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

{
  cmd: 'connect',
  protocolId: 'MQTT', // Or 'MQIsdp' in MQTT 3.1 and 5.0
  protocolVersion: 4, // Or 3 in MQTT 3.1, or 5 in MQTT 5.0
  clean: true, // Can also be false
  clientId: 'my-device',
  keepalive: 0, // Seconds which can be any positive number, with 0 as the default setting
  username: 'matteo',
  password: Buffer.from('collina'), // Passwords are buffers
  will: {
    topic: 'mydevice/status',
    payload: Buffer.from('dead'), // Payloads are buffers
    properties: { // MQTT 5.0
      willDelayInterval: 1234,
      payloadFormatIndicator: false,
      messageExpiryInterval: 4321,
      contentType: 'test',
      responseTopic: 'topic',
      correlationData: Buffer.from([1, 2, 3, 4]),
      userProperties: {
        'test': 'test'
      }
    }
  },
  properties: { // MQTT 5.0 properties
      sessionExpiryInterval: 1234,
      receiveMaximum: 432,
      maximumPacketSize: 100,
      topicAliasMaximum: 456,
      requestResponseInformation: true,
      requestProblemInformation: true,
      userProperties: {
        'test': 'test'
      },
      authenticationMethod: 'test',
      authenticationData: Buffer.from([1, 2, 3, 4])
  }
}

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

{
  cmd: 'connack',
  returnCode: 0, // Or whatever else you see fit MQTT < 5.0
  sessionPresent: false, // Can also be true.
  reasonCode: 0, // reason code MQTT 5.0
  properties: { // MQTT 5.0 properties
      sessionExpiryInterval: 1234,
      receiveMaximum: 432,
      maximumQoS: 2,
      retainAvailable: true,
      maximumPacketSize: 100,
      assignedClientIdentifier: 'test',
      topicAliasMaximum: 456,
      reasonString: 'test',
      userProperties: {
        'test': 'test'
      },
      wildcardSubscriptionAvailable: true,
      subscriptionIdentifiersAvailable: true,
      sharedSubscriptionAvailable: false,
      serverKeepAlive: 1234,
      responseInformation: 'test',
      serverReference: 'test',
      authenticationMethod: 'test',
      authenticationData: Buffer.from([1, 2, 3, 4])
  }
}

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

Subscribe

{
  cmd: 'subscribe',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    subscriptionIdentifier: 145,
    userProperties: {
      test: 'test'
    }
  }
  subscriptions: [{
    topic: 'test',
    qos: 0,
    nl: false, // no Local MQTT 5.0 flag
    rap: true, // Retain as Published MQTT 5.0 flag
    rh: 1 // Retain Handling MQTT 5.0
  }]
}

All properties are mandatory.

Suback

{
  cmd: 'suback',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    reasonString: 'test',
    userProperties: {
      'test': 'test'
    }
  }
  granted: [0, 1, 2, 128]
}

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

Unsubscribe

{
  cmd: 'unsubscribe',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    userProperties: {
      'test': 'test'
    }
  }
  unsubscriptions: [
    'test',
    'a/topic'
  ]
}

All properties are mandatory.

Unsuback

{
  cmd: 'unsuback',
  messageId: 42,
  properties: { // MQTT 5.0 properties
    reasonString: 'test',
    userProperties: {
      'test': 'test'
    }
  }
}

All properties are mandatory.

Publish

{
  cmd: 'publish',
  messageId: 42,
  qos: 2,
  dup: false,
  topic: 'test',
  payload: Buffer.from('test'),
  retain: false,
  properties: { // optional properties MQTT 5.0
      payloadFormatIndicator: true,
      messageExpiryInterval: 4321,
      topicAlias: 100,
      responseTopic: 'topic',
      correlationData: Buffer.from([1, 2, 3, 4]),
      userProperties: {
        'test': 'test'
      },
      subscriptionIdentifier: 120, // can be an Array in message from broker, if message included in few another subscriptions
      contentType: 'test'
   }
}

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

Puback

{
  cmd: 'puback',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // MQTT 5.0 properties
      reasonString: 'test',
      userProperties: {
        'test': 'test'
      }
  }
}

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

Pubrec

{
  cmd: 'pubrec',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // properties MQTT 5.0
    reasonString: 'test',
    userProperties: {
      'test': 'test'
    }
  }
}

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

Pubrel

{
  cmd: 'pubrel',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // properties MQTT 5.0
     reasonString: 'test',
     userProperties: {
       'test': 'test'
     }
  }
}

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

Pubcomp

{
  cmd: 'pubcomp',
  messageId: 42,
  reasonCode: 16, // only for MQTT 5.0
  properties: { // properties MQTT 5.0
    reasonString: 'test',
    userProperties: {
       'test': 'test'
    }
  }
}

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

Pingreq

{
  cmd: 'pingreq'
}

Pingresp

{
  cmd: 'pingresp'
}

Disconnect

{
  cmd: 'disconnect',
  reasonCode: 0, // MQTT 5.0 code
  properties: { // properties MQTT 5.0
     sessionExpiryInterval: 145,
     reasonString: 'test',
     userProperties: {
       'test': 'test'
     },
     serverReference: 'test'
  }
}

Auth

{
  cmd: 'auth',
  reasonCode: 0, // MQTT 5.0 code
  properties: { // properties MQTT 5.0
     authenticationMethod: 'test',
     authenticationData: Buffer.from([0, 1, 2, 3]),
     reasonString: 'test',
     userProperties: {
       'test': 'test'
     }
  }
}