1// Copyright 2014 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 5package oauth2 6 7import ( 8 "errors" 9 "io" 10 "net/http" 11 "sync" 12) 13 14// Transport is an http.RoundTripper that makes OAuth 2.0 HTTP requests, 15// wrapping a base RoundTripper and adding an Authorization header 16// with a token from the supplied Sources. 17// 18// Transport is a low-level mechanism. Most code will use the 19// higher-level Config.Client method instead. 20type Transport struct { 21 // Source supplies the token to add to outgoing requests' 22 // Authorization headers. 23 Source TokenSource 24 25 // Base is the base RoundTripper used to make HTTP requests. 26 // If nil, http.DefaultTransport is used. 27 Base http.RoundTripper 28 29 mu sync.Mutex // guards modReq 30 modReq map[*http.Request]*http.Request // original -> modified 31} 32 33// RoundTrip authorizes and authenticates the request with an 34// access token. If no token exists or token is expired, 35// tries to refresh/fetch a new token. 36func (t *Transport) RoundTrip(req *http.Request) (*http.Response, error) { 37 if t.Source == nil { 38 return nil, errors.New("oauth2: Transport's Source is nil") 39 } 40 token, err := t.Source.Token() 41 if err != nil { 42 return nil, err 43 } 44 45 req2 := cloneRequest(req) // per RoundTripper contract 46 token.SetAuthHeader(req2) 47 t.setModReq(req, req2) 48 res, err := t.base().RoundTrip(req2) 49 if err != nil { 50 t.setModReq(req, nil) 51 return nil, err 52 } 53 res.Body = &onEOFReader{ 54 rc: res.Body, 55 fn: func() { t.setModReq(req, nil) }, 56 } 57 return res, nil 58} 59 60// CancelRequest cancels an in-flight request by closing its connection. 61func (t *Transport) CancelRequest(req *http.Request) { 62 type canceler interface { 63 CancelRequest(*http.Request) 64 } 65 if cr, ok := t.base().(canceler); ok { 66 t.mu.Lock() 67 modReq := t.modReq[req] 68 delete(t.modReq, req) 69 t.mu.Unlock() 70 cr.CancelRequest(modReq) 71 } 72} 73 74func (t *Transport) base() http.RoundTripper { 75 if t.Base != nil { 76 return t.Base 77 } 78 return http.DefaultTransport 79} 80 81func (t *Transport) setModReq(orig, mod *http.Request) { 82 t.mu.Lock() 83 defer t.mu.Unlock() 84 if t.modReq == nil { 85 t.modReq = make(map[*http.Request]*http.Request) 86 } 87 if mod == nil { 88 delete(t.modReq, orig) 89 } else { 90 t.modReq[orig] = mod 91 } 92} 93 94// cloneRequest returns a clone of the provided *http.Request. 95// The clone is a shallow copy of the struct and its Header map. 96func cloneRequest(r *http.Request) *http.Request { 97 // shallow copy of the struct 98 r2 := new(http.Request) 99 *r2 = *r 100 // deep copy of the Header 101 r2.Header = make(http.Header, len(r.Header)) 102 for k, s := range r.Header { 103 r2.Header[k] = append([]string(nil), s...) 104 } 105 return r2 106} 107 108type onEOFReader struct { 109 rc io.ReadCloser 110 fn func() 111} 112 113func (r *onEOFReader) Read(p []byte) (n int, err error) { 114 n, err = r.rc.Read(p) 115 if err == io.EOF { 116 r.runFunc() 117 } 118 return 119} 120 121func (r *onEOFReader) Close() error { 122 err := r.rc.Close() 123 r.runFunc() 124 return err 125} 126 127func (r *onEOFReader) runFunc() { 128 if fn := r.fn; fn != nil { 129 fn() 130 r.fn = nil 131 } 132} 133