134 lines
3.1 KiB
Go
134 lines
3.1 KiB
Go
// Copyright 2011 The Go Authors. All rights reserved.
|
|
// Use of this source code is governed by a BSD-style
|
|
// license that can be found in the LICENSE file.
|
|
|
|
// Package proxy provides support for a variety of protocols to proxy network
|
|
// data.
|
|
package proxy // import "golang.org/x/net/proxy"
|
|
|
|
import (
|
|
"errors"
|
|
"net"
|
|
"net/url"
|
|
"os"
|
|
"sync"
|
|
)
|
|
|
|
// A Dialer is a means to establish a connection.
|
|
type Dialer interface {
|
|
// Dial connects to the given address via the proxy.
|
|
Dial(network, addr string) (c net.Conn, err error)
|
|
}
|
|
|
|
// Auth contains authentication parameters that specific Dialers may require.
|
|
type Auth struct {
|
|
User, Password string
|
|
}
|
|
|
|
// FromEnvironment returns the dialer specified by the proxy related variables in
|
|
// the environment.
|
|
func FromEnvironment() Dialer {
|
|
allProxy := allProxyEnv.Get()
|
|
if len(allProxy) == 0 {
|
|
return Direct
|
|
}
|
|
|
|
proxyURL, err := url.Parse(allProxy)
|
|
if err != nil {
|
|
return Direct
|
|
}
|
|
proxy, err := FromURL(proxyURL, Direct)
|
|
if err != nil {
|
|
return Direct
|
|
}
|
|
|
|
noProxy := noProxyEnv.Get()
|
|
if len(noProxy) == 0 {
|
|
return proxy
|
|
}
|
|
|
|
perHost := NewPerHost(proxy, Direct)
|
|
perHost.AddFromString(noProxy)
|
|
return perHost
|
|
}
|
|
|
|
// proxySchemes is a map from URL schemes to a function that creates a Dialer
|
|
// from a URL with such a scheme.
|
|
var proxySchemes map[string]func(*url.URL, Dialer) (Dialer, error)
|
|
|
|
// RegisterDialerType takes a URL scheme and a function to generate Dialers from
|
|
// a URL with that scheme and a forwarding Dialer. Registered schemes are used
|
|
// by FromURL.
|
|
func RegisterDialerType(scheme string, f func(*url.URL, Dialer) (Dialer, error)) {
|
|
if proxySchemes == nil {
|
|
proxySchemes = make(map[string]func(*url.URL, Dialer) (Dialer, error))
|
|
}
|
|
proxySchemes[scheme] = f
|
|
}
|
|
|
|
// FromURL returns a Dialer given a URL specification and an underlying
|
|
// Dialer for it to make network requests.
|
|
func FromURL(u *url.URL, forward Dialer) (Dialer, error) {
|
|
var auth *Auth
|
|
if u.User != nil {
|
|
auth = new(Auth)
|
|
auth.User = u.User.Username()
|
|
if p, ok := u.User.Password(); ok {
|
|
auth.Password = p
|
|
}
|
|
}
|
|
|
|
switch u.Scheme {
|
|
case "socks5":
|
|
return SOCKS5("tcp", u.Host, auth, forward)
|
|
}
|
|
|
|
// If the scheme doesn't match any of the built-in schemes, see if it
|
|
// was registered by another package.
|
|
if proxySchemes != nil {
|
|
if f, ok := proxySchemes[u.Scheme]; ok {
|
|
return f(u, forward)
|
|
}
|
|
}
|
|
|
|
return nil, errors.New("proxy: unknown scheme: " + u.Scheme)
|
|
}
|
|
|
|
var (
|
|
allProxyEnv = &envOnce{
|
|
names: []string{"ALL_PROXY", "all_proxy"},
|
|
}
|
|
noProxyEnv = &envOnce{
|
|
names: []string{"NO_PROXY", "no_proxy"},
|
|
}
|
|
)
|
|
|
|
// envOnce looks up an environment variable (optionally by multiple
|
|
// names) once. It mitigates expensive lookups on some platforms
|
|
// (e.g. Windows).
|
|
// (Borrowed from net/http/transport.go)
|
|
type envOnce struct {
|
|
names []string
|
|
once sync.Once
|
|
val string
|
|
}
|
|
|
|
func (e *envOnce) Get() string {
|
|
e.once.Do(e.init)
|
|
return e.val
|
|
}
|
|
|
|
func (e *envOnce) init() {
|
|
for _, n := range e.names {
|
|
e.val = os.Getenv(n)
|
|
if e.val != "" {
|
|
return
|
|
}
|
|
}
|
|
}
|
|
|
|
// reset is used by tests
|
|
func (e *envOnce) reset() {
|
|
e.once = sync.Once{}
|
|
e.val = ""
|
|
}
|