mqtt

An MQTT v3.1.1 Toit client, with support for QoS 0 and 1.

Example

These simple examples show how to publish and subscribe to an MQTT broker. You can find more examples in the examples/ folder.

Simple client

The simple client is useful, if advanced features, like automatic reconnects, topic routing, parallel sending, etc., are not needed.

In many cases it is easier to use than the Client or FullClient.

import mqtt

main:
  transport := mqtt.TcpTransport --host="127.0.0.1"
  client := mqtt.SimpleClient --transport=transport

  client.start --client_id="toit-client-id"

  client.subscribe "device/events"

  // Note that we publish to a different topic than we subscribed to.
  // If you want to receive the message you published, make sure to change
  // one of the topics.
  client.publish "device/data" "Hello, world!"

  while true:
    received := client.receive
    print "Received: $received.topic: $received.payload.to_string_non_throwing"

Routing client

The routing Client is a wrapper around the FullClient. It routes incoming messages to the appropriate handler based on the topic.

Since it is based on the FullClient it automatically reconnects to the broker if the connection is lost. It also resends unacknowledged messages and has many more features. It is heavier and more complicated than the SimpleClient.

import mqtt

main:
  transport := mqtt.TcpTransport --host="127.0.0.1"
  client := mqtt.Client --transport=transport

  client.start --client_id="toit-client-id"

  client.subscribe "device/events":: | topic/string payload/ByteArray |
    print "Received: $topic: $payload.to_string_non_throwing"

  // Note that we publish to a different topic than we subscribed to.
  // If you want to receive the message you published, make sure to change
  // one of the topics.
  client.publish "device/data" "Hello, world!"