ALPN support

[gkc]

websocat doesn't currently send any ALPN info as part of the TLS handshake ... Is there any work planned to support ALPN?

[vi]

Pending Websocat4 already includes setting ALPN values (though currently without a nice UI and by default it is not set).

What is your use case for ALPN mode? HTTP2 is not currently supported anyway.

Note that you can workaround missing support in Websocat1 by using external program as TLS connector:

$ websocat -t - --ws-c-uri=wss://ws.vi-server.org/mirror ws-c:cmd:'openssl s_client -alpn http/1.1  -connect ws.vi-server.org:443 -quiet'

depth=2 C = US, O = Internet Security Research Group, CN = ISRG Root X1
verify return:1
depth=1 C = US, O = Let's Encrypt, CN = E5
verify return:1
depth=0 CN = ws.vi-server.org
verify return:1
sdf
sdf
adfadsfdsf
adfadsfdsf

[gkc]

That's very helpful @vi thank you!

My use case for ALPN is a service which wishes to handle communication via (a) http/1.1 upgrading to websocket (b) socket with a different protocol