golink: preserve query during HTTP -> HTTPS redirects

golink.go

@@ -384,7 +384,13 @@ func deleteLinkStats(link *Link) {
 // requests. It redirects all requests to the HTTPs version of the same URL.
 func redirectHandler(hostname string) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		http.Redirect(w, r, (&url.URL{Scheme: "https", Host: hostname, Path: r.URL.Path}).String(), http.StatusFound)
+		u := &url.URL{
+			Scheme:   "https",
+			Host:     hostname,
+			Path:     r.URL.Path,
+			RawQuery: r.URL.RawQuery,
+		}
+		http.Redirect(w, r, u.String(), http.StatusFound)
 	})
 }
 

golink_test.go

@@ -637,3 +637,16 @@ func TestNoHSTSShortDomain(t *testing.T) {
 		})
 	}
 }
+
+func TestHTTPSRedirectHandlerWithQuery(t *testing.T) {
+	h := redirectHandler("foobar.com")
+	r := httptest.NewRequest("GET", "http://example.com/?query=bar", nil)
+	w := httptest.NewRecorder()
+	h.ServeHTTP(w, r)
+	if w.Code != http.StatusFound {
+		t.Errorf("got %d; want %d", w.Code, http.StatusFound)
+	}
+	if w.Header().Get("Location") != "https://foobar.com/?query=bar" {
+		t.Errorf("got %q; want %q", w.Header().Get("Location"), "https://foobar.com/?query=bar")
+	}
+}