Class MqttClientConnection

MQTT client connection

Hierarchy

Constructors

Properties

client: MqttClient

The client that owns this connection

Methods

  • Open the actual connection to the server (async).

    Returns Promise<boolean>

    A Promise which completes whether the connection succeeds or fails. If connection fails, the Promise will reject with an exception. If connection succeeds, the Promise will return a boolean that is true for resuming an existing session, or false if the session is new

  • The connection will automatically reconnect when disconnected, removing the need for this function. To cease automatic reconnection attempts, call disconnect.

    Returns Promise<boolean>

    Deprecated

  • Publish message (async). If the device is offline, the PUBLISH packet will be sent once the connection resumes.

    Parameters

    • topic: string

      Topic name

    • payload: Payload

      Contents of message

    • qos: QoS

      Quality of Service for delivering this message

    • retain: boolean = false

      If true, the server will store the message and its QoS so that it can be delivered to future subscribers whose subscriptions match the topic name

    Returns Promise<MqttRequest>

    Promise which returns a MqttRequest which will contain the packet id of the PUBLISH packet.

    • For QoS 0, completes as soon as the packet is sent.
    • For QoS 1, completes when PUBACK is received.
    • For QoS 2, completes when PUBCOMP is received.
  • Subscribe to a topic filter (async). The client sends a SUBSCRIBE packet and the server responds with a SUBACK.

    subscribe() may be called while the device is offline, though the async operation cannot complete successfully until the connection resumes.

    Once subscribed, callback is invoked each time a message matching the topic is received. It is possible for such messages to arrive before the SUBACK is received.

    Parameters

    • topic: string

      Subscribe to this topic filter, which may include wildcards

    • qos: QoS

      Maximum requested QoS that server may use when sending messages to the client. The server may grant a lower QoS in the SUBACK

    • Optional on_message: OnMessageCallback

      Optional callback invoked when message received.

    Returns Promise<MqttSubscribeRequest>

    Promise which returns a MqttSubscribeRequest which will contain the result of the SUBSCRIBE. The Promise resolves when a SUBACK is returned from the server or is rejected when an exception occurs.

  • Unsubscribe from a topic filter (async). The client sends an UNSUBSCRIBE packet, and the server responds with an UNSUBACK.

    Parameters

    • topic: string

      The topic filter to unsubscribe from. May contain wildcards.

    Returns Promise<MqttRequest>

    Promise wihch returns a MqttRequest which will contain the packet id of the UNSUBSCRIBE packet being acknowledged. Promise is resolved when an UNSUBACK is received from the server or is rejected when an exception occurs.

  • Close the connection (async).

    Will free all native resources, rendering the connection unusable after the disconnect() call.

    Returns Promise<void>

    Promise which completes when the connection is closed.

  • Forces all written events to be buffered in memory. The buffered data will be flushed when uncork is called.

    Returns void

  • Flushes all data buffered since cork was called.

    NOTE: It is HIGHLY recommended that uncorking should always be done via process.nextTick, not during the EventEmitter.on() call.

    Returns void

  • Synchronously calls each of the listeners registered for the event key supplied in registration order. If the BufferedEventEmitter is currently corked, the event will be buffered until uncork is called.

    Parameters

    • event: EventKey

      The name of the event

    • Rest ...args: any[]

      Event payload

    Returns boolean

Events

CONNECT: string = 'connect'

Emitted when the connection successfully establishes itself for the first time

DISCONNECT: string = 'disconnect'

Emitted when connection has disconnected successfully.

ERROR: string = 'error'

Emitted when an error occurs. The error will contain the error code and message.

INTERRUPT: string = 'interrupt'

Emitted when the connection is dropped unexpectedly. The error will contain the error code and message. The underlying mqtt implementation will attempt to reconnect.

RESUME: string = 'resume'

Emitted when the connection reconnects (after an interrupt). Only triggers on connections after the initial one.

MESSAGE: string = 'message'

Emitted when any MQTT publish message arrives.

CONNECTION_SUCCESS: string = 'connection_success'

Emitted on every successful connect and reconnect. Will contain a number with the connection reason code and a boolean indicating whether the connection resumed a session.

CONNECTION_FAILURE: string = 'connection_failure'

Emitted on an unsuccessful connect and reconnect. Will contain an error code indicating the reason for the unsuccessful connection.

CLOSED: string = 'closed'

Emitted when the MQTT connection was disconnected and shutdown successfully.

Node-only

  • Queries a small set of numerical statistics about the current state of the connection's operation queue

    Returns ConnectionStatistics

    Deprecated

    use getOperationalStatistics instead

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