Support HTTP3

[muuvmuuv]

Describe the feature

Support for HTTP2/3 in order to be a replacement for Vite dev-server and other build tools.

Upstream: http-party/node-http-proxy#1237

Additional information

• Would you be willing to help implement this feature?

[pi0]

@SukkaW would you like to take this?

[SukkaW]

@SukkaW would you like to take this?

Sure, I will take a look at it when I have time.

[SukkaW]

Implementing an HTTP/2 server is kinda easy. But implementing an HTTP/2 client (enabling proxy HTTP/2 upstream) is very difficult.

I am considering using an existing HTTP/2 client (undici could be a good start? Don't know if undici.request supports HTTP/2 or not) for proxying HTTP/2 upstream support.

[pi0]

I think the most important part is that if the proxy request is "coming from an HTTP2 server," it can be proxied properly. Http2 requests have special headers starting with : that has to be handled.

Supporting proxy< h2 >target might be nice too maybe with undici but i think it is really not that important (h1 is way more stable for back proxy)

[pi0]

H2 support landed via #102