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micropython-mqtt

Async MQTT client library with auto reconnect for MicroPython devices such as the ESP32 or Pycom devices

Installation

• Download the mqtt.py file and add it to your /libs folder

Features

The MQTTClient class is a simple lightweight MQTT client for basic MQTT pub / sub functionality. It has the following features:

• Auto reconnect to the broker when the connection is lost
• Supports QOS 0 and 1 for publish and subscribe
• Publish, subscribe and receipt of published messages are all async
• Automatically handles ping requests if no messages are sent for a period of time

Usage

See the basic-example.py file in the examples folder for a simple example of using the MQTTClient class

from libs.mqtt import MQTTClient

Import the MQTTClient class

client = MQTTClient('192.168.1.1', port=1883)

Construct a new instance of the MQTTClient class

• Parameter: server - the address of the MQTT broker
  • Type: string
• Parameter: port - the TCP/IP port to connect to
  • Type: number
• Optional Parameter: reconnect_retry_time - the time in seconds between reconnect retry attempts
  • Type: number
  • Default: 10
• Optional Parameter: keep_alive - the time in seconds of no activity before a ping is sent to the broker
  • Type: number
  • Default: 15
• Optional Parameter: ssl - set True to use SSL
  • Type: boolean
  • Default: False
• Optional Parameter: ssl_params - the SSL parameters to use if using SSL
  • Type: object

set_connected_callback(cb)

Set the callback method which is fired when the connected status changes. This callback is optional

• Parameter: cb - the callback method
  • Type: method name
  • Callback Signature: def connected_cb(status) where status is True if the client is connected or False if disconnected

set_message_callback(cb)

Set the callback method which is fired when a new MQTT message arrives. This callback is optional

• Parameter: cb - the callback method
  • Type: method name
  • Callback Signature: def message_cb(topic, payload) where topic is the message topic and payload is the message payload

set_puback_callback(cb)

Set the callback method which is fired when a publish command succeeds. This callback is optional

• Parameter: cb - the callback method
  • Type: method name
  • Callback Signature: def puback_cb(msg_id) where msg_id is a message ID. This can be matched with a message ID returned from the publish method to confirm that a publish has succeeded

set_suback_callback(cb)

Set the callback method which is fired when a subscribe command succeeds. This callback is optional

• Parameter: cb - the callback method
  • Type: method name
  • Callback Signature: def suback_cb(msg_id) where msg_id is a message ID. This can be matched with a message ID returned from the subscribe method to confirm that a subscribe has succeeded

set_unsuback_callback(cb)

Set the callback method which is fired when an ubsubscribe command succeeds. This callback is optional

• Parameter: cb - the callback method
  • Type: method name
  • Callback Signature: def unsuback_cb(msg_id) where msg_id is a message ID. This can be matched with a message ID returned from the unsubscribe method to confirm that an unsubscribe has succeeded

connect(client_id, user=None, password=None, clean_session=True, will_topic=None, will_qos=0, will_retain=False, will_payload=None)

Connect the MQTT client to the broker. This method is non-blocking and returns before the connection has completed.

• Parameter: client_id - the ID of this MQTT client
  • Type: string
• Optional Parameter: user - the username used to authenticate with the broker
  • Type: string
  • Default: None
• Optional Parameter: password - the password used to authenticate with the broker
  • Type: string
  • Default: None
• Optional Parameter: clean_session - set true to start a clean session with the broker
  • Type: boolean
  • Default: True
• Optional Parameter: will_topic - the last will and testament topic.
  • Type: string
  • Default: None
• Optional Parameter: will_qos - the last will and testament QOS level. QOS values of 0, 1 and 2 are valid
  • Type: number
  • Default: 0
• Optional Parameter: will_retain - the last will and testament message retain flag
  • Type: boolean
  • Default: False
• Optional Parameter: will_payload - the last will and testament message payload
  • Type: string
  • Default: None

disconnect()

Disconnect the MQTT client from the broker

isconnected()

Get the status of the connection between the MQTT client and broker

• Returns: True if the client is connected, else False

publish(topic, payload, retain=False, qos=0)

Publish an MQTT message to the broker

• Parameter: topic - the message topic
  • Type: string
• Parameter: payload - the message payload
  • Type: string
• Optional Parameter: retain - the message retain flag
  • Type: boolean
  • Default: False
• Optional Parameter: qos - the message QOS level. QOS values of 0 and 1 are valid. This library does not currently support QOS 2
  • Type: number
  • Default: 0
• Returns: QOS = 0, None. QOS = 1, the publish message ID. This can be used with the set_puback_callback to verify that a message has been published
• Raises: MQTTException if the message cannot be published

subscribe(topic, qos=0)

Subscribe to an MQTT topic

• Parameter: topic - the topic to subscribe to. MQTT wildcards can be used
  • Type: string
• Optional Parameter: qos - the subscription QOS level. QOS values of 0 and 1 are valid. This library does not currently support QOS 2
  • Type: boolean
  • Default: False
• Returns: the subscribe message ID. This can be used with the set_suback_callback to verify that a subscription was successful
• Raises: MQTTException if the subscribe message cannot be sent

unsubscribe(topic)

Unsubscribe from an MQTT topic

• Parameter: topic - the topic to unsubscribe from. MQTT wildcards can be used
  • Type: string
• Returns: the unsubscribe message ID. This can be used with the set_unsuback_callback to verify that an unsubscription was successful
• Raises: MQTTException if the unsubscribe message cannot be sent