feat: mutex processing in a chat to preserve order of events

src/Socket/chats.ts

@@ -2,7 +2,7 @@ import { Boom } from '@hapi/boom'
 import { proto } from '../../WAProto'
 import { AppStateChunk, Chat, ChatModification, ChatMutation, Contact, LTHashState, PresenceData, SocketConfig, WABusinessHoursConfig, WABusinessProfile, WAMediaUpload, WAPatchCreate, WAPatchName, WAPresence } from '../Types'
 import { chatModificationToAppPatch, decodePatches, decodeSyncdSnapshot, encodeSyncdPatch, extractSyncdPatches, generateProfilePicture, newLTHashState, toNumber } from '../Utils'
-import makeMutex from '../Utils/make-mutex'
+import { makeMutex } from '../Utils/make-mutex'
 import { BinaryNode, getBinaryNodeChild, getBinaryNodeChildren, jidNormalizedUser, reduceBinaryNodeToDictionary, S_WHATSAPP_NET } from '../WABinary'
 import { makeMessagesSocket } from './messages-send'
 

src/Socket/messages-recv.ts

@@ -3,6 +3,7 @@ import { proto } from '../../WAProto'
 import { KEY_BUNDLE_TYPE } from '../Defaults'
 import { Chat, GroupMetadata, MessageUserReceipt, ParticipantAction, SocketConfig, WAMessageStubType } from '../Types'
 import { decodeMessageStanza, downloadAndProcessHistorySyncNotification, encodeBigEndian, generateSignalPubKey, toNumber, xmppPreKey, xmppSignedPreKey } from '../Utils'
+import { makeKeyedMutex } from '../Utils/make-mutex'
 import { areJidsSameUser, BinaryNode, BinaryNodeAttributes, getAllBinaryNodeChildren, getBinaryNodeChildren, isJidGroup, jidDecode, jidEncode, jidNormalizedUser } from '../WABinary'
 import { makeChatsSocket } from './chats'
 import { extractGroupMetadata } from './groups'
@@ -37,6 +38,9 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 		resyncMainAppState,
 	} = sock
 
+	/** the mutex ensures that the notifications (receipts, messages etc.) are processed in order */
+	const processingMutex = makeKeyedMutex()
+
 	const msgRetryMap = config.msgRetryCounterMap || { }
 
 	const historyCache = new Set<string>()
@@ -338,24 +342,30 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 	}
 
 	// recv a message
-	ws.on('CB:message', async(stanza: BinaryNode) => {
-		const msg = await decodeMessageStanza(stanza, authState)
-		// message failed to decrypt
-		if(msg.messageStubType === proto.WebMessageInfo.WebMessageInfoStubType.CIPHERTEXT) {
-			logger.error(
-				{ msgId: msg.key.id, params: msg.messageStubParameters }, 
-				'failure in decrypting message'
-			)
-			await sendRetryRequest(stanza)
-		} else {
-			await sendMessageAck(stanza, { class: 'receipt' })
-			// no type in the receipt => message delivered
-			await sendReceipt(msg.key.remoteJid!, msg.key.participant, [msg.key.id!], undefined)
-			logger.debug({ msg: msg.key }, 'sent delivery receipt')
-		}
-        
-		msg.key.remoteJid = jidNormalizedUser(msg.key.remoteJid!)
-		ev.emit('messages.upsert', { messages: [msg], type: stanza.attrs.offline ? 'append' : 'notify' })
+	ws.on('CB:message', (stanza: BinaryNode) => {
+		const { fullMessage: msg, decryptionTask } = decodeMessageStanza(stanza, authState)
+		processingMutex.mutex(
+			msg.key.remoteJid!,
+			async() => {
+				await decryptionTask
+				// message failed to decrypt
+				if(msg.messageStubType === proto.WebMessageInfo.WebMessageInfoStubType.CIPHERTEXT) {
+					logger.error(
+						{ msgId: msg.key.id, params: msg.messageStubParameters }, 
+						'failure in decrypting message'
+					)
+					await sendRetryRequest(stanza)
+				} else {
+					await sendMessageAck(stanza, { class: 'receipt' })
+					// no type in the receipt => message delivered
+					await sendReceipt(msg.key.remoteJid!, msg.key.participant, [msg.key.id!], undefined)
+					logger.debug({ msg: msg.key }, 'sent delivery receipt')
+				}
+				
+				msg.key.remoteJid = jidNormalizedUser(msg.key.remoteJid!)
+				ev.emit('messages.upsert', { messages: [msg], type: stanza.attrs.offline ? 'append' : 'notify' })
+			}
+		)
 	})
 
 	ws.on('CB:ack,class:message', async(node: BinaryNode) => {
@@ -428,82 +438,92 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 			participant: attrs.participant
 		}
 
-		const status = getStatusFromReceiptType(attrs.type)
-		if(
-			typeof status !== 'undefined' &&
-            (
-			// basically, we only want to know when a message from us has been delivered to/read by the other person
-			// or another device of ours has read some messages
-            	status > proto.WebMessageInfo.WebMessageInfoStatus.DELIVERY_ACK ||
-                !isNodeFromMe
-            )
-		) {
-			if(isJidGroup(remoteJid)) {
-				const updateKey: keyof MessageUserReceipt = status === proto.WebMessageInfo.WebMessageInfoStatus.DELIVERY_ACK ? 'receiptTimestamp' : 'readTimestamp'
-				ev.emit(
-					'message-receipt.update',
-					ids.map(id => ({
-						key: { ...key, id },
-						receipt: {
-							userJid: jidNormalizedUser(attrs.participant),
-							[updateKey]: +attrs.t
-						}
-					}))
-				)
-			} else {
-				ev.emit(
-					'messages.update', 
-					ids.map(id => ({
-						key: { ...key, id },
-						update: { status }
-					}))
-				)
-			}
+		await processingMutex.mutex(
+			remoteJid,
+			async() => {
+				const status = getStatusFromReceiptType(attrs.type)
+				if(
+					typeof status !== 'undefined' &&
+					(
+					// basically, we only want to know when a message from us has been delivered to/read by the other person
+					// or another device of ours has read some messages
+						status > proto.WebMessageInfo.WebMessageInfoStatus.DELIVERY_ACK ||
+						!isNodeFromMe
+					)
+				) {
+					if(isJidGroup(remoteJid)) {
+						const updateKey: keyof MessageUserReceipt = status === proto.WebMessageInfo.WebMessageInfoStatus.DELIVERY_ACK ? 'receiptTimestamp' : 'readTimestamp'
+						ev.emit(
+							'message-receipt.update',
+							ids.map(id => ({
+								key: { ...key, id },
+								receipt: {
+									userJid: jidNormalizedUser(attrs.participant),
+									[updateKey]: +attrs.t
+								}
+							}))
+						)
+					} else {
+						ev.emit(
+							'messages.update', 
+							ids.map(id => ({
+								key: { ...key, id },
+								update: { status }
+							}))
+						)
+					}
 
-		}
-
-		if(attrs.type === 'retry') {
-			// correctly set who is asking for the retry
-			key.participant = key.participant || attrs.from
-			if(key.fromMe) {
-				try {
-					logger.debug({ attrs }, 'recv retry request')
-					await sendMessagesAgain(key, ids)
-				} catch(error) {
-					logger.error({ key, ids, trace: error.stack }, 'error in sending message again')
-					shouldAck = false
 				}
-			} else {
-				logger.info({ attrs, key }, 'recv retry for not fromMe message')
-			}
-		}
 
-		if(shouldAck) {
-			await sendMessageAck(node, { class: 'receipt', type: attrs.type })
-		}
-        
+				if(attrs.type === 'retry') {
+					// correctly set who is asking for the retry
+					key.participant = key.participant || attrs.from
+					if(key.fromMe) {
+						try {
+							logger.debug({ attrs }, 'recv retry request')
+							await sendMessagesAgain(key, ids)
+						} catch(error) {
+							logger.error({ key, ids, trace: error.stack }, 'error in sending message again')
+							shouldAck = false
+						}
+					} else {
+						logger.info({ attrs, key }, 'recv retry for not fromMe message')
+					}
+				}
+
+				if(shouldAck) {
+					await sendMessageAck(node, { class: 'receipt', type: attrs.type })
+				}
+			}
+		)
 	}
 
 	ws.on('CB:receipt', handleReceipt)
 
 	ws.on('CB:notification', async(node: BinaryNode) => {
-		await sendMessageAck(node, { class: 'notification', type: node.attrs.type })
-
-		const msg = processNotification(node)
-		if(msg) {
-			const fromMe = areJidsSameUser(node.attrs.participant || node.attrs.from, authState.creds.me!.id)
-			msg.key = {
-				remoteJid: node.attrs.from,
-				fromMe,
-				participant: node.attrs.participant,
-				id: node.attrs.id,
-				...(msg.key || {})
+		const remoteJid = node.attrs.from
+		processingMutex.mutex(
+			remoteJid,
+			() => {
+				const msg = processNotification(node)
+				if(msg) {
+					const fromMe = areJidsSameUser(node.attrs.participant || node.attrs.from, authState.creds.me!.id)
+					msg.key = {
+						remoteJid: node.attrs.from,
+						fromMe,
+						participant: node.attrs.participant,
+						id: node.attrs.id,
+						...(msg.key || {})
+					}
+					msg.messageTimestamp = +node.attrs.t
+					
+					const fullMsg = proto.WebMessageInfo.fromObject(msg)
+					ev.emit('messages.upsert', { messages: [fullMsg], type: 'append' })
+				}
 			}
-			msg.messageTimestamp = +node.attrs.t
-            
-			const fullMsg = proto.WebMessageInfo.fromObject(msg)
-			ev.emit('messages.upsert', { messages: [fullMsg], type: 'append' })
-		}
+		)
+
+		await sendMessageAck(node, { class: 'notification', type: node.attrs.type })
 	})
 
 	ev.on('messages.upsert', async({ messages, type }) => {
@@ -520,7 +540,11 @@ export const makeMessagesRecvSocket = (config: SocketConfig) => {
 					}
 				}
 
-				await processMessage(msg, chat)
+				await processingMutex.mutex(
+					'p-' + chat.id!,
+					() => processMessage(msg, chat)
+				)
+				
 				if(!!msg.message && !msg.message!.protocolMessage) {
 					chat.conversationTimestamp = toNumber(msg.messageTimestamp)
 					if(!msg.key.fromMe) {

src/Utils/decode-wa-message.ts

@@ -7,7 +7,7 @@ import { decryptGroupSignalProto, decryptSignalProto, processSenderKeyMessage }
 
 type MessageType = 'chat' | 'peer_broadcast' | 'other_broadcast' | 'group' | 'direct_peer_status' | 'other_status'
 
-export const decodeMessageStanza = async(stanza: BinaryNode, auth: AuthenticationState) => {
+export const decodeMessageStanza = (stanza: BinaryNode, auth: AuthenticationState) => {
 	//const deviceIdentity = (stanza.content as BinaryNodeM[])?.find(m => m.tag === 'device-identity')
 	//const deviceIdentityBytes = deviceIdentity ? deviceIdentity.content as Buffer : undefined
 
@@ -81,48 +81,51 @@ export const decodeMessageStanza = async(stanza: BinaryNode, auth: Authenticatio
 		fullMessage.status = proto.WebMessageInfo.WebMessageInfoStatus.SERVER_ACK
 	}
 
-	if(Array.isArray(stanza.content)) {
-		for(const { tag, attrs, content } of stanza.content) {
-			if(tag !== 'enc') {
-				continue
+	return {
+		fullMessage,
+		decryptionTask: (async() => {
+			if(Array.isArray(stanza.content)) {
+				for(const { tag, attrs, content } of stanza.content) {
+					if(tag !== 'enc') {
+						continue
+					}
+		
+					if(!(content instanceof Uint8Array)) {
+						continue
+					} 
+		
+					let msgBuffer: Buffer
+		
+					try {
+						const e2eType = attrs.type
+						switch (e2eType) {
+						case 'skmsg':
+							msgBuffer = await decryptGroupSignalProto(sender, author, content, auth)
+							break
+						case 'pkmsg':
+						case 'msg':
+							const user = isJidUser(sender) ? sender : author
+							msgBuffer = await decryptSignalProto(user, e2eType, content as Buffer, auth)
+							break
+						}
+		
+						let msg: proto.IMessage = proto.Message.decode(unpadRandomMax16(msgBuffer))
+						msg = msg.deviceSentMessage?.message || msg
+						if(msg.senderKeyDistributionMessage) {
+							await processSenderKeyMessage(author, msg.senderKeyDistributionMessage, auth)
+						}
+		
+						if(fullMessage.message) {
+							Object.assign(fullMessage.message, msg)
+						} else {
+							fullMessage.message = msg
+						}
+					} catch(error) {
+						fullMessage.messageStubType = proto.WebMessageInfo.WebMessageInfoStubType.CIPHERTEXT
+						fullMessage.messageStubParameters = [error.message]
+					}
+				}
 			}
-
-			if(!(content instanceof Uint8Array)) {
-				continue
-			} 
-
-			let msgBuffer: Buffer
-
-			try {
-				const e2eType = attrs.type
-				switch (e2eType) {
-				case 'skmsg':
-					msgBuffer = await decryptGroupSignalProto(sender, author, content, auth)
-					break
-				case 'pkmsg':
-				case 'msg':
-					const user = isJidUser(sender) ? sender : author
-					msgBuffer = await decryptSignalProto(user, e2eType, content as Buffer, auth)
-					break
-				}
-
-				let msg: proto.IMessage = proto.Message.decode(unpadRandomMax16(msgBuffer))
-				msg = msg.deviceSentMessage?.message || msg
-				if(msg.senderKeyDistributionMessage) {
-					await processSenderKeyMessage(author, msg.senderKeyDistributionMessage, auth)
-				}
-
-				if(fullMessage.message) {
-					Object.assign(fullMessage.message, msg)
-				} else {
-					fullMessage.message = msg
-				}
-			} catch(error) {
-				fullMessage.messageStubType = proto.WebMessageInfo.WebMessageInfoStubType.CIPHERTEXT
-				fullMessage.messageStubParameters = [error.message]
-			}
-		}
+		})()
 	}
-
-	return fullMessage
 }

src/Utils/make-mutex.ts

@@ -1,22 +1,36 @@
-
-export default () => {
+export const makeMutex = () => {
 	let task = Promise.resolve() as Promise<any>
 	return {
-	  mutex<T>(code: () => Promise<T>):Promise<T> {
+		mutex<T>(code: () => Promise<T> | T): Promise<T> {
 			task = (async() => {
-		  // wait for the previous task to complete
-		  // if there is an error, we swallow so as to not block the queue
-		  try {
-					await task 
+				// wait for the previous task to complete
+				// if there is an error, we swallow so as to not block the queue
+				try {
+					await task
 				} catch{ }
 
-		  // execute the current task
-		  return code()
+				// execute the current task
+				return code()
 			})()
 			// we replace the existing task, appending the new piece of execution to it
 			// so the next task will have to wait for this one to finish
 			return task
-	  },
+		},
+	}
+}
+
+export type Mutex = ReturnType<typeof makeMutex>
+
+export const makeKeyedMutex = () => {
+	const map: { [id: string]: Mutex } = {}
+
+	return {
+		mutex<T>(key: string, task: () => Promise<T> | T): Promise<T> {
+			if(!map[key]) {
+				map[key] = makeMutex()
+			}
+
+			return map[key].mutex(task)
+		}
 	}
 }
-