1 files changed, 44 insertions, 15 deletions

diff --git a/src/pkg/http/client.go b/src/pkg/http/client.go
index daba3a89b..d73cbc855 100644
--- a/src/pkg/http/client.go
+++ b/src/pkg/http/client.go
@@ -22,6 +22,16 @@ import (
 // Client is not yet very configurable.
 type Client struct {
 	Transport RoundTripper // if nil, DefaultTransport is used
+
+	// If CheckRedirect is not nil, the client calls it before
+	// following an HTTP redirect. The arguments req and via
+	// are the upcoming request and the requests made already,
+	// oldest first. If CheckRedirect returns an error, the client
+	// returns that error instead of issue the Request req.
+	//
+	// If CheckRedirect is nil, the Client uses its default policy,
+	// which is to stop after 10 consecutive requests.
+	CheckRedirect func(req *Request, via []*Request) os.Error
 }
 
 // DefaultClient is the default Client and is used by Get, Head, and Post.
@@ -109,7 +119,7 @@ func shouldRedirect(statusCode int) bool {
 }
 
 // Get issues a GET to the specified URL.  If the response is one of the following
-// redirect codes, it follows the redirect, up to a maximum of 10 redirects:
+// redirect codes, Get follows the redirect, up to a maximum of 10 redirects:
 //
 //    301 (Moved Permanently)
 //    302 (Found)
@@ -126,35 +136,33 @@ func Get(url string) (r *Response, finalURL string, err os.Error) {
 	return DefaultClient.Get(url)
 }
 
-// Get issues a GET to the specified URL.  If the response is one of the following
-// redirect codes, it follows the redirect, up to a maximum of 10 redirects:
+// Get issues a GET to the specified URL.  If the response is one of the
+// following redirect codes, Get follows the redirect after calling the
+// Client's CheckRedirect function.
 //
 //    301 (Moved Permanently)
 //    302 (Found)
 //    303 (See Other)
 //    307 (Temporary Redirect)
 //
-// finalURL is the URL from which the response was fetched -- identical to the
-// input URL unless redirects were followed.
+// finalURL is the URL from which the response was fetched -- identical
+// to the input URL unless redirects were followed.
 //
 // Caller should close r.Body when done reading from it.
 func (c *Client) Get(url string) (r *Response, finalURL string, err os.Error) {
 	// TODO: if/when we add cookie support, the redirected request shouldn't
 	// necessarily supply the same cookies as the original.
-	// TODO: set referrer header on redirects.
 	var base *URL
-	// TODO: remove this hard-coded 10 and use the Client's policy
-	// (ClientConfig) instead.
-	for redirect := 0; ; redirect++ {
-		if redirect >= 10 {
-			err = os.ErrorString("stopped after 10 redirects")
-			break
-		}
+	redirectChecker := c.CheckRedirect
+	if redirectChecker == nil {
+		redirectChecker = defaultCheckRedirect
+	}
+	var via []*Request
 
+	for redirect := 0; ; redirect++ {
 		var req Request
 		req.Method = "GET"
-		req.ProtoMajor = 1
-		req.ProtoMinor = 1
+		req.Header = make(Header)
 		if base == nil {
 			req.URL, err = ParseURL(url)
 		} else {
@@ -163,6 +171,19 @@ func (c *Client) Get(url string) (r *Response, finalURL string, err os.Error) {
 		if err != nil {
 			break
 		}
+		if len(via) > 0 {
+			// Add the Referer header.
+			lastReq := via[len(via)-1]
+			if lastReq.URL.Scheme != "https" {
+				req.Referer = lastReq.URL.String()
+			}
+
+			err = redirectChecker(&req, via)
+			if err != nil {
+				break
+			}
+		}
+
 		url = req.URL.String()
 		if r, err = send(&req, c.Transport); err != nil {
 			break
@@ -174,6 +195,7 @@ func (c *Client) Get(url string) (r *Response, finalURL string, err os.Error) {
 				break
 			}
 			base = req.URL
+			via = append(via, &req)
 			continue
 		}
 		finalURL = url
@@ -184,6 +206,13 @@ func (c *Client) Get(url string) (r *Response, finalURL string, err os.Error) {
 	return
 }
 
+func defaultCheckRedirect(req *Request, via []*Request) os.Error {
+	if len(via) >= 10 {
+		return os.ErrorString("stopped after 10 redirects")
+	}
+	return nil
+}
+
 // Post issues a POST to the specified URL.
 //
 // Caller should close r.Body when done reading from it.