Changes to support multiple WiFi networks.

[srt19170]

These changes allow you to specify multiple WiFi networks in config.cpp, and the code will try to connect to them in order of signal strength until it succeeds. If you specify only one network, the behavior is the same as the original code.

This may be useful in the case where the weather app will be moved around to different parts of a house where there are different networks, or between different houses, etc.

[lmarzen]

This is a great idea. I'll check it out when I have more time. Looks like it has some compile errors, though.

[srt19170]

src/client_utils.cpp:97:32: error: invalid application of 'sizeof' to incomplete type 'const String [][2]'
   int length = sizeof(WIFI_INFO) / sizeof(WIFI_INFO[0]);

Yeah, that's my bad. I was trying to avoid having to specify the length of the array holding the WiFi information. That may not be possible. I'll think about it.

[lmarzen]

I think the issue is that it is extern'ed. The reason I used a separate .cpp and extern everything rather than putting everything in the header is to reduce compile times when people are modifying settings and want to make a small configuration change and reupload. Any changes to the config header will require a bunch of files to be recompiled since it is included in quite a few places. This makes it the job of the linker to find and replace across translation units. I've considered moving everything to the header file, now that there is a collection of preprocessor macro settings that must be in the header. There are probably better configuration schemes that I should look into.

[srt19170]

Your fix seems to work, so thumbs-up from me!

[lmarzen]

I haven't gotten to look to closely at it yet. Can you tell me, how do these changes affect time spent awake?

[srt19170]

There's no impact if you only list one network.

If you list more than one network, there's an added "scan" to identify the available networks. You should then connect to the strongest of your listed networks.

If the strongest of your listed networks fails to connect (e.g., you've listed an incorrect password) you will fall through to the next available network, and so on. So in the worst case, you'll try all the networks you've listed and get them all wrong, resulting in as many connection attempts as you have listed networks.

[lmarzen]

Thanks, this seems acceptable. I'll review it this week.

[lmarzen]

I have been very busy with school work. Still haven't gotten a chance to look at this more closely. Thanks for your patience. It might be another week or two before I have time to check this out.

[lmarzen]

Just following up to let you know that I haven't forgotten about this. It may be another week yet until I get to it.

[lmarzen]

Going to close this PR. I am overhauling the project's configuration to enable configuration from a phone (default options will still be able set at compile time). I will add multiple networks as an option at that point. So, this feature is planned (for this summer) but will be implemented when the new setup process has been implemented.