http: add Request.SetBasicAuth method

R=golang-dev, dsymonds, rsc
CC=golang-dev
https://golang.org/cl/4543050

src/pkg/http/request.go

@@ -12,6 +12,7 @@ import (
 	"bufio"
 	"crypto/tls"
 	"container/vector"
+	"encoding/base64"
 	"fmt"
 	"io"
 	"io/ioutil"
@@ -479,6 +480,18 @@ func NewRequest(method, url string, body io.Reader) (*Request, os.Error) {
 	return req, nil
 }
 
+// SetBasicAuth sets the request's Authorization header to use HTTP
+// Basic Authentication with the provided username and password.
+//
+// With HTTP Basic Authentication the provided username and password
+// are not encrypted.
+func (r *Request) SetBasicAuth(username, password string) {
+	s := username + ":" + password
+	buf := make([]byte, base64.StdEncoding.EncodedLen(len(s)))
+	base64.StdEncoding.Encode(buf, []byte(s))
+	r.Header.Set("Authorization", "Basic "+string(buf))
+}
+
 // ReadRequest reads and parses a request from b.
 func ReadRequest(b *bufio.Reader) (req *Request, err os.Error) {
 

src/pkg/http/request_test.go

@@ -173,6 +173,14 @@ func TestRedirect(t *testing.T) {
 	}
 }
 
+func TestSetBasicAuth(t *testing.T) {
+	r, _ := NewRequest("GET", "http://example.com/", nil)
+	r.SetBasicAuth("Aladdin", "open sesame")
+	if g, e := r.Header.Get("Authorization"), "Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ=="; g != e {
+		t.Errorf("got header %q, want %q", g, e)
+	}
+}
+
 func TestMultipartRequest(t *testing.T) {
 	// Test that we can read the values and files of a 
 	// multipart request with FormValue and FormFile,