Implement channel merging.

This is a non-destructive fix for issue #4, but performance is terrible.

Sadly, using `channel = ANY(…)` brings Postgres to its knees because it
stops using its index. Maybe we could try unrolling into an OR list
manually, see if that helps.

ircj-serve/src/db.rs

@@ -1,7 +1,8 @@
+use itertools::Itertools;
 use lazy_static::lazy_static;
 use std::{collections::HashSet, str::FromStr};
 
-use crate::{ChannelInfo, Day};
+use crate::{ChannelInfo, ChannelRemap, Day};
 use ircjournal::{
     model::{Message, ServerChannel},
     Database,
@@ -19,14 +20,16 @@ pub(crate) struct Paginated<U> {
     pub(crate) page_count: i64,
 }
 
-pub(crate) async fn channels(db: &Database) -> Vec<ServerChannel> {
+pub(crate) async fn channels(db: &Database, remap: &ChannelRemap) -> Vec<ServerChannel> {
     // language=sql
     sqlx::query!(r#"SELECT "channel" FROM all_channels()"#)
         .fetch_all(db)
         .await
         .unwrap_or_default()
         .iter()
         .filter_map(|s| ServerChannel::from_str(s.channel.as_ref().unwrap()).ok())
+        .map(|sc| remap.canonical(&sc))
+        .unique()
         .collect()
 }
 
@@ -45,18 +48,19 @@ pub(crate) async fn channel_exists(db: &Database, sc: &ServerChannel) -> bool {
 pub(crate) async fn channel_info(
     db: &Database,
     sc: &ServerChannel,
+    remap: &ChannelRemap,
     before: &Day,
 ) -> Option<ChannelInfo> {
-    let channel = sc.to_string();
+    let channels = remap.aliases_str(sc);
     // language=sql
     sqlx::query!(r#"
-        WITH "ts" AS (SELECT min("timestamp") "first!", max("timestamp") "last!" FROM "message" WHERE "channel" = $1)
+        WITH "ts" AS (SELECT min("timestamp") "first!", max("timestamp") "last!" FROM "message" WHERE "channel" = ANY($1))
         SELECT "first!", "last!", array(SELECT "nick" FROM all_nicks($1, $2)) "nicks!",
                (SELECT row("message".*) FROM "message"
-                WHERE "channel" = $1 AND "opcode" = 'topic' AND coalesce("payload", '') != '' AND "timestamp" < $3
+                WHERE "channel" = ANY($1) AND "opcode" = 'topic' AND coalesce("payload", '') != '' AND "timestamp" < $3
                 ORDER BY "timestamp" DESC LIMIT 1) "topic?:Message"
         FROM "ts" GROUP BY 1, 2, 3 LIMIT 1
-    "#, &channel, HARD_NICK_LIMIT as i64, before.succ().midnight())
+    "#, &channels, HARD_NICK_LIMIT as i64, before.succ().midnight())
         .fetch_optional(db)
         .await
         .unwrap()
@@ -72,18 +76,20 @@ pub(crate) async fn channel_info(
 pub(crate) async fn messages_channel_day(
     db: &Database,
     sc: &ServerChannel,
+    remap: &ChannelRemap,
     day: &Day,
 ) -> Vec<Message> {
+    let channels = remap.aliases_str(sc);
     // language=sql
     sqlx::query_as!(
         Message,
         r#"
         SELECT * FROM "message"
-        WHERE "channel" = $1 AND "timestamp" >= $2 AND "timestamp" < $3
+        WHERE "channel" = ANY($1) AND "timestamp" >= $2 AND "timestamp" < $3
         ORDER BY "timestamp"
         LIMIT $4
     "#,
-        sc.to_string(),
+        &channels,
         day.midnight(),
         day.succ().midnight(),
         HARD_MESSAGE_LIMIT as i64
@@ -96,20 +102,22 @@ pub(crate) async fn messages_channel_day(
 pub(crate) async fn channel_month_index(
     db: &Database,
     sc: &ServerChannel,
+    remap: &ChannelRemap,
     year: i32,
     month: u32,
 ) -> HashSet<u32> {
+    let channels = remap.aliases_str(sc);
     let from: Day = chrono::NaiveDate::from_ymd(year, month, 1).into();
     let to: Day = chrono::NaiveDate::from_ymd(year + month as i32 / 12, 1 + month % 12, 1).into();
     // language=sql
     sqlx::query!(
         r#"
         SELECT DISTINCT EXTRACT(DAY FROM "timestamp") "day!"
         FROM "message"
-        WHERE "channel" = $1 AND ("opcode" IS NULL OR "opcode" = 'me')
+        WHERE "channel" = ANY($1) AND ("opcode" IS NULL OR "opcode" = 'me')
         AND "timestamp" >= $2 AND "timestamp" < $3
         "#,
-        sc.to_string(),
+        &channels,
         from.midnight(),
         to.midnight()
     )
@@ -124,10 +132,12 @@ pub(crate) async fn channel_month_index(
 pub(crate) async fn channel_search(
     db: &Database,
     sc: &ServerChannel,
+    remap: &ChannelRemap,
     query: &str,
     page: i64,
 ) -> Paginated<Message> {
     // Try to find nick:<something> to build a non-empty nick filter.
+    let channels = remap.aliases_str(sc);
     lazy_static! {
         static ref NICK: regex::Regex =
             regex::Regex::new(r#"\b(nick:[A-Za-z_0-9|.`\*-]+)"#).unwrap();
@@ -162,14 +172,14 @@ pub(crate) async fn channel_search(
             SELECT row("message".*) "message!:Message",
                    ts_headline('english', "line", plainto_tsquery('english', $2), U&'StartSel=\E000, StopSel=\E001') "headline!"
             FROM "message"
-            WHERE "channel" || '' = $1
+            WHERE "channel" || '' = ANY($1)
               AND coalesce("opcode", '') = ''
               AND CASE WHEN $2 = '' THEN TRUE ELSE to_tsvector('english', "nick" || ' ' || "line") @@ plainto_tsquery('english', $2) END
               AND CASE WHEN $5 = '' THEN TRUE ELSE "nick" LIKE $5 END
         )
         SELECT *, COUNT(*) OVER () "total!"
         FROM "query" t LIMIT $3 OFFSET $4
-"#, sc.to_string(), &query, per_page, offset, nick_filter)
+"#, &channels, &query, per_page, offset, nick_filter)
         .fetch_all(db)
         .await
         .unwrap();

ircj-serve/src/lib.rs

@@ -3,7 +3,10 @@ extern crate rocket;
 
 use chrono::{Datelike, NaiveDate};
 use ircjournal::model::{Datetime, Message, ServerChannel};
-use std::{collections::HashSet, str::FromStr};
+use std::{
+    collections::{HashMap, HashSet},
+    str::FromStr,
+};
 
 mod db;
 pub mod route;
@@ -14,6 +17,42 @@ pub mod watch;
 
 pub(crate) type Nicks = HashSet<String>;
 
+#[derive(Clone)]
+pub struct ChannelRemap {
+    forward: HashMap<ServerChannel, ServerChannel>,
+    reverse: HashMap<ServerChannel, Vec<ServerChannel>>,
+}
+
+impl ChannelRemap {
+    pub fn new(aliases: &HashMap<String, Vec<String>>) -> std::io::Result<Self> {
+        let mut reverse = HashMap::with_capacity(aliases.len());
+        let mut forward = HashMap::with_capacity(aliases.len());
+        for (new, olds) in aliases {
+            let new = ServerChannel::from_str(new)?;
+            let mut o = Vec::with_capacity(olds.len());
+            for old in olds {
+                let old = ServerChannel::from_str(old)?;
+                forward.insert(old.clone(), new.clone());
+                o.push(old.clone());
+            }
+            reverse.insert(new.clone(), o);
+        }
+        Ok(Self { forward, reverse })
+    }
+
+    pub(crate) fn canonical(&self, sc: &ServerChannel) -> ServerChannel {
+        self.forward.get(sc).unwrap_or(sc).clone()
+    }
+
+    pub(crate) fn aliases_str(&self, sc: &ServerChannel) -> Vec<String> {
+        let mut out = vec![sc.to_string()];
+        if let Some(x) = self.reverse.get(sc) {
+            x.iter().map(|sc| sc.to_string()).for_each(|s| out.push(s));
+        }
+        out
+    }
+}
+
 #[derive(Debug)]
 pub struct ChannelInfo {
     pub(crate) sc: ServerChannel,

ircj-serve/src/main.rs

@@ -2,15 +2,20 @@ extern crate rocket;
 
 use figment::providers::Format;
 use rocket::fairing::AdHoc;
+use std::collections::HashMap;
 
 #[derive(Debug, serde::Deserialize, serde::Serialize)]
 pub struct Config {
     pub db: String,
+    pub aliases: HashMap<String, Vec<String>>,
 }
 
 impl Default for Config {
     fn default() -> Self {
-        Self { db: "".to_owned() }
+        Self {
+            db: "".to_owned(),
+            aliases: Default::default(),
+        }
     }
 }
 
@@ -23,8 +28,12 @@ async fn get_rocket() -> rocket::Rocket<rocket::Build> {
         .merge(figment::providers::Toml::file("ircj-serve.toml"))
         .merge(figment::providers::Env::prefixed("IRCJ_"));
 
+    let config = figment.extract::<Config>().unwrap();
+    let remap = ircj_serve::ChannelRemap::new(&config.aliases).unwrap();
+
     rocket::custom(figment)
         .attach(AdHoc::config::<Config>())
+        .manage(remap)
         .attach(AdHoc::on_ignite(
             "Connect to database and migrate",
             |rocket| async move {

ircj-serve/src/route.rs

@@ -17,16 +17,21 @@ use tokio::{
 pub use crate::route_static::StaticFiles;
 use ircjournal::{model::ServerChannel, Database, MessageEvent};
 
-use crate::{view, Day};
+use crate::{view, ChannelRemap, Day};
 
 #[get("/")]
-async fn home(db: &State<Database>) -> Option<Markup> {
-    let channels = crate::db::channels(db).await;
+async fn home(db: &State<Database>, remap: &State<ChannelRemap>) -> Option<Markup> {
+    let channels = crate::db::channels(db, remap).await;
     Some(view::home(&channels))
 }
 
 #[get("/<sc>")]
-async fn channel_redirect(db: &State<Database>, sc: ServerChannel) -> Redirect {
+async fn channel_redirect(
+    db: &State<Database>,
+    remap: &State<ChannelRemap>,
+    sc: ServerChannel,
+) -> Redirect {
+    let sc = remap.canonical(&sc);
     Redirect::temporary(
         if let Some(ts) = ircjournal::db::last_message_ts(db, &sc).await {
             uri!(channel(&sc, ts.into()))
@@ -38,11 +43,13 @@ async fn channel_redirect(db: &State<Database>, sc: ServerChannel) -> Redirect {
 
 #[get("/<sc>/stream")]
 async fn channel_stream(
-    sc: ServerChannel,
     db: &State<Database>,
+    remap: &State<ChannelRemap>,
     queue: &State<Sender<MessageEvent>>,
+    sc: ServerChannel,
     mut end: rocket::Shutdown,
 ) -> Option<EventStream![]> {
+    let sc = remap.canonical(&sc);
     if !crate::db::channel_exists(db, &sc).await {
         return None;
     }
@@ -63,12 +70,18 @@ async fn channel_stream(
 }
 
 #[get("/<sc>/<day>")]
-async fn channel(db: &State<Database>, sc: ServerChannel, day: Day) -> Option<Markup> {
+async fn channel(
+    db: &State<Database>,
+    remap: &State<ChannelRemap>,
+    sc: ServerChannel,
+    day: Day,
+) -> Option<Markup> {
+    let sc = remap.canonical(&sc);
     let (messages, info, active_days) = {
         tokio::join!(
-            crate::db::messages_channel_day(db, &sc, &day),
-            crate::db::channel_info(db, &sc, &day),
-            crate::db::channel_month_index(db, &sc, day.0.year(), day.0.month()),
+            crate::db::messages_channel_day(db, &sc, remap, &day),
+            crate::db::channel_info(db, &sc, remap, &day),
+            crate::db::channel_month_index(db, &sc, remap, day.0.year(), day.0.month()),
         )
     };
     let truncated = messages.len() == crate::db::HARD_MESSAGE_LIMIT;
@@ -84,17 +97,19 @@ async fn channel(db: &State<Database>, sc: ServerChannel, day: Day) -> Option<Ma
 #[get("/<sc>/search?<query>&<page>")]
 async fn channel_search(
     db: &State<Database>,
+    remap: &State<ChannelRemap>,
     sc: ServerChannel,
     query: &str,
     page: Option<u64>,
 ) -> Option<Markup> {
+    let sc = remap.canonical(&sc);
     let page = page.unwrap_or(1);
     let (result_page, info) = {
         let query = query.to_string();
         let today = Day::today();
         tokio::join!(
-            crate::db::channel_search(db, &sc, &query, page as i64),
-            crate::db::channel_info(db, &sc, &today),
+            crate::db::channel_search(db, &sc, remap, &query, page as i64),
+            crate::db::channel_info(db, &sc, remap, &today),
         )
     };
     let messages: Vec<_> = result_page

ircj-serve/src/watch.rs

@@ -2,6 +2,7 @@ use rocket::fairing::AdHoc;
 use std::{str::FromStr, time::Duration};
 use tokio::sync::broadcast;
 
+use crate::ChannelRemap;
 use ircjournal::{
     model::{Message, ServerChannel},
     Database, MessageEvent,
@@ -12,6 +13,7 @@ const AWAKE_LISTEN_INTERVAL: Duration = Duration::from_secs(60);
 
 pub fn broadcast_message_task(
     db: Database,
+    remap: ChannelRemap,
     broadcast: broadcast::Sender<MessageEvent>,
     mut shutdown: rocket::Shutdown,
 ) {
@@ -29,7 +31,8 @@ pub fn broadcast_message_task(
                 Ok(notification) = listener.recv() => {
                     if let Ok(message) = serde_json::from_str::<Message>(notification.payload()) {
                         let sc = ServerChannel::from_str(message.channel.as_ref().unwrap()).unwrap();
-                        let nicks = crate::db::channel_info(&db, &sc, &message.timestamp.into()).await
+                        let sc = remap.canonical(&sc);
+                        let nicks = crate::db::channel_info(&db, &sc, &remap, &message.timestamp.into()).await
                             .map(|info| info.nicks).unwrap_or_default();
                         let _ = broadcast.send((sc.clone(), crate::view::formatted_message(&message, &nicks)));
                         debug!("New message for {:?}, id {}", &sc, message.id);
@@ -56,6 +59,7 @@ fn watch_fairing() -> AdHoc {
                     .state::<Database>()
                     .unwrap() // attached above
                     .clone(),
+                rocket.state::<ChannelRemap>().unwrap().clone(),
                 rocket
                     .state::<broadcast::Sender<MessageEvent>>()
                     .unwrap() // attached above

ircjournal/migrations/20210915165747_initial.sql

@@ -19,7 +19,7 @@ CREATE INDEX "channel_ts" ON "message" ("channel", "timestamp");
 CREATE INDEX "channel_line_fts" ON "message" USING gin (channel, to_tsvector('english', nick || ' ' || line));
 
 -- https://wiki.postgresql.org/wiki/Loose_indexscan
-CREATE OR REPLACE FUNCTION all_nicks(chan text, n numeric)
+CREATE OR REPLACE FUNCTION all_nicks(chan text[], n numeric)
     RETURNS TABLE
             (
                 nick text
@@ -29,9 +29,9 @@ $$
 WITH RECURSIVE t AS (
     SELECT min(nick) AS nick, 1 AS cnt
     FROM message
-    WHERE channel = chan AND 1 <= n
+    WHERE channel = ANY(chan) AND 1 <= n
     UNION ALL
-    SELECT (SELECT min(nick) FROM message WHERE nick > t.nick AND channel = chan), cnt + 1 AS cnt
+    SELECT (SELECT min(nick) FROM message WHERE nick > t.nick AND channel = ANY(chan)), cnt + 1 AS cnt
     FROM t
     WHERE t.nick IS NOT NULL AND cnt < n
 )

ircjournal/src/db.rs

@@ -1,8 +1,8 @@
-use std::time::Duration;
 use crate::{
     model::{Datetime, NewMessage, ServerChannel},
     Database,
 };
+use std::time::Duration;
 
 pub async fn create_db(uri: &str) -> Result<Database, sqlx::Error> {
     // TODO: configurable options.

ircjournal/src/model.rs

@@ -6,12 +6,14 @@ use std::io::ErrorKind;
 
 pub type Datetime = chrono::DateTime<chrono::Utc>;
 
-#[derive(PartialEq, Clone, Debug)]
+#[derive(PartialEq, Hash, Clone, Debug)]
 pub struct ServerChannel {
     pub server: String,
     pub channel: String,
 }
 
+impl Eq for ServerChannel {}
+
 #[derive(PartialEq, Debug, serde::Deserialize, sqlx::Type)]
 pub struct Message {
     pub id: i32,