Allow to connect as WiFi Client to existing networks

[dereulenspiegel]

As of now the cbpi firmware can either be connected via the Ethernet port or it can create it's own WiFi network to allow clients to access the Web interface.
But users should be able to configure the cbpi firmware so it can connect to existing WiFi networks.

[prash3r]

It could be done via a cbpi4 plugin and the config files for cbpi4. It would be easy to add WLAN_SSID and WLAN_PASSWORD to the cbpi4 config file and initiate the connection on startup. But but i dont think the WLAN credentials should be stored in the config forever in cleartext. Its never used on this machine ever again once the Pi connected to the network once. Maybe it will be used again when the config is imported to another Hardware. Even if its only WiFi passwords i dont like storing credentials like that. The credentials could also be stored in a seperate special text file that gets deleted after successful connection - from now on the Pi remembers the credentials anyway. If this file is present it could just connect and delete the file.

I think this problem should be solved with a cbpi4 plugin. So it can be used if needed - if you connect it via LAN cable you will never need it. That plugin should then add the WLAN credential parameters to the config and if there are credentials provided it should try to connect to the listed network on startup. You could even go further and open an AP if the Pi doesnt find any known networks like this https://raspberrypi.stackexchange.com/questions/100195/automatically-create-hotspot-if-no-network-is-available

Maybe it could be done in python with something like this: https://stackoverflow.com/questions/20470626/python-script-for-raspberrypi-to-connect-wifi-automatically. And we could even allow connecting to an existing WLAN from the AP while listing the existing networks in a drop down ... Can we connect to WLANs without having root privs?

Sorry for spamming this in your issue, i just wanted to let you know that i plan to look into this. Although i only plan to do it for cbpi4 and not cbpi3, but i guess it could be adapted for cbpi3 as well.

[dereulenspiegel]

Providing this via a plugin looks like nice longterm solution. Ideally I would this plugin communicate with wpa_supplicant and the network manager (by DBus or something) so that plugin ideally never stores any information itself, but is just a simple frontend for the linux wireless stack.
Short term I would think that a config file like for the hotspot mode would be sufficient together with some systemd-magic around conditionals unit activation.
I have to look closer at your link regarding the python wifi library, but that could be a good starting point.
Regarding root privileges I would not like to have a solution where CraftBeerPi itself requires root privileges. Right CBPi has its own user and group in this image and has only very limited and specific permissions to do the necessary things (like connecting to I2C, 1-Wire, GPIO, opening a port etc.).