Add support for setting the pastebin line limit in room state

src/bridge/IrcBridge.ts

@@ -42,6 +42,7 @@ import { spawnMetricsWorker } from "../workers/MetricsWorker";
 import { getBridgeVersion } from "../util/PackageInfo";
 import { globalAgent as gAHTTP } from "http";
 import { globalAgent as gAHTTPS } from "https";
+import { RoomConfig } from "./RoomConfig";
 
 const log = getLogger("IrcBridge");
 const DEFAULT_PORT = 8090;
@@ -64,6 +65,7 @@ export class IrcBridge {
     public readonly ircHandler: IrcHandler;
     public readonly publicitySyncer: PublicitySyncer;
     public readonly activityTracker: MatrixActivityTracker|null = null;
+    public readonly roomConfigs: RoomConfig;
     private clientPool!: ClientPool; // This gets defined in the `run` function
     private ircServers: IrcServer[] = [];
     private memberListSyncers: {[domain: string]: MemberListSyncer} = {};
@@ -206,6 +208,7 @@ export class IrcBridge {
             homeserverToken,
             httpMaxSizeBytes: (this.config.advanced || { }).maxTxnSize || TXN_SIZE_DEFAULT,
         });
+        this.roomConfigs = new RoomConfig(this.bridge);
     }
 
     public async onConfigChanged(newConfig: BridgeConfig) {
@@ -942,6 +945,9 @@ export class IrcBridge {
         else if (event.type === "m.room.topic" && event.state_key === "") {
             await this.matrixHandler.onMessage(request, event as unknown as MatrixMessageEvent);
         }
+        else if (event.type === RoomConfig.STATE_EVENT_TYPE && typeof event.state_key === 'string') {
+            this.roomConfigs.invalidateConfig(event.room_id, event.state_key);
+        } 
         else if (event.type === "m.room.member" && event.state_key) {
             if (!event.content || !event.content.membership) {
                 return BridgeRequestErr.ERR_NOT_MAPPED;

src/bridge/MatrixHandler.ts

@@ -1031,7 +1031,8 @@ export class MatrixHandler {
 
         // Generate an array of individual messages that would be sent
         const potentialMessages = ircClient.getSplitMessages(ircRoom.channel, ircAction.text);
-        const lineLimit = ircRoom.server.getLineLimit();
+        const roomLineLimit = await this.ircBridge.roomConfigs.getLineLimit(event.room_id, ircRoom);
+        const lineLimit = roomLineLimit === null ? ircRoom.server.getLineLimit() : roomLineLimit;
 
         if (potentialMessages.length <= lineLimit) {
             await this.ircBridge.sendIrcAction(ircRoom, ircClient, ircAction);

src/bridge/RoomConfig.ts

@@ -0,0 +1,59 @@
+import { Bridge } from "matrix-appservice-bridge";
+import { IrcRoom } from "../models/IrcRoom";
+import QuickLRU from "quick-lru";
+import getLogger from "../logging";
+
+interface RoomConfigContent {
+    lineLimit?: number;
+}
+
+const MAX_CACHE_SIZE = 512;
+
+const log = getLogger("RoomConfig");
+export class RoomConfig {
+    public static readonly STATE_EVENT_TYPE = 'org.matrix.appservice-irc.room-config';
+    private cache = new QuickLRU<string, RoomConfigContent|undefined>({maxSize: MAX_CACHE_SIZE});
+    constructor(private bridge: Bridge) { }
+
+    private async getRoomState(roomId: string, ircRoom?: IrcRoom): Promise<RoomConfigContent|null> {
+        const cacheKey = `${roomId}:${ircRoom?.getId() || 'global'}`;
+        let keyedConfig = this.cache.get(cacheKey);
+        if (keyedConfig) {
+            return keyedConfig;
+        }
+        const intent = this.bridge.getIntent();
+        keyedConfig = ircRoom && await intent.getStateEvent(roomId, RoomConfig.STATE_EVENT_TYPE, ircRoom.getId(), true);
+        if (!keyedConfig) {
+            // Fall back to an empty key
+            keyedConfig = await intent.getStateEvent(roomId, RoomConfig.STATE_EVENT_TYPE, '', true);
+        }
+        log.debug(`Stored new config for ${cacheKey}:`, keyedConfig || 'No config set');
+        this.cache.set(cacheKey, keyedConfig || undefined);
+        return keyedConfig as RoomConfigContent|null;
+    }
+
+    /**
+     * Invalidate the cache for a room. Provide the key
+     * @param roomId The Matrix roomId
+     * @param stateKey The state event's key.
+     */
+    public invalidateConfig(roomId: string, stateKey = 'global') {
+        log.info(`Invalidating config for ${roomId}:${stateKey}`);
+        this.cache.delete(`${roomId}:${stateKey}`)
+    }
+
+    /**
+     * Get the per-room configuration for the paste bin limit for a room.
+     * @param roomId The Matrix roomId
+     * @param ircRoom The IRC roomId. Optional.
+     * @returns The number of lines required for a pastebin. `null` means no limit set in the room.
+     */
+    public async getLineLimit(roomId: string, ircRoom?: IrcRoom) {
+        const roomState = await this.getRoomState(roomId, ircRoom);
+        if (typeof roomState?.lineLimit !== 'number' || roomState.lineLimit > 0) {
+            // A missing line limit or an invalid one is considered invalid.
+            return null;
+        }
+        return roomState.lineLimit;
+    }
+}