x/net/http2: support CONNECT method

[ayanamist]

According to h2 spec https://httpwg.github.io/specs/rfc7540.html#CONNECT
If i want to implement a h2 proxy like nghttpx in golang, i have to use low-level h2 stream to send and receive data frame while multiplexing other normal get/post requests, but i found it can not be archieved in current h2 support.
Is there a way to expose such thing?

[bradfitz]

See #13444 (comment)

I think that's all you have to do. You can stay in high-level Go and not think about frames.

We don't have any tests that Go's http2 server even accepts such CONNECT requests, though. It sounds like it could just work, though.

[bradfitz]

Assigning to me to write a test for receiving and correctly mapping h2 CONNECT requests into *http.Requests.

[gopherbot]

CL https://golang.org/cl/18266 mentions this issue.

[gopherbot]

CL https://golang.org/cl/18269 mentions this issue.

[ayanamist]

@bradfitz I see changes, but i still can not use h2 client to proceed CONNECT request, when such request get a response, it needs to behave as a net.Conn to send & receive data like a socket. When used in http 1.1, we can use Hijacker to archive this, but i don't see such implementation in h2 client.

[bradfitz]

With h2 you don't need to hijack. Just read and write from the provided ResponseWriter. See the first link I provided above for an example.

[ayanamist]

Oh i see the example which use io.Pipe, thank you!

[lysu]

Hi~ @bradfitz I meet some problem like ayanamist, and want to implement a h2 proxy, too.... - -!

base on http://httpwg.org/specs/rfc7540.html#CONNECT and above comment..maybe we should do something like this? (without something like hijack????)

handler := func(rw http.ResponseWriter, req *http.Request) {
    if req.Method == "CONNECT" {
        // 1. receive CONNECT request..
        fmt.Println("Handle https")

        // 2. establishes a TCP connection to the server identified in the :authority
        remoteConn, err := net.Dial("tcp", req.Host)
        if err != nil {
            panic(err)
        }

        // 3. sends a HEADERS frame containing a 2xx series status code to the client, as defined in [RFC7231], Section 4.3.6
        rw.WriteHeader(http.StatusOK)

        // 4. transmitted DATA between client and TCP server
        go Pipe(&clientConn{Reader: req.Body, Writer: rw}, remoteConn)
    } else {
        fmt.Println("Handle as http")
        //...
    }
}

but, when we try proxy Chrome to this code using h2...it doesn't work

in chrome://net-internals see some log like this..

t=   27 [st=    0] +HTTP2_SESSION  [dt=42430]
                    --> host = "www.sulicc.com:443"
                    --> proxy = "DIRECT"
t=   27 [st=    0]    HTTP2_SESSION_INITIALIZED
                      --> protocol = "h2"
                      --> source_dependency = 546424 (SOCKET)
t=   27 [st=    0]    HTTP2_SESSION_SEND_SETTINGS
                      --> settings = ["[id:3 flags:0 value:1000]","[id:4 flags:0 value:6291456]"]
t=   27 [st=    0]    HTTP2_STREAM_UPDATE_RECV_WINDOW
                      --> delta = 15663105
                      --> window_size = 15728640
t=   27 [st=    0]    HTTP2_SESSION_SENT_WINDOW_UPDATE_FRAME
                      --> delta = 15663105
                      --> stream_id = 0
t=   27 [st=    0]    HTTP2_SESSION_SEND_HEADERS
                      --> fin = false
                      --> :method: CONNECT
                          :authority: imququ.com:443
                          user-agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10_11_4) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.112 Safari/537.36
                      --> priority = 4
                      --> stream_id = 1
                      --> unidirectional = false
t=   27 [st=    0]    HTTP2_SESSION_RECV_SETTINGS
                      --> clear_persisted = false
                      --> host = "www.sulicc.com:443"
t=   27 [st=    0]    HTTP2_SESSION_RECV_SETTING
                      --> flags = 0
                      --> id = 5
                      --> value = 1048576
t=   27 [st=    0]    HTTP2_SESSION_RECV_SETTING
                      --> flags = 0
                      --> id = 3
                      --> value = 250
t=   27 [st=    0]    HTTP2_SESSION_RECV_SETTING
                      --> flags = 0
                      --> id = 6
                      --> value = 1048896
t= 1056 [st= 1029]    HTTP2_SESSION_RECV_HEADERS
                      --> fin = true
                      --> :status: 200
                          content-type: text/plain; charset=utf-8
                          content-length: 0
                          date: Thu, 14 Apr 2016 17:34:28 GMT
                      --> stream_id = 1
t= 1056 [st= 1029]    HTTP2_SESSION_RECV_DATA
                      --> fin = true
                      --> size = 0
                      --> stream_id = 1
t= 1056 [st= 1029]    HTTP2_SESSION_RST_STREAM
                      --> description = ""
                      --> status = 5
                      --> stream_id = 1
t= 1056 [st= 1029]    HTTP2_STREAM_ERROR
                      --> description = "SPDY stream closed with status: 5"
                      --> status = -337
                      --> stream_id = 1 

After CONNECT, it receive HEADERS

t= 1056 [st= 1029]    HTTP2_SESSION_RECV_HEADERS
                      --> fin = true
                      --> :status: 200
                          content-type: text/plain; charset=utf-8
                          content-length: 0
                          date: Thu, 14 Apr 2016 17:34:28 GMT
                      --> stream_id = 1 

then HTTP2_SESSION_RECV_DATA...and browser doesn't send any more data....

In http://httpwg.org/specs/rfc7231.html#CONNECT, it said

A server MUST NOT send any Transfer-Encoding or Content-Length header fields in a 2xx (Successful) response to CONNECT. A client MUST ignore any Content-Length or Transfer-Encoding header fields received in a successful response to CONNECT.

but rw.WriteHeader(http.StatusOK) still write a header content-length: 0... maybe it's a question?

without hijack, how can we write only httpcode and without header... just "HTTP/1.0 200 Connection established\r\n\r\n"?

thank you~

[bradfitz]

Sorry, this bug is closed. If you have a bug report, please file a new bug with a complete repro and a description of the bug. General questions should go to https://golang.org/wiki/Questions.

[bradfitz]

In #17227 (comment), @ayanamist thinks this bug still isn't solved. That was not my impression.

Can you not use http.Transport to do a CONNECT request with a io.Pipe Request.Body and simultaneously write to it while reading from the Response.Body?