MQTT Server: mqtt_server_app_cbs Struct Reference

Connection request from remote client - assess credentials. This routine presents, to the application, the information about the credentials of the remote client that is trying to establish a MQTT connection with the server. The application shall utilize these data in conjunction with its policy to either allow or deny connection to the server.

Should the application choose to allow the remote client to establish a MQTT connection, then it must provide in 'app-user' (place-holder), a handle that refers to the user of this connection. The server will provide this handle in follow-up routines to enable the application to refer to the associated connection in its implementation.

Parameters:

[in]	client_id	UTF8 based ID of the remote client - is set to NULL to indicate a zero-length client id.
[in]	user_name	UTF8 based user-name provided by the remote client. It is set to NULL if the client did not provide an user name
[in]	pass_word	UTF8 based pass-word provided by the remote client. It is set to NULL if the client did not provide a pass-word
[out]	app_usr	place-holder for application to provide a handle to the user of this specific connection / client.

Returns:

16bit value for the variable header in the CONNACK message. The MSB in the return value refers to the 8bit parameter of the acknowledge flags and must be set 0. The LSB in the return value refers to the 8bit 'return code' parameter in the CONNACK message and must be set accordingly.

Notify disconnection to the remote client. This routine is invoked by the server to declare to the application to a particular client has been terminated and follow-up, if needed, can now commence. This routine aids the application by indicating if an error condition had caused the disconnection.

Parameters:

[in]	app_usr	handle to refer to the user of the connection in the application
[in]	due2err	has the connection been closed due to an error?

Returns:

none

Indicate a PUBLISH message from the network. This routine presents, to the application, the topic and the related data along with other qualifiers published by one of the clients associated with this server. The application must enroll with the server the particular topic for which the data should be notified.

Parameters:

[in]	topic	UTF8 topic Name for which data has been published
[in]	data_buf	the published binary data for the topic
[in]	data_len	the length of the binary data
[in]	dup	is this a duplicate data from remote client?
[in]	qos	quality of service of the message / data
[in]	retain	should the server retain the data?

Returns:

none