fix cors filter (#1080)

transport/http/route_test.go

@@ -17,6 +17,17 @@ type User struct {
 	Name string `json:"name"`
 }
 
+func corsFilter(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodOptions {
+			log.Println("cors:", r.Method, r.RequestURI)
+			w.Header().Set("Access-Control-Allow-Methods", r.Method)
+			return
+		}
+		next.ServeHTTP(w, r)
+	})
+}
+
 func authFilter(next http.Handler) http.Handler {
 	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
 		// Do stuff here
@@ -37,7 +48,7 @@ func loggingFilter(next http.Handler) http.Handler {
 func TestRoute(t *testing.T) {
 	ctx := context.Background()
 	srv := NewServer(
-		Filter(loggingFilter),
+		Filter(corsFilter, loggingFilter),
 	)
 	route := srv.Route("/v1")
 	route.GET("/users/{name}", func(ctx Context) error {
@@ -141,4 +152,17 @@ func testRoute(t *testing.T, srv *Server) {
 	if u.Name != "bar" {
 		t.Fatalf("got %s want bar", u.Name)
 	}
+	// OPTIONS
+	req, _ = http.NewRequest("OPTIONS", base+"/users", nil)
+	resp, err = http.DefaultClient.Do(req)
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer resp.Body.Close()
+	if resp.StatusCode != 200 {
+		t.Fatalf("code: %d", resp.StatusCode)
+	}
+	if resp.Header.Get("Access-Control-Allow-Methods") != "OPTIONS" {
+		t.Fatal("cors failed")
+	}
 }

transport/http/server.go

@@ -121,7 +121,9 @@ func NewServer(opts ...ServerOption) *Server {
 	for _, o := range opts {
 		o(srv)
 	}
-	srv.Server = &http.Server{Handler: srv}
+	srv.Server = &http.Server{
+		Handler: FilterChain(srv.filters...)(srv),
+	}
 	srv.router = mux.NewRouter()
 	srv.router.Use(srv.filter())
 	return srv
@@ -154,7 +156,6 @@ func (s *Server) ServeHTTP(res http.ResponseWriter, req *http.Request) {
 
 func (s *Server) filter() mux.MiddlewareFunc {
 	return func(next http.Handler) http.Handler {
-		next = FilterChain(s.filters...)(next)
 		return http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
 			ctx, cancel := ic.Merge(req.Context(), s.ctx)
 			defer cancel()