chat: Move chat message handling to `handleMessage` hook

CHANGELOG.md

@@ -92,6 +92,9 @@
   * `padUpdate`: The `author` context property is deprecated; use the new
     `authorId` context property instead. Also, the hook now runs asynchronously.
 * Chat API deprecations and removals (no replacements planned):
+  * Server-side:
+    * The `sendChatMessageToPadClients()` function in
+      `src/node/handler/PadMessageHandler.js` is deprecated.
   * Client-side:
     * The `pad.determineChatVisibility()` method was removed.
     * The `pad.determineChatAndUsersVisibility()` method was removed.

doc/api/hooks_server-side.md

@@ -1086,7 +1086,7 @@ exports.userLeave = async (hookName, {author, padId}) => {
 
 ## `chatNewMessage`
 
-Called from: `src/node/handler/PadMessageHandler.js`
+Called from: `src/node/chat.js`
 
 Called when a user (or plugin) generates a new chat message, just before it is
 saved to the pad and relayed to all connected users.

src/ep.json

@@ -22,7 +22,9 @@
       },
       "hooks": {
         "eejsBlock_mySettings": "ep_etherpad-lite/node/chat",
-        "eejsBlock_stickyContainer": "ep_etherpad-lite/node/chat"
+        "eejsBlock_stickyContainer": "ep_etherpad-lite/node/chat",
+        "handleMessage": "ep_etherpad-lite/node/chat",
+        "socketio": "ep_etherpad-lite/node/chat"
       }
     },
     {

src/node/chat.js

@@ -1,5 +1,28 @@
 'use strict';
 
+const ChatMessage = require('../static/js/ChatMessage');
+const api = require('./db/API');
+const authorManager = require('./db/AuthorManager');
+const hooks = require('../static/js/pluginfw/hooks.js');
+const padManager = require('./db/PadManager');
+const padMessageHandler = require('./handler/PadMessageHandler');
+
+let socketio;
+
+const sendChatMessageToPadClients = async (message, padId) => {
+  const pad = await padManager.getPad(padId, null, message.authorId);
+  await hooks.aCallAll('chatNewMessage', {message, pad, padId});
+  // pad.appendChatMessage() ignores the displayName property so we don't need to wait for
+  // authorManager.getAuthorName() to resolve before saving the message to the database.
+  const promise = pad.appendChatMessage(message);
+  message.displayName = await authorManager.getAuthorName(message.authorId);
+  socketio.sockets.in(padId).json.send({
+    type: 'COLLABROOM',
+    data: {type: 'CHAT_MESSAGE', message},
+  });
+  await promise;
+};
+
 exports.eejsBlock_mySettings = (hookName, context) => {
   context.content += `
     <p class="hide-for-mobile">
@@ -42,3 +65,49 @@ exports.eejsBlock_stickyContainer = (hookName, context) => {
   `;
   /* eslint-enable max-len */
 };
+
+exports.handleMessage = async (hookName, {message, sessionInfo, socket}) => {
+  const {authorId, padId, readOnly} = sessionInfo;
+  if (message.type !== 'COLLABROOM' || readOnly) return;
+  switch (message.data.type) {
+    case 'CHAT_MESSAGE': {
+      const chatMessage = ChatMessage.fromObject(message.data.message);
+      // Don't trust the user-supplied values.
+      chatMessage.time = Date.now();
+      chatMessage.authorId = authorId;
+      await sendChatMessageToPadClients(chatMessage, padId);
+      break;
+    }
+    case 'GET_CHAT_MESSAGES': {
+      const {start, end} = message.data;
+      if (!Number.isInteger(start)) throw new Error(`missing or invalid start: ${start}`);
+      if (!Number.isInteger(end)) throw new Error(`missing or invalid end: ${end}`);
+      const count = end - start;
+      if (count < 0 || count > 100) throw new Error(`invalid number of messages: ${count}`);
+      const pad = await padManager.getPad(padId, null, authorId);
+      socket.json.send({
+        type: 'COLLABROOM',
+        data: {
+          type: 'CHAT_MESSAGES',
+          messages: await pad.getChatMessages(start, end),
+        },
+      });
+      break;
+    }
+    default:
+      return;
+  }
+  return null; // Important! Returning null (not undefined!) stops further processing.
+};
+
+exports.socketio = (hookName, {io}) => {
+  socketio = io;
+};
+
+api.registerChatHandlers({
+  sendChatMessageToPadClients,
+});
+
+padMessageHandler.registerLegacyChatHandlers({
+  sendChatMessageToPadClients,
+});

src/node/db/API.js

@@ -289,6 +289,9 @@ exports.setHTML = async (padID, html, authorId = '') => {
  * CHAT FUNCTIONS *
  **************** */
 
+let chat = null;
+exports.registerChatHandlers = (handlers) => chat = handlers;
+
 /**
 getChatHistory(padId, start, end), returns a part of or the whole chat-history of this pad
 
@@ -363,7 +366,7 @@ exports.appendChatMessage = async (padID, text, authorID, time) => {
   // @TODO - missing getPadSafe() call ?
 
   // save chat message to database and send message to all connected clients
-  await padMessageHandler.sendChatMessageToPadClients(new ChatMessage(text, authorID, time), padID);
+  await chat.sendChatMessageToPadClients(new ChatMessage(text, authorID, time), padID);
 };
 
 /* ***************

src/node/handler/PadMessageHandler.js

@@ -40,6 +40,7 @@ const assert = require('assert').strict;
 const {RateLimiterMemory} = require('rate-limiter-flexible');
 const webaccess = require('../hooks/express/webaccess');
 
+let chat = null;
 let rateLimiter;
 let socketio = null;
 
@@ -54,6 +55,8 @@ const addContextToError = (err, pfx) => {
   return err;
 };
 
+exports.registerLegacyChatHandlers = (handlers) => chat = handlers;
+
 exports.socketio = () => {
   // The rate limiter is created in this hook so that restarting the server resets the limiter. The
   // settings.commitRateLimiting object is passed directly to the rate limiter so that the limits
@@ -335,8 +338,6 @@ exports.handleMessage = async (socket, message) => {
               await padChannels.enqueue(thisSession.padId, {socket, message});
               break;
             case 'USERINFO_UPDATE': await handleUserInfoUpdate(socket, message); break;
-            case 'CHAT_MESSAGE': await handleChatMessage(socket, message); break;
-            case 'GET_CHAT_MESSAGES': await handleGetChatMessages(socket, message); break;
             case 'SAVE_REVISION': await handleSaveRevisionMessage(socket, message); break;
             case 'CLIENT_MESSAGE': {
               const {type} = message.data.payload;
@@ -413,23 +414,10 @@ exports.handleCustomMessage = (padID, msgString) => {
   socketio.sockets.in(padID).json.send(msg);
 };
 
-/**
- * Handles a Chat Message
- * @param socket the socket.io Socket object for the client
- * @param message the message from the client
- */
-const handleChatMessage = async (socket, message) => {
-  const chatMessage = ChatMessage.fromObject(message.data.message);
-  const {padId, author: authorId} = sessioninfos[socket.id];
-  // Don't trust the user-supplied values.
-  chatMessage.time = Date.now();
-  chatMessage.authorId = authorId;
-  await exports.sendChatMessageToPadClients(chatMessage, padId);
-};
-
 /**
  * Adds a new chat message to a pad and sends it to connected clients.
  *
+ * @deprecated Use chat.sendChatMessageToPadClients() instead.
  * @param {(ChatMessage|number)} mt - Either a chat message object (recommended) or the timestamp of
  *     the chat message in ms since epoch (deprecated).
  * @param {string} puId - If `mt` is a chat message object, this is the destination pad ID.
@@ -439,40 +427,11 @@ const handleChatMessage = async (socket, message) => {
  *     object as the first argument and the destination pad ID as the second argument instead.
  */
 exports.sendChatMessageToPadClients = async (mt, puId, text = null, padId = null) => {
+  padutils.warnDeprecated('PadMessageHandler.sendChatMessageToPadClients() is deprecated; ' +
+                          'use chat.sendChatMessageToPadClients() instead');
   const message = mt instanceof ChatMessage ? mt : new ChatMessage(text, puId, mt);
   padId = mt instanceof ChatMessage ? puId : padId;
-  const pad = await padManager.getPad(padId, null, message.authorId);
-  await hooks.aCallAll('chatNewMessage', {message, pad, padId});
-  // pad.appendChatMessage() ignores the displayName property so we don't need to wait for
-  // authorManager.getAuthorName() to resolve before saving the message to the database.
-  const promise = pad.appendChatMessage(message);
-  message.displayName = await authorManager.getAuthorName(message.authorId);
-  socketio.sockets.in(padId).json.send({
-    type: 'COLLABROOM',
-    data: {type: 'CHAT_MESSAGE', message},
-  });
-  await promise;
-};
-
-/**
- * Handles the clients request for more chat-messages
- * @param socket the socket.io Socket object for the client
- * @param message the message from the client
- */
-const handleGetChatMessages = async (socket, {data: {start, end}}) => {
-  if (!Number.isInteger(start)) throw new Error(`missing or invalid start: ${start}`);
-  if (!Number.isInteger(end)) throw new Error(`missing or invalid end: ${end}`);
-  const count = end - start;
-  if (count < 0 || count > 100) throw new Error(`invalid number of messages: ${count}`);
-  const {padId, author: authorId} = sessioninfos[socket.id];
-  const pad = await padManager.getPad(padId, null, authorId);
-  socket.json.send({
-    type: 'COLLABROOM',
-    data: {
-      type: 'CHAT_MESSAGES',
-      messages: await pad.getChatMessages(start, end),
-    },
-  });
+  await chat.sendChatMessageToPadClients(message, padId);
 };
 
 /**