Minor changes and more elaborate test docs

parser.js

@@ -39,21 +39,14 @@ Parser.prototype.parse = function (buf) {
 
   this._list.append(buf)
 
-  try {
+  while ((this.packet.length != -1 || this._list.length > 0) &&
+         (noError = this[this._states[this._stateCounter]]())) {
+    this._stateCounter++
 
-    while ((this.packet.length != -1 || this._list.length > 0) &&
-           (noError = this[this._states[this._stateCounter]]())) {
-      this._stateCounter++
-
-      if (this._stateCounter >= this._states.length) {
-        this._stateCounter = 0
-      }
+    if (this._stateCounter >= this._states.length) {
+      this._stateCounter = 0
     }
   }
-  catch (e) {
-
-    return this.emit('error', e);
-  }
 
   return this._list.length
 }
@@ -101,7 +94,7 @@ Parser.prototype._parseLength = function () {
     this._list.consume(bytes)
   }
 
-  return result 
+  return result
 }
 
 Parser.prototype._parsePayload = function () {
@@ -171,7 +164,7 @@ Parser.prototype._parseConnect = function () {
   if (protocolId === null)
     return this.emit('error', new Error('cannot parse protocol id'))
 
-  if (['MQTT', 'MQIsdp'].indexOf(protocolId) < 0) {
+  if (protocolId != 'MQTT' && protocolId != 'MQIsdp') {
 
     return this.emit('error', new Error('invalid protocol id'))
   }
@@ -184,7 +177,7 @@ Parser.prototype._parseConnect = function () {
 
   packet.protocolVersion = this._list.readUInt8(this._pos)
 
-  if([3,4].indexOf(packet.protocolVersion) < 0) {
+  if(packet.protocolVersion != 3 && packet.protocolVersion != 4) {
 
     return this.emit('error', new Error('invalid protocol version'))
   }

test.js

@@ -898,6 +898,9 @@ testParseError('packet too short', new Buffer([
   3
 ]))
 
+// CONNECT Packets that show other protocol ids than
+// the valid values MQTT and MQIsdp should cause an error
+// those packets are a hint that this is not a mqtt connection
 testParseError('invalid protocol id', new Buffer([
   16, 18,
   0, 6,
@@ -909,6 +912,8 @@ testParseError('invalid protocol id', new Buffer([
   116, 101, 115, 116 // Client id
 ]))
 
+// CONNECT Packets that contain an unsupported protocol version 
+// flag (i.e. not `3` or `4`) should cause an error
 testParseError('invalid protocol version', new Buffer([
   16, 18,
   0, 6,
@@ -920,9 +925,16 @@ testParseError('invalid protocol version', new Buffer([
   116, 101, 115, 116 // Client id
 ]))
 
+// when a packet contains a string in the variable header and the
+// given string length of this exceeds the overall length of the packet that 
+// was specified in the fixed header, parsing must fail.
+// this case simulates this behavior with the protocol id string of the
+// CONNECT packet. The fixed header suggests a remaining length of 8 bytes
+// which would be exceeded by the string length of 15
+// in this case, a protocol id parse error is expected
 testParseError('cannot parse protocol id', new Buffer([
-  16, 8,
-  0, 15,
+  16, 8, // fixed header
+  0, 15, // string length 15 --> 15 > 8 --> error!
   77, 81, 73, 115, 100, 112,
   77, 81, 73, 115, 100, 112,
   77, 81, 73, 115, 100, 112,