视频流中的导航，golang中的反向代理

Question

I'm testing a reverse proxy in go. Mainly for playing videos though underlying nginx and streaming videos from other backend servers.

Problem is when navigating through video. For example when playing with vlc through proxy - video starts normally, but stops when trying to navigate. But if i play this video directly from nginx - it works fine.

I expected that on navigation player would create new connection with Range: N- header, but there is no new connections, only when starting video again.

Question:

How does player navigates, when playing video stream? What requests it sends to server? Maybe i'm missing something in connection handling?

This is very basic version for testing, it streams video from local nginx, (local video url - http://localhost/31285611):

package main

import (
    "net/http"
)

func main() {
    (&proxy{}).start()
}

type proxy struct {
    // ...
}

func (p *proxy) start() {
    http.HandleFunc("/play", p.connection)
    http.ListenAndServe("localhost:8040", nil)
}

func (p *proxy) connection(w http.ResponseWriter, r *http.Request) {
    disconnect := make(chan bool, 1)
    go p.send(w, r, disconnect)

    // ...

    <-disconnect
}


func (p *proxy) send(rv http.ResponseWriter, rvq *http.Request, disconnect chan bool) {

    rq, _ := http.NewRequest("GET", "http://localhost/31285611", rvq.Body)
    rq.Header = rvq.Header

    rs, _ := http.DefaultClient.Do(rq)
    for k, v := range rs.Header {
        rv.Header().Set(k, v[0])
    }
    rv.WriteHeader(http.StatusOK)

    buf := make([]byte, 1024)

    // for testing sending only first part.
    for i := 0; i < 100000; i++ {
        n, e := rs.Body.Read(buf[0:])
        if n == 0 || e != nil {
            break
        }
        rv.Write(buf[0:])
    }

    disconnect <- true

}

Update (headers dump):

First player connection:

map[User-Agent:[VLC/2.0.0 LibVLC/2.0.0] Range:[bytes=0-] Connection:[close] Icy-Metadata:[1]]

Response from nginx, when creating connection in go:

map[Server:[nginx/1.3.4] Date:[Tue, 23 Apr 2013 13:29:00 GMT] Content-Type:[application/octet-stream] Content-Length:[8147855699] Last-Modified:[Tue, 21 Aug 2012 20:47:20 GMT] Etag:["5033f3d8-1e5a66953"] Content-Range:[bytes 0-8147855698/8147855699]]

Answer 1

I know it's not really answering your question (and I don't have enough points to comment yet, so sorry for providing this as an answer!) but have you tried using Go's built in http.ReverseProxy (http://golang.org/pkg/net/http/httputil/#ReverseProxy)?

There seems to be a nice, simple example here https://groups.google.com/forum/?fromgroups=#!topic/golang-nuts/1ufEw_IEVM4 which I've very slightly modified below:

package main

import (
    "log"
    "net/http"
    "net/http/httputil"
    "net/url"
)

func main() {
    proxy := httputil.NewSingleHostReverseProxy(&url.URL{Scheme: "http", Host: "www.google.com", Path: "/"})

    err := http.ListenAndServe(":8080", proxy)
    if err != nil {
        log.Fatal("ListenAndServe: ", err)
    }
}

See if that does the job.

Also, in the previously linked Google Groups discussion, there is mention of NginX having issues with chunked encoding. It might be worth checking if this is related.