sys_bus - Session Bus

2023-08-31

This feature subscribes to messages and publishes one-to-many broadcasts with multithreading, similar to an internal MQTT protocol.

Subscribe to Topics

sys_bus.subscribe

sys_bus.subscribe(topic, handler)

Parameter

  • topic – String or integer type. The topic to be subscribed to.
  • handler – Function type. Event handler function. This function will be called to handle the subscribed topics. This function has two parameters, topic and msg (See sys_bus.publish() for details).

Publish Topics

sys_bus.publish

sys_bus.publish(topic , msg)

Publishes messages. The server will receive the subscribed topics and process the message with multithreading.

Parameter

  • topic – String or integer type. The topic to be subscribed to.
  • msg – The published messages.

View Session Bus Registry

sys_bus.sub_table

sys_bus.sub_table(topic=None)

Views the subscription registry, including all topics and the subscribed functions.

Parameter

  • topic – String or integer type. Topics. If this parameter is specified, view the registry of the specified topic. If this parameter is omitted, view the registry of all topics.

Return Value

Dict or list type. The list or registry of the subscribed functions.

Unsubscribe from Topics

sys_bus.unsubscribe

sys_bus.unsubscribe(topic , cb=None)

Unsubscribes from the subscribed topics or a function under the topics. If only topic is specified, unsubscribe from the topics and all subscribed functions under the topics. If both topic and cb are specified, unsubscribe from the callback function under the subscribed topics.

Parameter

  • topic– String or integer type. The subscribed topics.
  • cb – Function type. Callback function. The function to be unsubscribed from. Unsubscribe from the subscribed topics if this parameter is omitted.

Return Value

True – Successful execution

False – Failed execution

Example

import sys_bus


def test(topic, msg):
    print("test ... topic = {} msg = {}".format(topic, msg))

# Subscribe
sys_bus.subscribe("test", test)
# Publish
sys_bus.publish("test", "this is a test msg")

#  test ... topic = test msg = this is a test msg

# Unsubscribe from the test function under the test topic
sys_bus.unsubscribe("test", test)

# Unsubscribe from all subscribed functions under the test topic
sys_bus.unsubscribe("test")