The rules engine can only process data that is sent to topics. This topic describes the data forwarding procedure and the data formats at different stages of data forwarding.

Custom topics

Custom topics are used to submit pass-through data of devices to IoT Platform. The structure of the data is not changed during data submission. The following figure shows the data forwarding procedure:

Custom topics

Topics for TSL communications

Data sent in topics for TSL communications is in the Alink JSON format. During data forwarding, the data is parsed based on the TSL and then processed by the SQL statement of the rules engine. For more information about data formats, see Data format. The following figure shows the data forwarding procedure:

Topics for TSL communications
Note During data forwarding, the params parameter in the payloads changes to the items parameter after the payloads are parsed based on the TSL.