http.ReverseProxy

[Brian Ketelsen]

I must be doing it wrong. I'm trying to write a simple reverse proxy - accept connections on a port and proxy them to another host. This seems to be what http.ReverseProxy is made for.

package main

import "http"
import "log"

func main(){

proxy := http.NewSingleHostReverseProxy( &http.URL{Scheme:"http",Host:"www.brianketelsen.com",Path:"/"})

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

}

But no matter what I do, I get HTTP 411 "content length required" errors.

Help?

Brian

[Brad Fitzpatrick]

If I run that program it just hangs there forever, waiting for an HTTP request.

I suppose there was a repro step you forgot to include, probably involving an HTTP request.  I'll speculate that your request involved a POST with a chunked body, which your origin server can't handle:

$ telnet www.brianketelsen.com 80

Trying 66.228.56.168...

Connected to www.brianketelsen.com.

Escape character is '^]'.

POST / HTTP/1.1

Host: www.brianketelsen.com

Transfer-Encoding: chunked

HTTP/1.1 411 Length Required

Server: nginx/1.0.0

Date: Wed, 10 Aug 2011 17:27:20 GMT

Content-Type: text/html

Content-Length: 180

Connection: close

.... so the bug is your server's and/or the request you're sending.

nginx or whatever is behind it claims to be HTTP/1.1 but can't handle chunking as HTTP/1.1 requires.

You'll need to include the Content-Length, but Go isn't going to pre-emptively guess that your server is non-compliant and buffer an unknown amount of data into memory just to count it and send a Content-Length header.  Go's just following the specs and forwarding along the request.

- Brad

[Brian Ketelsen]

You assumed correctly. I poked around until I found a server that wasn't proxied/served by Nginx and got my simple reverse proxy to work. Thanks!

[Dave Cheney]

Yup, Nginx doesn't currently (I think there is a 3rd party patch)
support requests with chunked bodies (so technically it's not HTTP/1.1
compliant). Clients that tend to hit this issue are WebDAV clients
using PUTs for dynamically generated content.

Cheers

Dave

[Vasiliy G Tolstov]

Yes, Nginx now officialy not support chunked bodies, but patch is
pending for adding to upstream now.

[Dave Cheney]

Thanks Vasiliy, that is good to know.

[dli...@gmail.com]

It was a long time when you wrote this post, but I tested your code  and I had some errors. I want to add working version of your program.

package main

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

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)
        }
}


среда, 10 августа 2011 г., 23:35:48 UTC+7 пользователь Brian Ketelsen написал: