329 lines
12 KiB
JavaScript
329 lines
12 KiB
JavaScript
import { connect } from 'mqtt'
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import EventEmitter from 'events'
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import btc from 'better-try-catch'
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import union from 'lodash.union'
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import xor from 'lodash.xor'
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import logger from '@uci-utils/logger'
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import isPlainObject from 'is-plain-object'
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import isTopicMatch from 'mqtt-match'
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let log = {}
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/**
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* MQTT - Client - An mqtt client that supports UCI packets
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* uses mqtt.js as basis
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*/
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class MQTTClient extends EventEmitter {
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/**
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* constructor - Description
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*
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* @param {object} [opts={}] Description
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*
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*/
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constructor(opts = {}) {
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super(opts)
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this.id = opts.id || opts.name || 'mqtt:' + new Date().getTime()
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log = logger({
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file: 'src/client.js',
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package:'@uci/mqttjs',
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class: 'MQTTClient',
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name: 'mqtt',
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id: this.id
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})
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this.url = opts.url || null
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this.client = opts.client || false
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this.sendTopic = opts.sendTopic || 'uci/send'
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// these are the "listen" topics to which the instance will subscribe. By default that will include the instance ID
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// default subscription topics can be string of commna delimited or array of strings. If none they by default topic is id
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this.topics = opts.topics ? (Array.isArray(opts.topics) ? opts.topics : opts.topics.split(',')) : []
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this.topics.push(this.client ? `${this.sendTopic}/return` : `${this.sendTopic}/receive`)
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this.connectOpts = opts.connect || {} // see options for new mqtt.Client
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this.mqtt = {} // orginal mqtt.js object when created by connect
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// self bindings
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this._connected = false
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this.connect = this.connect.bind(this)
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this.publish = this.publish.bind(this)
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this._subscribe = this._subscribe.bind(this)
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this.client ? this.send = this._send.bind(this) : this.push = this._push.bind(this)
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}
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get connected() { return this._connected }
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/**
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* connect - Description
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*
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* @returns {type} Description
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*/
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async connect() {
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return new Promise((resolve, reject) => {
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this.mqtt = connect(
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this.url,
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this.connectOpts
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)
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let timeout = this.connecOpts || 5000
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setTimeout(() => {
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reject({msg:'ending mqtt connection attempt, no broker', url:this.url, options:this.connectOpts})
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}, timeout)
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this.mqtt.once('connect', async () => {
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this._log()
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this._listen()
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this.mqtt.on('reconnect', () => {
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log.debug({method:'connect', line:71, msg:'mqtt client reconnected to broker'})
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this._connected=true
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this._subscribe(this.topics) // resubscribe
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})
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this.mqtt.on('error', err => {
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this.emit('status',{level:'fatal', method:'connect', err: err, msg:'connection error to broker'})
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log.fatal({method:'connect', line:76, err: err, msg:'connection error to broker'})
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this._connected=false
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})
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this.mqtt.on('close', () => {
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this.emit('status',{level:'fatal', msg:'mqtt connection to broker was closed'})
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log.debug({method:'_log', line:193, msg:'connection to broker was closed'})
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this._connected=false
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})
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this.mqtt.on('offline', () => {
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this.emit('status',{level:'fatal',msg:'this client has gone offline from broker'})
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log.warn({method:'_log', line:197, msg:'this client has gone offline from broker'})
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this._connected=false
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})
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log.debug({method:'connect', line:80, options: this.mqtt.options, msg:`mqtt client connected to broker at ${this.mqtt.options.hostname}:${this.mqtt.options.port}`})
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this._connected=true
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let [err] = await btc(this._subscribe)(this.topics) // initial subscriptions
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if (err) reject({error:'unable to subscribe to topics after connection', err:err})
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resolve(`mqtt client connected to broker at ${this.mqtt.options.hostname}:${this.mqtt.options.port}`)
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})
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}) //end promise
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}
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async subscribe(topic, options = {}) {
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// topic is only comma delimited string or array of topics
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if (typeof topic === 'string') topic = topic.split(',')
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this.topics = union(this.topics, topic || [])
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log.debug({method:'subscribe', line:91, msg:`subscription for topic ${topic} added`})
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return this._subscribe(topic,options)
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}
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async unsubscribe(topic, options = {}) {
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if (typeof topic === 'string') topic = topic.split(',')
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this.topics = xor(this.topics, topic || [])
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return new Promise((resolve, reject) => {
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if (!topic) reject('no topic supplied')
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if (!this._connected) reject('no connection to broker')
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this.mqtt.unsubscribe(topic,options, (err, granted) => {
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if (err) reject(err)
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else resolve(granted)
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})
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})
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}
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// solely for primary of sending uci packets. Use publish for typical mqtt messaging
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// if topic not passed, nor a severID supplied in the options then it will send to teh topic given by the cmd
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async _send(ipacket, topic, options) { // packet is required
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if (isPlainObject(topic)) { // if neither then assume none and what is passed is options
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options = topic || {}
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topic = ''
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}
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return new Promise(async resolve => {
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if (!this._connected) {
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log.error({method:'send', line:105, url:this.url, opts:this.opts, msg:'no active connection to broker'})
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resolve({ error: 'client not connected to a broker, aborting send' })
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}
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let packet = Object.assign({}, ipacket) // need to avoid mutuation for different consumers using same packet instance
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packet._header = {
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id: Math.random()
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.toString()
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.slice(2), // need this for when multiple sends for different consumers use same packet instanceack
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returnTopic: `${this.sendTopic}/return`
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}
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topic = topic || `${this.sendTopic}/receive`
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let payload = this._serialize(packet) // payload is entire packet
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if (!payload) {
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log.error({method:'send', line:163, msg:'not able to serilaize packet', packet:packet})
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resolve({error:'not able to serilaize packet', packet:packet})
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}
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setTimeout(() => {resolve({ error: 'no response from socket in 10sec' })}, 10000)
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this.once(packet._header.id, async reply => {
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let res = await this._packetProcess(reply)
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if (!res) { // if packetProcess was not promise
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res = reply
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log.debug({method:'send', line:180, msg:'consumer function was not promise returning further processing may be out of sequence'})
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}
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resolve(res) // resolves processed packet not returned packet
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})
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let res = await this._publish(packet,topic,options)
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if (res) resolve(res)
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}) // end promise
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}
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async _push(packet={}, topic, options) {
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if (!this._connected) {
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log.error({method:'send', line:105, url:this.url, opts:this.opts, msg:'no active connection to broker'})
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return {error:'no active connection to broker'}
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}
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if (isPlainObject(topic)) { // if neither then assume none and what is passed is options
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options = topic || {}
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topic = ''
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}
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topic = topic || packet.cmd ? packet.cmd.replace(/\./gi,'/') : ''
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if (!topic) {
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log.warn({msg:'push aborted, no topic pass nor command in packet', packet:packet, topic:topic})
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return {error:'push aborted, no topic given or no command in packet', packet:packet, topic:topic}
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}
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packet._header ={id:'pushed'}
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log.info({method:'push', line:194, msg:'mqtt publishing a uci pushed packet', packet:packet, topic:topic})
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return await this._publish(packet, topic, options)
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}
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// this is internal UCI publish
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async _publish(packet,topic,options) {
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if(!topic) return {error: 'no topic to which to publish packet'}
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let payload = this._serialize(packet) // payload is entire packet
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if (!payload) {
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log.error({method:'send', line:163, msg:'not able to serilaize packet', packet:packet})
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return {error:'not able to serilaize packet', packet:packet}
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}
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// all ready publish packets
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log.info(({msg:'sending a uci packet vis mqtt', packet:packet,topic:topic,payload:payload, options:options}))
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let [err] = await btc(this.publish)(topic,payload,options)
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if (err) return {error:err}
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}
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publish (...args) {
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return new Promise((resolve, reject) => {
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if (!this._connected) reject('publish failed - no connection to broker')
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this.mqtt.publish(...args, (err, result) => {
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if (err) {
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reject(err)
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}
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else resolve(result)
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})
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})
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}
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end (...args) {
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return new Promise((resolve, reject) => {
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this.mqtt.end(...args, (err, result) => {
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if (err) reject(err)
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else resolve(result)
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})
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})
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}
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registerPacketProcessor(func) {
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this._packetProcess = func
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}
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async _subscribe (topic, options={}) {
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return new Promise((resolve, reject) => {
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if (!this._connected) reject('no connection to broker during subscription attempt')
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if (!topic) reject('no topic supplied')
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this.mqtt.subscribe(topic,options, (err, granted) => {
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if (err) reject(err)
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else resolve(granted)
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})
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})
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}
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_serialize(json) {
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let [err, payload] = btc(JSON.stringify)(json)
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if (err) {
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log.warn({method:'_serialize', line:140, msg:`unable to stringify json for payload:${json}`})
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return null
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}
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return payload
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}
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// TODO if client set up reply subscription with message id and then emit that for resolving send
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// if server then take id and send message back with that appended to topic
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_listen() {
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log.debug({method:'_listen', line:147, msg:`listening for incoming mqtt packets from broker on topics ${this.topics}`})
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this.mqtt.on('message', messageProcess.bind(this))
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async function messageProcess(topic, payload) {
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log.debug({method:'_listen', line:153 ,msg:'incoming mqtt message to process', topic:topic, payload:payload})
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let packet = this._handlePayload(payload)
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if (isPlainObject(packet)) packet.cmd = packet.cmd || topic // if payload had no command so use topic as cmd
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else packet = { cmd: topic, data:packet } // payload was not json packet, create a packet and emit payload
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this.emit('payload',{topic:topic, payload:payload}) // emit 'payload' event for use for standard mqtt pub/sub
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let header = Object.assign({},packet._header) // save the header in case a packet processor deletes it
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let res = await this._packetProcess(packet)
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if (header && this.client) this.emit(header.id,packet)
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else {
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res._header = header
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log.info({method:'_listen', line:159, msg:'processed packet - return only if sent not published', processed:res})
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if (res._header) {
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if(res._header.returnTopic) this._publish(res,res._header.returnTopic)
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}
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}
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}
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}
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_handlePayload(payload) {
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let [err, packet] = btc(JSON.parse)(payload.toString())
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if (err) log.debug({method:'_handlePayload', line:201, msg:'payload is not json returning as prop data:<payload>'})
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if (!isPlainObject(packet)) return payload.toString()
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return packet
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}
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_validateTopic (topic) {
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if (this.topics.some(ctopic => isTopicMatch(ctopic,topic))) {
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log.warn({msg:'topic not valid for publishing, matches a subscribed topic or error topic', topic:topic, errorTopic:this.errorTopics, subscribed:this.topics})
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return false
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}
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return true
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}
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// default packet process just a simple console logger. ignores any cmd: prop
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_packetProcess(packet) {
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console.log('=========================')
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console.log('received packet to be processed=>',packet)
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console.log('replace this by setting new function with .registerPacketProcessor')
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packet.msg='the default packet processeor processed this packet'
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console.log('========================')
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return packet
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}
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async _log() {
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log = logger({
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file: 'src/client.js',
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class: 'Client',
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package: '@uci/mqtt',
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id: this.id
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})
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this.mqtt.on('packetsend', packet => {
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log.debug({method:'_log', line:201, packet: packet, msg:'outgoing packet to mqtt broker'})
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})
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this.mqtt.on('packetreceive', packet => {
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log.debug({method:'_log', line:205, packet: packet, msg:'incoming packet from mqtt broker'})
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})
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}
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} // end mqtt client class
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export default MQTTClient
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