Websocket over HTTP/2 support

[ckmichael8@…]

Hello,

Will NGINX ever support Websocket over HTTP/2?

​https://tools.ietf.org/html/rfc8441

[Maxim Dounin]

First of all, two basic things to understand:

1. nginx does not talk Websocket protocol by itself, but rather provides a way to proxy HTTP/1.1 connection upgrades to backends;
2. RFC 8441 defines a completely different way to establish websocket communication, using a CONNECT method.

Support for Websockets over HTTP/2 basically means that nginx will have to translate these CONNECT requests to HTTP/1.1 Upgrade requests somehow when proxying. While this might work, this doesn't look like a good solution.

Alternatively, we may consider passing such CONNECT requests as is to HTTP/2 backends (for example, when using grpc_pass), but this approach also have problems. In particular, this doesn't look compatible with HTTP/1.1 backends, which makes it hardly useful.

Overall, this is unlikely to happen unless there is a practical demand. For now it looks like there is no such demand.

For there record, it RFC 8441 currently seems to work somehow in Firefox (​https://bugzilla.mozilla.org/show_bug.cgi?id=1434137) and under a flag in Chrome (​https://www.chromestatus.com/feature/6251293127475200).

[stesaunde@…]

Now that HTTP/3 usage is exceeding HTTP/1.1 usage it looks like there is practical demand. Look at YARP:
​https://microsoft.github.io/reverse-proxy/articles/websockets.html

NGINX and Apache web servers making HTTP/2 the default would practically eliminate the remaining HTTP/1.1 usage on the Internet and with it all corresponding compatibility issues.

[liudongmiao@…]

Just implement RFC 8441 and test with Chrome and Firefox, http2 with a http/1.1 websocket backend.

However, as Chrome and Firefox doesn't support RFC 9220 (WebSockets over HTTP/3) yet, don't know how to implement.