add user middleware chain function (#1913)

* add user middleware chain function

* fix staticcheck SA4006

* chang code Implementation style

Co-authored-by: kemq1 <kemq1@spdb.com.cn>

rest/engine_test.go

@@ -229,6 +229,44 @@ func TestEngine_checkedMaxBytes(t *testing.T) {
 	}
 }
 
+func TestEngine_checkedChain(t *testing.T) {
+	var called int32
+	middleware1 := func() func(http.Handler) http.Handler {
+		return func(next http.Handler) http.Handler {
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				atomic.AddInt32(&called, 1)
+				next.ServeHTTP(w, r)
+				atomic.AddInt32(&called, 1)
+			})
+		}
+	}
+	middleware2 := func() func(http.Handler) http.Handler {
+		return func(next http.Handler) http.Handler {
+			return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+				atomic.AddInt32(&called, 1)
+				next.ServeHTTP(w, r)
+				atomic.AddInt32(&called, 1)
+			})
+		}
+	}
+
+	server := MustNewServer(RestConf{}, WithChain(middleware1(), middleware2()))
+	server.router = chainRouter{}
+	server.AddRoutes(
+		[]Route{
+			{
+				Method: http.MethodGet,
+				Path:   "/",
+				Handler: func(_ http.ResponseWriter, _ *http.Request) {
+					atomic.AddInt32(&called, 1)
+				},
+			},
+		},
+	)
+	server.ngin.bindRoutes(chainRouter{})
+	assert.Equal(t, int32(5), atomic.LoadInt32(&called))
+}
+
 func TestEngine_notFoundHandler(t *testing.T) {
 	logx.Disable()
 
@@ -343,3 +381,19 @@ func (m mockedRouter) SetNotFoundHandler(_ http.Handler) {
 
 func (m mockedRouter) SetNotAllowedHandler(_ http.Handler) {
 }
+
+type chainRouter struct{}
+
+func (c chainRouter) ServeHTTP(_ http.ResponseWriter, _ *http.Request) {
+}
+
+func (c chainRouter) Handle(_, _ string, handler http.Handler) error {
+	handler.ServeHTTP(nil, nil)
+	return nil
+}
+
+func (c chainRouter) SetNotFoundHandler(_ http.Handler) {
+}
+
+func (c chainRouter) SetNotAllowedHandler(_ http.Handler) {
+}