do not emit packet events and stop parsing after a parse error

.travis.yml

@@ -1,14 +1,7 @@
 language: node_js
 sudo: false
 node_js:
-  - 5
+  - 6
   - 4
-  - iojs-v3
-  - iojs-v2
-  - iojs-v1
-  - 0.12
-  - 0.10
 script:
   npm run ci
-before_install:
-  - node -v | grep v0.8 && npm install npm@1.4.28 -g || echo "no need to update NPM"

README.md

@@ -10,9 +10,8 @@ Encode and Decode MQTT 3.1.1 packets the node way.
   * <a href="#contributing">Contributing</a>
   * <a href="#license">Licence &amp; copyright</a>
 
-This library works with node v4.x, v0.12.x, v0.10.x and all iojs releases, but it requires at
-least NPM 1.4. To upgrade NPM on node v0.8, run `npm install
-npm@1.4.28 -g`.
+This library is tested with node v4 and v6. The last version to support
+older versions of node was mqtt-packet@4.1.2.
 
 Install
 ------------
@@ -122,6 +121,10 @@ will emit:
 Parse a given `Buffer` and emits synchronously all the MQTT packets that
 are included. Returns the number of bytes left to parse.
 
+If an error happens, an `error` event will be emitted, but no `packet` events
+will be emitted after that. Calling `parse()` again clears the error and
+previous buffer as if you created a new `Parser`.
+
 Packets
 -------
 

parser.js

@@ -10,37 +10,35 @@ function Parser() {
     return new Parser()
   }
 
-  this._list = bl()
-  this._newPacket()
-
   this._states = [
       '_parseHeader'
     , '_parseLength'
     , '_parsePayload'
     , '_newPacket'
   ]
-  this._stateCounter = 0
+
+  this._resetState()
 }
 
 inherits(Parser, EE)
 
-Parser.prototype._newPacket = function () {
-  if (this.packet) {
-    this._list.consume(this.packet.length)
-    this.emit('packet', this.packet)
-  }
-
+Parser.prototype._resetState = function () {
   this.packet = new Packet()
-
-  return true
+  this.error = null
+  this._list = bl()
+  this._stateCounter = 0
 }
 
 Parser.prototype.parse = function (buf) {
+  if (this.error) {
+    this._resetState()
+  }
 
   this._list.append(buf)
 
   while ((this.packet.length != -1 || this._list.length > 0) &&
-         this[this._states[this._stateCounter]]()) {
+         this[this._states[this._stateCounter]]() &&
+         !this.error) {
     this._stateCounter++
 
     if (this._stateCounter >= this._states.length) {
@@ -140,7 +138,7 @@ Parser.prototype._parsePayload = function () {
         // these are empty, nothing to do
         break
       default:
-        this.emit('error', new Error('not supported'))
+        this._emitError(new Error('not supported'))
     }
 
     result = true
@@ -162,29 +160,29 @@ Parser.prototype._parseConnect = function () {
   // Parse constants id
   protocolId = this._parseString()
   if (protocolId === null)
-    return this.emit('error', new Error('cannot parse protocol id'))
+    return this._emitError(new Error('cannot parse protocol id'))
 
   if (protocolId != 'MQTT' && protocolId != 'MQIsdp') {
 
-    return this.emit('error', new Error('invalid protocol id'))
+    return this._emitError(new Error('invalid protocol id'))
   }
 
   packet.protocolId = protocolId
 
   // Parse constants version number
   if(this._pos >= this._list.length)
-    return this.emit('error', new Error('packet too short'))
+    return this._emitError(new Error('packet too short'))
 
   packet.protocolVersion = this._list.readUInt8(this._pos)
 
   if(packet.protocolVersion != 3 && packet.protocolVersion != 4) {
 
-    return this.emit('error', new Error('invalid protocol version'))
+    return this._emitError(new Error('invalid protocol version'))
   }
 
   this._pos++
   if(this._pos >= this._list.length)
-    return this.emit('error', new Error('packet too short'))
+    return this._emitError(new Error('packet too short'))
 
   // Parse connect flags
   flags.username  = (this._list.readUInt8(this._pos) & constants.USERNAME_MASK)
@@ -204,41 +202,41 @@ Parser.prototype._parseConnect = function () {
   // Parse keepalive
   packet.keepalive = this._parseNum()
   if(packet.keepalive === -1)
-    return this.emit('error', new Error('packet too short'))
+    return this._emitError(new Error('packet too short'))
 
   // Parse client ID
   clientId = this._parseString()
   if(clientId === null)
-    return this.emit('error', new Error('packet too short'))
+    return this._emitError(new Error('packet too short'))
   packet.clientId = clientId
 
   if (flags.will) {
     // Parse will topic
     topic = this._parseString()
     if (topic === null)
-      return this.emit('error', new Error('cannot parse will topic'))
+      return this._emitError(new Error('cannot parse will topic'))
     packet.will.topic = topic
 
     // Parse will payload
     payload = this._parseBuffer()
     if (payload === null)
-      return this.emit('error', new Error('cannot parse will payload'))
+      return this._emitError(new Error('cannot parse will payload'))
     packet.will.payload = payload
   }
 
   // Parse username
   if (flags.username) {
     username = this._parseString()
     if(username === null)
-      return this.emit('error', new Error('cannot parse username'))
+      return this._emitError(new Error('cannot parse username'))
     packet.username = username
   }
 
   // Parse password
   if(flags.password) {
     password = this._parseBuffer()
     if(password === null)
-      return this.emit('error', new Error('cannot parse username'))
+      return this._emitError(new Error('cannot parse username'))
     packet.password = password
   }
 
@@ -252,15 +250,15 @@ Parser.prototype._parseConnack = function () {
   packet.sessionPresent = !!(this._list.readUInt8(this._pos++) & constants.SESSIONPRESENT_MASK)
   packet.returnCode = this._list.readUInt8(this._pos)
   if(packet.returnCode === -1)
-    return this.emit('error', new Error('cannot parse return code'))
+    return this._emitError(new Error('cannot parse return code'))
 }
 
 Parser.prototype._parsePublish = function () {
   var packet = this.packet
   packet.topic = this._parseString()
 
   if(packet.topic === null)
-    return this.emit('error', new Error('cannot parse topic'))
+    return this._emitError(new Error('cannot parse topic'))
 
   // Parse message ID
   if (packet.qos > 0) {
@@ -276,7 +274,7 @@ Parser.prototype._parseSubscribe = function() {
     , qos
 
   if (packet.qos != 1) {
-    return this.emit('error', new Error('wrong subscribe header'))
+    return this._emitError(new Error('wrong subscribe header'))
   }
 
   packet.subscriptions = []
@@ -288,7 +286,7 @@ Parser.prototype._parseSubscribe = function() {
     // Parse topic
     topic = this._parseString()
     if (topic === null)
-      return this.emit('error', new Error('Parse error - cannot parse topic'))
+      return this._emitError(new Error('Parse error - cannot parse topic'))
 
     qos = this._list.readUInt8(this._pos++)
 
@@ -322,7 +320,7 @@ Parser.prototype._parseUnsubscribe = function() {
     // Parse topic
     topic = this._parseString()
     if (topic === null)
-      return this.emit('error', new Error('cannot parse topic'))
+      return this._emitError(new Error('cannot parse topic'))
 
     // Push topic to unsubscriptions
     packet.unsubscriptions.push(topic);
@@ -331,7 +329,7 @@ Parser.prototype._parseUnsubscribe = function() {
 
 Parser.prototype._parseUnsuback = function() {
   if (!this._parseMessageId())
-    return this.emit('error', new Error('cannot parse message id'))
+    return this._emitError(new Error('cannot parse message id'))
 }
 
 Parser.prototype._parseMessageId = function() {
@@ -340,7 +338,7 @@ Parser.prototype._parseMessageId = function() {
   packet.messageId = this._parseNum()
 
   if(packet.messageId === null) {
-    this.emit('error', new Error('cannot parse message id'))
+    this._emitError(new Error('cannot parse message id'))
     return false
   }
 
@@ -385,4 +383,20 @@ Parser.prototype._parseNum = function() {
   return result
 }
 
+Parser.prototype._newPacket = function () {
+  if (this.packet) {
+    this._list.consume(this.packet.length)
+    this.emit('packet', this.packet)
+  }
+
+  this.packet = new Packet()
+
+  return true
+}
+
+Parser.prototype._emitError = function(err) {
+  this.error = err
+  this.emit('error', err)
+}
+
 module.exports = Parser

test.js

@@ -56,6 +56,10 @@ function testParseError(expected, fixture) {
       t.equal(err.message, expected, 'expected error message')
     })
 
+    parser.on('packet', function() {
+      t.fail('parse errors should not be followed by packet events')
+    })
+
     parser.parse(fixture)
   })
 }
@@ -949,3 +953,76 @@ testParseError('cannot parse protocol id', new Buffer([
   77, 81, 73, 115, 100, 112,
   77, 81, 73, 115, 100, 112
 ]))
+
+test('stops parsing after first error', function(t) {
+  t.plan(4)
+
+  var parser = mqtt.parser()
+
+  var packetCount = 0
+  var errorCount = 0
+  var expectedPackets = 1
+  var expectedErrors = 1
+
+  parser.on('packet', function(packet) {
+    t.ok(++packetCount <= expectedPackets, 'expected <= ' + expectedPackets + ' packets')
+  })
+
+  parser.on('error', function(err) {
+    t.ok(++errorCount <= expectedErrors, 'expected <= ' + expectedErrors + ' errors')
+  })
+
+  parser.parse(new Buffer([
+    // first, a valid connect packet:
+
+    16, 12, // Header
+    0, 4, // Protocol id length
+    77, 81, 84, 84, // Protocol id
+    4, // Protocol version
+    2, // Connect flags
+    0, 30, // Keepalive
+    0, 0, //Client id length
+
+    // then an invalid subscribe packet:
+
+    128, 9, // Header (subscribe, qos=0, length=9)
+    0, 6, // message id (6)
+    0, 4, // topic length,
+    116, 101, 115, 116, // Topic (test)
+    0, // qos (0)
+
+    // and another invalid subscribe packet:
+
+    128, 9, // Header (subscribe, qos=0, length=9)
+    0, 6, // message id (6)
+    0, 4, // topic length,
+    116, 101, 115, 116, // Topic (test)
+    0, // qos (0)
+
+    // finally, a valid disconnect packet:
+
+    224, 0, // Header
+  ]))
+
+  // calling parse again clears the error and continues parsing
+  packetCount = 0
+  errorCount = 0
+  expectedPackets = 2
+  expectedErrors = 0
+
+  parser.parse(new Buffer([
+    // connect:
+
+    16, 12, // Header
+    0, 4, // Protocol id length
+    77, 81, 84, 84, // Protocol id
+    4, // Protocol version
+    2, // Connect flags
+    0, 30, // Keepalive
+    0, 0, //Client id length
+
+    // disconnect:
+
+    224, 0, // Header
+  ]))
+})