[cln-grpc] Simplify auth flow on mobile devices

[bubelov]

I've been prototyping an Android app which uses cln-grpc plugin in order to connect to my Core Lightning node via Tor. Everything works like a charm so far, but the login flow looks a bit hardcore. As far as I understand, the client needs the following things:

• Tor hostname
• gRPC port
• Server cert
• Client cert
• Client private key

This is the first time I had to setup mTLS so I might be doing something wrong but it works and I doubt that it's possible to cut this list dramatically, which makes the whole process a usability nightmare =)

Are there any plans to introduce a standard for client auth credentials? It would be nice to bundle all the required data in a single QR code so the client can simply scan it in a single step. It would be trivial to adapt this standard in projects like RaspiBlitz. The plugin can probably fetch all the required data easily. I'm not sure about Tor hostname, but everything else should be in its scope.

Attaching the screenshots below:

[bubelov]

Figuring out correct IP address might be hard since there could be many of them, but even bundling the PEMs in a single QR would cut the number of scans from 4 to 1 or 2:

Currently, I have a hacky script which works well with RaspiBlitz, but it would be really nice if QR generation was supported directly by grpc plugin