The MQTT Library functions provide access to publish/subscribe using MQTT protocol. All of the publish functions below use QOS level 1. For more information about Medium One MQTT, check out the MQTT section.

Note that even though you define the device in the arguments, these functions only work if you are interacting with the same device that triggered the workflow. In other words, if device1 triggers a workflow, you cannot publish an event to device2 from that workflow.

Import

To use this library and its functions, you must use the import line at the beginning of your Base Python code.

import MQTT

Publish event to client

**MQTT.publish_event_to_client(device, payload, encoding='utf-8')**

Publishes the string payload encoded as encoding via the Medium One MQTT broker to the topic 1/<project_mqtt_id>/<user_mqtt_id>/<device>/event . To find <project_mqtt_id> and <user_mqtt_id>, refer to the Medium One MQTT Introduction.

Credit cost: 1

Parameters

device: str|unicode sub-division of topic to publish to.
payload: str|unicode data to publish.
encoding: str|unicode encoding of payload. Supported encodings: utf-8, latin1

Return Value

None

Example

Sample Code:

import MQTT

if IONode.get_input('heartrate')['event_data']['value'] > 140:
    MQTT.publish_event_to_client('smart-watch', 'Heartrate is too high!')

Exceptions

Exception

Any error communicating with broker

Publish update to client

MQTT.publish_update_to_client(device, update_type, payload, encoding='utf-8')

Publishes the string payload encoded as encoding via the Medium One MQTT broker to the topic 1/<project_mqtt_id>/<user_mqtt_id>/<device>/update/<update_type>. To find <project_mqtt_id> and <user_mqtt_id>, refer to the Medium One MQTT Introduction.

Credit cost: 1

Parameters

device: str|unicode sub-division of topic to publish to.
update_type: str|unicode sub-division of topic to publish to.
payload: str|unicode data to publish.
encoding: str|unicode encoding of payload. Supported encodings: utf-8, latin1

Return Value

None

Example

Sample Code:

import MQTT

MQTT.publish_update_to_client('smart-watch', 'name', 'smart')

Exceptions

Exception

Any error communicating with broker

Publish update to group

MQTT.publish_update_to_group(group_id, update_type, payload, encoding='utf-8')

Publishes the string payload encoded as encoding via the Medium One MQTT broker to the topic 2/<project_mqtt_id>/<group_id>/<update_type>. To find<project_mqtt_id>, refer to the Medium One MQTT Introduction.

Credit cost: 1

Parameters

group_id: str|unicode sub-division of topic to publish to.
update_type: str|unicode sub-division of topic to publish to.
payload: str|unicode data to publish.
encoding: str|unicode encoding of payload. Supported encodings: utf-8, latin1

Return Value

None

Example

Sample Code:

import MQTT

 MQTT.publish_update_to_group('watches', 'firmware', '2.1')

Exceptions

Exception

Any error communicating with broker