refactor: flash messages framework (resolve #446)

middlewares/authenticate.go

@@ -22,10 +22,11 @@ var (
 )
 
 type AuthenticateMiddleware struct {
-	config           *conf.Config
-	userSrvc         services.IUserService
-	optionalForPaths []string
-	redirectTarget   string // optional
+	config               *conf.Config
+	userSrvc             services.IUserService
+	optionalForPaths     []string
+	redirectTarget       string // optional
+	redirectErrorMessage string // optional
 }
 
 func NewAuthenticateMiddleware(userService services.IUserService) *AuthenticateMiddleware {
@@ -46,6 +47,11 @@ func (m *AuthenticateMiddleware) WithRedirectTarget(path string) *AuthenticateMi
 	return m
 }
 
+func (m *AuthenticateMiddleware) WithRedirectErrorMessage(message string) *AuthenticateMiddleware {
+	m.redirectErrorMessage = message
+	return m
+}
+
 func (m *AuthenticateMiddleware) Handler(h http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		m.ServeHTTP(w, r, h.ServeHTTP)
@@ -73,6 +79,11 @@ func (m *AuthenticateMiddleware) ServeHTTP(w http.ResponseWriter, r *http.Reques
 			w.WriteHeader(http.StatusUnauthorized)
 			w.Write([]byte(conf.ErrUnauthorized))
 		} else {
+			if m.redirectErrorMessage != "" {
+				session, _ := conf.GetSessionStore().Get(r, conf.SessionKeyDefault)
+				session.AddFlash(m.redirectErrorMessage, "error")
+				session.Save(r, w)
+			}
 			http.SetCookie(w, m.config.GetClearCookie(models.AuthCookieKey))
 			http.Redirect(w, r, m.redirectTarget, http.StatusFound)
 		}