feat: collab hocuspocus v4 upgrade (#2351)

* WIP 1

* complete v4 migration

* add flushDelay

* feat: multiplexing

* fix: survive hocuspocus v4 message timeout

* fix: searchTerm type error

apps/server/package.json

@@ -88,7 +88,6 @@
     "kysely-migration-cli": "0.4.2",
     "kysely-postgres-js": "3.0.0",
     "ldapts": "8.1.7",
-    "lib0": "0.2.117",
     "mammoth": "1.12.0",
     "mime-types": "3.0.2",
     "msgpackr": "^1.11.9",
@@ -118,7 +117,6 @@
     "stripe": "^17.7.0",
     "tlds": "1.261.0",
     "tmp-promise": "3.0.3",
-    "tseep": "1.3.1",
     "typesense": "3.0.5",
     "undici": "7.28.0",
     "ws": "8.21.0",

apps/server/src/collaboration/collaboration.gateway.ts

@@ -15,6 +15,7 @@ import {
   RedisSyncExtension,
   SerializedHTTPRequest,
 } from './extensions/redis-sync';
+import { toWebRequest } from './extensions/redis-sync/redis-sync.types';
 import { WsSocketWrapper } from './extensions/redis-sync/ws-socket-wrapper';
 import RedisClient from 'ioredis';
 import { pack, unpack } from 'msgpackr';
@@ -98,34 +99,36 @@ export class CollaborationGateway {
       const serializedHTTPRequest = this.serializeRequest(request);
       const socketId = serializedHTTPRequest.headers['sec-websocket-key'];
 
-      // Create wrapper socket that only receives events via emit()
-      // This prevents double-handling since Hocuspocus won't listen to raw WebSocket events
       const wrappedSocket = new WsSocketWrapper(client);
 
       // Route through RedisSync extension (this calls handleConnection internally)
-      this.redisSync.onSocketOpen(wrappedSocket as any, serializedHTTPRequest);
+      this.redisSync.onSocketOpen(wrappedSocket, serializedHTTPRequest);
 
-      // Forward raw WebSocket messages to the extension
       client.on('message', (data: ArrayBuffer) => {
-        this.redisSync!.onSocketMessage(
-          wrappedSocket as any,
-          serializedHTTPRequest,
-          data,
-        );
+        this.redisSync!.onSocketMessage(serializedHTTPRequest, data);
       });
 
-      // Forward close events
       client.on('close', (code: number, reason: Buffer) => {
-        this.redisSync!.onSocketClose(socketId, code, reason.buffer as ArrayBuffer);
-      });
-
-      // Forward pong events for keepalive
-      client.on('pong', (data: Buffer) => {
-        wrappedSocket.emit('pong', data);
+        this.redisSync!.onSocketClose(
+          socketId,
+          code,
+          new Uint8Array(reason).buffer,
+        );
       });
     } else {
       // Fallback to direct Hocuspocus connection
-      this.hocuspocus.handleConnection(client, request);
+      const clientConnection = this.hocuspocus.handleConnection(
+        client,
+        toWebRequest(this.serializeRequest(request)),
+      );
+
+      client.on('message', (data: Buffer) => {
+        clientConnection.handleMessage(new Uint8Array(data));
+      });
+
+      client.on('close', (code: number, reason: Buffer) => {
+        clientConnection.handleClose({ code, reason: reason.toString() });
+      });
     }
   }
 
@@ -178,6 +181,7 @@ export class CollaborationGateway {
 
         if (this.hocuspocus.getDocumentsCount() === 0) resolve('');
         this.hocuspocus.closeConnections();
+        this.hocuspocus.flushPendingStores();
       } catch (error) {
         console.error(error);
       }

apps/server/src/collaboration/extensions/persistence.extension.ts

@@ -96,7 +96,7 @@ export class PersistenceExtension implements Extension {
   }
 
   async onStoreDocument(data: onStoreDocumentPayload) {
-    const { documentName, document, context } = data;
+    const { documentName, document, lastContext } = data;
 
     const pageId = getPageId(documentName);
 
@@ -151,7 +151,7 @@ export class PersistenceExtension implements Extension {
             content: tiptapJson,
             textContent: textContent,
             ydoc: ydocState,
-            lastUpdatedById: context.user.id,
+            lastUpdatedById: lastContext.user.id,
             contributorIds: contributorIds,
           },
           pageId,
@@ -169,12 +169,12 @@ export class PersistenceExtension implements Extension {
         JSON.stringify({
           type: 'page.updated',
           updatedAt: new Date().toISOString(),
-          lastUpdatedById: context?.user?.id,
-          lastUpdatedBy: context?.user
+          lastUpdatedById: lastContext?.user?.id,
+          lastUpdatedBy: lastContext?.user
             ? {
-                id: context.user?.id,
-                name: context.user?.name,
-                avatarUrl: context.user?.avatarUrl,
+                id: lastContext.user?.id,
+                name: lastContext.user?.name,
+                avatarUrl: lastContext.user?.avatarUrl,
               }
             : undefined,
         }),

apps/server/src/collaboration/extensions/redis-sync/collab-proxy-socket.ts

@@ -1,61 +1,37 @@
 import type RedisClient from 'ioredis';
-import { EventEmitter } from 'tseep';
-import type {
-  Pack,
-  RSAMessageClose,
-  RSAMessagePing,
-  RSAMessageSend,
-} from './redis-sync.types';
+import type { WebSocketLike } from '@hocuspocus/server';
+import type { Pack, RSAMessageClose, RSAMessageSend } from './redis-sync.types';
 
-export class CollabProxySocket extends EventEmitter {
+// Stands in for the client WebSocket on the server that owns the document.
+// Outgoing traffic is relayed over redis to the origin server, which holds the real socket.
+export class CollabProxySocket implements WebSocketLike {
   private readonly replyTo: string;
-  private readonly serverChannel: string;
   private readonly socketId: string;
   private pub: RedisClient;
   private readonly pack: Pack;
   readyState = 1;
+  onClose?: (code?: number, reason?: string) => void;
 
-  constructor(
-    pub: RedisClient,
-    pack: Pack,
-    replyTo: string,
-    serverChannel: string,
-    socketId: string,
-  ) {
-    super();
+  constructor(pub: RedisClient, pack: Pack, replyTo: string, socketId: string) {
     this.replyTo = replyTo;
     this.socketId = socketId;
-    this.serverChannel = serverChannel;
     this.pub = pub;
     this.pack = pack;
-    this.once('close', () => {
-      this.readyState = 3;
-    });
   }
 
-  private publish(msg: RSAMessageClose | RSAMessagePing | RSAMessageSend) {
+  private publish(msg: RSAMessageClose | RSAMessageSend) {
     this.pub.publish(this.replyTo, this.pack(msg));
   }
 
+  // The origin server already closed the real socket; stop relaying without echoing a close back
+  markClosed() {
+    this.readyState = 3;
+  }
+
   close(code?: number, reason?: string) {
     if (this.readyState !== 1) return;
-    const msg: RSAMessageClose = {
-      type: 'close',
-      code,
-      reason,
-      socketId: this.socketId,
-    };
-    this.publish(msg);
-  }
-
-  ping() {
-    if (this.readyState !== 1) return;
-    const msg: RSAMessagePing = {
-      type: 'ping',
-      socketId: this.socketId,
-      replyTo: this.serverChannel,
-    };
-    this.publish(msg);
+    this.readyState = 3;
+    this.onClose?.(code, reason);
   }
 
   send(message: Uint8Array) {

apps/server/src/collaboration/extensions/redis-sync/redis-sync.extension.ts

@@ -3,27 +3,30 @@ import {
   Extension,
   Hocuspocus,
   IncomingMessage,
-  afterUnloadDocumentPayload,
   onConfigurePayload,
   onLoadDocumentPayload,
+  afterUnloadDocumentPayload,
+  WebSocketLike,
 } from '@hocuspocus/server';
+import { ConnectionTimeout, Unauthorized } from '@hocuspocus/common';
 import RedisClient from 'ioredis';
-import { readVarString } from 'lib0/decoding.js';
 import { CollabProxySocket } from './collab-proxy-socket';
 import {
-  BaseWebSocket,
   Configuration,
   CustomEvents,
   Pack,
   RSAMessage,
+  RSAMessageClose,
   RSAMessageCloseProxy,
   RSAMessageCustomEventComplete,
   RSAMessageCustomEventStart,
-  RSAMessagePong,
   RSAMessageProxy,
   RSAMessageUnload,
   SerializedHTTPRequest,
   Unpack,
+  OriginConnection,
+  ProxyConnection,
+  toWebRequest,
 } from './redis-sync.types';
 
 export type { Pack, SerializedHTTPRequest } from './redis-sync.types';
@@ -38,10 +41,10 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
   private sub: RedisClient;
   private readonly pack: Pack;
   private readonly unpack: Unpack;
-  private originSockets: Record<SocketId, BaseWebSocket> = {};
+  private originConnections: Record<SocketId, OriginConnection> = {};
   private locks: Record<DocumentName, NodeJS.Timeout> = {};
   private lockPromises: Record<DocumentName, Promise<ServerId | null>> = {};
-  private proxySockets: Record<SocketId, CollabProxySocket> = {};
+  private proxyConnections: Record<SocketId, ProxyConnection> = {};
   private readonly prefix: string;
   private readonly lockPrefix: string;
   private readonly msgChannel: string;
@@ -54,6 +57,9 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
   // @ts-ignore
   private pendingReplies: Record<number, PromiseWithResolvers<any>['resolve']> =
     {};
+  private deriveContext: (
+    serializedHTTPRequest: SerializedHTTPRequest,
+  ) => Record<string, any>;
 
   constructor(configuration: Configuration<TCE>) {
     const {
@@ -65,6 +71,7 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       prefix,
       customEvents,
       customEventTTL,
+      deriveContext,
     } = configuration;
     this.pub = redis.duplicate();
     this.sub = redis.duplicate();
@@ -77,6 +84,7 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
     this.lockPrefix = `${this.prefix}Lock`;
     this.msgChannel = `${this.prefix}Msg`;
     this.customEvents = (customEvents as any) ?? ({} as any as CustomEvents);
+    this.deriveContext = deriveContext ?? (() => ({}));
     this.sub.subscribe(this.msgChannel, `${this.msgChannel}:${this.serverId}`);
     this.sub.on('messageBuffer', this.handleRedisMessage);
     this.pub.on('error', () => {});
@@ -87,44 +95,63 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
   }
 
   private closeProxy(socketId: string) {
-    const proxySocket = this.proxySockets[socketId];
-    if (proxySocket) {
-      proxySocket.emit(
-        'close',
-        1000,
-        Buffer.from('provider_initiated', 'utf-8'),
-      );
-      delete this.proxySockets[socketId];
+    const entry = this.proxyConnections[socketId];
+    if (entry) {
+      delete this.proxyConnections[socketId];
+      const { socket, clientConnection } = entry;
+      // The origin socket is already gone; don't echo a close message back
+      socket.markClosed();
+      clientConnection.handleClose({
+        code: 1000,
+        reason: 'provider_initiated',
+      });
     }
   }
 
-  private pongProxy(socketId: string) {
-    this.proxySockets[socketId]?.emit('pong');
-  }
-
   private handleProxyMessage(
     msg: Pick<RSAMessageProxy, 'replyTo' | 'message' | 'serializedHTTPRequest'>,
   ) {
     const { replyTo, message, serializedHTTPRequest } = msg;
     const { headers } = serializedHTTPRequest;
-    const socketId = headers['sec-websocket-key']!;
-    let socket = this.proxySockets[socketId];
-    if (!socket) {
-      socket = new CollabProxySocket(
+    const socketId = headers['sec-websocket-key'];
+    let entry = this.proxyConnections[socketId];
+    if (!entry) {
+      const socket = new CollabProxySocket(
         this.pub,
         this.pack,
         replyTo,
-        `${this.msgChannel}:${this.serverId}`,
         socketId,
       );
-      this.proxySockets[socketId] = socket;
-      this.instance.handleConnection(
-        socket as any,
-        serializedHTTPRequest as any,
-        {},
+      // A proxy connection with no live documents (client left the page, auth
+      // failed, or the origin server crashed) is reaped by hocuspocus' message
+      // timeout. Dispose it silently in that case: relaying the timeout close
+      // to the origin would kill the client's real socket, which may be busy
+      // serving other documents. Genuine protocol closes are still relayed.
+      socket.onClose = (code, reason) => {
+        delete this.proxyConnections[socketId];
+        if (code !== ConnectionTimeout.code) {
+          const msg: RSAMessageClose = {
+            type: 'close',
+            code,
+            reason,
+            socketId,
+          };
+          this.pub.publish(replyTo, this.pack(msg));
+        }
+      };
+      const clientConnection = this.instance.handleConnection(
+        socket,
+        toWebRequest(serializedHTTPRequest),
+        this.deriveContext(serializedHTTPRequest),
       );
+      entry = { clientConnection, socket };
+      this.proxyConnections[socketId] = entry;
     }
-    socket.emit('message', message);
+    entry.clientConnection.handleMessage(message);
+  }
+
+  private getLock(documentName: string) {
+    return this.pub.get(this.getKey(documentName));
   }
 
   private getOrClaimLock(documentName: string) {
@@ -166,10 +193,6 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       this.closeProxy(msg.socketId);
       return;
     }
-    if (type === 'pong') {
-      this.pongProxy(msg.socketId);
-      return;
-    }
     if (type === 'unload') {
       delete this.lockPromises[msg.documentName];
       return;
@@ -198,22 +221,14 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       return;
     }
     const { socketId } = msg;
-    const socket = this.originSockets[socketId];
-    if (!socket) {
+    const entry = this.originConnections[socketId];
+    if (!entry) {
       // origin socket already cleaned up
       return;
     }
+    const { socket } = entry;
     if (type === 'close') {
       socket.close(msg.code, msg.reason);
-    } else if (type === 'ping') {
-      // Reply instantly to the proxy socket, without forwarding to client
-      // The origin socket handles heartbeat for itself
-      const { replyTo, socketId } = msg;
-      const reply: RSAMessagePong = {
-        type: 'pong',
-        socketId,
-      };
-      this.pub.publish(`${replyTo}`, this.pack(reply));
     } else if (type === 'send') {
       socket.send(msg.message);
     }
@@ -251,6 +266,8 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
     eventName: TName,
     documentName: string,
     payload: any,
+    // if true, don't claim the lock. Useful for targeting pages that are currently open
+    onlyIfOpen = false,
   ) {
     const isDocLoadedOnInstance = this.instance.documents.has(documentName);
 
@@ -258,7 +275,14 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       return this.handleEventLocally(eventName, documentName, payload);
     }
 
-    const proxyTo = await this.getOrClaimLockThrottled(documentName);
+    const proxyTo = await (onlyIfOpen
+      ? this.getLock(documentName)
+      : this.getOrClaimLockThrottled(documentName));
+
+    if (!proxyTo && onlyIfOpen) {
+      return;
+    }
+
     if (proxyTo && proxyTo !== this.serverId) {
       ++this.replyIdCounter; // bug in biome thinks this.replyIdCounter is not used if written on the line below
       const replyId = this.replyIdCounter;
@@ -277,7 +301,8 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       const { promise, resolve, reject } = Promise.withResolvers();
       this.pendingReplies[replyId] = resolve;
       setTimeout(() => {
-        reject('TIMEOUT');
+        delete this.pendingReplies[replyId];
+        reject(new Error('TIMEOUT'));
       }, this.customEventTTL);
       return promise as Promise<ReturnType<TCE[TName]>>;
     }
@@ -296,36 +321,59 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
 
   /* WebSocket Server Hooks */
   onSocketOpen(
-    ws: BaseWebSocket,
+    ws: WebSocketLike,
     serializedHTTPRequest: SerializedHTTPRequest,
-    context = {},
   ) {
-    const socketId = serializedHTTPRequest.headers['sec-websocket-key']!;
-    this.originSockets[socketId] = ws;
-    this.instance.handleConnection(
-      ws as any,
-      serializedHTTPRequest as any,
-      context,
+    const socketId = serializedHTTPRequest.headers['sec-websocket-key'];
+    const clientConnection = this.instance.handleConnection(
+      ws,
+      toWebRequest(serializedHTTPRequest),
+      this.deriveContext(serializedHTTPRequest),
     );
+    this.originConnections[socketId] = { clientConnection, socket: ws };
   }
 
   async onSocketMessage(
-    ws: BaseWebSocket,
     serializedHTTPRequest: SerializedHTTPRequest,
     detachableMsg: ArrayBuffer,
   ) {
-    const message = new Uint8Array(detachableMsg.slice());
-    const tmpMsg = new IncomingMessage(detachableMsg);
-    const documentName = readVarString(tmpMsg.decoder);
+    const socketId = serializedHTTPRequest.headers['sec-websocket-key'];
+    const entry = this.originConnections[socketId];
+    if (!entry) return;
+    const { clientConnection } = entry;
+
+    let message: Uint8Array;
+    let documentName: string;
+    try {
+      message = new Uint8Array(detachableMsg.slice());
+      const tmpMsg = new IncomingMessage(detachableMsg);
+      const documentNameAndSessionId = tmpMsg.readVarString();
+      // session-aware providers suffix the documentName with \0sessionId
+      const sepIdx = documentNameAndSessionId.indexOf('\0');
+      documentName =
+        sepIdx === -1
+          ? documentNameAndSessionId
+          : documentNameAndSessionId.slice(0, sepIdx);
+    } catch (error) {
+      entry.socket.close(Unauthorized.code, Unauthorized.reason);
+      return;
+    }
     const isDocLoadedOnInstance = this.instance.documents.has(documentName);
 
     if (isDocLoadedOnInstance) {
-      ws.emit('message', message);
+      clientConnection.handleMessage(message);
       return;
     }
 
     const proxyTo = await this.getOrClaimLockThrottled(documentName);
     if (proxyTo && proxyTo !== this.serverId) {
+      // Proxied messages bypass handleMessage, so refresh the connection's
+      // liveness fields manually or hocuspocus' message timeout would reap the
+      // real socket every `timeout` ms. connectionEstablishedAt is the
+      // reference while unauthenticated (auth for remote docs is proxied too)
+      // and is private upstream.
+      clientConnection.lastMessageReceivedAt = Date.now();
+      (clientConnection as any).connectionEstablishedAt = Date.now();
       // another server owns the doc
       const proxyMessage: RSAMessageProxy = {
         serializedHTTPRequest: serializedHTTPRequest,
@@ -338,16 +386,17 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
       return;
     }
     // This server owns the document, but hocuspocus hasn't loaded it yet
-    ws.emit('message', message);
+    clientConnection.handleMessage(message);
   }
 
   onSocketClose(socketId: string, code?: number, reason?: ArrayBuffer) {
-    const socket = this.originSockets[socketId];
-    if (!socket) return;
-    // at this point the socket is considered GC'd and we cannot call close
-    // The origin socket did not set up any connections for the proxy, so none of the hooks will work if we just emit
-    socket?.emit('close', code, reason);
-    delete this.originSockets[socketId];
+    const entry = this.originConnections[socketId];
+    if (!entry) return;
+    delete this.originConnections[socketId];
+    entry.clientConnection.handleClose({
+      code: code ?? 1000,
+      reason: reason ? Buffer.from(reason).toString() : '',
+    });
     const msg: RSAMessageCloseProxy = { type: 'closeProxy', socketId };
     this.pub.publish(this.msgChannel, this.pack(msg)).catch(() => {});
   }
@@ -372,6 +421,7 @@ export class RedisSyncExtension<TCE extends CustomEvents> implements Extension {
   }
 
   async onDestroy() {
+    this.pendingReplies = {};
     this.pub.disconnect(false);
     this.sub.disconnect(false);
   }

apps/server/src/collaboration/extensions/redis-sync/redis-sync.types.ts

@@ -1,12 +1,13 @@
-import EventEmitter from 'node:events';
 import { IncomingHttpHeaders } from 'node:http2';
 import RedisClient from 'ioredis';
+import { CollabProxySocket } from './collab-proxy-socket';
+import { type Hocuspocus, type WebSocketLike } from '@hocuspocus/server';
 
 export type SecondParam<T> = T extends (
-  arg1: unknown,
+  arg1: any,
   arg2: infer A,
-  ...args: unknown[]
-) => unknown
+  ...args: any[]
+) => any
   ? A
   : never;
 
@@ -41,17 +42,6 @@ export type RSAMessageClose = {
   socketId: string;
 };
 
-export type RSAMessagePing = {
-  type: 'ping';
-  socketId: string;
-  replyTo: string;
-};
-
-export type RSAMessagePong = {
-  type: 'pong';
-  socketId: string;
-};
-
 export type RSAMessageSend = {
   type: 'send';
   // @ts-ignore
@@ -59,7 +49,7 @@ export type RSAMessageSend = {
   socketId: string;
 };
 
-export type RSAMessageCustomEventStart<TName = string, TPayload = unknown> = {
+export type RSAMessageCustomEventStart<TName = string, TPayload = any> = {
   type: 'customEventStart';
   documentName: string;
   eventName: TName;
@@ -71,7 +61,7 @@ export type RSAMessageCustomEventStart<TName = string, TPayload = unknown> = {
 export type RSAMessageCustomEventComplete = {
   type: 'customEventComplete';
   replyId: number;
-  payload: unknown;
+  payload: any;
 };
 
 export type RSAMessage =
@@ -79,8 +69,6 @@ export type RSAMessage =
   | RSAMessageCloseProxy
   | RSAMessageUnload
   | RSAMessageClose
-  | RSAMessagePing
-  | RSAMessagePong
   | RSAMessageSend
   | RSAMessageCustomEventStart
   | RSAMessageCustomEventComplete;
@@ -99,9 +87,20 @@ type CustomEventName = string;
 
 export type CustomEvents = Record<
   CustomEventName,
-  (documentName: string, payload: unknown) => Promise<unknown>
+  (documentName: string, payload: any) => Promise<any>
 >;
 
+// Not exported by @hocuspocus/server
+export type ClientConnection = ReturnType<Hocuspocus['handleConnection']>;
+export type OriginConnection = {
+  clientConnection: ClientConnection;
+  socket: WebSocketLike;
+};
+export type ProxyConnection = {
+  clientConnection: ClientConnection;
+  socket: CollabProxySocket;
+};
+
 export interface Configuration<TCE> {
   redis: RedisClient;
   pack: Pack;
@@ -111,11 +110,29 @@ export interface Configuration<TCE> {
   customEventTTL?: number;
   prefix?: string;
   customEvents?: TCE;
+  // Derive the hocuspocus context once per socket instead of re-deriving it in a
+  // per-document hook like onConnect/onAuthenticate. Runs on the origin server when
+  // the socket opens and on the doc owner when the first proxied message arrives.
+  deriveContext?: (
+    serializedHTTPRequest: SerializedHTTPRequest,
+  ) => Record<string, any>;
 }
 
-export type BaseWebSocket = EventEmitter & {
-  readyState: number;
-  close(code?: number, reason?: string): void;
-  ping(): void;
-  send(message: Uint8Array): void;
+// Hocuspocus expects a web-standard Request, so rehydrate one from what crossed the wire
+export const toWebRequest = (serializedHTTPRequest: SerializedHTTPRequest) => {
+  const { method, url, headers } = serializedHTTPRequest;
+  const webHeaders = new Headers();
+  Object.entries(headers).forEach(([name, value]) => {
+    if (Array.isArray(value)) {
+      value.forEach((v) => {
+        webHeaders.append(name, v);
+      });
+    } else if (value !== undefined) {
+      webHeaders.set(name, value);
+    }
+  });
+  return new Request(new URL(url, 'http://localhost'), {
+    method,
+    headers: webHeaders,
+  });
 };

apps/server/src/collaboration/extensions/redis-sync/ws-socket-wrapper.ts

@@ -1,20 +1,17 @@
-import { EventEmitter } from 'events';
 import type WebSocket from 'ws';
+import type { WebSocketLike } from '@hocuspocus/server';
 
 /**
- * Wrapper around ws WebSocket that only receives events via emit().
- * This prevents double-handling when used with RedisSyncExtension.
+ * Wrapper around ws WebSocket that Hocuspocus only writes to.
+ * Incoming socket events are forwarded separately by the gateway,
+ * which prevents double-handling with RedisSyncExtension.
  */
-export class WsSocketWrapper extends EventEmitter {
+export class WsSocketWrapper implements WebSocketLike {
   private ws: WebSocket;
   readyState = 1;
 
   constructor(ws: WebSocket) {
-    super();
     this.ws = ws;
-    this.once('close', () => {
-      this.readyState = 3;
-    });
   }
 
   close(code?: number, reason?: string) {
@@ -27,15 +24,6 @@ export class WsSocketWrapper extends EventEmitter {
     }
   }
 
-  ping() {
-    if (this.readyState !== 1) return;
-    try {
-      this.ws.ping();
-    } catch (e) {
-      // Socket already closed
-    }
-  }
-
   send(message: Uint8Array) {
     if (this.readyState !== 1) return;
     try {