@mangar2/mqttservice

Abstract

Library module to communicate with the mqtt broker . It includes Publish to send messsages to the broker and OnPublish to receive messages published by the broker

Contents

• Meta
• Class OnPublish
  • Parameters
  • Members
  • Methods
    • close
    • listen
    • on
• Class PublishMessage
  • Parameters
  • Methods
    • close
    • publish

Meta

File	mqttservice.js
Abstract	Library module to communicate with the mqtt broker . It includes Publish to send messsages to the broker and OnPublish to receive messages published by 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 .

Callback definitions

ProcessMessage

ProcessMessage Parameters

Name	Type	Description
message	Object	the message received
qos	0, 1, 2	the quality of service information
dup	0, 1	flag signaling duplicates

Class OnPublish

new OnPublish(listenerPort, logSettings, qos2PubrelTimeoutInSeconds)

Creates a new server receiving messages Supports registering a callback with on ( 'publish' , ( payload , qos ) = > { } ) called for each received message

OnPublish Parameters

Name	Type	Description
listenerPort	number	port to listen on
logSettings	Object	logging settings
qos2PubrelTimeoutInSeconds	number	time to delete qos2 related packageid´s from the qos2 queue . This will happen , if a pubrel does not follow the publish call for a this amount of seconds

OnPublish Members

Name	Type	description
logFilter	LogFilter	Logging filter
port	number	Port the server uses , only defined after listen has been called !

OnPublish Methods

close

close ()

Closes all connections

listen

listen ()

Starts to listen and wait for input

on

on (event, callback)

Sets a callback . Usually , there is no need to set anything here

on Parameters

Name	Type	Description
event	string	event name , supported 'publish'
callback	ProcessMessage	callback to be called , to process messages received

Class PublishMessage

new PublishMessage(host, port, configuration)

Creates a client for publishing messages

Example

//Publish the message with topic /a/a, value 1, reason "test", QoS 0, retain 0:
const publish = new PublishMessage('myhost', 10000, { retry: 60 })
result = await publish.publish(publishtoken, new Message("/a/a", 1, "test"), 0, 0);

PublishMessage Parameters

Name	Type	Description
host	string	host name ( or ip )
port	number	port number
configuration	Object	configuration options

configuration properties

Name	Type	Attribute	Default	Description
retry	number	optional	60	amount of retries to send a message

PublishMessage Methods

close

async close ()

Closes the connection to the broker

publish

async publish (token, message, qos, retain, version)

Publishes a message with a defined quality of service automatically generating an id

publish Parameters

Name	Type	Description
token	string	connection token
message	Object	message to publish .
qos	number	0 , 1 , 2 quality of service
retain	boolean	True , if message shall be retained for future subscriptions
version	string, undefined	interface version , supports 0 . 0 and 1 . 0 ( default )

publish throws

Type	Description
string	on any connection error