modified wifi.py to use wifi.json files containing lists of networks

[prehensile]

Allows connections to wifi networks in >1 locations (say, home + work) without having to update wifi.json every time.

Requires a small modification to wifi.json: the root entity is now a list of dicts, rather than just a dict, e.g.
[{"ssid": "emfcamp-insecure"},{"ssid": "home-insecure"}]
(still supports the original format, though)

Has a corresponding PR on emfcamp/micropython to support the new format during bootstrap.

[mattbrejza]

Thanks for looking at this, its one thing we've been meaning to do.

Does this work on the home screen where connect() is used in a non-blocking way? Here, connect() is called, and is exited before the wifi gets a chance to complete the connect proceedure.

[thibault-ml]

Also, this is a bit brute force, where it's trying to connect to all known SSIDs until it manages to connect to a known one.

I think a better way would be to use list_aps() and lookup the SSID of each returned AP, and connecting to it if the SSID is one we have in wifi.json.

[marekventur]

could we check the list of currently visible ssids first and filter the ones out that are not in there?

[thibault-ml]

Agreed (this is also what I suggested in the PR conversation tab)

[prehensile]

@thibault-ml @marekventur yep, I was going to have a look at comparing with a list of visible ssids in the next iteration :) This way works for now, depends if we want to wait 'til the ssid checking is done to have multiple APs.

@mattbrejza it does work on the home screen, but it's a good point about the blocking calls - I haven't specifically tested that, maybe it happens to work at the moment by accident!

[thibault-ml]

I think it'd be good to have the code going through known APs only rather than connecting to all those we know about even if they are out of range. But then I'm not a maintainer of this repo, so not my decision. Just my 2cts.

[prehensile]

OK, I've made a few improvements. Should be safer for the non-blocking uses now (@mattbrejza) , and uses the list of visible ssids from list_aps() (thanks, @thibault-ml!).

I've also amended create_default_config() to write in the new format, and amended bootstrap.py to use the new format, and use visible ssids in the same way.

[prehensile]

Note there are some currently some wider issues with merging this into the firmware that are discussed in the PR on emfcamp/micropython.