net/http: add client option to retain the auth/cookie headers

src/net/http/client.go

@@ -104,6 +104,10 @@ type Client struct {
 	// RoundTripper implementations should use the Request's Context
 	// for cancellation instead of implementing CancelRequest.
 	Timeout time.Duration
+
+	// RetainHeaders indicates whether to keep the auth/cookie headers when redirect across different primary domains.
+	// For example, if you want to retain the auth/cookie headers after redirecting from a.com to b.com, set it to true.
+	RetainHeaders bool
 }
 
 // DefaultClient is the default Client and is used by Get, Head, and Post.
@@ -797,12 +801,18 @@ func (c *Client) makeHeadersCopier(ireq *Request) func(*Request) {
 		}
 
 		// Copy the initial request's Header values
-		// (at least the safe ones).
+		// (at least the safe ones when Client.RetainHeaders is false).
+		if !c.RetainHeaders {
 			for k, vv := range ireqhdr {
 				if shouldCopyHeaderOnRedirect(k, preq.URL, req.URL) {
 					req.Header[k] = vv
 				}
 			}
+		} else {
+			for k, vv := range ireqhdr {
+				req.Header[k] = vv
+			}
+		}
 
 		preq = req // Update previous Request with the current request
 	}