@mangar2/broker

Abstract

The ( mqtt ) broker is a central service receiving and distributing messages to all subscribed receipiens . Use the "brokerservice" module to start the broker .

Contents

• Meta
• Class Broker
  • Parameters
  • Methods
    • close
    • connect
    • on
    • run

Meta

File	broker.js
Abstract	The ( mqtt ) broker is a central service receiving and distributing messages to all subscribed receipiens . Use the "brokerservice" module to start the broker .
Author	Volker Böhm
Copyright	Copyright ( c ) 2020 Volker Böhm
License	This software is licensed under the GNU LESSER GENERAL PUBLIC LICENSE Version 3 . It is furnished "as is" , without any support , and with no warranty , express or implied , as to its usefulness for any purpose .

Class Broker

new Broker(configuration)

Creates a new broker

Example

const configuration = {
     port: 10000,
     persistInterval: 0,
     connections: {
          directory: '.',
          fileName: 'broker',
          log: [
              {
                  module: 'received',
                  topic: '#'
              }
          ]
      }
  }
const broker = new Broker(configuration)
broker.run()

Broker Parameters

Name	Type	Description
configuration	Object	configuration for the broker

configuration properties

Name	Type	Attribute	Default	Description
port	number, string			port number the broker will listen on
persistInterval	number	optional	60 * 1000	Intervall between persisting internal state to file in milliseconds . Persistance is not called if this value is 0
connections	Object			connection settings for the broker

connections properties

Name	Type	Attribute	Default	Description
fileName	string			filename for persistence
directory	string			directory ( file path ) for persistence
replyTimeoutInMilliseconds	number			timeout to wait for an answer of a http call
inFlightWindow	number	optional	1	amount of qos 1 and qos 2 messages send for the same topic at the same time
pubrelTimeoutInMilliseconds	number	optional	one day	temeout to wait for a corresponding pubrel message
maxRetryCount	number			amount of resend of messages before forcing a disconnect
maxQueuSize	number			maximal amount of entries in a message queue
log	Object			log settings

Broker Methods

close

async close ()

Closes the broker , stops listening

connect

connect (host, port)

Connects to a friendly broker and subscribs for all messages

connect Parameters

Name	Type	Description
host	string	name of the host ( or his ip )
port	number	port number to connect to

on

on (event, callback)

Sets a callback .

on Parameters

Name	Type	Description
event	string	callback name ( supports 'send' and 'publish' ) 'send' is called to send data . This function is provided by the broker but could be overwritten 'publish' is called on receiving data . This function if provided by the broker but could be overwritten
callback	function

on throws

Type	Description
Error	if the event is not supported
Error	if the callback is not 'function'

run

run ()

Starts the broker . It will listen to message , send messages and periodically store its status