From a quick glance, looks like maybe cmd/go needs to use http.ProxyFromEnvironment.

i tried to find if there is a spec for http.proxy, but found nothing.

Yes, we don't support SOCK5 proxies in the standard library and thus we don't support it in the cmd/go tool.

We have SOCK5 support elsewhere, so we could vendor it into std at least for use by cmd/go, but it's not clear how much it matters. Is SOCK5 still widely used?

@davecheney useful informations that i can found about http.proxy is http://unix.stackexchange.com/a/212972

@bradfitz In China, shadowsocks is used widely

cmd/go does use http.ProxyFromEnvironment, because http.DefaultTransport does.

http.ProxyFromEnvironment does not support socks5. @bradfitz, where is the socks5 code we have elsewhere? It seems like it should be a tiny amount of code (under 100 lines plus tests) to proxy TCP connections into socks5. Assuming it really is small, I would not object to putting that into the standard library, on by default. It's very useful combined with ssh -D. I used to use that and tsocks, but Go doesn't play well with tsocks if I remember correctly, and tsocks is a bit of a hack.

As @davecheney says, at the least we should give a better error. But it would be nice to add support.

@rsc, SOCK5 support is at https://godoc.org/golang.org/x/net/proxy#SOCKS5

@bruceauyeung Just suggest to use privoxy / squid alike tool to setup a local http proxy server over socks5 one to get workaround of this issue.

@bradfitz it would be useful if socks proxy could be supported. As to me it would also be ok if not as for the workaround I mentioned above.

@bruceauyeung Just suggest to use privoxy / squid alike tool to setup a local http proxy server over socks5 one to get workaround of this issue.

@iamzhout thanks for your tip. now i go get packages through a http proxy (XX-Net), although it's slow.

@bradfitz actually there is another issue #18519 which really bothers me a lot. Hope there would be a fix or workaround also.

@iamzhout it looks like your employer is MITM'ing your SSL communications.

Go get is just a wrapper over git, I recommend git cloning that repository directly.

@bruceauyeung, I do suggest you to give privoxy/squid a try, as the speed should be the same as to your socks5 one. and the configuration is really simple, take privoxy as an example, you just add below line to your /etc/privoxy/config file, and then do service privoxy restart, all done.

listen-address  0.0.0.0:12345
forward-socks5  /  your-socks5-ip:port  .

@bruceauyeung You may want this github.com/icexin/sockhttp. It's a small tool written in go that makes a HTTP proxy over SOCK5.

@icexin i'll give it a shot, thanks for your work!

Maybe, implementaion will be like below.

package main

import (
	"context"
	"io"
	"log"
	"net"
	"net/http"
	"os"

	"golang.org/x/net/proxy"
)

type dialer struct {
	addr   string
	socks5 proxy.Dialer
}

func (d *dialer) DialContext(ctx context.Context, network, addr string) (net.Conn, error) {
	// TODO: golang.org/x/net/proxy need to add DialContext
	return d.Dial(network, addr)
}

func (d *dialer) Dial(network, addr string) (net.Conn, error) {
	var err error
	if d.socks5 == nil {
		d.socks5, err = proxy.SOCKS5("tcp", d.addr, nil, proxy.Direct)
		if err != nil {
			return nil, err
		}
	}
	return d.socks5.Dial(network, addr)
}

func Socks5Proxy(addr string) *http.Transport {
	d := &dialer{addr: addr}
	return &http.Transport{
		DialContext: d.DialContext,
		Dial:        d.Dial,
	}
}

func main() {
	http.DefaultTransport = Socks5Proxy("127.0.0.1:1080")

	resp, err := http.Get("http://www.google.com/")
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()
	io.Copy(os.Stdout, resp.Body)
}

tested with server written in go https://github.com/armon/go-socks5

So, to add common interfaces between http_proxy and socks5, I guess we should not modify ProxyFromEnvironment. it's better to add new API for set-up proxy.

I could use this feature too, and I've been looking into implementing it.

This has probably been answered before, but how do I go about importing a golang.org package (such as golang_org/x/net/proxy) so that the net/http package can use it ? I know this would require creating a src/vendor/golang_org/x/net/proxy directory but I'm not sure if it needs any tracking metadata, if the import needs to be a separate commit, etc...

Prototype in https://go-review.googlesource.com/35488

CL https://golang.org/cl/35488 mentions this issue.

Change https://golang.org/cl/41031 mentions this issue: net/http: replace SOCKS client implementation