proxy.go raw

   1  // Copyright 2017 The Gorilla WebSocket Authors. All rights reserved.
   2  // Use of this source code is governed by a BSD-style
   3  // license that can be found in the LICENSE file.
   4  
   5  package websocket
   6  
   7  import (
   8  	"bufio"
   9  	"encoding/base64"
  10  	"errors"
  11  	"net"
  12  	"net/http"
  13  	"net/url"
  14  	"strings"
  15  )
  16  
  17  type netDialerFunc func(network, addr string) (net.Conn, error)
  18  
  19  func (fn netDialerFunc) Dial(network, addr string) (net.Conn, error) {
  20  	return fn(network, addr)
  21  }
  22  
  23  func init() {
  24  	proxy_RegisterDialerType("http", func(proxyURL *url.URL, forwardDialer proxy_Dialer) (proxy_Dialer, error) {
  25  		return &httpProxyDialer{proxyURL: proxyURL, forwardDial: forwardDialer.Dial}, nil
  26  	})
  27  }
  28  
  29  type httpProxyDialer struct {
  30  	proxyURL    *url.URL
  31  	forwardDial func(network, addr string) (net.Conn, error)
  32  }
  33  
  34  func (hpd *httpProxyDialer) Dial(network string, addr string) (net.Conn, error) {
  35  	hostPort, _ := hostPortNoPort(hpd.proxyURL)
  36  	conn, err := hpd.forwardDial(network, hostPort)
  37  	if err != nil {
  38  		return nil, err
  39  	}
  40  
  41  	connectHeader := make(http.Header)
  42  	if user := hpd.proxyURL.User; user != nil {
  43  		proxyUser := user.Username()
  44  		if proxyPassword, passwordSet := user.Password(); passwordSet {
  45  			credential := base64.StdEncoding.EncodeToString([]byte(proxyUser + ":" + proxyPassword))
  46  			connectHeader.Set("Proxy-Authorization", "Basic "+credential)
  47  		}
  48  	}
  49  
  50  	connectReq := &http.Request{
  51  		Method: http.MethodConnect,
  52  		URL:    &url.URL{Opaque: addr},
  53  		Host:   addr,
  54  		Header: connectHeader,
  55  	}
  56  
  57  	if err := connectReq.Write(conn); err != nil {
  58  		conn.Close()
  59  		return nil, err
  60  	}
  61  
  62  	// Read response. It's OK to use and discard buffered reader here becaue
  63  	// the remote server does not speak until spoken to.
  64  	br := bufio.NewReader(conn)
  65  	resp, err := http.ReadResponse(br, connectReq)
  66  	if err != nil {
  67  		conn.Close()
  68  		return nil, err
  69  	}
  70  
  71  	if resp.StatusCode != 200 {
  72  		conn.Close()
  73  		f := strings.SplitN(resp.Status, " ", 2)
  74  		return nil, errors.New(f[1])
  75  	}
  76  	return conn, nil
  77  }
  78