Use referer in error template

handlers/handlers.go

@@ -495,14 +495,19 @@ func DefaultHomeHandler() http.Handler {
 }
 
 func (m *rootMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	err := m.fn(w, r) // Call handler function
-	if err == nil {
+	var errData struct {
+		Error   error
+		Referer string
+	}
+	errData.Error = m.fn(w, r) // Call handler function
+	if errData.Error == nil {
 		return
 	}
 	// This is where our error handling logic starts.
 	if m.h.Config.LogLevel > config.LOG_LEVEL_OFF {
-		log.Printf("An error accured: %v", err) // Log the error.
+		log.Printf("An error accured: %v", errData.Error) // Log the error.
 	}
 
-	respondWithError(m.h, w, r, err)
+	errData.Referer = r.Header.Get("Referer")
+	respondWithError(m.h, w, r, errData)
 }