David K. Bainbridge | 215e024 | 2017-09-05 23:18:24 -0700 | [diff] [blame] | 1 | // Copyright 2011 The Go 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 proxy provides support for a variety of protocols to proxy network |
| 6 | // data. |
| 7 | package proxy // import "golang.org/x/net/proxy" |
| 8 | |
| 9 | import ( |
| 10 | "errors" |
| 11 | "net" |
| 12 | "net/url" |
| 13 | "os" |
| 14 | ) |
| 15 | |
| 16 | // A Dialer is a means to establish a connection. |
| 17 | type Dialer interface { |
| 18 | // Dial connects to the given address via the proxy. |
| 19 | Dial(network, addr string) (c net.Conn, err error) |
| 20 | } |
| 21 | |
| 22 | // Auth contains authentication parameters that specific Dialers may require. |
| 23 | type Auth struct { |
| 24 | User, Password string |
| 25 | } |
| 26 | |
| 27 | // FromEnvironment returns the dialer specified by the proxy related variables in |
| 28 | // the environment. |
| 29 | func FromEnvironment() Dialer { |
| 30 | allProxy := os.Getenv("all_proxy") |
| 31 | if len(allProxy) == 0 { |
| 32 | return Direct |
| 33 | } |
| 34 | |
| 35 | proxyURL, err := url.Parse(allProxy) |
| 36 | if err != nil { |
| 37 | return Direct |
| 38 | } |
| 39 | proxy, err := FromURL(proxyURL, Direct) |
| 40 | if err != nil { |
| 41 | return Direct |
| 42 | } |
| 43 | |
| 44 | noProxy := os.Getenv("no_proxy") |
| 45 | if len(noProxy) == 0 { |
| 46 | return proxy |
| 47 | } |
| 48 | |
| 49 | perHost := NewPerHost(proxy, Direct) |
| 50 | perHost.AddFromString(noProxy) |
| 51 | return perHost |
| 52 | } |
| 53 | |
| 54 | // proxySchemes is a map from URL schemes to a function that creates a Dialer |
| 55 | // from a URL with such a scheme. |
| 56 | var proxySchemes map[string]func(*url.URL, Dialer) (Dialer, error) |
| 57 | |
| 58 | // RegisterDialerType takes a URL scheme and a function to generate Dialers from |
| 59 | // a URL with that scheme and a forwarding Dialer. Registered schemes are used |
| 60 | // by FromURL. |
| 61 | func RegisterDialerType(scheme string, f func(*url.URL, Dialer) (Dialer, error)) { |
| 62 | if proxySchemes == nil { |
| 63 | proxySchemes = make(map[string]func(*url.URL, Dialer) (Dialer, error)) |
| 64 | } |
| 65 | proxySchemes[scheme] = f |
| 66 | } |
| 67 | |
| 68 | // FromURL returns a Dialer given a URL specification and an underlying |
| 69 | // Dialer for it to make network requests. |
| 70 | func FromURL(u *url.URL, forward Dialer) (Dialer, error) { |
| 71 | var auth *Auth |
| 72 | if u.User != nil { |
| 73 | auth = new(Auth) |
| 74 | auth.User = u.User.Username() |
| 75 | if p, ok := u.User.Password(); ok { |
| 76 | auth.Password = p |
| 77 | } |
| 78 | } |
| 79 | |
| 80 | switch u.Scheme { |
| 81 | case "socks5": |
| 82 | return SOCKS5("tcp", u.Host, auth, forward) |
| 83 | } |
| 84 | |
| 85 | // If the scheme doesn't match any of the built-in schemes, see if it |
| 86 | // was registered by another package. |
| 87 | if proxySchemes != nil { |
| 88 | if f, ok := proxySchemes[u.Scheme]; ok { |
| 89 | return f(u, forward) |
| 90 | } |
| 91 | } |
| 92 | |
| 93 | return nil, errors.New("proxy: unknown scheme: " + u.Scheme) |
| 94 | } |