build: bump version to 0.6.2

Updating async-trait v0.1.56 -> v0.1.57
Removing block-buffer v0.7.3
Removing block-padding v0.1.5
Updating bumpalo v3.10.0 -> v3.11.0
Removing byte-tools v0.3.1
Updating bytes v1.1.0 -> v1.2.1
Updating cpufeatures v0.2.2 -> v0.2.3
Updating crossbeam-utils v0.8.10 -> v0.8.11
Updating crypto-common v0.1.4 -> v0.1.6
Removing digest v0.8.1
Removing fake-simd v0.1.2
Updating fastrand v1.7.0 -> v1.8.0
Updating futures v0.3.21 -> v0.3.23
Updating futures-channel v0.3.21 -> v0.3.23
Updating futures-core v0.3.21 -> v0.3.23
Updating futures-executor v0.3.21 -> v0.3.23
Updating futures-io v0.3.21 -> v0.3.23
Updating futures-macro v0.3.21 -> v0.3.23
Updating futures-sink v0.3.21 -> v0.3.23
Updating futures-task v0.3.21 -> v0.3.23
Updating futures-util v0.3.21 -> v0.3.23
Removing generic-array v0.12.4
Removing generic-array v0.14.5
Adding   generic-array v0.14.6
Updating h2 v0.3.13 -> v0.3.14
Updating hashbrown v0.12.1 -> v0.12.3
Updating hyper v0.14.19 -> v0.14.20
Updating itoa v1.0.2 -> v1.0.3
Updating js-sys v0.3.58 -> v0.3.59
Updating libc v0.2.126 -> v0.2.132
Removing maplit v1.0.2
Updating once_cell v1.12.1 -> v1.13.1
Removing opaque-debug v0.2.3
Updating openssl v0.10.40 -> v0.10.41
Updating openssl-sys v0.9.74 -> v0.9.75
Updating pest v2.1.3 -> v2.2.1
Updating pest_derive v2.1.0 -> v2.2.1
Updating pest_generator v2.1.3 -> v2.2.1
Updating pest_meta v2.1.3 -> v2.2.1
Updating proc-macro2 v1.0.40 -> v1.0.43
Updating quote v1.0.20 -> v1.0.21
Updating raw-cpuid v10.3.0 -> v10.5.0
Updating redox_syscall v0.2.13 -> v0.2.16
Updating regex v1.5.6 -> v1.6.0
Updating regex-syntax v0.6.26 -> v0.6.27
Updating ryu v1.0.10 -> v1.0.11
Updating security-framework v2.6.1 -> v2.7.0
Updating serde v1.0.138 -> v1.0.143
Updating serde_derive v1.0.138 -> v1.0.143
Updating serde_json v1.0.82 -> v1.0.83
Removing sha-1 v0.8.2
Updating slab v0.4.6 -> v0.4.7
Updating syn v1.0.98 -> v1.0.99
Updating thiserror v1.0.31 -> v1.0.32
Updating thiserror-impl v1.0.31 -> v1.0.32
Updating tokio v1.19.2 -> v1.20.1
Updating tokio-tungstenite v0.17.1 -> v0.17.2
Updating tracing v0.1.35 -> v0.1.36
Updating tracing-core v0.1.28 -> v0.1.29
Updating tungstenite v0.17.2 -> v0.17.3
Updating ucd-trie v0.1.3 -> v0.1.4
Updating unicode-ident v1.0.1 -> v1.0.3
Updating wasm-bindgen v0.2.81 -> v0.2.82
Updating wasm-bindgen-backend v0.2.81 -> v0.2.82
Updating wasm-bindgen-macro v0.2.81 -> v0.2.82
Updating wasm-bindgen-macro-support v0.2.81 -> v0.2.82
Updating wasm-bindgen-shared v0.2.81 -> v0.2.82
Updating web-sys v0.3.58 -> v0.3.59

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "nostr-rs-relay"
-version = "0.5.1"
+version = "0.6.2"
 edition = "2021"
 
 [dependencies]
@@ -9,17 +9,17 @@ env_logger = "^0.9"
 tokio = { version = "^1.16", features = ["full"] }
 futures = "^0.3"
 futures-util = "^0.3"
-tokio-tungstenite = "^0.16"
-tungstenite = "^0.16"
+tokio-tungstenite = "^0.17"
+tungstenite = "^0.17"
 thiserror = "^1"
 uuid = { version = "^0.8", features = ["v4"] }
-config = { version = "0.11", features = ["toml"] }
-bitcoin_hashes = { version = "^0.9", features = ["serde"] }
+config = { version = "^0.12", features = ["toml"] }
+bitcoin_hashes = { version = "^0.10", features = ["serde"] }
 secp256k1 = {version = "^0.21", features = ["rand", "rand-std", "serde", "bitcoin_hashes"] }
 serde = { version = "^1.0", features = ["derive"] }
 serde_json = {version = "^1.0", features = ["preserve_order"]}
 hex = "^0.4"
-rusqlite = { version = "^0.26", features = ["limits"]}
+rusqlite = { version = "^0.26", features = ["limits","bundled"]}
 r2d2 = "^0.8"
 r2d2_sqlite = "^0.19"
 lazy_static = "^1.4"

Dockerfile

@@ -1,4 +1,4 @@
-FROM rust:1.58.1 as builder
+FROM docker.io/library/rust:1.63.0@sha256:d7e3f69edcdcd03b145d8d9361765b816656755e49c1c1fe28224a4505f91b0a as builder
 
 RUN USER=root cargo new --bin nostr-rs-relay
 WORKDIR ./nostr-rs-relay
@@ -12,7 +12,7 @@ COPY ./src ./src
 RUN rm ./target/release/deps/nostr*relay*
 RUN cargo build --release
 
-FROM debian:bullseye-20220125-slim
+FROM docker.io/library/debian:bullseye-20220801-slim@sha256:139a42fa3bde3e5bad6ae912aaaf2103565558a7a73afe6ce6ceed6e46a6e519
 ARG APP=/usr/src/app
 ARG APP_DATA=/usr/src/app/db
 RUN apt-get update \

README.md

@@ -18,9 +18,11 @@ NIPs with a relay-specific implementation are listed here.
 - [x] NIP-02: Hide old contact list events
 - [ ] NIP-03: OpenTimestamps
 - [x] NIP-05: Mapping Nostr keys to DNS identifiers
-- [ ] NIP-09: Event deletion
+- [x] NIP-09: Event deletion
 - [x] NIP-11: Relay information document
 - [x] NIP-12: Generic tag search (_experimental_)
+- [x] NIP-15: End of stored events notice
+- [x] NIP-16: Replaceable and ephemeral events
 
 ## Quick Start
 
@@ -79,8 +81,10 @@ termination, load balancing, and other features), see [Reverse
 Proxy](reverse-proxy.md).
 
 ## Dev Channel
-The current dev discussions for this project is happening at https://discord.gg/ufG6fH52Vk.
-Drop in to query any development related questions.
+
+For development discussions, please feel free to use the [sourcehut
+mailing list](https://lists.sr.ht/~gheartsfield/nostr-rs-relay-devel).
+Or, drop by the [Nostr Telegram Channel](https://t.me/nostr_protocol).
 
 License
 ---

config.toml

@@ -63,8 +63,8 @@ reject_future_seconds = 1800
 #broadcast_buffer = 16384
 
 # Event persistence buffer size, in number of events.  This provides
-# backpressure to senders if writes are slow.  Defaults to 16.
-#event_persist_buffer = 16
+# backpressure to senders if writes are slow.
+#event_persist_buffer = 4096
 
 [authorization]
 # Pubkey addresses in this array are whitelisted for event publishing.

src/config.rs

@@ -1,4 +1,5 @@
 //! Configuration file and settings management
+use config::{Config, ConfigError, File};
 use lazy_static::lazy_static;
 use log::*;
 use serde::{Deserialize, Serialize};
@@ -138,27 +139,29 @@ pub struct Settings {
 
 impl Settings {
     pub fn new() -> Self {
-        let d = Self::default();
+        let default_settings = Self::default();
         // attempt to construct settings with file
-        //        Self::new_from_default(&d).unwrap_or(d)
-        let from_file = Self::new_from_default(&d);
+        let from_file = Self::new_from_default(&default_settings);
         match from_file {
             Ok(f) => f,
             Err(e) => {
                 warn!("Error reading config file ({:?})", e);
-                d
+                default_settings
             }
         }
     }
 
-    fn new_from_default(default: &Settings) -> Result<Self, config::ConfigError> {
-        let config: config::Config = config::Config::new();
-        let mut settings: Settings = config
+    fn new_from_default(default: &Settings) -> Result<Self, ConfigError> {
+        let builder = Config::builder();
+        let config: Config = builder
             // use defaults
-            .with_merged(config::Config::try_from(default).unwrap())?
+            .add_source(Config::try_from(default)?)
             // override with file contents
-            .with_merged(config::File::with_name("config"))?
-            .try_into()?;
+            .add_source(File::with_name("config"))
+            .build()?
+            .try_into()
+            .unwrap();
+        let mut settings: Settings = config.try_deserialize()?;
         // ensure connection pool size is logical
         if settings.database.min_conn > settings.database.max_conn {
             panic!(

src/db.rs

@@ -2,13 +2,14 @@
 use crate::config::SETTINGS;
 use crate::error::Error;
 use crate::error::Result;
-use crate::event::Event;
+use crate::event::{single_char_tagname, Event};
 use crate::hexrange::hex_range;
 use crate::hexrange::HexSearch;
 use crate::nip05;
 use crate::schema::{upgrade_db, STARTUP_SQL};
+use crate::subscription::ReqFilter;
 use crate::subscription::Subscription;
-use crate::utils::is_hex;
+use crate::utils::{is_hex, is_lower_hex};
 use governor::clock::Clock;
 use governor::{Quota, RateLimiter};
 use hex;
@@ -207,30 +208,41 @@ pub async fn db_writer(
             }
             // TODO: cache recent list of authors to remove a DB call.
             let start = Instant::now();
-            match write_event(&mut pool.get()?, &event) {
-                Ok(updated) => {
-                    if updated == 0 {
-                        trace!("ignoring duplicate event");
-                    } else {
-                        info!(
-                            "persisted event {:?} from {:?} in {:?}",
-                            event.get_event_id_prefix(),
-                            event.get_author_prefix(),
-                            start.elapsed()
-                        );
-                        event_write = true;
-                        // send this out to all clients
-                        bcast_tx.send(event.clone()).ok();
+            if event.kind >= 20000 && event.kind < 30000 {
+                info!(
+                    "published ephemeral event {:?} from {:?} in {:?}",
+                    event.get_event_id_prefix(),
+                    event.get_author_prefix(),
+                    start.elapsed()
+                );
+                bcast_tx.send(event.clone()).ok();
+                event_write = true
+            } else {
+                match write_event(&mut pool.get()?, &event) {
+                    Ok(updated) => {
+                        if updated == 0 {
+                            trace!("ignoring duplicate event");
+                        } else {
+                            info!(
+                                "persisted event {:?} from {:?} in {:?}",
+                                event.get_event_id_prefix(),
+                                event.get_author_prefix(),
+                                start.elapsed()
+                            );
+                            event_write = true;
+                            // send this out to all clients
+                            bcast_tx.send(event.clone()).ok();
+                        }
+                    }
+                    Err(err) => {
+                        warn!("event insert failed: {:?}", err);
+                        notice_tx
+                            .try_send(
+                                "relay experienced an error trying to publish the latest event"
+                                    .to_owned(),
+                            )
+                            .ok();
                     }
-                }
-                Err(err) => {
-                    warn!("event insert failed: {:?}", err);
-                    notice_tx
-                        .try_send(
-                            "relay experienced an error trying to publish the latest event"
-                                .to_owned(),
-                        )
-                        .ok();
                 }
             }
 
@@ -288,49 +300,66 @@ pub fn write_event(conn: &mut PooledConnection, e: &Event) -> Result<usize> {
         if tag.len() >= 2 {
             let tagname = &tag[0];
             let tagval = &tag[1];
-            // if tagvalue is hex;
-            if is_hex(tagval) {
-                tx.execute(
-                    "INSERT OR IGNORE INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3)",
-                    params![ev_id, &tagname, hex::decode(&tagval).ok()],
-                )?;
-            } else {
-                tx.execute(
-                    "INSERT OR IGNORE INTO tag (event_id, name, value) VALUES (?1, ?2, ?3)",
-                    params![ev_id, &tagname, &tagval],
-                )?;
+            // only single-char tags are searchable
+            let tagchar_opt = single_char_tagname(tagname);
+            match &tagchar_opt {
+                Some(_) => {
+                    // if tagvalue is lowercase hex;
+                    if is_lower_hex(&tagval) && (tagval.len() % 2 == 0) {
+                        tx.execute(
+			    "INSERT OR IGNORE INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3)",
+			    params![ev_id, &tagname, hex::decode(&tagval).ok()],
+			)?;
+                    } else {
+                        tx.execute(
+                            "INSERT OR IGNORE INTO tag (event_id, name, value) VALUES (?1, ?2, ?3)",
+                            params![ev_id, &tagname, &tagval],
+                        )?;
+                    }
+                }
+                None => {}
             }
         }
     }
-    // if this event is for a metadata update, hide every other kind=0
-    // event from the same author that was issued earlier than this.
-    if e.kind == 0 {
+    // if this event is replaceable update, hide every other replaceable
+    // event with the same kind from the same author that was issued
+    // earlier than this.
+    if e.kind == 0 || e.kind == 3 || (e.kind >= 10000 && e.kind < 20000) {
         let update_count = tx.execute(
-            "UPDATE event SET hidden=TRUE WHERE id!=? AND kind=0 AND author=? AND created_at <= ? and hidden!=TRUE",
-            params![ev_id, hex::decode(&e.pubkey).ok(), e.created_at],
+            "UPDATE event SET hidden=TRUE WHERE id!=? AND kind=? AND author=? AND created_at <= ? and hidden!=TRUE",
+            params![ev_id, e.kind, hex::decode(&e.pubkey).ok(), e.created_at],
         )?;
         if update_count > 0 {
             info!(
-                "hid {} older metadata events for author {:?}",
+                "hid {} older replaceable kind {} events for author {:?}",
                 update_count,
+                e.kind,
                 e.get_author_prefix()
             );
         }
     }
-    // if this event is for a contact update, hide every other kind=3
-    // event from the same author that was issued earlier than this.
-    if e.kind == 3 {
-        let update_count = tx.execute(
-            "UPDATE event SET hidden=TRUE WHERE id!=? AND kind=3 AND author=? AND created_at <= ? and hidden!=TRUE",
-            params![ev_id, hex::decode(&e.pubkey).ok(), e.created_at],
-        )?;
-        if update_count > 0 {
-            info!(
-                "hid {} older contact events for author {:?}",
-                update_count,
-                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 mut params: Vec<Box<dyn ToSql>> = vec![];
+        // first parameter will be author
+        params.push(Box::new(hex::decode(&e.pubkey)?));
+        event_candidates
+            .iter()
+            .filter(|x| is_hex(x) && x.len() == 64)
+            .filter_map(|x| hex::decode(x).ok())
+            .for_each(|x| params.push(Box::new(x)));
+        let query = format!(
+            "UPDATE event SET hidden=TRUE WHERE author=? AND event_hash IN ({})",
+            repeat_vars(params.len() - 1)
+        );
+        let mut stmt = tx.prepare(&query)?;
+        let update_count = stmt.execute(rusqlite::params_from_iter(params))?;
+        info!(
+            "hid {} deleted events for author {:?}",
+            update_count,
+            e.get_author_prefix()
+        );
     }
     tx.commit()?;
     Ok(ins_count)
@@ -356,142 +385,166 @@ fn repeat_vars(count: usize) -> String {
     s
 }
 
-/// Create a dynamic SQL query string and params from a subscription.
-fn query_from_sub(sub: &Subscription) -> (String, Vec<Box<dyn ToSql>>) {
+/// Create a dynamic SQL subquery and params from a subscription filter.
+fn query_from_filter(f: &ReqFilter) -> (String, Vec<Box<dyn ToSql>>) {
     // build a dynamic SQL query.  all user-input is either an integer
     // (sqli-safe), or a string that is filtered to only contain
     // hexadecimal characters.  Strings that require escaping (tag
     // names/values) use parameters.
-    let mut query =
-        "SELECT DISTINCT(e.content) FROM event e LEFT JOIN tag t ON e.id=t.event_id ".to_owned();
-    // parameters
+
+    // if the filter is malformed, don't return anything.
+    if f.force_no_match {
+        let empty_query =
+            "SELECT DISTINCT(e.content), e.created_at FROM event e WHERE 1=0".to_owned();
+        // query parameters for SQLite
+        let empty_params: Vec<Box<dyn ToSql>> = vec![];
+        return (empty_query, empty_params);
+    }
+
+    let mut query = "SELECT DISTINCT(e.content), e.created_at FROM event e  ".to_owned();
+    // query parameters for SQLite
     let mut params: Vec<Box<dyn ToSql>> = vec![];
 
-    // for every filter in the subscription, generate a where clause
-    let mut filter_clauses: Vec<String> = Vec::new();
-    for f in sub.filters.iter() {
-        // individual filter components
-        let mut filter_components: Vec<String> = Vec::new();
-        // Query for "authors", allowing prefix matches
-        if let Some(authvec) = &f.authors {
-            // take each author and convert to a hexsearch
-            let mut auth_searches: Vec<String> = vec![];
-            for auth in authvec {
-                match hex_range(auth) {
-                    Some(HexSearch::Exact(ex)) => {
-                        auth_searches.push("author=?".to_owned());
-                        params.push(Box::new(ex));
-                    }
-                    Some(HexSearch::Range(lower, upper)) => {
-                        auth_searches.push("(author>? AND author<?)".to_owned());
-                        params.push(Box::new(lower));
-                        params.push(Box::new(upper));
-                    }
-                    Some(HexSearch::LowerOnly(lower)) => {
-                        auth_searches.push("author>?".to_owned());
-                        params.push(Box::new(lower));
-                    }
-                    None => {
-                        info!("Could not parse hex range from author {:?}", auth);
-                    }
+    // individual filter components (single conditions such as an author or event ID)
+    let mut filter_components: Vec<String> = Vec::new();
+    // Query for "authors", allowing prefix matches
+    if let Some(authvec) = &f.authors {
+        // take each author and convert to a hexsearch
+        let mut auth_searches: Vec<String> = vec![];
+        for auth in authvec {
+            match hex_range(auth) {
+                Some(HexSearch::Exact(ex)) => {
+                    auth_searches.push("author=?".to_owned());
+                    params.push(Box::new(ex));
+                }
+                Some(HexSearch::Range(lower, upper)) => {
+                    auth_searches.push("(author>? AND author<?)".to_owned());
+                    params.push(Box::new(lower));
+                    params.push(Box::new(upper));
+                }
+                Some(HexSearch::LowerOnly(lower)) => {
+                    auth_searches.push("author>?".to_owned());
+                    params.push(Box::new(lower));
+                }
+                None => {
+                    info!("Could not parse hex range from author {:?}", auth);
                 }
             }
-            let authors_clause = format!("({})", auth_searches.join(" OR "));
-            filter_components.push(authors_clause);
         }
-        // Query for Kind
-        if let Some(ks) = &f.kinds {
-            // kind is number, no escaping needed
-            let str_kinds: Vec<String> = ks.iter().map(|x| x.to_string()).collect();
-            let kind_clause = format!("kind IN ({})", str_kinds.join(", "));
-            filter_components.push(kind_clause);
-        }
-        // Query for event, allowing prefix matches
-        if let Some(idvec) = &f.ids {
-            // take each author and convert to a hexsearch
-            let mut id_searches: Vec<String> = vec![];
-            for id in idvec {
-                match hex_range(id) {
-                    Some(HexSearch::Exact(ex)) => {
-                        id_searches.push("event_hash=?".to_owned());
-                        params.push(Box::new(ex));
-                    }
-                    Some(HexSearch::Range(lower, upper)) => {
-                        id_searches.push("(event_hash>? AND event_hash<?)".to_owned());
-                        params.push(Box::new(lower));
-                        params.push(Box::new(upper));
-                    }
-                    Some(HexSearch::LowerOnly(lower)) => {
-                        id_searches.push("event_hash>?".to_owned());
-                        params.push(Box::new(lower));
-                    }
-                    None => {
-                        info!("Could not parse hex range from id {:?}", id);
-                    }
+        let authors_clause = format!("({})", auth_searches.join(" OR "));
+        filter_components.push(authors_clause);
+    }
+    // Query for Kind
+    if let Some(ks) = &f.kinds {
+        // kind is number, no escaping needed
+        let str_kinds: Vec<String> = ks.iter().map(|x| x.to_string()).collect();
+        let kind_clause = format!("kind IN ({})", str_kinds.join(", "));
+        filter_components.push(kind_clause);
+    }
+    // Query for event, allowing prefix matches
+    if let Some(idvec) = &f.ids {
+        // take each author and convert to a hexsearch
+        let mut id_searches: Vec<String> = vec![];
+        for id in idvec {
+            match hex_range(id) {
+                Some(HexSearch::Exact(ex)) => {
+                    id_searches.push("event_hash=?".to_owned());
+                    params.push(Box::new(ex));
+                }
+                Some(HexSearch::Range(lower, upper)) => {
+                    id_searches.push("(event_hash>? AND event_hash<?)".to_owned());
+                    params.push(Box::new(lower));
+                    params.push(Box::new(upper));
+                }
+                Some(HexSearch::LowerOnly(lower)) => {
+                    id_searches.push("event_hash>?".to_owned());
+                    params.push(Box::new(lower));
+                }
+                None => {
+                    info!("Could not parse hex range from id {:?}", id);
                 }
             }
-            let id_clause = format!("({})", id_searches.join(" OR "));
-            filter_components.push(id_clause);
         }
-        // Query for tags
-        if let Some(map) = &f.tags {
-            for (key, val) in map.iter() {
-                let mut str_vals: Vec<Box<dyn ToSql>> = vec![];
-                let mut blob_vals: Vec<Box<dyn ToSql>> = vec![];
-                for v in val {
-                    if is_hex(v) {
-                        if let Ok(h) = hex::decode(&v) {
-                            blob_vals.push(Box::new(h));
-                        }
-                    } else {
-                        str_vals.push(Box::new(v.to_owned()));
+        let id_clause = format!("({})", id_searches.join(" OR "));
+        filter_components.push(id_clause);
+    }
+    // Query for tags
+    if let Some(map) = &f.tags {
+        for (key, val) in map.iter() {
+            let mut str_vals: Vec<Box<dyn ToSql>> = vec![];
+            let mut blob_vals: Vec<Box<dyn ToSql>> = vec![];
+            for v in val {
+                if (v.len()%2==0) && is_lower_hex(v) {
+                    if let Ok(h) = hex::decode(&v) {
+                        blob_vals.push(Box::new(h));
                     }
+                } else {
+                    str_vals.push(Box::new(v.to_owned()));
                 }
-                // create clauses with "?" params for each tag value being searched
-                let str_clause = format!("value IN ({})", repeat_vars(str_vals.len()));
-                let blob_clause = format!("value_hex IN ({})", repeat_vars(blob_vals.len()));
-                let tag_clause = format!("(name=? AND ({} OR {}))", str_clause, blob_clause);
-                // add the tag name as the first parameter
-                params.push(Box::new(key.to_owned()));
-                // add all tag values that are plain strings as params
-                params.append(&mut str_vals);
-                // add all tag values that are blobs as params
-                params.append(&mut blob_vals);
-                filter_components.push(tag_clause);
             }
-        }
-        // Query for timestamp
-        if f.since.is_some() {
-            let created_clause = format!("created_at > {}", f.since.unwrap());
-            filter_components.push(created_clause);
-        }
-        // Query for timestamp
-        if f.until.is_some() {
-            let until_clause = format!("created_at < {}", f.until.unwrap());
-            filter_components.push(until_clause);
-        }
-
-        // combine all clauses, and add to filter_clauses
-        if !filter_components.is_empty() {
-            let mut fc = "( ".to_owned();
-            fc.push_str(&filter_components.join(" AND "));
-            fc.push_str(" )");
-            filter_clauses.push(fc);
+            // create clauses with "?" params for each tag value being searched
+            let str_clause = format!("value IN ({})", repeat_vars(str_vals.len()));
+            let blob_clause = format!("value_hex IN ({})", repeat_vars(blob_vals.len()));
+            // find evidence of the target tag name/value existing for this event.
+            let tag_clause = format!("e.id IN (SELECT e.id FROM event e LEFT JOIN tag t on e.id=t.event_id WHERE hidden!=TRUE and (name=? AND ({} OR {})))", str_clause, blob_clause);
+            // add the tag name as the first parameter
+            params.push(Box::new(key.to_string()));
+            // add all tag values that are plain strings as params
+            params.append(&mut str_vals);
+            // add all tag values that are blobs as params
+            params.append(&mut blob_vals);
+            filter_components.push(tag_clause);
         }
     }
-
+    // Query for timestamp
+    if f.since.is_some() {
+        let created_clause = format!("created_at > {}", f.since.unwrap());
+        filter_components.push(created_clause);
+    }
+    // Query for timestamp
+    if f.until.is_some() {
+        let until_clause = format!("created_at < {}", f.until.unwrap());
+        filter_components.push(until_clause);
+    }
     // never display hidden events
-    query.push_str(" WHERE hidden!=TRUE ");
-
-    // combine all filters with OR clauses, if any exist
-    if !filter_clauses.is_empty() {
-        query.push_str(" AND (");
-        query.push_str(&filter_clauses.join(" OR "));
-        query.push_str(") ");
+    query.push_str(" WHERE hidden!=TRUE");
+    // build filter component conditions
+    if !filter_components.is_empty() {
+        query.push_str(" AND ");
+        query.push_str(&filter_components.join(" AND "));
     }
-    // add order clause
-    query.push_str(" ORDER BY created_at ASC");
-    debug!("query string: {}", query);
+    // Apply per-filter limit to this subquery.
+    // The use of a LIMIT implies a DESC order, to capture only the most recent events.
+    if let Some(lim) = f.limit {
+        query.push_str(&format!(" ORDER BY e.created_at DESC LIMIT {}", lim))
+    } else {
+        query.push_str(" ORDER BY e.created_at ASC")
+    }
+    (query, params)
+}
+
+/// Create a dynamic SQL query string and params from a subscription.
+fn query_from_sub(sub: &Subscription) -> (String, Vec<Box<dyn ToSql>>) {
+    // build a dynamic SQL query for an entire subscription, based on
+    // SQL subqueries for filters.
+    let mut subqueries: Vec<String> = Vec::new();
+    // subquery params
+    let mut params: Vec<Box<dyn ToSql>> = vec![];
+    // for every filter in the subscription, generate a subquery
+    for f in sub.filters.iter() {
+        let (f_subquery, mut f_params) = query_from_filter(&f);
+        subqueries.push(f_subquery);
+        params.append(&mut f_params);
+    }
+    // encapsulate subqueries into select statements
+    let subqueries_selects: Vec<String> = subqueries
+        .iter()
+        .map(|s| {
+            return format!("SELECT content, created_at FROM ({})", s);
+        })
+        .collect();
+    let query: String = subqueries_selects.join(" UNION ");
+    info!("final query string: {}", query);
     (query, params)
 }
 
@@ -503,7 +556,8 @@ fn query_from_sub(sub: &Subscription) -> (String, Vec<Box<dyn ToSql>>) {
 /// query is immediately aborted.
 pub async fn db_query(
     sub: Subscription,
-    conn: PooledConnection,
+    client_id: String,
+    pool: SqlitePool,
     query_tx: tokio::sync::mpsc::Sender<QueryResult>,
     mut abandon_query_rx: tokio::sync::oneshot::Receiver<()>,
 ) {
@@ -513,29 +567,56 @@ pub async fn db_query(
         let start = Instant::now();
         // generate SQL query
         let (q, p) = query_from_sub(&sub);
-        // execute the query. Don't cache, since queries vary so much.
-        let mut stmt = conn.prepare(&q)?;
-        let mut event_rows = stmt.query(rusqlite::params_from_iter(p))?;
-        while let Some(row) = event_rows.next()? {
-            // check if this is still active (we could do this every N rows)
-            if abandon_query_rx.try_recv().is_ok() {
-                debug!("query aborted");
-                return Ok(());
+        debug!("SQL generated in {:?}", start.elapsed());
+        // show pool stats
+        debug!("DB pool stats: {:?}", pool.state());
+        let start = Instant::now();
+        if let Ok(conn) = pool.get() {
+            // execute the query. Don't cache, since queries vary so much.
+            let mut stmt = conn.prepare(&q)?;
+            let mut event_rows = stmt.query(rusqlite::params_from_iter(p))?;
+            let mut first_result = true;
+            while let Some(row) = event_rows.next()? {
+                if first_result {
+                    debug!(
+                        "time to first result: {:?} (cid={}, sub={:?})",
+                        start.elapsed(),
+                        client_id,
+                        sub.id
+                    );
+                    first_result = false;
+                }
+                // check if this is still active
+                // TODO:  check every N rows
+                if abandon_query_rx.try_recv().is_ok() {
+                    debug!("query aborted (sub={:?})", sub.id);
+                    return Ok(());
+                }
+                row_count += 1;
+                let event_json = row.get(0)?;
+                query_tx
+                    .blocking_send(QueryResult {
+                        sub_id: sub.get_id(),
+                        event: event_json,
+                    })
+                    .ok();
             }
-            row_count += 1;
-            let event_json = row.get(0)?;
             query_tx
                 .blocking_send(QueryResult {
                     sub_id: sub.get_id(),
-                    event: event_json,
+                    event: "EOSE".to_string(),
                 })
                 .ok();
+            debug!(
+                "query completed ({} rows) in {:?} (cid={}, sub={:?})",
+                row_count,
+                start.elapsed(),
+		client_id,
+                sub.id
+            );
+        } else {
+            warn!("Could not get a database connection for querying");
         }
-        debug!(
-            "query completed ({} rows) in {:?}",
-            row_count,
-            start.elapsed()
-        );
         let ok: Result<()> = Ok(());
         ok
     });

src/error.rs

@@ -48,6 +48,8 @@ pub enum Error {
     JoinError,
     #[error("Hyper Client error")]
     HyperError(hyper::Error),
+    #[error("Hex encoding error")]
+    HexError(hex::FromHexError),
     #[error("Unknown/Undocumented")]
     UnknownError,
 }
@@ -58,6 +60,12 @@ pub enum Error {
 //    }
 //}
 
+impl From<hex::FromHexError> for Error {
+    fn from(h: hex::FromHexError) -> Self {
+        Error::HexError(h)
+    }
+}
+
 impl From<hyper::Error> for Error {
     fn from(h: hyper::Error) -> Self {
         Error::HyperError(h)

src/event.rs

@@ -39,9 +39,9 @@ pub struct Event {
     pub(crate) tags: Vec<Vec<String>>,
     pub(crate) content: String,
     pub(crate) sig: String,
-    // Optimization for tag search, built on demand
+    // Optimization for tag search, built on demand.
     #[serde(skip)]
-    pub(crate) tagidx: Option<HashMap<String, HashSet<String>>>,
+    pub(crate) tagidx: Option<HashMap<char, HashSet<String>>>,
 }
 
 /// Simple tag type for array of array of strings.
@@ -56,6 +56,25 @@ where
     Ok(opt.unwrap_or_else(Vec::new))
 }
 
+/// Attempt to form a single-char tag name.
+pub fn single_char_tagname(tagname: &str) -> Option<char> {
+    // We return the tag character if and only if the tagname consists
+    // of a single char.
+    let mut tagnamechars = tagname.chars();
+    let firstchar = tagnamechars.next();
+    return match firstchar {
+        Some(_) => {
+            // check second char
+            if tagnamechars.next().is_none() {
+                firstchar
+            } else {
+                None
+            }
+        }
+        None => None,
+    };
+}
+
 /// Convert network event to parsed/validated event.
 impl From<EventCmd> for Result<Event> {
     fn from(ec: EventCmd) -> Result<Event> {
@@ -99,17 +118,22 @@ impl Event {
             return;
         }
         // otherwise, build an index
-        let mut idx: HashMap<String, HashSet<String>> = HashMap::new();
+        let mut idx: HashMap<char, HashSet<String>> = HashMap::new();
         // iterate over tags that have at least 2 elements
         for t in self.tags.iter().filter(|x| x.len() > 1) {
             let tagname = t.get(0).unwrap();
+            let tagnamechar_opt = single_char_tagname(tagname);
+            if tagnamechar_opt.is_none() {
+                continue;
+            }
+            let tagnamechar = tagnamechar_opt.unwrap();
             let tagval = t.get(1).unwrap();
             // ensure a vector exists for this tag
-            if !idx.contains_key(tagname) {
-                idx.insert(tagname.clone(), HashSet::new());
+            if !idx.contains_key(&tagnamechar) {
+                idx.insert(tagnamechar.clone(), HashSet::new());
             }
             // get the tag vec and insert entry
-            let tidx = idx.get_mut(tagname).expect("could not get tag vector");
+            let tidx = idx.get_mut(&tagnamechar).expect("could not get tag vector");
             tidx.insert(tagval.clone());
         }
         // save the tag structure
@@ -124,6 +148,16 @@ impl Event {
         self.pubkey.chars().take(8).collect()
     }
 
+    /// Retrieve tag values
+    pub fn tag_values_by_name(&self, tag_name: &str) -> Vec<String> {
+        self.tags
+            .iter()
+            .filter(|x| x.len() > 1)
+            .filter(|x| x.get(0).unwrap() == tag_name)
+            .map(|x| x.get(1).unwrap().to_owned())
+            .collect()
+    }
+
     /// Check if this event has a valid signature.
     fn is_valid(&self) -> bool {
         // TODO: return a Result with a reason for invalid events
@@ -136,7 +170,7 @@ impl Event {
             if curr_time + (allowable_future as u64) < self.created_at {
                 let delta = self.created_at - curr_time;
                 debug!(
-                    "Event is too far in the future ({} seconds), rejecting",
+                    "event is too far in the future ({} seconds), rejecting",
                     delta
                 );
                 return false;
@@ -169,11 +203,11 @@ impl Event {
                 let verify = SECP.verify_schnorr(&sig, &msg, &pubkey);
                 matches!(verify, Ok(()))
             } else {
-                debug!("Client sent malformed pubkey");
+                debug!("client sent malformed pubkey");
                 false
             }
         } else {
-            info!("Error converting digest to secp256k1 message");
+            info!("error converting digest to secp256k1 message");
             false
         }
     }
@@ -216,9 +250,10 @@ impl Event {
     }
 
     /// Determine if the given tag and value set intersect with tags in this event.
-    pub fn generic_tag_val_intersect(&self, tagname: &str, check: &HashSet<String>) -> bool {
+    pub fn generic_tag_val_intersect(&self, tagname: char, check: &HashSet<String>) -> bool {
         match &self.tagidx {
-            Some(idx) => match idx.get(tagname) {
+            // check if this is indexable tagname
+            Some(idx) => match idx.get(&tagname) {
                 Some(valset) => {
                     let common = valset.intersection(check);
                     common.count() > 0
@@ -266,7 +301,7 @@ mod tests {
     fn empty_event_tag_match() -> Result<()> {
         let 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()])));
         Ok(())
     }
 
@@ -277,7 +312,7 @@ mod tests {
         event.build_index();
         assert_eq!(
             event.generic_tag_val_intersect(
-                "e",
+                'e',
                 &HashSet::from(["foo".to_owned(), "bar".to_owned()])
             ),
             true
@@ -332,6 +367,32 @@ mod tests {
         assert_eq!(c, expected);
     }
 
+    #[test]
+    fn event_tag_select() {
+        let e = Event {
+            id: "999".to_owned(),
+            pubkey: "012345".to_owned(),
+            created_at: 501234,
+            kind: 1,
+            tags: vec![
+                vec!["j".to_owned(), "abc".to_owned()],
+                vec!["e".to_owned(), "foo".to_owned()],
+                vec!["e".to_owned(), "bar".to_owned()],
+                vec!["e".to_owned(), "baz".to_owned()],
+                vec![
+                    "p".to_owned(),
+                    "aaaa".to_owned(),
+                    "ws://example.com".to_owned(),
+                ],
+            ],
+            content: "this is a test".to_owned(),
+            sig: "abcde".to_owned(),
+            tagidx: None,
+        };
+        let v = e.tag_values_by_name("e");
+        assert_eq!(v, vec!["foo", "bar", "baz"]);
+    }
+
     #[test]
     fn event_canonical_with_tags() {
         let e = Event {

src/hexrange.rs

@@ -80,6 +80,7 @@ pub fn hex_range(s: &str) -> Option<HexSearch> {
 #[cfg(test)]
 mod tests {
     use super::*;
+    use crate::error::Result;
 
     #[test]
     fn hex_range_exact() -> Result<()> {

src/info.rs

@@ -35,7 +35,7 @@ impl From<config::Info> for RelayInfo {
             description: i.description,
             pubkey: i.pubkey,
             contact: i.contact,
-            supported_nips: Some(vec![1, 2, 11]),
+            supported_nips: Some(vec![1, 2, 11, 15, 16]),
             software: Some("https://git.sr.ht/~gheartsfield/nostr-rs-relay".to_owned()),
             version: CARGO_PKG_VERSION.map(|x| x.to_owned()),
         }

src/main.rs

@@ -21,6 +21,7 @@ use nostr_rs_relay::info::RelayInfo;
 use nostr_rs_relay::nip05;
 use nostr_rs_relay::subscription::Subscription;
 use serde::{Deserialize, Serialize};
+use serde_json::json;
 use std::collections::HashMap;
 use std::convert::Infallible;
 use std::env;
@@ -61,7 +62,7 @@ async fn handle_web_request(
     ) {
         // Request for / as websocket
         ("/", true) => {
-            debug!("websocket with upgrade request");
+            trace!("websocket with upgrade request");
             //assume request is a handshake, so create the handshake response
             let response = match handshake::server::create_response_with_body(&request, || {
                 Body::empty()
@@ -133,14 +134,17 @@ async fn handle_web_request(
                         return Ok(Response::builder()
                             .status(200)
                             .header("Content-Type", "application/nostr+json")
+                            .header("Access-Control-Allow-Origin", "*")
                             .body(b)
                             .unwrap());
                     }
                 }
             }
-            Ok(Response::new(Body::from(
-                "Please use a Nostr client to connect.",
-            )))
+            Ok(Response::builder()
+                .status(200)
+                .header("Content-Type", "text/plain")
+                .body(Body::from("Please use a Nostr client to connect."))
+                .unwrap())
         }
         (_, _) => {
             //handle any other url
@@ -355,6 +359,11 @@ fn convert_to_msg(msg: String) -> Result<NostrMessage> {
     }
 }
 
+/// Turn a string into a NOTICE message ready to send over a WebSocket
+fn make_notice_message(msg: &str) -> Message {
+    Message::text(json!(["NOTICE", msg]).to_string())
+}
+
 /// Handle new client connections.  This runs through an event loop
 /// for all client communication.
 async fn nostr_server(
@@ -375,11 +384,7 @@ async fn nostr_server(
     // Create channel for receiving NOTICEs
     let (notice_tx, mut notice_rx) = mpsc::channel::<String>(32);
 
-    // maintain a hashmap of a oneshot channel for active subscriptions.
-    // when these subscriptions are cancelled, make a message
-    // available to the executing query so it knows to stop.
-
-    // last time this client sent data
+    // last time this client sent data (message, ping, etc.)
     let mut last_message_time = Instant::now();
 
     // ping interval (every 5 minutes)
@@ -391,7 +396,11 @@ async fn nostr_server(
     let start = tokio::time::Instant::now() + default_ping_dur;
     let mut ping_interval = tokio::time::interval_at(start, default_ping_dur);
 
+    // maintain a hashmap of a oneshot channel for active subscriptions.
+    // when these subscriptions are cancelled, make a message
+    // available to the executing query so it knows to stop.
     let mut running_queries: HashMap<String, oneshot::Sender<()>> = HashMap::new();
+
     // for stats, keep track of how many events the client published,
     // and how many it received from queries.
     let mut client_published_event_count: usize = 0;
@@ -414,16 +423,20 @@ async fn nostr_server(
                 ws_stream.send(Message::Ping(Vec::new())).await.ok();
             },
             Some(notice_msg) = notice_rx.recv() => {
-                let n = notice_msg.to_string().replace("\"", "");
-                ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", n))).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
-                client_received_event_count += 1;
-                // send a result
                 let subesc = query_result.sub_id.replace("\"", "");
-                let send_str = format!("[\"EVENT\",\"{}\",{}]", subesc, &query_result.event);
-                ws_stream.send(Message::Text(send_str)).await.ok();
+                if query_result.event == "EOSE" {
+                    let send_str = format!("[\"EOSE\",\"{}\"]", subesc);
+                    ws_stream.send(Message::Text(send_str)).await.ok();
+                } else {
+                    client_received_event_count += 1;
+                    // send a result
+                    let send_str = format!("[\"EVENT\",\"{}\",{}]", subesc, &query_result.event);
+                    ws_stream.send(Message::Text(send_str)).await.ok();
+                }
             },
             // TODO: consider logging the LaggedRecv error
             Ok(global_event) = bcast_rx.recv() => {
@@ -455,20 +468,32 @@ async fn nostr_server(
                         convert_to_msg(m)
                     },
                     Some(Ok(Message::Binary(_))) => {
-                        ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", "binary messages are not accepted"))).await.ok();
+                        ws_stream.send(make_notice_message("binary messages are not accepted")).await.ok();
                         continue;
                     },
                     Some(Ok(Message::Ping(_))) | Some(Ok(Message::Pong(_))) => {
-                        // get a ping/pong, ignore
+                        // get a ping/pong, ignore.  tungstenite will
+                        // send responses automatically.
                         continue;
                     },
-                    None | Some(Ok(Message::Close(_))) | Some(Err(WsError::AlreadyClosed)) | Some(Err(WsError::ConnectionClosed))  => {
-                        debug!("normal websocket close from client: {:?}",cid);
+                    None |
+                    Some(Ok(Message::Close(_))) |
+                    Some(Err(WsError::AlreadyClosed)) |
+                    Some(Err(WsError::ConnectionClosed)) |
+                    Some(Err(WsError::Protocol(tungstenite::error::ProtocolError::ResetWithoutClosingHandshake)))
+                        => {
+                        debug!("websocket close from client: {:?}",cid);
                         break;
                     },
+                    Some(Err(WsError::Io(e))) => {
+                        // IO errors are considered fatal
+                        warn!("IO error (client: {:?}): {:?}", cid, e);
+                        break;
+                    }
                     x => {
-                        info!("message was: {:?} (ignoring)", x);
-                        continue;
+                        // default condition on error is to close the client connection
+                        info!("unknown error (client: {:?}): {:?} (closing conn)", cid, x);
+                        break;
                     }
                 };
 
@@ -489,7 +514,7 @@ async fn nostr_server(
                             },
                             Err(_) => {
                                 info!("client {:?} sent an invalid event", cid);
-                                ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", "event was invalid"))).await.ok();
+                                ws_stream.send(make_notice_message("event was invalid")).await.ok();
                             }
                         }
                     },
@@ -507,14 +532,11 @@ async fn nostr_server(
                                     previous_query.send(()).ok();
                                 }
                                 // start a database query
-                                // show pool stats
-                                debug!("DB pool stats: {:?}", pool.state());
-                                db::db_query(s, pool.get().expect("could not get connection"), query_tx.clone(), abandon_query_rx).await;
+                                db::db_query(s, cid.to_owned(), pool.clone(), query_tx.clone(), abandon_query_rx).await;
                             },
                             Err(e) => {
                                 info!("Subscription error: {}", e);
-                                let s = e.to_string().replace("\"", "");
-                                ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", s))).await.ok();
+                                ws_stream.send(make_notice_message(&e.to_string())).await.ok();
                             }
                         }
                     },
@@ -535,7 +557,7 @@ async fn nostr_server(
                             },
                             Err(_) => {
                                 info!("invalid command ignored");
-                                ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", "could not parse command"))).await.ok();
+                                ws_stream.send(make_notice_message("could not parse command")).await.ok();
                             }
                         }
                     },
@@ -545,11 +567,11 @@ async fn nostr_server(
                     }
                     Err(Error::EventMaxLengthError(s)) => {
                         info!("client {:?} sent event larger ({} bytes) than max size", cid, s);
-                        ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", "event exceeded max size"))).await.ok();
+                        ws_stream.send(make_notice_message("event exceeded max size")).await.ok();
                     },
                     Err(Error::ProtoParseError) => {
                         info!("client {:?} sent event that could not be parsed", cid);
-                        ws_stream.send(Message::Text(format!("[\"NOTICE\",\"{}\"]", "could not parse command"))).await.ok();
+                        ws_stream.send(make_notice_message("could not parse command")).await.ok();
                     },
                     Err(e) => {
                         info!("got non-fatal error from client: {:?}, error: {:?}", cid, e);

src/schema.rs

@@ -1,13 +1,13 @@
 //! Database schema and migrations
 use crate::db::PooledConnection;
 use crate::error::Result;
-use crate::utils::is_hex;
+use crate::event::{single_char_tagname, Event};
+use crate::utils::is_lower_hex;
 use log::*;
 use rusqlite::limits::Limit;
 use rusqlite::params;
 use rusqlite::Connection;
-
-// TODO: drop the pubkey_ref and event_ref tables
+use std::time::Instant;
 
 /// Startup DB Pragmas
 pub const STARTUP_SQL: &str = r##"
@@ -24,7 +24,7 @@ PRAGMA journal_mode=WAL;
 PRAGMA main.synchronous=NORMAL;
 PRAGMA foreign_keys = ON;
 PRAGMA application_id = 1654008667;
-PRAGMA user_version = 5;
+PRAGMA user_version = 6;
 
 -- Event Table
 CREATE TABLE IF NOT EXISTS event (
@@ -53,7 +53,7 @@ id INTEGER PRIMARY KEY,
 event_id INTEGER NOT NULL, -- an event ID that contains a tag.
 name TEXT, -- the tag name ("p", "e", whatever)
 value TEXT, -- the tag value, if not hex.
-value_hex BLOB, -- the tag value, if it can be interpreted as a hex string.
+value_hex BLOB, -- the tag value, if it can be interpreted as a lowercase hex string.
 FOREIGN KEY(event_id) REFERENCES event(id) ON UPDATE CASCADE ON DELETE CASCADE
 );
 CREATE INDEX IF NOT EXISTS tag_val_index ON tag(value);
@@ -103,7 +103,7 @@ pub fn upgrade_db(conn: &mut PooledConnection) -> Result<()> {
     if curr_version == 0 {
         match conn.execute_batch(INIT_SQL) {
             Ok(()) => {
-                info!("database pragma/schema initialized to v4, and ready");
+                info!("database pragma/schema initialized to v6, and ready");
             }
             Err(err) => {
                 error!("update failed: {}", err);
@@ -154,7 +154,6 @@ PRAGMA user_version = 3;
                 panic!("database could not be upgraded");
             }
         }
-        info!("Starting transaction");
         // iterate over every event/pubkey tag
         let tx = conn.transaction()?;
         {
@@ -166,7 +165,7 @@ PRAGMA user_version = 3;
                 let tag_name: String = row.get(1)?;
                 let tag_value: String = row.get(2)?;
                 // this will leave behind p/e tags that were non-hex, but they are invalid anyways.
-                if is_hex(&tag_value) {
+                if is_lower_hex(&tag_value) {
                     tx.execute(
                         "INSERT INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3);",
                         params![event_id, tag_name, hex::decode(&tag_value).ok()],
@@ -225,9 +224,63 @@ PRAGMA user_version=5;
             }
         }
     } else if curr_version == 5 {
-        debug!("Database version was already current");
-    } else if curr_version > 5 {
-        panic!("Database version is newer than supported by this executable");
+        info!("database schema needs update from 5->6");
+        // We need to rebuild the tags table.  iterate through the
+        // event table.  build event from json, insert tags into a
+        // fresh tag table.  This was needed due to a logic error in
+        // how hex-like tags got indexed.
+        let start = Instant::now();
+        let tx = conn.transaction()?;
+        {
+            // Clear out table
+            tx.execute("DELETE FROM tag;", [])?;
+            let mut stmt = tx.prepare("select id, content from event order by id;")?;
+            let mut tag_rows = stmt.query([])?;
+            while let Some(row) = tag_rows.next()? {
+                // we want to capture the event_id that had the tag, the tag name, and the tag hex value.
+                let event_id: u64 = row.get(0)?;
+                let event_json: String = row.get(1)?;
+                let event: Event = serde_json::from_str(&event_json)?;
+                // look at each event, and each tag, creating new tag entries if appropriate.
+                for t in event.tags.iter().filter(|x| x.len() > 1) {
+                    let tagname = t.get(0).unwrap();
+                    let tagnamechar_opt = single_char_tagname(tagname);
+                    if tagnamechar_opt.is_none() {
+                        continue;
+                    }
+                    // safe because len was > 1
+                    let tagval = t.get(1).unwrap();
+                    // insert as BLOB if we can restore it losslessly.
+                    // this means it needs to be even length and lowercase.
+                    if (tagval.len() % 2 == 0) && is_lower_hex(&tagval) {
+                        tx.execute(
+                            "INSERT INTO tag (event_id, name, value_hex) VALUES (?1, ?2, ?3);",
+                            params![event_id, tagname, hex::decode(&tagval).ok()],
+                        )?;
+                    } else {
+                        // otherwise, insert as text
+                        tx.execute(
+                            "INSERT INTO tag (event_id, name, value) VALUES (?1, ?2, ?3);",
+                            params![event_id, tagname, &tagval],
+                        )?;
+                    }
+                }
+            }
+            tx.execute("PRAGMA user_version = 6;", [])?;
+        }
+        tx.commit()?;
+        info!("database schema upgraded v5 -> v6 in {:?}", start.elapsed());
+        // vacuum after large table modification
+        let start = Instant::now();
+        conn.execute("VACUUM;", [])?;
+        info!("vacuumed DB after tags rebuild in {:?}", start.elapsed());
+    } else if curr_version == 6 {
+        debug!("Database version was already current (v6)");
+    } else if curr_version > 7 {
+        panic!(
+            "Database version is newer than supported by this executable (v{})",
+            curr_version
+        );
     }
 
     // Setup PRAGMA

src/subscription.rs

@@ -31,9 +31,13 @@ pub struct ReqFilter {
     pub until: Option<u64>,
     /// List of author public keys
     pub authors: Option<Vec<String>>,
+    /// Limit number of results
+    pub limit: Option<u64>,
     /// Set of tags
     #[serde(skip)]
-    pub tags: Option<HashMap<String, HashSet<String>>>,
+    pub tags: Option<HashMap<char, HashSet<String>>>,
+    /// Force no matches due to malformed data
+    pub force_no_match: bool,
 }
 
 impl<'de> Deserialize<'de> for ReqFilter {
@@ -54,7 +58,9 @@ impl<'de> Deserialize<'de> for ReqFilter {
             since: None,
             until: None,
             authors: None,
+            limit: None,
             tags: None,
+            force_no_match: false,
         };
         let mut ts = None;
         // iterate through each key, and assign values that exist
@@ -68,22 +74,28 @@ impl<'de> Deserialize<'de> for ReqFilter {
                 rf.since = Deserialize::deserialize(val).ok();
             } else if key == "until" {
                 rf.until = Deserialize::deserialize(val).ok();
+            } else if key == "limit" {
+                rf.limit = Deserialize::deserialize(val).ok();
             } else if key == "authors" {
                 rf.authors = Deserialize::deserialize(val).ok();
             } else if key.starts_with('#') && key.len() > 1 && val.is_array() {
-                // remove the prefix
-                let tagname = &key[1..];
-                if ts.is_none() {
-                    // Initialize the tag if necessary
-                    ts = Some(HashMap::new());
-                }
-                if let Some(m) = ts.as_mut() {
-                    let tag_vals: Option<Vec<String>> = Deserialize::deserialize(val).ok();
-                    if let Some(v) = tag_vals {
-                        let hs = HashSet::from_iter(v.into_iter());
-                        m.insert(tagname.to_owned(), hs);
+                if let Some(tag_search) = tag_search_char_from_filter(key) {
+                    if ts.is_none() {
+                        // Initialize the tag if necessary
+                        ts = Some(HashMap::new());
                     }
-                };
+                    if let Some(m) = ts.as_mut() {
+                        let tag_vals: Option<Vec<String>> = Deserialize::deserialize(val).ok();
+                        if let Some(v) = tag_vals {
+                            let hs = HashSet::from_iter(v.into_iter());
+                            m.insert(tag_search.to_owned(), hs);
+                        }
+                    };
+                } else {
+                    // tag search that is multi-character, don't add to subscription
+                    rf.force_no_match = true;
+                    continue;
+                }
             }
         }
         rf.tags = ts;
@@ -91,6 +103,26 @@ impl<'de> Deserialize<'de> for ReqFilter {
     }
 }
 
+/// Attempt to form a single-char identifier from a tag search filter
+fn tag_search_char_from_filter(tagname: &str) -> Option<char> {
+    let tagname_nohash = &tagname[1..];
+    // We return the tag character if and only if the tagname consists
+    // of a single char.
+    let mut tagnamechars = tagname_nohash.chars();
+    let firstchar = tagnamechars.next();
+    return match firstchar {
+        Some(_) => {
+            // check second char
+            if tagnamechars.next().is_none() {
+                firstchar
+            } else {
+                None
+            }
+        }
+        None => None,
+    };
+}
+
 impl<'de> Deserialize<'de> for Subscription {
     /// Custom deserializer for subscriptions, which have a more
     /// complex structure than the other message types.
@@ -189,7 +221,7 @@ impl ReqFilter {
         // get the hashset from the filter.
         if let Some(map) = &self.tags {
             for (key, val) in map.iter() {
-                let tag_match = event.generic_tag_val_intersect(key, val);
+                let tag_match = event.generic_tag_val_intersect(*key, val);
                 // if there is no match for this tag, the match fails.
                 if !tag_match {
                     return false;
@@ -214,9 +246,11 @@ impl ReqFilter {
         //        self.id.as_ref().map(|v| v == &event.id).unwrap_or(true)
         self.ids_match(event)
             && self.since.map(|t| event.created_at > t).unwrap_or(true)
+            && self.until.map(|t| event.created_at < t).unwrap_or(true)
             && self.kind_match(event.kind)
             && self.authors_match(event)
             && self.tag_match(event)
+            && !self.force_no_match
     }
 }
 
@@ -321,6 +355,50 @@ mod tests {
         Ok(())
     }
 
+    #[test]
+    fn interest_until() -> Result<()> {
+        // subscription with a filter for ID and time
+        let s: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "until": 1000}]"#)?;
+        let e = Event {
+            id: "abc".to_owned(),
+            pubkey: "".to_owned(),
+            created_at: 50,
+            kind: 0,
+            tags: Vec::new(),
+            content: "".to_owned(),
+            sig: "".to_owned(),
+            tagidx: None,
+        };
+        assert!(s.interested_in_event(&e));
+        Ok(())
+    }
+
+    #[test]
+    fn interest_range() -> Result<()> {
+        // subscription with a filter for ID and time
+        let s_in: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 100, "until": 200}]"#)?;
+        let s_before: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 100, "until": 140}]"#)?;
+        let s_after: Subscription =
+            serde_json::from_str(r#"["REQ","xyz",{"ids": ["abc"], "since": 160, "until": 200}]"#)?;
+        let e = Event {
+            id: "abc".to_owned(),
+            pubkey: "".to_owned(),
+            created_at: 150,
+            kind: 0,
+            tags: Vec::new(),
+            content: "".to_owned(),
+            sig: "".to_owned(),
+            tagidx: None,
+        };
+        assert!(s_in.interested_in_event(&e));
+        assert!(!s_before.interested_in_event(&e));
+        assert!(!s_after.interested_in_event(&e));
+        Ok(())
+    }
+
     #[test]
     fn interest_time_and_id() -> Result<()> {
         // subscription with a filter for ID and time

src/utils.rs

@@ -13,3 +13,21 @@ pub fn unix_time() -> u64 {
 pub fn is_hex(s: &str) -> bool {
     s.chars().all(|x| char::is_ascii_hexdigit(&x))
 }
+
+/// Check if a string contains only lower-case hex chars.
+pub fn is_lower_hex(s: &str) -> bool {
+    s.chars().all(|x| {
+        (char::is_ascii_lowercase(&x) || char::is_ascii_digit(&x)) && char::is_ascii_hexdigit(&x)
+    })
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn lower_hex() {
+        let hexstr = "abcd0123";
+        assert_eq!(is_lower_hex(hexstr), true);
+    }
+}