'use strict'
|
|
var bl = require('bl')
|
var inherits = require('inherits')
|
var EE = require('events').EventEmitter
|
var Packet = require('./packet')
|
var constants = require('./constants')
|
|
function Parser () {
|
if (!(this instanceof Parser)) return new Parser()
|
|
this._states = [
|
'_parseHeader',
|
'_parseLength',
|
'_parsePayload',
|
'_newPacket'
|
]
|
|
this._resetState()
|
}
|
|
inherits(Parser, EE)
|
|
Parser.prototype._resetState = function () {
|
this.packet = new Packet()
|
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.error) {
|
this._stateCounter++
|
|
if (this._stateCounter >= this._states.length) this._stateCounter = 0
|
}
|
|
return this._list.length
|
}
|
|
Parser.prototype._parseHeader = function () {
|
// There is at least one byte in the buffer
|
var zero = this._list.readUInt8(0)
|
this.packet.cmd = constants.types[zero >> constants.CMD_SHIFT]
|
this.packet.retain = (zero & constants.RETAIN_MASK) !== 0
|
this.packet.qos = (zero >> constants.QOS_SHIFT) & constants.QOS_MASK
|
this.packet.dup = (zero & constants.DUP_MASK) !== 0
|
|
this._list.consume(1)
|
|
return true
|
}
|
|
Parser.prototype._parseLength = function () {
|
// There is at least one byte in the list
|
var bytes = 0
|
var mul = 1
|
var length = 0
|
var result = true
|
var current
|
|
while (bytes < 5) {
|
current = this._list.readUInt8(bytes++)
|
length += mul * (current & constants.LENGTH_MASK)
|
mul *= 0x80
|
|
if ((current & constants.LENGTH_FIN_MASK) === 0) break
|
if (this._list.length <= bytes) {
|
result = false
|
break
|
}
|
}
|
|
if (result) {
|
this.packet.length = length
|
this._list.consume(bytes)
|
}
|
|
return result
|
}
|
|
Parser.prototype._parsePayload = function () {
|
var result = false
|
|
// Do we have a payload? Do we have enough data to complete the payload?
|
// PINGs have no payload
|
if (this.packet.length === 0 || this._list.length >= this.packet.length) {
|
this._pos = 0
|
|
switch (this.packet.cmd) {
|
case 'connect':
|
this._parseConnect()
|
break
|
case 'connack':
|
this._parseConnack()
|
break
|
case 'publish':
|
this._parsePublish()
|
break
|
case 'puback':
|
case 'pubrec':
|
case 'pubrel':
|
case 'pubcomp':
|
this._parseMessageId()
|
break
|
case 'subscribe':
|
this._parseSubscribe()
|
break
|
case 'suback':
|
this._parseSuback()
|
break
|
case 'unsubscribe':
|
this._parseUnsubscribe()
|
break
|
case 'unsuback':
|
this._parseUnsuback()
|
break
|
case 'pingreq':
|
case 'pingresp':
|
case 'disconnect':
|
// These are empty, nothing to do
|
break
|
default:
|
this._emitError(new Error('Not supported'))
|
}
|
|
result = true
|
}
|
|
return result
|
}
|
|
Parser.prototype._parseConnect = function () {
|
var protocolId // Protocol ID
|
var clientId // Client ID
|
var topic // Will topic
|
var payload // Will payload
|
var password // Password
|
var username // Username
|
var flags = {}
|
var packet = this.packet
|
|
// Parse protocolId
|
protocolId = this._parseString()
|
|
if (protocolId === null) return this._emitError(new Error('Cannot parse protocolId'))
|
if (protocolId !== 'MQTT' && protocolId !== 'MQIsdp') {
|
return this._emitError(new Error('Invalid protocolId'))
|
}
|
|
packet.protocolId = protocolId
|
|
// Parse constants version number
|
if (this._pos >= this._list.length) return this._emitError(new Error('Packet too short'))
|
|
packet.protocolVersion = this._list.readUInt8(this._pos)
|
|
if (packet.protocolVersion !== 3 && packet.protocolVersion !== 4) {
|
return this._emitError(new Error('Invalid protocol version'))
|
}
|
|
this._pos++
|
|
if (this._pos >= this._list.length) {
|
return this._emitError(new Error('Packet too short'))
|
}
|
|
// Parse connect flags
|
flags.username = (this._list.readUInt8(this._pos) & constants.USERNAME_MASK)
|
flags.password = (this._list.readUInt8(this._pos) & constants.PASSWORD_MASK)
|
flags.will = (this._list.readUInt8(this._pos) & constants.WILL_FLAG_MASK)
|
|
if (flags.will) {
|
packet.will = {}
|
packet.will.retain = (this._list.readUInt8(this._pos) & constants.WILL_RETAIN_MASK) !== 0
|
packet.will.qos = (this._list.readUInt8(this._pos) &
|
constants.WILL_QOS_MASK) >> constants.WILL_QOS_SHIFT
|
}
|
|
packet.clean = (this._list.readUInt8(this._pos) & constants.CLEAN_SESSION_MASK) !== 0
|
this._pos++
|
|
// Parse keepalive
|
packet.keepalive = this._parseNum()
|
if (packet.keepalive === -1) return this._emitError(new Error('Packet too short'))
|
|
// Parse clientId
|
clientId = this._parseString()
|
if (clientId === null) 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._emitError(new Error('Cannot parse will topic'))
|
packet.will.topic = topic
|
|
// Parse will payload
|
payload = this._parseBuffer()
|
if (payload === null) 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._emitError(new Error('Cannot parse username'))
|
packet.username = username
|
}
|
|
// Parse password
|
if (flags.password) {
|
password = this._parseBuffer()
|
if (password === null) return this._emitError(new Error('Cannot parse password'))
|
packet.password = password
|
}
|
|
return packet
|
}
|
|
Parser.prototype._parseConnack = function () {
|
var packet = this.packet
|
|
if (this._list.length < 2) return null
|
|
packet.sessionPresent = !!(this._list.readUInt8(this._pos++) & constants.SESSIONPRESENT_MASK)
|
packet.returnCode = this._list.readUInt8(this._pos)
|
|
if (packet.returnCode === -1) 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._emitError(new Error('Cannot parse topic'))
|
|
// Parse messageId
|
if (packet.qos > 0) if (!this._parseMessageId()) { return }
|
|
packet.payload = this._list.slice(this._pos, packet.length)
|
}
|
|
Parser.prototype._parseSubscribe = function () {
|
var packet = this.packet
|
var topic
|
var qos
|
|
if (packet.qos !== 1) {
|
return this._emitError(new Error('Wrong subscribe header'))
|
}
|
|
packet.subscriptions = []
|
|
if (!this._parseMessageId()) { return }
|
|
while (this._pos < packet.length) {
|
// Parse topic
|
topic = this._parseString()
|
if (topic === null) return this._emitError(new Error('Cannot parse topic'))
|
|
if (this._pos >= packet.length) return this._emitError(new Error('Malformed Subscribe Payload'))
|
qos = this._list.readUInt8(this._pos++)
|
|
// Push pair to subscriptions
|
packet.subscriptions.push({ topic: topic, qos: qos })
|
}
|
}
|
|
Parser.prototype._parseSuback = function () {
|
this.packet.granted = []
|
|
if (!this._parseMessageId()) { return }
|
|
// Parse granted QoSes
|
while (this._pos < this.packet.length) {
|
this.packet.granted.push(this._list.readUInt8(this._pos++))
|
}
|
}
|
|
Parser.prototype._parseUnsubscribe = function () {
|
var packet = this.packet
|
|
packet.unsubscriptions = []
|
|
// Parse messageId
|
if (!this._parseMessageId()) { return }
|
|
while (this._pos < packet.length) {
|
var topic
|
|
// Parse topic
|
topic = this._parseString()
|
if (topic === null) return this._emitError(new Error('Cannot parse topic'))
|
|
// Push topic to unsubscriptions
|
packet.unsubscriptions.push(topic)
|
}
|
}
|
|
Parser.prototype._parseUnsuback = function () {
|
if (!this._parseMessageId()) return this._emitError(new Error('Cannot parse messageId'))
|
}
|
|
Parser.prototype._parseMessageId = function () {
|
var packet = this.packet
|
|
packet.messageId = this._parseNum()
|
|
if (packet.messageId === null) {
|
this._emitError(new Error('Cannot parse messageId'))
|
return false
|
}
|
|
return true
|
}
|
|
Parser.prototype._parseString = function (maybeBuffer) {
|
var length = this._parseNum()
|
var result
|
var end = length + this._pos
|
|
if (length === -1 || end > this._list.length || end > this.packet.length) return null
|
|
result = this._list.toString('utf8', this._pos, end)
|
this._pos += length
|
|
return result
|
}
|
|
Parser.prototype._parseBuffer = function () {
|
var length = this._parseNum()
|
var result
|
var end = length + this._pos
|
|
if (length === -1 || end > this._list.length || end > this.packet.length) return null
|
|
result = this._list.slice(this._pos, end)
|
|
this._pos += length
|
|
return result
|
}
|
|
Parser.prototype._parseNum = function () {
|
if (this._list.length - this._pos < 2) return -1
|
|
var result = this._list.readUInt16BE(this._pos)
|
this._pos += 2
|
|
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
|
