_and {
+        query.push(" AND e.hidden != 1::bit(1)");
+    } else {
+        query.push("e.hidden != 1::bit(1)");
+    }
+
+    // Apply per-filter limit to this query.
+    // The use of a LIMIT implies a DESC order, to capture only the most recent events.
+    if let Some(lim) = f.limit {
+        query.push(" ORDER BY e.created_at DESC LIMIT ");
+        query.push(lim.min(1000));
+    } else {
+        query.push(" ORDER BY e.created_at ASC LIMIT ");
+        query.push(1000);
+    }
+    Some(query)
+}
+
+impl FromRow<'_, PgRow> for VerificationRecord {
+    fn from_row(row: &'_ PgRow) -> std::result::Result<Self, Error> {
+        let name =
+            Nip05Name::try_from(row.get::<'_, &str, &str>("name")).or(Err(RowNotFound))?;
+        Ok(VerificationRecord {
+            rowid: row.get::<'_, i64, &str>("id") as u64,
+            name,
+            address: hex::encode(row.get::<'_, Vec<u8>, &str>("pub_key")),
+            event: hex::encode(row.get::<'_, Vec<u8>, &str>("event_id")),
+            event_created: row.get::<'_, DateTime<Utc>, &str>("created_at").timestamp() as u64,
+            last_success: None,
+            last_failure: match row.try_get::<'_, DateTime<Utc>, &str>("failed_at") {
+                Ok(x) => Some(x.timestamp() as u64),
+                _ => None,
+            },
+            failure_count: row.get::<'_, i32, &str>("fail_count") as u64,
+        })
+    }
+}

src/repo/postgres_migration.rs

@@ -0,0 +1,258 @@
+use crate::repo::postgres::PostgresPool;
+use async_trait::async_trait;
+use sqlx::{Executor, Postgres, Transaction};
+
+#[async_trait]
+pub trait Migration {
+    fn serial_number(&self) -> i64;
+    async fn run(&self, tx: &mut Transaction<Postgres>);
+}
+
+struct SimpleSqlMigration {
+    pub serial_number: i64,
+    pub sql: Vec<&'static str>,
+}
+
+#[async_trait]
+impl Migration for SimpleSqlMigration {
+    fn serial_number(&self) -> i64 {
+        self.serial_number
+    }
+
+    async fn run(&self, tx: &mut Transaction<Postgres>) {
+        for sql in self.sql.iter() {
+            tx.execute(*sql).await.unwrap();
+        }
+    }
+}
+
+/// Execute all migrations on the database.
+pub async fn run_migrations(db: &PostgresPool) -> crate::error::Result<usize> {
+    prepare_migrations_table(db).await;
+    run_migration(m001::migration(), db).await;
+    let m002_result = run_migration(m002::migration(), db).await;
+    if m002_result == MigrationResult::Upgraded {
+        m002::rebuild_tags(db).await?;
+    }
+    run_migration(m003::migration(), db).await;
+    Ok(current_version(db).await as usize)
+}
+
+async fn current_version(db: &PostgresPool) -> i64 {
+    sqlx::query_scalar("SELECT max(serial_number) FROM migrations;")
+        .fetch_one(db)
+        .await
+        .unwrap()
+}
+
+async fn prepare_migrations_table(db: &PostgresPool) {
+    sqlx::query("CREATE TABLE IF NOT EXISTS migrations (serial_number bigint)")
+        .execute(db)
+        .await
+        .unwrap();
+}
+
+// Running a migration was either unnecessary, or completed
+#[derive(PartialEq, Eq, Debug, Clone)]
+enum MigrationResult {
+    Upgraded,
+    NotNeeded,
+}
+
+async fn run_migration(migration: impl Migration, db: &PostgresPool) -> MigrationResult {
+    let row: i64 =
+        sqlx::query_scalar("SELECT COUNT(*) AS count FROM migrations WHERE serial_number = $1")
+            .bind(migration.serial_number())
+            .fetch_one(db)
+            .await
+            .unwrap();
+
+    if row > 0 {
+        return MigrationResult::NotNeeded;
+    }
+
+    let mut transaction = db.begin().await.unwrap();
+    migration.run(&mut transaction).await;
+
+    sqlx::query("INSERT INTO migrations VALUES ($1)")
+        .bind(migration.serial_number())
+        .execute(&mut transaction)
+        .await
+        .unwrap();
+
+    transaction.commit().await.unwrap();
+    MigrationResult::Upgraded
+}
+
+mod m001 {
+    use crate::repo::postgres_migration::{Migration, SimpleSqlMigration};
+
+    pub const VERSION: i64 = 1;
+
+    pub fn migration() -> impl Migration {
+        SimpleSqlMigration {
+            serial_number: VERSION,
+            sql: vec![
+                r#"
+-- Events table
+CREATE TABLE "event" (
+	id bytea NOT NULL,
+	pub_key bytea NOT NULL,
+	created_at timestamp with time zone NOT NULL,
+	kind integer NOT NULL,
+	"content" bytea NOT NULL,
+	hidden bit(1) NOT NULL DEFAULT 0::bit(1),
+	delegated_by bytea NULL,
+	first_seen timestamp with time zone NOT NULL DEFAULT now(),
+	CONSTRAINT event_pkey PRIMARY KEY (id)
+);
+CREATE INDEX event_created_at_idx ON "event" (created_at,kind);
+CREATE INDEX event_pub_key_idx ON "event" (pub_key);
+CREATE INDEX event_delegated_by_idx ON "event" (delegated_by);
+
+-- Tags table
+CREATE TABLE "tag" (
+	id int8 NOT NULL GENERATED BY DEFAULT AS IDENTITY,
+	event_id bytea NOT NULL,
+	"name" varchar NOT NULL,
+	value bytea NOT NULL,
+	CONSTRAINT tag_fk FOREIGN KEY (event_id) REFERENCES "event"(id) ON DELETE CASCADE
+);
+CREATE INDEX tag_event_id_idx ON tag USING btree (event_id, name);
+CREATE INDEX tag_value_idx ON tag USING btree (value);
+
+-- NIP-05 Verfication table
+CREATE TABLE "user_verification" (
+	id int8 NOT NULL GENERATED BY DEFAULT AS IDENTITY,
+	event_id bytea NOT NULL,
+	"name" varchar NOT NULL,
+	verified_at timestamptz NULL,
+	failed_at timestamptz NULL,
+	fail_count int4 NULL DEFAULT 0,
+	CONSTRAINT user_verification_pk PRIMARY KEY (id),
+	CONSTRAINT user_verification_fk FOREIGN KEY (event_id) REFERENCES "event"(id) ON DELETE CASCADE
+);
+CREATE INDEX user_verification_event_id_idx ON user_verification USING btree (event_id);
+CREATE INDEX user_verification_name_idx ON user_verification USING btree (name);
+        "#,
+            ],
+        }
+    }
+}
+
+mod m002 {
+    use async_std::stream::StreamExt;
+    use indicatif::{ProgressBar, ProgressStyle};
+    use sqlx::Row;
+    use std::time::Instant;
+    use tracing::info;
+
+    use crate::event::{single_char_tagname, Event};
+    use crate::repo::postgres::PostgresPool;
+    use crate::repo::postgres_migration::{Migration, SimpleSqlMigration};
+    use crate::utils::is_lower_hex;
+
+    pub const VERSION: i64 = 2;
+
+    pub fn migration() -> impl Migration {
+        SimpleSqlMigration {
+            serial_number: VERSION,
+            sql: vec![
+                r#"
+-- Add tag value column
+ALTER TABLE tag ADD COLUMN value_hex bytea;
+-- Remove not-null constraint
+ALTER TABLE tag ALTER COLUMN value DROP NOT NULL;
+-- Add value index
+CREATE INDEX tag_value_hex_idx ON tag USING btree (value_hex);
+        "#,
+            ],
+        }
+    }
+
+    pub async fn rebuild_tags(db: &PostgresPool) -> crate::error::Result<()> {
+        // Check how many events we have to process
+        let start = Instant::now();
+        let mut tx = db.begin().await.unwrap();
+        let mut update_tx = db.begin().await.unwrap();
+        // Clear out table
+        sqlx::query("DELETE FROM tag;")
+            .execute(&mut update_tx)
+            .await?;
+        {
+            let event_count: i64 = sqlx::query_scalar("SELECT COUNT(*) from event;")
+                .fetch_one(&mut tx)
+                .await
+                .unwrap();
+            let bar = ProgressBar::new(event_count.try_into().unwrap())
+                .with_message("rebuilding tags table");
+            bar.set_style(
+                ProgressStyle::with_template(
+                    "[{elapsed_precise}] {bar:40.white/blue} {pos:>7}/{len:7} [{percent}%] {msg}",
+                )
+                .unwrap(),
+            );
+            let mut events =
+                sqlx::query("SELECT id, content FROM event ORDER BY id;").fetch(&mut tx);
+            while let Some(row) = events.next().await {
+                bar.inc(1);
+                // get the row id and content
+                let row = row.unwrap();
+                let event_id: Vec<u8> = row.get(0);
+                let event_bytes: Vec<u8> = row.get(1);
+                let event: Event = serde_json::from_str(&String::from_utf8(event_bytes).unwrap())?;
+
+                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) {
+                        let q = "INSERT INTO tag (event_id, \"name\", value_hex) VALUES ($1, $2, $3) ON CONFLICT DO NOTHING;";
+                        sqlx::query(q)
+                            .bind(&event_id)
+                            .bind(tagname)
+                            .bind(hex::decode(tagval).ok())
+                            .execute(&mut update_tx)
+                            .await?;
+                    } else {
+                        let q = "INSERT INTO tag (event_id, \"name\", value) VALUES ($1, $2, $3) ON CONFLICT DO NOTHING;";
+                        sqlx::query(q)
+                            .bind(&event_id)
+                            .bind(tagname)
+                            .bind(tagval.as_bytes())
+                            .execute(&mut update_tx)
+                            .await?;
+                    }
+                }
+            }
+            update_tx.commit().await?;
+            bar.finish();
+        }
+        info!("rebuilt tags in {:?}", start.elapsed());
+        Ok(())
+    }
+}
+
+mod m003 {
+    use crate::repo::postgres_migration::{Migration, SimpleSqlMigration};
+
+    pub const VERSION: i64 = 3;
+
+    pub fn migration() -> impl Migration {
+        SimpleSqlMigration {
+            serial_number: VERSION,
+            sql: vec![
+                r#"
+-- Add unique constraint on tag
+ALTER TABLE tag ADD CONSTRAINT unique_constraint_name UNIQUE (event_id, "name", value);
+        "#,
+            ],
+        }
+    }
+}

src/repo/sqlite_migration.rs

@@ -10,17 +10,20 @@ use rusqlite::Connection;
 use std::cmp::Ordering;
 use std::time::Instant;
 use tracing::{debug, error, info};
+use indicatif::{ProgressBar, ProgressStyle};
 
 /// Startup DB Pragmas
 pub const STARTUP_SQL: &str = r##"
 PRAGMA main.synchronous = NORMAL;
 PRAGMA foreign_keys = ON;
 PRAGMA journal_size_limit = 32768;
+PRAGMA temp_store = 2; -- use memory, not temp files
+PRAGMA main.cache_size = 20000; -- 80MB max cache size per conn
 pragma mmap_size = 17179869184; -- cap mmap at 16GB
 "##;
 
 /// Latest database version
-pub const DB_VERSION: usize = 13;
+pub const DB_VERSION: usize = 16;
 
 /// Schema definition
 const INIT_SQL: &str = formatcp!(
@@ -50,27 +53,34 @@ 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 author_index ON event(author);
+CREATE INDEX IF NOT EXISTS kind_index ON event(kind);
 CREATE INDEX IF NOT EXISTS created_at_index ON event(created_at);
 CREATE INDEX IF NOT EXISTS delegated_by_index ON event(delegated_by);
 CREATE INDEX IF NOT EXISTS event_composite_index ON event(kind,created_at);
 CREATE INDEX IF NOT EXISTS kind_author_index ON event(kind,author);
+CREATE INDEX IF NOT EXISTS kind_created_at_index ON event(kind,created_at);
+CREATE INDEX IF NOT EXISTS author_created_at_index ON event(author,created_at);
+CREATE INDEX IF NOT EXISTS author_kind_index ON event(author,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.
+-- We duplicate the kind/created_at to make indexes much more efficient.
 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.
+created_at INTEGER NOT NULL, -- when the event was authored
+kind INTEGER NOT NULL, -- event kind
 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);
-CREATE INDEX IF NOT EXISTS tag_composite_index ON tag(event_id,name,value_hex,value);
-CREATE INDEX IF NOT EXISTS tag_name_eid_index ON tag(name,event_id,value_hex);
+CREATE INDEX IF NOT EXISTS tag_composite_index ON tag(event_id,name,value);
+CREATE INDEX IF NOT EXISTS tag_name_eid_index ON tag(name,event_id,value);
+CREATE INDEX IF NOT EXISTS tag_covering_index ON tag(name,kind,value,created_at,event_id);
 
 -- NIP-05 User Validation
 CREATE TABLE IF NOT EXISTS user_verification (
@@ -95,7 +105,21 @@ pub fn curr_db_version(conn: &mut Connection) -> Result<usize> {
     Ok(curr_version)
 }
 
-fn mig_init(conn: &mut PooledConnection) -> Result<usize> {
+/// Determine event count
+pub fn db_event_count(conn: &mut Connection) -> Result<usize> {
+    let query = "SELECT count(*) FROM event;";
+    let count = conn.query_row(query, [], |row| row.get(0))?;
+    Ok(count)
+}
+
+/// Determine tag count
+pub fn db_tag_count(conn: &mut Connection) -> Result<usize> {
+    let query = "SELECT count(*) FROM tag;";
+    let count = conn.query_row(query, [], |row| row.get(0))?;
+    Ok(count)
+}
+
+fn mig_init(conn: &mut PooledConnection) -> usize {
     match conn.execute_batch(INIT_SQL) {
         Ok(()) => {
             info!(
@@ -108,11 +132,11 @@ fn mig_init(conn: &mut PooledConnection) -> Result<usize> {
             panic!("database could not be initialized");
         }
     }
-    Ok(DB_VERSION)
+    DB_VERSION
 }
 
 /// Upgrade DB to latest version, and execute pragma settings
-pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
+pub fn upgrade_db(conn: &mut PooledConnection) -> Result<usize> {
     // check the version.
     let mut curr_version = curr_db_version(conn)?;
     info!("DB version = {:?}", curr_version);
@@ -123,11 +147,11 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
     );
     debug!(
         "SQLite max table/blob/text length: {} MB",
-        (conn.limit(Limit::SQLITE_LIMIT_LENGTH) as f64 / (1024 * 1024) as f64).floor()
+        (f64::from(conn.limit(Limit::SQLITE_LIMIT_LENGTH)) / f64::from(1024 * 1024)).floor()
     );
     debug!(
         "SQLite max SQL length: {} MB",
-        (conn.limit(Limit::SQLITE_LIMIT_SQL_LENGTH) as f64 / (1024 * 1024) as f64).floor()
+        (f64::from(conn.limit(Limit::SQLITE_LIMIT_SQL_LENGTH)) / f64::from(1024 * 1024)).floor()
     );
 
     match curr_version.cmp(&DB_VERSION) {
@@ -135,26 +159,22 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
         Ordering::Less => {
             // initialize from scratch
             if curr_version == 0 {
-                curr_version = mig_init(conn)?;
+                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)?;
             }
@@ -179,6 +199,15 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
             if curr_version == 12 {
                 curr_version = mig_12_to_13(conn)?;
             }
+            if curr_version == 13 {
+                curr_version = mig_13_to_14(conn)?;
+            }
+            if curr_version == 14 {
+                curr_version = mig_14_to_15(conn)?;
+            }
+            if curr_version == 15 {
+                curr_version = mig_15_to_16(conn)?;
+            }
 
             if curr_version == DB_VERSION {
                 info!(
@@ -189,13 +218,12 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
         }
         // Database is current, all is good
         Ordering::Equal => {
-            debug!("Database version was already current (v{})", DB_VERSION);
+            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
+                "Database version is newer than supported by this executable (v{curr_version} > v{DB_VERSION})",
             );
         }
     }
@@ -203,9 +231,65 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
     // Setup PRAGMA
     conn.execute_batch(STARTUP_SQL)?;
     debug!("SQLite PRAGMA startup completed");
+    Ok(DB_VERSION)
+}
+
+pub fn rebuild_tags(conn: &mut PooledConnection) -> Result<()> {
+    // Check how many events we have to process
+    let count = db_event_count(conn)?;
+    let update_each_percent = 0.05;
+    let mut percent_done = 0.0;
+    let mut events_processed = 0;
+    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()? {
+            if (events_processed as f32)/(count as f32) > percent_done {
+                info!("Tag update {}% complete...", (100.0*percent_done).round());
+                percent_done += update_each_percent;
+            }
+            // 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],
+                    )?;
+                }
+            }
+            events_processed += 1;
+        }
+    }
+    tx.commit()?;
+    info!("rebuilt tags in {:?}", start.elapsed());
     Ok(())
 }
 
+
+
 //// Migration Scripts
 
 fn mig_1_to_2(conn: &mut PooledConnection) -> Result<usize> {
@@ -337,7 +421,6 @@ fn mig_5_to_6(conn: &mut PooledConnection) -> Result<usize> {
         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)?;
@@ -485,6 +568,7 @@ fn mig_11_to_12(conn: &mut PooledConnection) -> Result<usize> {
         // Lookup every replaceable event
         let mut stmt = tx.prepare("select kind,author from event where kind in (0,3,41) or (kind>=10000 and kind<20000) order by id;")?;
         let mut replaceable_rows = stmt.query([])?;
+        info!("updating replaceable events; this could take awhile...");
         while let Some(row) = replaceable_rows.next()? {
             // we want to capture the event_id that had the tag, the tag name, and the tag hex value.
             let event_kind: u64 = row.get(0)?;
@@ -524,3 +608,124 @@ PRAGMA user_version = 13;
     }
     Ok(13)
 }
+
+fn mig_13_to_14(conn: &mut PooledConnection) -> Result<usize> {
+    info!("database schema needs update from 13->14");
+    let upgrade_sql = r##"
+CREATE INDEX IF NOT EXISTS kind_index ON event(kind);
+CREATE INDEX IF NOT EXISTS kind_created_at_index ON event(kind,created_at);
+pragma optimize;
+PRAGMA user_version = 14;
+"##;
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v13 -> v14");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    Ok(14)
+}
+
+fn mig_14_to_15(conn: &mut PooledConnection) -> Result<usize> {
+    info!("database schema needs update from 14->15");
+    let upgrade_sql = r##"
+CREATE INDEX IF NOT EXISTS author_created_at_index ON event(author,created_at);
+CREATE INDEX IF NOT EXISTS author_kind_index ON event(author,kind);
+PRAGMA user_version = 15;
+"##;
+    match conn.execute_batch(upgrade_sql) {
+        Ok(()) => {
+            info!("database schema upgraded v14 -> v15");
+        }
+        Err(err) => {
+            error!("update failed: {}", err);
+            panic!("database could not be upgraded");
+        }
+    }
+    // clear out hidden events
+    let clear_hidden_sql = r##"DELETE FROM event WHERE HIDDEN=true;"##;
+    info!("removing hidden events; this may take awhile...");
+    match conn.execute_batch(clear_hidden_sql) {
+        Ok(()) => {
+            info!("all hidden events removed");
+        },
+        Err(err) => {
+            error!("delete failed: {}", err);
+            panic!("could not remove hidden events");
+        }
+    }
+    Ok(15)
+}
+
+fn mig_15_to_16(conn: &mut PooledConnection) -> Result<usize> {
+    let count = db_event_count(conn)?;
+    info!("database schema needs update from 15->16 (this make take a few minutes)");
+    let upgrade_sql = r##"
+DROP TABLE tag;
+CREATE TABLE 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.
+created_at INTEGER NOT NULL, -- when the event was authored
+kind INTEGER NOT NULL, -- event kind
+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_composite_index ON tag(event_id,name,value);
+CREATE INDEX IF NOT EXISTS tag_name_eid_index ON tag(name,event_id,value);
+CREATE INDEX IF NOT EXISTS tag_covering_index ON tag(name,kind,value,created_at,event_id);
+"##;
+
+    let start = Instant::now();
+    let tx = conn.transaction()?;
+
+    let bar = ProgressBar::new(count.try_into().unwrap())
+        .with_message("rebuilding tags table");
+    bar.set_style(
+        ProgressStyle::with_template(
+            "[{elapsed_precise}] {bar:40.white/blue} {pos:>7}/{len:7} [{percent}%] {msg}",
+        )
+            .unwrap(),
+    );
+    {
+        tx.execute_batch(upgrade_sql)?;
+        let mut stmt = tx.prepare("select id, kind, created_at, content from event order by id;")?;
+        let mut tag_rows = stmt.query([])?;
+        let mut count = 0;
+        while let Some(row) = tag_rows.next()? {
+            count += 1;
+            if count%10==0 {
+                bar.inc(10);
+            }
+            let event_id: u64 = row.get(0)?;
+            let kind: u64 = row.get(1)?;
+            let created_at: u64 = row.get(2)?;
+            let event_json: String = row.get(3)?;
+            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();
+                // otherwise, insert as text
+                tx.execute(
+                    "INSERT INTO tag (event_id, name, value, kind, created_at) VALUES (?1, ?2, ?3, ?4, ?5);",
+                    params![event_id, tagname, &tagval, kind, created_at],
+                )?;
+            }
+        }
+        tx.execute("PRAGMA user_version = 16;", [])?;
+    }
+    bar.finish();
+    tx.commit()?;
+    info!("database schema upgraded v15 -> v16 in {:?}", start.elapsed());
+    Ok(16)
+}

src/server.rs

@@ -3,6 +3,7 @@ use crate::close::Close;
 use crate::close::CloseCmd;
 use crate::config::{Settings, VerifiedUsersMode};
 use crate::conn;
+use crate::repo::NostrRepo;
 use crate::db;
 use crate::db::SubmittedEvent;
 use crate::error::{Error, Result};
@@ -12,6 +13,9 @@ use crate::info::RelayInfo;
 use crate::nip05;
 use crate::notice::Notice;
 use crate::subscription::Subscription;
+use prometheus::IntCounterVec;
+use prometheus::IntGauge;
+use prometheus::{Encoder, Histogram, IntCounter, HistogramOpts, Opts, Registry, TextEncoder};
 use futures::SinkExt;
 use futures::StreamExt;
 use governor::{Jitter, Quota, RateLimiter};
@@ -22,10 +26,8 @@ use hyper::upgrade::Upgraded;
 use hyper::{
     header, server::conn::AddrStream, upgrade, Body, Request, Response, Server, StatusCode,
 };
-use rusqlite::OpenFlags;
 use serde::{Deserialize, Serialize};
 use serde_json::json;
-use tokio::sync::Mutex;
 use std::collections::HashMap;
 use std::convert::Infallible;
 use std::net::SocketAddr;
@@ -40,23 +42,25 @@ use tokio::sync::broadcast::{self, Receiver, Sender};
 use tokio::sync::mpsc;
 use tokio::sync::oneshot;
 use tokio_tungstenite::WebSocketStream;
-use tracing::*;
+use tracing::{debug, error, info, trace, warn};
 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.
+/// Handle arbitrary HTTP requests, including for `WebSocket` upgrades.
+#[allow(clippy::too_many_arguments)]
 async fn handle_web_request(
     mut request: Request<Body>,
-    pool: db::SqlitePool,
+    repo: Arc<dyn NostrRepo>,
     settings: Settings,
     remote_addr: SocketAddr,
     broadcast: Sender<Event>,
     event_tx: tokio::sync::mpsc::Sender<SubmittedEvent>,
     shutdown: Receiver<()>,
-    safe_to_read: Arc<Mutex<u64>>,
+    registry: Registry,
+    metrics: NostrMetrics,
 ) -> Result<Response<Body>, Infallible> {
     match (
         request.uri().path(),
@@ -92,7 +96,7 @@ async fn handle_web_request(
                                     tokio_tungstenite::tungstenite::protocol::Role::Server,
                                     Some(config),
                                 )
-                                .await;
+                                    .await;
                                 let origin = get_header_string("origin", request.headers());
                                 let user_agent = get_header_string("user-agent", request.headers());
                                 // determine the remote IP from headers if the exist
@@ -111,22 +115,21 @@ async fn handle_web_request(
                                 };
                                 // spawn a nostr server with our websocket
                                 tokio::spawn(nostr_server(
-                                    pool,
+                                    repo,
                                     client_info,
                                     settings,
                                     ws_stream,
                                     broadcast,
                                     event_tx,
                                     shutdown,
-				    safe_to_read,
+                                    metrics,
                                 ));
                             }
                             // todo: trace, don't print...
                             Err(e) => println!(
                                 "error when trying to upgrade connection \
-                                 from address {} to websocket connection. \
-                                 Error is: {}",
-                                remote_addr, e
+                                 from address {remote_addr} to websocket connection. \
+                                 Error is: {e}",
                             ),
                         }
                     });
@@ -136,7 +139,7 @@ async fn handle_web_request(
                 Err(error) => {
                     warn!("websocket response failed");
                     let mut res =
-                        Response::new(Body::from(format!("Failed to create websocket: {}", error)));
+                        Response::new(Body::from(format!("Failed to create websocket: {error}")));
                     *res.status_mut() = StatusCode::BAD_REQUEST;
                     return Ok(res);
                 }
@@ -157,26 +160,38 @@ async fn handle_web_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());
+                                  .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())
+               .status(200)
+               .header("Content-Type", "text/plain")
+               .body(Body::from("Please use a Nostr client to connect."))
+               .unwrap())
+        }
+        ("/metrics", false) => {
+            let mut buffer = vec![];
+            let encoder = TextEncoder::new();
+            let metric_families = registry.gather();
+            encoder.encode(&metric_families, &mut buffer).unwrap();
+
+            Ok(Response::builder()
+               .status(StatusCode::OK)
+               .header("Content-Type", "text/plain")
+               .body(Body::from(buffer))
+               .unwrap())
         }
         (_, _) => {
             //handle any other url
             Ok(Response::builder()
-                .status(StatusCode::NOT_FOUND)
-                .body(Body::from("Nothing here."))
-                .unwrap())
+               .status(StatusCode::NOT_FOUND)
+               .body(Body::from("Nothing here."))
+               .unwrap())
         }
     }
 }
@@ -184,7 +199,7 @@ async fn handle_web_request(
 fn get_header_string(header: &str, headers: &HeaderMap) -> Option<String> {
     headers
         .get(header)
-        .and_then(|x| x.to_str().ok().map(|x| x.to_string()))
+        .and_then(|x| x.to_str().ok().map(std::string::ToString::to_string))
 }
 
 // return on a control-c or internally requested shutdown signal
@@ -194,24 +209,98 @@ async fn ctrl_c_or_signal(mut shutdown_signal: Receiver<()>) {
     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;
+                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;
             },
-        _ = term_signal.recv() => {
-        info!("Shutting down webserver due to SIGTERM");
-        break;
-        },
         }
     }
 }
 
+fn create_metrics() -> (Registry, NostrMetrics) {
+    // setup prometheus registry
+    let registry = Registry::new();
+
+    let query_sub = Histogram::with_opts(HistogramOpts::new(
+        "nostr_query_seconds",
+        "Subscription response times",
+    )).unwrap();
+    let query_db = Histogram::with_opts(HistogramOpts::new(
+        "nostr_filter_seconds",
+        "Filter SQL query times",
+    )).unwrap();
+    let write_events = Histogram::with_opts(HistogramOpts::new(
+        "nostr_events_write_seconds",
+        "Event writing response times",
+    )).unwrap();
+    let sent_events = IntCounterVec::new(
+	Opts::new("nostr_events_sent_total", "Events sent to clients"),
+	vec!["source"].as_slice(),
+    ).unwrap();
+    let connections = IntCounter::with_opts(Opts::new(
+        "nostr_connections_total",
+        "New connections",
+    )).unwrap();
+    let db_connections = IntGauge::with_opts(Opts::new(
+        "nostr_db_connections", "Active database connections"
+    )).unwrap();
+    let query_aborts = IntCounterVec::new(
+        Opts::new("nostr_query_abort_total", "Aborted queries"),
+        vec!["reason"].as_slice(),
+    ).unwrap();
+    let cmd_req = IntCounter::with_opts(Opts::new(
+        "nostr_cmd_req_total",
+        "REQ commands",
+    )).unwrap();
+    let cmd_event = IntCounter::with_opts(Opts::new(
+        "nostr_cmd_event_total",
+        "EVENT commands",
+    )).unwrap();
+    let cmd_close = IntCounter::with_opts(Opts::new(
+        "nostr_cmd_close_total",
+        "CLOSE commands",
+    )).unwrap();
+    let disconnects = IntCounterVec::new(
+        Opts::new("nostr_disconnects_total", "Client disconnects"),
+        vec!["reason"].as_slice(),
+        ).unwrap();
+    registry.register(Box::new(query_sub.clone())).unwrap();
+    registry.register(Box::new(query_db.clone())).unwrap();
+    registry.register(Box::new(write_events.clone())).unwrap();
+    registry.register(Box::new(sent_events.clone())).unwrap();
+    registry.register(Box::new(connections.clone())).unwrap();
+    registry.register(Box::new(db_connections.clone())).unwrap();
+    registry.register(Box::new(query_aborts.clone())).unwrap();
+    registry.register(Box::new(cmd_req.clone())).unwrap();
+    registry.register(Box::new(cmd_event.clone())).unwrap();
+    registry.register(Box::new(cmd_close.clone())).unwrap();
+    registry.register(Box::new(disconnects.clone())).unwrap();
+    let metrics = NostrMetrics {
+        query_sub,
+        query_db,
+        write_events,
+        sent_events,
+        connections,
+        db_connections,
+	disconnects,
+        query_aborts,
+	cmd_req,
+	cmd_event,
+	cmd_close,
+    };
+    (registry,metrics)
+}
+
 /// Start running a Nostr relay server.
-pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result<(), Error> {
+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() {
@@ -254,18 +343,18 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
     let rt = Builder::new_multi_thread()
         .enable_all()
         .thread_name_fn(|| {
-	    // give each thread a unique numeric name
-	    static ATOMIC_ID: std::sync::atomic::AtomicUsize = std::sync::atomic::AtomicUsize::new(0);
-	    let id = ATOMIC_ID.fetch_add(1,Ordering::SeqCst);
-	    format!("tokio-ws-{}", id)
-		})
-        // limit concurrent SQLite blocking threads
+            // give each thread a unique numeric name
+            static ATOMIC_ID: std::sync::atomic::AtomicUsize = std::sync::atomic::AtomicUsize::new(0);
+            let id = ATOMIC_ID.fetch_add(1,Ordering::SeqCst);
+            format!("tokio-ws-{id}")
+        })
+    // limit concurrent SQLite blocking threads
         .max_blocking_threads(settings.limits.max_blocking_threads)
         .on_thread_start(|| {
             trace!("started new thread: {:?}", std::thread::current().name());
         })
         .on_thread_stop(|| {
-	    trace!("stopped thread: {:?}", std::thread::current().name());
+            trace!("stopped thread: {:?}", std::thread::current().name());
         })
         .build()
         .unwrap();
@@ -274,8 +363,6 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
         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
@@ -298,23 +385,28 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
         // 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
+
+	let (registry, metrics) = create_metrics();
+        // build a repository for events
+        let repo = db::build_repo(&settings, metrics.clone()).await;
+        // start the database writer task.  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;
+        tokio::task::spawn(
+            db::db_writer(
+                repo.clone(),
+                settings.clone(),
+                event_rx,
+                bcast_tx.clone(),
+                metadata_tx.clone(),
+                shutdown_listen,
+            ));
         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());
+                nip05::Verifier::new(repo.clone(), metadata_rx, bcast_tx.clone(), settings.clone());
             if let Ok(mut v) = verifier_opt {
                 if verified_users_active {
                     tokio::task::spawn(async move {
@@ -324,22 +416,6 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
                 }
             }
         }
-        // build a connection pool for DB maintenance
-        let maintenance_pool = db::build_pool(
-            "maintenance writer",
-            &settings,
-            OpenFlags::SQLITE_OPEN_READ_WRITE | OpenFlags::SQLITE_OPEN_CREATE,
-            1,
-            2,
-            false,
-        );
-
-	// Create a mutex that will block readers, so that a
-	// checkpoint can be performed quickly.
-	let safe_to_read = Arc::new(Mutex::new(0));
-
-        db::db_optimize_task(maintenance_pool.clone()).await;
-        db::db_checkpoint_task(maintenance_pool, safe_to_read.clone()).await;
 
         // listen for (external to tokio) shutdown request
         let controlled_shutdown = invoke_shutdown.clone();
@@ -349,10 +425,9 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
                 Ok(()) => {
                     info!("control message requesting shutdown");
                     controlled_shutdown.send(()).ok();
-                }
+                },
                 Err(std::sync::mpsc::RecvError) => {
-                    // FIXME: spurious error on startup?
-                    debug!("shutdown requestor is disconnected");
+                    trace!("shutdown requestor is disconnected (this is normal)");
                 }
             };
         });
@@ -366,41 +441,34 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
             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,
-            db_min_conn,
-            db_max_conn,
-            true,
-        );
-	// spawn a task to check the pool size.
-	let pool_monitor = pool.clone();
-	tokio::spawn(async move {db::monitor_pool("reader", pool_monitor).await;});
+        // spawn a task to check the pool size.
+        //let pool_monitor = pool.clone();
+        //tokio::spawn(async move {db::monitor_pool("reader", pool_monitor).await;});
 
         // 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 repo = repo.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();
-            let safe_to_read = safe_to_read.clone();
+            let registry = registry.clone();
+            let metrics = metrics.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(),
+                        repo.clone(),
                         settings.clone(),
                         remote_addr,
                         bcast.clone(),
                         event.clone(),
                         stop.subscribe(),
-			safe_to_read.clone(),
+                        registry.clone(),
+                        metrics.clone(),
                     )
                 }))
             }
@@ -410,7 +478,7 @@ pub fn start_server(settings: Settings, shutdown_rx: MpscReceiver<()>) -> Result
             .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);
+            eprintln!("server error: {e}");
         }
     });
     Ok(())
@@ -428,11 +496,15 @@ pub enum NostrMessage {
     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());
+/// Convert Message to `NostrMessage`
+fn convert_to_msg(msg: &str, max_bytes: Option<usize>) -> Result<NostrMessage> {
+    let parsed_res: Result<NostrMessage> = serde_json::from_str(msg).map_err(std::convert::Into::into);
     match parsed_res {
         Ok(m) => {
+            if let NostrMessage::SubMsg(_) = m {
+                // note; this only prints the first 16k of a REQ and then truncates.
+                trace!("REQ: {:?}",msg);
+            };
             if let NostrMessage::EventMsg(_) = m {
                 if let Some(max_size) = max_bytes {
                     // check length, ensure that some max size is set.
@@ -444,15 +516,15 @@ fn convert_to_msg(msg: String, max_bytes: Option<usize>) -> Result<NostrMessage>
             Ok(m)
         }
         Err(e) => {
-            debug!("proto parse error: {:?}", e);
-            debug!("parse error on message: {}", msg.trim());
+            trace!("proto parse error: {:?}", e);
+            trace!("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(notice: Notice) -> Message {
+/// Turn a string into a NOTICE message ready to send over a `WebSocket`
+fn make_notice_message(notice: &Notice) -> Message {
     let json = match notice {
         Notice::Message(ref msg) => json!(["NOTICE", msg]),
         Notice::EventResult(ref res) => json!(["OK", res.id, res.status.to_bool(), res.msg]),
@@ -469,15 +541,16 @@ struct ClientInfo {
 
 /// Handle new client connections.  This runs through an event loop
 /// for all client communication.
+#[allow(clippy::too_many_arguments)]
 async fn nostr_server(
-    pool: db::SqlitePool,
+    repo: Arc<dyn NostrRepo>,
     client_info: ClientInfo,
     settings: Settings,
     mut ws_stream: WebSocketStream<Upgraded>,
     broadcast: Sender<Event>,
     event_tx: mpsc::Sender<SubmittedEvent>,
     mut shutdown: Receiver<()>,
-    safe_to_read: Arc<Mutex<u64>>,
+    metrics: NostrMetrics,
 ) {
     // the time this websocket nostr server started
     let orig_start = Instant::now();
@@ -504,7 +577,7 @@ async fn nostr_server(
     // we will send out the tx handle to any query we generate.
     // this has capacity for some of the larger requests we see, which
     // should allow the DB thread to release the handle earlier.
-    let (query_tx, mut query_rx) = mpsc::channel::<db::QueryResult>(20000);
+    let (query_tx, mut query_rx) = mpsc::channel::<db::QueryResult>(20_000);
     // Create channel for receiving NOTICEs
     let (notice_tx, mut notice_rx) = mpsc::channel::<Notice>(128);
 
@@ -528,19 +601,26 @@ async fn nostr_server(
     // and how many it received from queries.
     let mut client_published_event_count: usize = 0;
     let mut client_received_event_count: usize = 0;
-    debug!("new client connection (cid: {}, ip: {:?})", cid, conn.ip());
-    let origin = client_info.origin.unwrap_or_else(|| "<unspecified>".into());
+
+    let unspec = "<unspecified>".to_string();
+    info!("new client connection (cid: {}, ip: {:?})", cid, conn.ip());
+    let origin = client_info.origin.as_ref().unwrap_or_else(|| &unspec);
     let user_agent = client_info
-        .user_agent
-        .unwrap_or_else(|| "<unspecified>".into());
-    debug!(
+        .user_agent.as_ref()
+        .unwrap_or_else(|| &unspec);
+    info!(
         "cid: {}, origin: {:?}, user-agent: {:?}",
         cid, origin, user_agent
     );
+
+    // Measure connections
+    metrics.connections.inc();
+
     loop {
         tokio::select! {
             _ = shutdown.recv() => {
-        info!("Close connection down due to shutdown, client: {}, ip: {:?}, connected: {:?}", cid, conn.ip(), orig_start.elapsed());
+		metrics.disconnects.with_label_values(&["shutdown"]).inc();
+                info!("Close connection down due to shutdown, client: {}, ip: {:?}, connected: {:?}", cid, conn.ip(), orig_start.elapsed());
                 // server shutting down, exit loop
                 break;
             },
@@ -549,22 +629,24 @@ async fn nostr_server(
                 // 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");
+		    metrics.disconnects.with_label_values(&["timeout"]).inc();
                     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();
+                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);
+                    let send_str = format!("[\"EOSE\",\"{subesc}\"]");
                     ws_stream.send(Message::Text(send_str)).await.ok();
                 } else {
                     client_received_event_count += 1;
+		    metrics.sent_events.with_label_values(&["db"]).inc();
                     // send a result
                     let send_str = format!("[\"EVENT\",\"{}\",{}]", subesc, &query_result.event);
                     ws_stream.send(Message::Text(send_str)).await.ok();
@@ -578,7 +660,6 @@ async fn nostr_server(
                     if !sub.interested_in_event(&global_event) {
                         continue;
                     }
-
                     // TODO: serialize at broadcast time, instead of
                     // once for each consumer.
                     if let Ok(event_str) = serde_json::to_string(&global_event) {
@@ -587,7 +668,8 @@ async fn nostr_server(
                                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();
+			metrics.sent_events.with_label_values(&["realtime"]).inc();
+                        ws_stream.send(Message::Text(format!("[\"EVENT\",\"{subesc}\",{event_str}]"))).await.ok();
                     } else {
                         warn!("could not serialize event: {:?}", global_event.get_event_id_prefix());
                     }
@@ -599,11 +681,11 @@ async fn nostr_server(
                 // 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)
+                        convert_to_msg(&m,settings.limits.max_event_bytes)
                     },
-            Some(Ok(Message::Binary(_))) => {
-            ws_stream.send(
-                make_notice_message(Notice::message("binary messages are not accepted".into()))).await.ok();
+                    Some(Ok(Message::Binary(_))) => {
+                        ws_stream.send(
+                            make_notice_message(&Notice::message("binary messages are not accepted".into()))).await.ok();
                         continue;
                     },
                     Some(Ok(Message::Ping(_) | Message::Pong(_))) => {
@@ -611,27 +693,32 @@ async fn nostr_server(
                         // send responses automatically.
                         continue;
                     },
-            Some(Err(WsError::Capacity(MessageTooLong{size, max_size}))) => {
-            ws_stream.send(
-                make_notice_message(Notice::message(format!("message too large ({} > {})",size, max_size)))).await.ok();
+                    Some(Err(WsError::Capacity(MessageTooLong{size, max_size}))) => {
+                        ws_stream.send(
+                            make_notice_message(&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)))
+                    Some(Ok(Message::Close(_)) |
+                         Err(WsError::AlreadyClosed | WsError::ConnectionClosed |
+                             WsError::Protocol(tungstenite::error::ProtocolError::ResetWithoutClosingHandshake)))
                         => {
                             debug!("websocket close from client (cid: {}, ip: {:?})",cid, conn.ip());
-                        break;
-                    },
+			    metrics.disconnects.with_label_values(&["normal"]).inc();
+                            break;
+                        },
                     Some(Err(WsError::Io(e))) => {
                         // IO errors are considered fatal
                         warn!("IO error (cid: {}, ip: {:?}): {:?}", cid, conn.ip(), e);
+			metrics.disconnects.with_label_values(&["error"]).inc();
+
                         break;
                     }
                     x => {
                         // default condition on error is to close the client connection
                         info!("unknown error (cid: {}, ip: {:?}): {:?} (closing conn)", cid, conn.ip(), x);
+			metrics.disconnects.with_label_values(&["error"]).inc();
+
                         break;
                     }
                 };
@@ -643,28 +730,29 @@ async fn nostr_server(
                         // handle each type of message
                         let evid = ec.event_id().to_owned();
                         let parsed : Result<Event> = Result::<Event>::from(ec);
+			metrics.cmd_event.inc();
                         match parsed {
                             Ok(e) => {
                                 let id_prefix:String = e.id.chars().take(8).collect();
-                                debug!("successfully parsed/validated event: {:?} (cid: {})", id_prefix, cid);
+                                debug!("successfully parsed/validated event: {:?} (cid: {}, kind: {})", id_prefix, cid, e.kind);
                                 // 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() };
+                                    let submit_event = SubmittedEvent { event: e.clone(), notice_tx: notice_tx.clone(), source_ip: conn.ip().to_string(), origin: client_info.origin.clone(), user_agent: client_info.user_agent.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 {
-                        let msg = format!("The event created_at field is out of the acceptable range (+{}sec) for this relay.",fut_sec);
-                        let notice = Notice::invalid(e.id, &msg);
-                        ws_stream.send(make_notice_message(notice)).await.ok();
-                    }
-                }
+                                } else {
+                                    info!("client: {} sent a far future-dated event", cid);
+                                    if let Some(fut_sec) = settings.options.reject_future_seconds {
+                                        let msg = format!("The event created_at field is out of the acceptable range (+{fut_sec}sec) for this relay.");
+                                        let notice = Notice::invalid(e.id, &msg);
+                                        ws_stream.send(make_notice_message(&notice)).await.ok();
+                                    }
+                                }
                             },
                             Err(e) => {
                                 info!("client sent an invalid event (cid: {})", cid);
-                                ws_stream.send(make_notice_message(Notice::invalid(evid, &format!("{}", e)))).await.ok();
+                                ws_stream.send(make_notice_message(&Notice::invalid(evid, &format!("{e}")))).await.ok();
                             }
                         }
                     },
@@ -675,61 +763,63 @@ async fn nostr_server(
                         // * registering the subscription so future events can be matched
                         // * making a channel to cancel to request later
                         // * sending a request for a SQL query
-            // Do nothing if the sub already exists.
-            if !conn.has_subscription(&s) {
-                if let Some(ref lim) = sub_lim_opt {
-                lim.until_ready_with_jitter(jitter).await;
-                }
+                        // Do nothing if the sub already exists.
+                        if conn.has_subscription(&s) {
+                            info!("client sent duplicate subscription, ignoring (cid: {}, sub: {:?})", cid, s.id);
+                        } else {
+			    metrics.cmd_req.inc();
+                            if let Some(ref lim) = sub_lim_opt {
+                                lim.until_ready_with_jitter(jitter).await;
+                            }
                             let (abandon_query_tx, abandon_query_rx) = oneshot::channel::<()>();
                             match conn.subscribe(s.clone()) {
-                Ok(()) => {
+                                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();
+                                    if let Some(previous_query) = running_queries.insert(s.id.clone(), abandon_query_tx) {
+                                        previous_query.send(()).ok();
                                     }
-		    if s.needs_historical_events() {
-                                    // start a database query.  this spawns a blocking database query on a worker thread.
-					db::db_query(s, cid.to_owned(), pool.clone(), query_tx.clone(), abandon_query_rx,safe_to_read.clone()).await;
-				    }
-                },
-                Err(e) => {
-                    info!("Subscription error: {} (cid: {}, sub: {:?})", e, cid, s.id);
-                                    ws_stream.send(make_notice_message(Notice::message(format!("Subscription error: {}", e)))).await.ok();
-                }
+                                    if s.needs_historical_events() {
+                                        // start a database query.  this spawns a blocking database query on a worker thread.
+                                        repo.query_subscription(s, cid.clone(), query_tx.clone(), abandon_query_rx).await.ok();
+                                    }
+                                },
+                                Err(e) => {
+                                    info!("Subscription error: {} (cid: {}, sub: {:?})", e, cid, s.id);
+                                    ws_stream.send(make_notice_message(&Notice::message(format!("Subscription error: {e}")))).await.ok();
+                                }
                             }
-            } else {
-        info!("client sent duplicate subscription, ignoring (cid: {}, sub: {:?})", cid, s.id);
-        }
+                        }
                     },
                     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(Notice::message("could not parse command".into()))).await.ok();
+                        if let Ok(c) = parsed {
+			    metrics.cmd_close.inc();
+                            // 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(&Notice::message("could not parse command".into()))).await.ok();
+                        }
                     },
                     Err(Error::ConnError) => {
                         debug!("got connection close/error, disconnecting cid: {}, ip: {:?}",cid, conn.ip());
                         break;
                     }
                     Err(Error::EventMaxLengthError(s)) => {
-                        info!("client sent event larger ({} bytes) than max size (cid: {})", s, cid);
-                        ws_stream.send(make_notice_message(Notice::message("event exceeded max size".into()))).await.ok();
+                        info!("client sent command larger ({} bytes) than max size (cid: {})", s, cid);
+                        ws_stream.send(make_notice_message(&Notice::message("event exceeded max size".into()))).await.ok();
                     },
                     Err(Error::ProtoParseError) => {
-                        info!("client sent event that could not be parsed (cid: {})", cid);
-                        ws_stream.send(make_notice_message(Notice::message("could not parse command".into()))).await.ok();
+                        info!("client sent command that could not be parsed (cid: {})", cid);
+                        ws_stream.send(make_notice_message(&Notice::message("could not parse command".into()))).await.ok();
                     },
                     Err(e) => {
                         info!("got non-fatal error from client (cid: {}, error: {:?}", cid, e);
@@ -748,6 +838,22 @@ async fn nostr_server(
         conn.ip(),
         client_published_event_count,
         client_received_event_count,
-	orig_start.elapsed()
+        orig_start.elapsed()
     );
 }
+
+#[derive(Clone)]
+pub struct NostrMetrics {
+    pub query_sub: Histogram, // response time of successful subscriptions
+    pub query_db: Histogram, // individual database query execution time
+    pub db_connections: IntGauge, // database connections in use
+    pub write_events: Histogram, // response time of event writes
+    pub sent_events: IntCounterVec, // count of events sent to clients
+    pub connections: IntCounter, // count of websocket connections
+    pub disconnects: IntCounterVec, // client disconnects
+    pub query_aborts: IntCounterVec, // count of queries aborted by server
+    pub cmd_req: IntCounter, // count of REQ commands received
+    pub cmd_event: IntCounter, // count of EVENT commands received
+    pub cmd_close: IntCounter, // count of CLOSE commands received
+
+}

src/subscription.rs

@@ -2,7 +2,8 @@
 use crate::error::Result;
 use crate::event::Event;
 use serde::de::Unexpected;
-use serde::{Deserialize, Deserializer, Serialize};
+use serde::ser::SerializeMap;
+use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use serde_json::Value;
 use std::collections::HashMap;
 use std::collections::HashSet;
@@ -19,7 +20,7 @@ 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, PartialEq, Eq, Debug, Clone)]
+#[derive(PartialEq, Eq, Debug, Clone)]
 pub struct ReqFilter {
     /// Event hashes
     pub ids: Option<Vec<String>>,
@@ -34,7 +35,6 @@ pub struct ReqFilter {
     /// 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
     // we can't represent it in the req filter, so we don't want to
@@ -43,6 +43,40 @@ pub struct ReqFilter {
     pub force_no_match: bool,
 }
 
+impl Serialize for ReqFilter {
+    fn serialize<S>(&self, serializer: S) -> Result<S::Ok, S::Error>
+    where S:Serializer,
+    {
+        let mut map = serializer.serialize_map(None)?;
+        if let Some(ids) = &self.ids {
+            map.serialize_entry("ids", &ids)?;
+        }
+        if let Some(kinds) = &self.kinds {
+            map.serialize_entry("kinds", &kinds)?;
+        }
+        if let Some(until) = &self.until {
+            map.serialize_entry("until", until)?;
+        }
+        if let Some(since) = &self.since {
+            map.serialize_entry("since", since)?;
+        }
+        if let Some(limit) = &self.limit {
+            map.serialize_entry("limit", limit)?;
+        }
+        if let Some(authors) = &self.authors {
+            map.serialize_entry("authors", &authors)?;
+        }
+        // serialize tags
+        if let Some(tags) = &self.tags {
+            for (k,v) in tags {
+                let vals:Vec<&String> = v.iter().collect();
+                map.serialize_entry(&format!("#{k}"), &vals)?;
+            }
+        }
+        map.end()
+    }
+}
+
 impl<'de> Deserialize<'de> for ReqFilter {
     fn deserialize<D>(deserializer: D) -> Result<ReqFilter, D::Error>
     where
@@ -65,21 +99,21 @@ impl<'de> Deserialize<'de> for ReqFilter {
             tags: None,
             force_no_match: false,
         };
-	let empty_string = "".into();
+        let empty_string = "".into();
         let mut ts = None;
         // iterate through each key, and assign values that exist
-        for (key, val) in filter.into_iter() {
+        for (key, val) in filter {
             // ids
             if key == "ids" {
-		let raw_ids: Option<Vec<String>>= Deserialize::deserialize(val).ok();
-		if let Some(a) = raw_ids.as_ref() {
-		    if a.contains(&empty_string) {
-		    return Err(serde::de::Error::invalid_type(
-                Unexpected::Other("prefix matches must not be empty strings"),
-                &"a json object"));
-		    }
-		}
-		rf.ids =raw_ids;
+                let raw_ids: Option<Vec<String>>= Deserialize::deserialize(val).ok();
+                if let Some(a) = raw_ids.as_ref() {
+                    if a.contains(&empty_string) {
+                        return Err(serde::de::Error::invalid_type(
+                            Unexpected::Other("prefix matches must not be empty strings"),
+                            &"a json object"));
+                    }
+                }
+                rf.ids =raw_ids;
             } else if key == "kinds" {
                 rf.kinds = Deserialize::deserialize(val).ok();
             } else if key == "since" {
@@ -90,14 +124,14 @@ impl<'de> Deserialize<'de> for ReqFilter {
                 rf.limit = Deserialize::deserialize(val).ok();
             } else if key == "authors" {
                 let raw_authors: Option<Vec<String>>= Deserialize::deserialize(val).ok();
-		if let Some(a) = raw_authors.as_ref() {
-		    if a.contains(&empty_string) {
-			return Err(serde::de::Error::invalid_type(
-			    Unexpected::Other("prefix matches must not be empty strings"),
-			    &"a json object"));
-		    }
-		}
-		rf.authors = raw_authors;
+                if let Some(a) = raw_authors.as_ref() {
+                    if a.contains(&empty_string) {
+                        return Err(serde::de::Error::invalid_type(
+                            Unexpected::Other("prefix matches must not be empty strings"),
+                            &"a json object"));
+                    }
+                }
+                rf.authors = raw_authors;
             } 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() {
@@ -107,7 +141,7 @@ impl<'de> Deserialize<'de> for ReqFilter {
                     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());
+                            let hs = v.into_iter().collect::<HashSet<_>>();
                             m.insert(tag_search.to_owned(), hs);
                         }
                     };
@@ -188,6 +222,7 @@ impl<'de> Deserialize<'de> for Subscription {
             // create indexes
             filters.push(f);
         }
+        filters.dedup();
         Ok(Subscription {
             id: sub_id.to_owned(),
             filters,
@@ -197,20 +232,20 @@ impl<'de> Deserialize<'de> for Subscription {
 
 impl Subscription {
     /// Get a copy of the subscription identifier.
-    pub fn get_id(&self) -> String {
+    #[must_use] pub fn get_id(&self) -> String {
         self.id.clone()
     }
 
     /// Determine if any filter is requesting historical (database)
     /// queries.  If every filter has limit:0, we do not need to query the DB.
-    pub fn needs_historical_events(&self) -> bool {
-	self.filters.iter().any(|f| f.limit!=Some(0))
+    #[must_use] pub fn needs_historical_events(&self) -> bool {
+        self.filters.iter().any(|f| f.limit!=Some(0))
     }
 
     /// Determine if this subscription matches a given [`Event`].  Any
     /// individual filter match is sufficient.
-    pub fn interested_in_event(&self, event: &Event) -> bool {
-        for f in self.filters.iter() {
+    #[must_use] pub fn interested_in_event(&self, event: &Event) -> bool {
+        for f in &self.filters {
             if f.interested_in_event(event) {
                 return true;
             }
@@ -233,23 +268,20 @@ impl ReqFilter {
     fn ids_match(&self, event: &Event) -> bool {
         self.ids
             .as_ref()
-            .map(|vs| prefix_match(vs, &event.id))
-            .unwrap_or(true)
+            .map_or(true, |vs| prefix_match(vs, &event.id))
     }
 
     fn authors_match(&self, event: &Event) -> bool {
         self.authors
             .as_ref()
-            .map(|vs| prefix_match(vs, &event.pubkey))
-            .unwrap_or(true)
+            .map_or(true, |vs| prefix_match(vs, &event.pubkey))
     }
 
     fn delegated_authors_match(&self, event: &Event) -> bool {
         if let Some(delegated_pubkey) = &event.delegated_by {
             self.authors
                 .as_ref()
-                .map(|vs| prefix_match(vs, delegated_pubkey))
-                .unwrap_or(true)
+                .map_or(true, |vs| prefix_match(vs, delegated_pubkey))
         } else {
             false
         }
@@ -275,16 +307,15 @@ impl ReqFilter {
     fn kind_match(&self, kind: u64) -> bool {
         self.kinds
             .as_ref()
-            .map(|ks| ks.contains(&kind))
-            .unwrap_or(true)
+            .map_or(true, |ks| ks.contains(&kind))
     }
 
     /// Determine if all populated fields in this filter match the provided event.
-    pub fn interested_in_event(&self, event: &Event) -> bool {
+    #[must_use] pub fn interested_in_event(&self, event: &Event) -> bool {
         //        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.since.map_or(true, |t| event.created_at > t)
+            && self.until.map_or(true, |t| event.created_at < t)
             && self.kind_match(event.kind)
             && (self.authors_match(event) || self.delegated_authors_match(event))
             && self.tag_match(event)
@@ -320,19 +351,19 @@ mod tests {
 
     #[test]
     fn req_empty_authors_prefix() {
-	let raw_json = "[\"REQ\",\"some-id\",{\"authors\": [\"\"]}]";
+        let raw_json = "[\"REQ\",\"some-id\",{\"authors\": [\"\"]}]";
         assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
     }
 
     #[test]
     fn req_empty_ids_prefix() {
-	let raw_json = "[\"REQ\",\"some-id\",{\"ids\": [\"\"]}]";
+        let raw_json = "[\"REQ\",\"some-id\",{\"ids\": [\"\"]}]";
         assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
     }
 
     #[test]
     fn req_empty_ids_prefix_mixed() {
-	let raw_json = "[\"REQ\",\"some-id\",{\"ids\": [\"\",\"aaa\"]}]";
+        let raw_json = "[\"REQ\",\"some-id\",{\"ids\": [\"\",\"aaa\"]}]";
         assert!(serde_json::from_str::<Subscription>(raw_json).is_err());
     }
 
@@ -343,6 +374,23 @@ mod tests {
         assert!(serde_json::from_str::<Subscription>(raw_json).is_ok());
     }
 
+    #[test]
+    fn dupe_filter() -> Result<()> {
+        let raw_json = r#"["REQ","some-id",{"kinds": [1984]}, {"kinds": [1984]}]"#;
+        let s: Subscription = serde_json::from_str(raw_json)?;
+        assert_eq!(s.filters.len(), 1);
+        Ok(())
+    }
+
+    #[test]
+    fn dupe_filter_many() -> Result<()> {
+        // duplicate filters in different order
+        let raw_json = r#"["REQ","some-id",{"kinds":[1984]},{"kinds":[1984]},{"kinds":[1984]},{"kinds":[1984]}]"#;
+        let s: Subscription = serde_json::from_str(raw_json)?;
+        assert_eq!(s.filters.len(), 1);
+        Ok(())
+    }
+
     #[test]
     fn author_filter() -> Result<()> {
         let raw_json = r#"["REQ","some-id",{"authors": ["test-author-id"]}]"#;
@@ -574,4 +622,22 @@ mod tests {
         assert!(!s.interested_in_event(&e));
         Ok(())
     }
+
+    #[test]
+    fn serialize_filter() -> Result<()> {
+        let s: Subscription = serde_json::from_str(r##"["REQ","xyz",{"authors":["abc", "bcd"], "since": 10, "until": 20, "limit":100, "#e": ["foo", "bar"], "#d": ["test"]}]"##)?;
+        let f = s.filters.get(0);
+        let serialized = serde_json::to_string(&f)?;
+        let serialized_wrapped = format!(r##"["REQ", "xyz",{}]"##, serialized);
+        let parsed: Subscription = serde_json::from_str(&serialized_wrapped)?;
+        let parsed_filter = parsed.filters.get(0);
+        if let Some(pf) = parsed_filter {
+            assert_eq!(pf.since, Some(10));
+            assert_eq!(pf.until, Some(20));
+            assert_eq!(pf.limit, Some(100));
+        } else {
+            assert!(false, "filter could not be parsed");
+        }
+        Ok(())
+    }
 }

src/utils.rs

@@ -1,8 +1,9 @@
 //! Common utility functions
+use bech32::FromBase32;
 use std::time::SystemTime;
 
 /// Seconds since 1970.
-pub fn unix_time() -> u64 {
+#[must_use] pub fn unix_time() -> u64 {
     SystemTime::now()
         .duration_since(SystemTime::UNIX_EPOCH)
         .map(|x| x.as_secs())
@@ -10,12 +11,23 @@ pub fn unix_time() -> u64 {
 }
 
 /// Check if a string contains only hex characters.
-pub fn is_hex(s: &str) -> bool {
+#[must_use] pub fn is_hex(s: &str) -> bool {
     s.chars().all(|x| char::is_ascii_hexdigit(&x))
 }
 
+/// Check if string is a nip19 string
+pub fn is_nip19(s: &str) -> bool {
+    s.starts_with("npub") || s.starts_with("note")
+}
+
+pub fn nip19_to_hex(s: &str) -> Result<String, bech32::Error> {
+    let (_hrp, data, _checksum) = bech32::decode(s)?;
+    let data = Vec::<u8>::from_base32(&data)?;
+    Ok(hex::encode(data))
+}
+
 /// Check if a string contains only lower-case hex chars.
-pub fn is_lower_hex(s: &str) -> bool {
+#[must_use] 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)
     })
@@ -30,4 +42,21 @@ mod tests {
         let hexstr = "abcd0123";
         assert_eq!(is_lower_hex(hexstr), true);
     }
+
+    #[test]
+    fn nip19() {
+        let hexkey = "3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d";
+        let nip19key = "npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6";
+        assert_eq!(is_nip19(hexkey), false);
+        assert_eq!(is_nip19(nip19key), true);
+    }
+
+    #[test]
+    fn nip19_hex() {
+        let nip19key = "npub180cvv07tjdrrgpa0j7j7tmnyl2yr6yr7l8j4s3evf6u64th6gkwsyjh6w6";
+        let expected = "3bf0c63fcb93463407af97a5e5ee64fa883d107ef9e558472c4eb9aaaefa459d";
+        let got = nip19_to_hex(nip19key).unwrap();
+
+        assert_eq!(expected, got);
+    }
 }

tests/cli.rs

@@ -0,0 +1,10 @@
+#[cfg(test)]
+mod tests {
+    use nostr_rs_relay::cli::CLIArgs;
+
+    #[test]
+    fn cli_tests() {
+        use clap::CommandFactory;
+        CLIArgs::command().debug_assert();
+    }
+}

tests/common/mod.rs

@@ -36,9 +36,9 @@ pub fn start_relay() -> Result<Relay> {
     settings.database.min_conn = 4;
     settings.database.max_conn = 8;
     let (shutdown_tx, shutdown_rx): (MpscSender<()>, MpscReceiver<()>) = syncmpsc::channel();
-    let handle = thread::spawn(|| {
+    let handle = thread::spawn(move || {
         // server will block the thread it is run on.
-        let _ = start_server(settings, shutdown_rx);
+        let _ = start_server(&settings, shutdown_rx);
     });
     // how do we know the relay has finished starting up?
     Ok(Relay {