x/net/http2: invalid Connection request header

[suconghou]

I meet the error and found the issue here

#15422

and the source code

https://github.com/golang/net/blob/6972930/http2/transport.go#L626-L634

as it said the keep-alive is valid

but why it is case-sensitive ,

many request failed due to Keep-Alive header

does HTTP/2 RFC say it must be case-sensitive ?

[bradfitz]

What is your issue?

How did you get this error?

HTTP/2 doesn't have connection-level headers, like the other bug says.

[suconghou]

@bradfitz I made a proxy for some urls

example code https://gist.github.com/suconghou/50dd30df10bd6faa2abe1805afe3216f

notice it works well then you use chrome , because chrome send keep-alive header

but some other software and services may send Keep-Alive header , eg: cloudflare , IE ( https://stackoverflow.com/questions/9650236/how-to-send-lower-case-keep-alive-header-through-httpwebrequest/30071784 the answers mentioned IE )

use curl -H "Connection:Keep-Alive" http://127.0.0.1:8080/ simulate this behavior

[suconghou]

@bradfitz

please replace this

(v != "" && v != "close" && v != "keep-alive") 

with

(v != "" && v != "close" && v != "keep-alive" && v != "Keep-Alive") 

in checkConnHeaders function

[crvv]

Please read https://httpwg.org/specs/rfc7230.html#rfc.section.6.1

A proxy or gateway MUST parse a received Connection header field before a message is forwarded and, for each connection-option in this field, remove any header field(s) from the message with the same name as the connection-option, and then remove the Connection header field itself (or replace it with the intermediary's own connection options for the forwarded message).

I don't know why Go accepts Connection: keep-alive, which I think is the same as Connection: Keep-Alive. But this is a bug in your proxy, not in http package.

I think it is better to use httputil.ReverseProxy for this.

[szuecs]

Doesn't it makes sense to handle this transparently?
I think Go should just drop the Connection header if H2 does not support Connection headers.
I see the same problem if I use plain http.Transport.RoundTrip(req) in case Connection: Keep-Alive is set and the backend called specified in the http.Request supports H2.

For me it sounds really weird to argue you should use httputil.ReverseProxy, instead of fixing this.

[gopherbot]

Change https://golang.org/cl/122588 mentions this issue: http2: compare Connection header value case-insensitively