Skip heavy tasks when they are already running

[peteruithoven]

The following tasks are heavy and take a while. At the moment you can keep requesting them trough the api but this makes the api (uhttpd) quite unresponsive.

• [x] Sign-in
• [ ] Creating access point
• [ ] Connecting to network
• [ ] Update firmware

We should store the status in a separate file and have a check before running these tasks. When they are already running we should skip them.

Sign-in (which also happens when saving the settings) is the only one that is currently giving problems. The other ones are prevented in the Doodle3D client. So skipping these others would be a less important api improvement.

[peteruithoven]

I've made a general status utility that stores and retrieves status to and from files. Currently it's only used in signin, not to break something accidentally just for the release. It can now skip the signin when it's already running. The problem is that it's very easy to break, when the lua handler is used and the request is aborted (say by a timeout) the status stays at signing in and from then on will always skip signins. For this to work the cgi-bin instead of the lua handler should be used so that it can run independently and always make it to the idle state again.

Signin is called when it connects to a network in client mode and after saving settings. The second isn't currently a cgi-bin request because lua handler has a better performance. So I'll make the signin after saving settings a separate cgi-bin request.

[peteruithoven]

The client will now make a separate cgi-bin request to signin after the settings have bin saved.

Still todo:

• Creating access point
• Connecting to network
• Update firmware