A custom topic category covers the topics for all devices in a product. This topic describes how to define a custom topic category for a product and how to use custom topics.
Background information
Add a custom topic category
Manage topic categories
On the Topic Category tab, find a custom topic category. You can perform multiple operations on the topic category. The following table describes the operations.
Operation | Procedure |
---|---|
Edit |
|
Delete |
Warning After you delete a custom topic category, communication services that are related
to the custom topic category become unavailable. This way, your business is interrupted.
Proceed with caution.
|
Custom topics with one or more wildcard characters
If you set the Device Operation Authorizations parameter to Subscribe, IoT Platform allows you to specify the following wildcard characters in a topic. This feature allows a device to subscribe to multiple topics at the same time.
Wildcard character | Description |
---|---|
# | This wildcard character must be specified for the last field in a topic and can match
all field values at the current level and sub-levels.
For example, you create the |
+ | This wildcard character can match all field values at the current level.
For example, you create the |
A topic that includes one or more wildcard characters represents a set of topics. A device can subscribe to the topic. However, on the Topic List tab of the Device Details page, the Publish Message action is unavailable for the topic. You cannot send messages to the device by using the topic.
Use custom topics for communication
- From IoT Platform to devices
IoT Platform calls the Pub API operation to publish messages to a specified topic. Devices receive messages from IoT Platform by subscribing to the topic.
- From devices to IoT Platform
A device publishes messages to a custom topic. IoT Platform can receive messages from the device by using an Advanced Message Queuing Protocol (AMQP) server-side subscription or the data forwarding feature.
For more information about topic-based communication, see Use custom topics for communication.