mqtt.generate(object, [opts])

mqtt.writeToStream(object, stream, [opts])

mqtt.parser([opts])

Returns a new Parser object. Parser inherits from EventEmitter and will emit:

Parser.parse(buffer)

Parses a given Buffer and emits synchronously all the MQTT packets that are included. Returns the number of bytes left to parse.

If an error happens, an error event will be emitted, but no packet events will be emitted after that. Calling parse() again clears the error and previous buffer, as if you created a new Parser.

Packets

This section describes the format of all packets emitted by the Parser and that you can input to generate.

Connect

1{
2  cmd: 'connect',
3  protocolId: 'MQTT', // Or 'MQIsdp' in MQTT 3.1 and 5.0
4  protocolVersion: 4, // Or 3 in MQTT 3.1, or 5 in MQTT 5.0
5  clean: true, // Can also be false
6  clientId: 'my-device',
7  keepalive: 0, // Seconds which can be any positive number, with 0 as the default setting
8  username: 'matteo',
9  password: Buffer.from('collina'), // Passwords are buffers
10  will: {
11    topic: 'mydevice/status',
12    payload: Buffer.from('dead'), // Payloads are buffers
13    properties: { // MQTT 5.0
14      willDelayInterval: 1234,
15      payloadFormatIndicator: false,
16      messageExpiryInterval: 4321,
17      contentType: 'test',
18      responseTopic: 'topic',
19      correlationData: Buffer.from([1, 2, 3, 4]),
20      userProperties: {
21        'test': 'test'
22      }
23    }
24  },
25  properties: { // MQTT 5.0 properties
26      sessionExpiryInterval: 1234,
27      receiveMaximum: 432,
28      maximumPacketSize: 100,
29      topicAliasMaximum: 456,
30      requestResponseInformation: true,
31      requestProblemInformation: true,
32      userProperties: {
33        'test': 'test'
34      },
35      authenticationMethod: 'test',
36      authenticationData: Buffer.from([1, 2, 3, 4])
37  }
38}

If protocolVersion is 3, clientId is mandatory and generate will throw if missing.

If password or will.payload are passed as strings, they will automatically be converted into a Buffer.

Connack

1{
2  cmd: 'connack',
3  returnCode: 0, // Or whatever else you see fit MQTT < 5.0
4  sessionPresent: false, // Can also be true.
5  reasonCode: 0, // reason code MQTT 5.0
6  properties: { // MQTT 5.0 properties
7      sessionExpiryInterval: 1234,
8      receiveMaximum: 432,
9      maximumQoS: 2,
10      retainAvailable: true,
11      maximumPacketSize: 100,
12      assignedClientIdentifier: 'test',
13      topicAliasMaximum: 456,
14      reasonString: 'test',
15      userProperties: {
16        'test': 'test'
17      },
18      wildcardSubscriptionAvailable: true,
19      subscriptionIdentifiersAvailable: true,
20      sharedSubscriptionAvailable: false,
21      serverKeepAlive: 1234,
22      responseInformation: 'test',
23      serverReference: 'test',
24      authenticationMethod: 'test',
25      authenticationData: Buffer.from([1, 2, 3, 4])
26  }
27}

The only mandatory argument is returnCode, as generate will throw if missing.

Subscribe

1{
2  cmd: 'subscribe',
3  messageId: 42,
4  properties: { // MQTT 5.0 properties
5    subscriptionIdentifier: 145,
6    userProperties: {
7      test: 'test'
8    }
9  }
10  subscriptions: [{
11    topic: 'test',
12    qos: 0,
13    nl: false, // no Local MQTT 5.0 flag
14    rap: true, // Retain as Published MQTT 5.0 flag
15    rh: 1 // Retain Handling MQTT 5.0
16  }]
17}

All properties are mandatory.

Suback

1{
2  cmd: 'suback',
3  messageId: 42,
4  properties: { // MQTT 5.0 properties
5    reasonString: 'test',
6    userProperties: {
7      'test': 'test'
8    }
9  }
10  granted: [0, 1, 2, 128]
11}

All the granted qos must be < 256, as they are encoded as UInt8. All properties are mandatory.

Unsubscribe

1{
2  cmd: 'unsubscribe',
3  messageId: 42,
4  properties: { // MQTT 5.0 properties
5    userProperties: {
6      'test': 'test'
7    }
8  }
9  unsubscriptions: [
10    'test',
11    'a/topic'
12  ]
13}

All properties are mandatory.

Unsuback

1{
2  cmd: 'unsuback',
3  messageId: 42,
4  properties: { // MQTT 5.0 properties
5    reasonString: 'test',
6    userProperties: {
7      'test': 'test'
8    }
9  }
10}

All properties are mandatory.

Publish

1{
2  cmd: 'publish',
3  messageId: 42,
4  qos: 2,
5  dup: false,
6  topic: 'test',
7  payload: Buffer.from('test'),
8  retain: false,
9  properties: { // optional properties MQTT 5.0
10      payloadFormatIndicator: true,
11      messageExpiryInterval: 4321,
12      topicAlias: 100,
13      responseTopic: 'topic',
14      correlationData: Buffer.from([1, 2, 3, 4]),
15      userProperties: {
16        'test': 'test'
17      },
18      subscriptionIdentifier: 120, // can be an Array in message from broker, if message included in few another subscriptions
19      contentType: 'test'
20   }
21}

Only the topic property is mandatory. Both topic and payload can be Buffer objects instead of strings. messageId is mandatory for qos > 0.

Puback

1{
2  cmd: 'puback',
3  messageId: 42,
4  reasonCode: 16, // only for MQTT 5.0
5  properties: { // MQTT 5.0 properties
6      reasonString: 'test',
7      userProperties: {
8        'test': 'test'
9      }
10  }
11}

The only mandatory property is messageId, as generate will throw if missing.

Pubrec

1{
2  cmd: 'pubrec',
3  messageId: 42,
4  reasonCode: 16, // only for MQTT 5.0
5  properties: { // properties MQTT 5.0
6    reasonString: 'test',
7    userProperties: {
8      'test': 'test'
9    }
10  }
11}

The only mandatory property is messageId, as generate will throw if missing.

Pubrel

1{
2  cmd: 'pubrel',
3  messageId: 42,
4  reasonCode: 16, // only for MQTT 5.0
5  properties: { // properties MQTT 5.0
6     reasonString: 'test',
7     userProperties: {
8       'test': 'test'
9     }
10  }
11}

The only mandatory property is messageId, as generate will throw if missing.

Pubcomp

1{
2  cmd: 'pubcomp',
3  messageId: 42,
4  reasonCode: 16, // only for MQTT 5.0
5  properties: { // properties MQTT 5.0
6    reasonString: 'test',
7    userProperties: {
8       'test': 'test'
9    }
10  }
11}

The only mandatory property is messageId, as generate will throw if missing.

Pingreq

1{
2  cmd: 'pingreq'
3}

Pingresp

1{
2  cmd: 'pingresp'
3}

Disconnect

1{
2  cmd: 'disconnect',
3  reasonCode: 0, // MQTT 5.0 code
4  properties: { // properties MQTT 5.0
5     sessionExpiryInterval: 145,
6     reasonString: 'test',
7     userProperties: {
8       'test': 'test'
9     },
10     serverReference: 'test'
11  }
12}

Auth

1{
2  cmd: 'auth',
3  reasonCode: 0, // MQTT 5.0 code
4  properties: { // properties MQTT 5.0
5     authenticationMethod: 'test',
6     authenticationData: Buffer.from([0, 1, 2, 3]),
7     reasonString: 'test',
8     userProperties: {
9       'test': 'test'
10     }
11  }
12}