Add configurable http client factory (fixes #120) (#121)

* new http client factory ready to install/override default http(s)
 * mv GitUploadPackServiceFactory to clients.common pkg
 * rename http.HTTPError to http.Err
 * rename http.HTTPAuthMethod to http.AuthMethod
 * add doc and examples/ usage
 * general improvements:
   - update install link in readme to v4 (example are already pointing v4)
   - fix indentation in package doc (styling for godoc.org)
   - use http.Status constants instead of integers
   - close leaked response body
   - rm named returns which stutter in doc
   - fix one format string
   - rm unnecessary if checks
   - documentation fixes

1 files changed, 59 insertions, 0 deletions

diff --git a/examples/custom_http_client/main.go b/examples/custom_http_client/main.go
new file mode 100644
index 0000000..f28590f
--- /dev/null
+++ b/examples/custom_http_client/main.go
@@ -0,0 +1,59 @@
+package main
+
+import (
+	"crypto/tls"
+	"net/http"
+	"time"
+
+	"github.com/fatih/color"
+
+	git "gopkg.in/src-d/go-git.v4"
+	"gopkg.in/src-d/go-git.v4/plumbing/client"
+	githttp "gopkg.in/src-d/go-git.v4/plumbing/client/http"
+)
+
+func main() {
+	// Create a custom http(s) client
+	customClient := &http.Client{
+		Transport: &http.Transport{
+			TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+		}, // accept any certificate (might be useful for testing)
+		Timeout: 15 * time.Second, // 15 second timeout
+		CheckRedirect: func(req *http.Request, via []*http.Request) error { // don't follow redirect
+			return http.ErrUseLastResponse
+		},
+	}
+	// Override http(s) default protocol to use our custom client
+	clients.InstallProtocol(
+		"https",
+		githttp.NewGitUploadPackServiceFactory(customClient))
+
+	// Create an in-memory repository
+	r := git.NewMemoryRepository()
+
+	const url = "https://github.com/git-fixtures/basic.git"
+
+	// Clone repo
+	if err := r.Clone(&git.CloneOptions{URL: url}); err != nil {
+		panic(err)
+	}
+
+	// Retrieve the branch pointed by HEAD
+	head, err := r.Head()
+	if err != nil {
+		panic(err)
+	}
+
+	// Print latest commit
+	commit, err := r.Commit(head.Hash())
+	if err != nil {
+		panic(err)
+	}
+	color.Green(commit.String())
+	// Output:
+	// commit 6ecf0ef2c2dffb796033e5a02219af86ec6584e5
+	// Author: Máximo Cuadros Ortiz <mcuadros@gmail.com>
+	// Date:   Sun Apr 05 23:30:47 2015 +0200
+	//
+	//    vendor stuff
+}