router: store params in context only if it has contents

Author: julienschmidt

router.go

@@ -255,9 +255,11 @@ func (r *Router) Handle(method, path string, handle Handle) {
 func (r *Router) Handler(method, path string, handler http.Handler) {
 	r.Handle(method, path,
 		func(w http.ResponseWriter, req *http.Request, p Params) {
-			ctx := req.Context()
-			ctx = context.WithValue(ctx, ParamsKey, p)
-			req = req.WithContext(ctx)
+			if len(p) > 0 {
+				ctx := req.Context()
+				ctx = context.WithValue(ctx, ParamsKey, p)
+				req = req.WithContext(ctx)
+			}
 			handler.ServeHTTP(w, req)
 		},
 	)

router_test.go

@@ -502,6 +502,7 @@ func TestRouterLookup(t *testing.T) {
 
 func TestRouterParamsFromContext(t *testing.T) {
 	routed := false
+
 	wantParams := Params{Param{"name", "gopher"}}
 	handlerFunc := func(_ http.ResponseWriter, req *http.Request) {
 		// get params from request context
@@ -513,7 +514,20 @@ func TestRouterParamsFromContext(t *testing.T) {
 
 		routed = true
 	}
+
+	var nilParams Params
+	handlerFuncNil := func(_ http.ResponseWriter, req *http.Request) {
+		// get params from request context
+		params := ParamsFromContext(req.Context())
+
+		if !reflect.DeepEqual(params, nilParams) {
+			t.Fatalf("Wrong parameter values: want %v, got %v", nilParams, params)
+		}
+
+		routed = true
+	}
 	router := New()
+	router.HandlerFunc(http.MethodGet, "/user", handlerFuncNil)
 	router.HandlerFunc(http.MethodGet, "/user/:name", handlerFunc)
 
 	w := new(mockResponseWriter)
@@ -522,6 +536,13 @@ func TestRouterParamsFromContext(t *testing.T) {
 	if !routed {
 		t.Fatal("Routing failed!")
 	}
+
+	routed = false
+	r, _ = http.NewRequest(http.MethodGet, "/user", nil)
+	router.ServeHTTP(w, r)
+	if !routed {
+		t.Fatal("Routing failed!")
+	}
 }
 
 type mockFileSystem struct {