If you call the loop manually then you will need to create code to handle reconnects. e.g pseudo code below: while.īecause the loop is a blocking function I call it with a timeout the default timeout is 1 second. If you do this you must remember to call it regularly. You can also manually call the l oop() method in your program. You should stop the loop before you exit the script. The loop can be stopped by calling loop.stop(). The loop_forever() function also handles automatic reconnects. The loop_forever() method blocks the program, and is useful when the program must run indefinitely. To stop the loop use the loop_stop() method. It also handles re-connects automatically. The loop_start() starts a new thread, that calls the loop method at regular intervals for you. The Paho Python client provides three methods: See network loop in docs for function reference. The loop function will read this buffer and send any messages it finds. Outgoing messages and message acknowledgements are placed in the send buffer. Now instead of manually reading the receive buffer you just need to process the callbacks. See Understanding callbacks.įor example if it sees a CONNACK message it triggers the on_connect() callback. On the receive side it looks at the messages, and depending on the message type, it will trigger the appropriate callback function. The loop() function is a built in function that will read the receive and send buffers, and process any messages it finds. You could program the client to manually read the receive buffers but this would be tedious. The messages sit in this receive buffer waiting to be read by the client program. When new messages arrive at the Python MQTT client they are placed in a receive buffer. In this tutorial we will look at what it does, and why it is necessary. When writing code using the Paho Python client you would have had to use the loop() function.
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