net-proxy-httpconnect

golang.org/x/net/proxy supports proxying over SOCKS5 but it lacks support for HTTP CONNECT proxies (which are more common).

This package adds a HTTPCONNECT Dialer (like SOCKS5) to fix that gap.

Credits are not mine as most of it was taken from pending changes to golang codebase (this and that).
But as they have been under review for a few years, I've pulled them into their own package to be able to use them.

This was built mainly to add SSH over HTTP proxy support to boringproxy, it is a great project (not mine), check it out.

Usage

You can create the Dialer directly

package main

import (
	"log"
	"net/url"

	httpproxy "github.com/fopina/net-proxy-httpconnect/proxy"
)

func main() {
  proxyURL, err := url.Parse(*proxyPtr)
  if err != nil {
    log.Fatal("invalid proxy URL", err)
  }
  dialer, err := httpproxy.HTTPCONNECT(proxyURL, nil)
  ...
}

Or use it through FromEnvironment (effortlessly add support toboth SOCKS5 and this).
For this to work httpproxy.RegisterSchemes() needs to called somewhere before FromEnvironment.

package main

import (
	httpproxy "github.com/fopina/net-proxy-httpconnect/proxy"
	"golang.org/x/net/proxy"
)

func init() {
	httpproxy.RegisterSchemes()
}

func main() {
		dialer := proxy.FromEnvironment()
    ...
}

Examples

Check the example of how to use this with golang.org/x/crypto/ssh.

It does the same as an ssh [email protected] whatever as it was the easiest public SSH test I could think of to validate proxy usage!

No proxy, same as ssh [email protected] whatever:

$ go run examples/main.go $HOME/.ssh/id_rsa
2022/07/06 18:15:52 github.com closed connection as expected, for an invalid command. Output:
Invalid command: 'whatever'
  You appear to be using ssh to clone a git:// URL.
  Make sure your core.gitProxy config option and the
  GIT_PROXY_COMMAND environment variable are NOT set.

With proxy, if you don't have one, launch tinyproxy:

docker run --rm -d --name tinyproxy -p8888:8888 vimagick/tinyproxy

Now, the same as ssh -o ProxyCommand='nc -x localhost:8888 -X connect %h %p' [email protected]:

$ go run examples/main.go -proxy http://localhost:8888 $HOME/.ssh/id_rsa
2022/07/06 18:16:28 github.com closed connection as expected, for an invalid command. Output:
Invalid command: 'whatever'
  You appear to be using ssh to clone a git:// URL.
  Make sure your core.gitProxy config option and the
  GIT_PROXY_COMMAND environment variable are NOT set.

Or using environment variable ALL_PROXY

$ ALL_PROXY=http://localhost:8888 go run examples/main.go -env $HOME/.ssh/id_rsa
2022/07/06 18:16:34 github.com closed connection as expected, for an invalid command. Output:
Invalid command: 'whatever'
  You appear to be using ssh to clone a git:// URL.
  Make sure your core.gitProxy config option and the
  GIT_PROXY_COMMAND environment variable are NOT set.

If using tinyproxy (as recommended) to test, you can verify the connections went through it in the logs

...
CONNECT   Jul 06 18:16:34.193 [1]: Connect (file descriptor 5): 172.17.0.1
CONNECT   Jul 06 18:16:34.193 [1]: Request (file descriptor 5): CONNECT github.com:22 HTTP/1.1
...

TODO

This is WIP.

Existing interfaces should not change but new helper functions will be added (such as a modified version of fromEnvironment).