[FEATURE] JS-Exposed APIs

[Matchlighter]

It would be really nice if there was an option that could enable access to certain app-features from the the JS running on the loaded page. It would be super useful to have at least the following functionality exposed:

• MQTT, publish & subscribe (or at least some way to read the MQTT settings for use with a JS MQTT client)
• Screen brightness, get & set
• Sensor data, read

This feature would need some sort of whitelist functionality so that the functionality will only be exposed to trusted domains.

[thanksmister]

Yeah, this something that the HA application does, it has a channel interface used to communicate from the web page to commands in the application. MQTT already has discovery, just enable in the settings. I don't know what's the difference for a JS MQTT client and a regular MQTT client, its not clear what you mean. I think you have two different features here, one is discovery which already exists, the other is JS commands from the web site, which do not. However, you didn't suggest any command you would use with JS from the web page, given that discovery already exists.

[Matchlighter]

It varies from discovery. The idea here is for WallPanel to expose an MQTT interface to the JS. For example, if WallPanel set window.wallpanel, it might be something like:

// Publishing
wallpaenl.mqtt_publish('some/topic', 'PAYLOAD')
// Subscribing
const unsubscribe = wallpanel.mqtt_subscribe('some/other/topic/#', (message) => {
  // Do something with message
})
// ... and maybe call unsubscibe() later if the JS no longer wants to listen to that topic.

There are multiple commands that I would want to use from the web page, but an example would be setBrightness. I'm running a custom JS app in WallPanel. It would be really nice if I could configure the app to (for example) set the screen brightness depending on the time of day, rather than having to configure some third- system to send an MQTT message to do that.

[thanksmister]

If your webpage is a JS app, can you just use the http server for commands directly from the webpage?

https://github.com/thanksmister/wallpanel-android/wiki/MQTT-and-HTTP-Commands