1 files changed, 87 insertions, 0 deletions

diff --git a/httputil/transport.go b/httputil/transport.go
new file mode 100644
index 0000000..fdad3b4
--- /dev/null
+++ b/httputil/transport.go
@@ -0,0 +1,87 @@
+// Copyright 2015 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 or at
+// https://developers.google.com/open-source/licenses/bsd.
+
+// This file implements a http.RoundTripper that authenticates
+// requests issued against api.github.com endpoint.
+
+package httputil
+
+import (
+        "net/http"
+        "net/url"
+)
+
+// AuthTransport is an implementation of http.RoundTripper that authenticates
+// with the GitHub API.
+//
+// When both a token and client credentials are set, the latter is preferred.
+type AuthTransport struct {
+        UserAgent          string
+        GithubToken        string
+        GithubClientID     string
+        GithubClientSecret string
+        Base               http.RoundTripper
+}
+
+// RoundTrip implements the http.RoundTripper interface.
+func (t *AuthTransport) RoundTrip(req *http.Request) (*http.Response, error) {
+        var reqCopy *http.Request
+        if t.UserAgent != "" {
+                reqCopy = copyRequest(req)
+                reqCopy.Header.Set("User-Agent", t.UserAgent)
+        }
+        if req.URL.Host == "api.github.com" && req.URL.Scheme == "https" {
+                switch {
+                case t.GithubClientID != "" && t.GithubClientSecret != "":
+                        if reqCopy == nil {
+                                reqCopy = copyRequest(req)
+                        }
+                        if reqCopy.URL.RawQuery == "" {
+                                reqCopy.URL.RawQuery = "client_id=" + t.GithubClientID + "&client_secret=" + t.GithubClientSecret
+                        } else {
+                                reqCopy.URL.RawQuery += "&client_id=" + t.GithubClientID + "&client_secret=" + t.GithubClientSecret
+                        }
+                case t.GithubToken != "":
+                        if reqCopy == nil {
+                                reqCopy = copyRequest(req)
+                        }
+                        reqCopy.Header.Set("Authorization", "token "+t.GithubToken)
+                }
+        }
+        if reqCopy != nil {
+                return t.base().RoundTrip(reqCopy)
+        }
+        return t.base().RoundTrip(req)
+}
+
+// CancelRequest cancels an in-flight request by closing its connection.
+func (t *AuthTransport) CancelRequest(req *http.Request) {
+        type canceler interface {
+                CancelRequest(req *http.Request)
+        }
+        if cr, ok := t.base().(canceler); ok {
+                cr.CancelRequest(req)
+        }
+}
+
+func (t *AuthTransport) base() http.RoundTripper {
+        if t.Base != nil {
+                return t.Base
+        }
+        return http.DefaultTransport
+}
+
+func copyRequest(req *http.Request) *http.Request {
+        req2 := new(http.Request)
+        *req2 = *req
+        req2.URL = new(url.URL)
+        *req2.URL = *req.URL
+        req2.Header = make(http.Header, len(req.Header))
+        for k, s := range req.Header {
+                req2.Header[k] = append([]string(nil), s...)
+        }
+        return req2
+}