Requests and descriptions

In this Local API solution we have three different types of topics the main one - discovery topics listen for devices and their information and the State and Comand topics are parts of responses to discovery topics.

Discovery requests

Subscription Requirement

The user needs to subscribe to the following wildcard topic before initiating a search:

<API-ID>/+/+/+/config

• The + wildcard means any value at that level.

• This subscription ensures that the user listens to all configuration messages for all devices and gateways.

How It Relates to Discovery

1. The user publishes a discovery request.
   <API id>/search

2. The system processes the search and publishes configuration payloads as responses to:

   <API id>/<type>/<gateway-id>/<device-id>/config

3. Since the user has subscribed to <API-ID>/+/+/+/config, they will receive all search results (in the form of configuration payloads) without needing to subscribe individually to every possible topic.

State descriptions

As part of payload for discovered device (from discovery topic) is the state_topic. This is information is seperate for each entity.

When you subscribe to this topic you will receive updates for this device.

The payload on this topic is only the data, meaning that values that are NOT in the payload have unchanged value. Let’s say you have a light where the state update is brightness: 100 and the next update is then color_temp: 400, the brightness is still 100.

Comand descriptions

For devices that listen to commands you will also get a command_topic on which Connect will listen to commands sent to the device.

This is a part of the device’s config payload on the discovery topic. Changing an attributes value and sending it is as payload to this topic will relay a message to the device.

For more information on state and comand responses go to Description topics