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Mini Shell
Mini Shell
'use strict'
const log = require('debug')('interactor:transporter')
const EventEmitter2 = require('eventemitter2').EventEmitter2
const dns = require('dns')
const cst = require('../../constants.js')
module.exports = class Transporter extends EventEmitter2 {
constructor () {
super({
delimiter: ':',
wildcard: true
})
}
/**
* Disconnect and connect to a url
* @param {String} url where the client will connect [optionnal]
* @param {Function} cb invoked with <err>
*/
reconnect (url, cb) {
log('Reconnect transporter')
this.disconnect()
this.connect(url, cb)
}
/**
* Broadcast the close event from websocket connection
* @private
* @param {Integer} code
* @param {String} reason
*/
_onClose (code, reason) {
log('Closed transporter')
this.disconnect()
this._reconnect()
this.emit('close', code, reason)
}
/**
* Broadcast the error event from websocket connection
* and eventually close the connection if it isnt already
* @private
* @param {Error} err
*/
_onError (err) {
log(`Error with transporter: ${err.message}`)
// close connection if needed
this.disconnect()
this._reconnect()
this.emit('error', err)
}
/**
* Worker that will empty the packet queue if the connection works.
* @private
*/
_emptyQueue () {
// create the queue if it doesn't exist
if (!this.queue) {
this.queue = []
return
}
if (this.queue.length === 0) return
if (!this.isConnected()) return
log('Emptying queue (size : %d)', this.queue.length)
// re-send all of the data
while (this.queue.length > 0) {
if (!this.isConnected()) return
let packet = this.queue[0]
this.send(packet.channel, packet.data)
this.queue.shift()
}
}
/**
* Is internet reachable via DNS
* @private
* @param {Function} cb invoked with <boolean>
*/
_checkInternet (cb) {
dns.lookup('google.com', (err) => {
if (err && (err.code === 'ENOTFOUND' || err.code === 'EAI_AGAIN')) {
if (this._online) {
log('Internet is unreachable (DNS)')
}
this._online = false
} else {
if (!this._online) {
log('Internet is reachable again')
}
this._online = true
}
return cb(this._online)
})
}
/**
* Strategy to reconnect to remote endpoint as soon as possible
* -> test internet connection with dns request (if fail retry in 2 sec)
* -> try to connect to endpoint (if fail retry in 5 sec)
*/
_reconnect () {
if (this._reconnecting === true) return
this._reconnecting = true
log('Trying to reconnect to remote endpoint')
this._checkInternet((online) => {
if (!online && !cst.PM2_DEBUG) {
log('Internet down, retry in 2 seconds ..')
this._reconnecting = false
return setTimeout(this._reconnect.bind(this), process.env.NODE_ENV === 'test' ? 1 : 2000)
}
this.connect((err) => {
if (err || !this.isConnected()) {
log('Endpoint down, retry in 5 seconds ...')
this._reconnecting = false
return setTimeout(this._reconnect.bind(this), process.env.NODE_ENV === 'test' ? 1 : 5000)
}
log('Connection etablished with remote endpoint')
this._reconnecting = false
this._emptyQueue()
})
})
}
}
Zerion Mini Shell 1.0