Add support for security system devices

[sumnerboy12]

https://developers.google.com/assistant/smarthome/guides/securitysystem

This would allow integration of a house alarm and using Google Assistant to "arm house alarm" etc.

[andrei-tatar]

The service already supports the trait and the device type.
It was contributed by Sebastian in this PR: andrei-tatar/nora-firebase-common#3

The only left thing is to add the node-red node and update the doc.

[sumnerboy12]

Brilliant - sorry didn't realise it was already in-progress. Only just found out about the wonders of Smart NORA - thanks for an awesome bit of software!

[andrei-tatar]

I guess the question is do we switch to an async flow for this one, being security critical?

Meaning, an arm command that comes from google outputs an arm command on the node output but doesn't immediately update the state.

[sumnerboy12]

I like the sound of this - I would much prefer state to be updated by the device itself, rather than assuming just because a command has been sent.

[sumnerboy12]

Is there a reason all nodes are not async, or at least provide an option for them to be? I would like my lock node to be async, and only have the state update on a successful action, based on feedback from the lock itself.

[andrei-tatar]

No good reason, mostly for simplicity.

[andrei-tatar]

Also there are 2 different ways going about async commands:

1. when a command is received, the node outputs the command, node-red handles it and it should pipe back into the node as a command response. All this time the command handler should be blocked. The problem is Google recommends the execution to take under 1 sec but this is now out of NORA's control (I mean NORA could timeout after 1 sec with an error code - device not responding or something similar).

2. Use follow-up responses. Meaning a command is outputed but now the handler is not blocked anymore and the device can come later with a follow-up response. The problem here is only a few traits support follow-up responses (LockUnlock, OpenClose).

[sumnerboy12]

Yeah that is a real shame more don't support the follow-up responses. Seems like the "right" and most accurate way to do things, even if only optionally (i.e. if you have the feedback loop in place).

[andrei-tatar]

@sumnerboy12 I released version v1.3.0-beta.0 of node-red-contrib-smartnora which includes a 1st version for the security system with ArmDisarm trait.
Let me know if you can have a look and provide any feedback.

[sumnerboy12]

Seems to be working well, thanks very much!