@mangar2/mqttservice/README.md

communicates with a MQTT-Style HTTP broker

<!-- This file is generated by jsmddoc version 0.1 -->

# 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](#Meta)
- [Class OnPublish](#Class-OnPublish)
  - [Parameters](#OnPublish-Parameters)
  - [Members](#OnPublish-Members)
  - [Methods](#OnPublish-Methods)
    - [close](#close)
    - [listen](#listen)
    - [on](#on)
- [Class PublishMessage](#Class-PublishMessage)
  - [Parameters](#PublishMessage-Parameters)
  - [Methods](#PublishMessage-Methods)
    - [close](#close)
    - [publish](#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

```javascript
//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 |