SIM800_MQTT

#AutoConnect CallBack function

• Use this function if you want to use autoconnect(and auto reconnect) facility
• This function is called whenever TCP connection is established (or re-established).

#connect function

• This function can be used to connect your client to MQTT broker.
• Use only if you do not use Auto connect functionality.
• Optionally you can use username, password, WILL topic and WILL Message.

#OnConnect CallBack function

• This call back function is called when MQTT connection is established.
• You can call subscription and publish functions inside it (according to your need).

publish function

• This function can be used to publish messages to different topics.
• You can select QoS levels and RETAIN flag according to your need.

subscribe function

• This function can be used to subscribe messages from different topics.

OnMessage CallBack function

• This callback function is called when messages are received from subscribed topics
• Topic, TopicLength, Message, MessageLength are the arguments of OnMessage callback function.
• Inside this, you can write your custom code.

#unsubscribe function

• This function can be used to unsubscribe from a previously subscribed topic.

#disconnect function

• This function can be used to disconnect your client from MQTT broker.

#available function

• return true when connection with mqtt brocker is existing

Other Features

• You can specify your KeepAlive duration while initializing.
• Ping requests are sent and received automatically.
• QoS 0,1,2

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