Confluentinc middleware (#228)

Co-authored-by: Cody A. Ray <cody@confluent.io>

Author: fenollp

openapi3filter/validation_error_test.go

@@ -547,7 +547,7 @@ func (e *mockErrorEncoder) Encode(ctx context.Context, err error, w http.Respons
 	e.W = w
 }
 
-func runTest(t *testing.T, handler http.Handler, encoder ErrorEncoder, req *http.Request) *http.Response {
+func runTest_ServeHTTP(t *testing.T, handler http.Handler, encoder ErrorEncoder, req *http.Request) *http.Response {
 	h := &ValidationHandler{
 		Handler:      handler,
 		ErrorEncoder: encoder,
@@ -560,6 +560,18 @@ func runTest(t *testing.T, handler http.Handler, encoder ErrorEncoder, req *http
 	return w.Result()
 }
 
+func runTest_Middleware(t *testing.T, handler http.Handler, encoder ErrorEncoder, req *http.Request) *http.Response {
+	h := &ValidationHandler{
+		ErrorEncoder: encoder,
+		SwaggerFile:  "fixtures/petstore.json",
+	}
+	err := h.Load()
+	require.NoError(t, err)
+	w := httptest.NewRecorder()
+	h.Middleware(handler).ServeHTTP(w, req)
+	return w.Result()
+}
+
 func TestValidationHandler_ServeHTTP(t *testing.T) {
 	t.Run("errors on invalid requests", func(t *testing.T) {
 		httpCtx := context.WithValue(context.Background(), "pig", "tails")
@@ -569,7 +581,49 @@ func TestValidationHandler_ServeHTTP(t *testing.T) {
 
 		handler := &testHandler{}
 		encoder := &mockErrorEncoder{}
-		runTest(t, handler, encoder.Encode, r)
+		runTest_ServeHTTP(t, handler, encoder.Encode, r)
+
+		require.False(t, handler.Called)
+		require.True(t, encoder.Called)
+		require.Equal(t, httpCtx, encoder.Ctx)
+		require.NotNil(t, encoder.Err)
+	})
+
+	t.Run("passes valid requests through", func(t *testing.T) {
+		r := newPetstoreRequest(t, http.MethodGet, "/pet/findByStatus?status=sold", nil)
+
+		handler := &testHandler{}
+		encoder := &mockErrorEncoder{}
+		runTest_ServeHTTP(t, handler, encoder.Encode, r)
+
+		require.True(t, handler.Called)
+		require.False(t, encoder.Called)
+	})
+
+	t.Run("uses error encoder", func(t *testing.T) {
+		r := newPetstoreRequest(t, http.MethodPost, "/pet", bytes.NewBufferString(`{"name":"Bahama","photoUrls":"http://cat"}`))
+
+		handler := &testHandler{}
+		encoder := &ValidationErrorEncoder{Encoder: (ErrorEncoder)(DefaultErrorEncoder)}
+		resp := runTest_ServeHTTP(t, handler, encoder.Encode, r)
+
+		body, err := ioutil.ReadAll(resp.Body)
+		require.NoError(t, err)
+		require.Equal(t, http.StatusUnprocessableEntity, resp.StatusCode)
+		require.Equal(t, "[422][][] Field must be set to array or not be present [source pointer=/photoUrls]", string(body))
+	})
+}
+
+func TestValidationHandler_Middleware(t *testing.T) {
+	t.Run("errors on invalid requests", func(t *testing.T) {
+		httpCtx := context.WithValue(context.Background(), "pig", "tails")
+		r, err := http.NewRequest(http.MethodGet, "http://unknown-host.com/v2/pet", nil)
+		require.NoError(t, err)
+		r = r.WithContext(httpCtx)
+
+		handler := &testHandler{}
+		encoder := &mockErrorEncoder{}
+		runTest_Middleware(t, handler, encoder.Encode, r)
 
 		require.False(t, handler.Called)
 		require.True(t, encoder.Called)
@@ -582,7 +636,7 @@ func TestValidationHandler_ServeHTTP(t *testing.T) {
 
 		handler := &testHandler{}
 		encoder := &mockErrorEncoder{}
-		runTest(t, handler, encoder.Encode, r)
+		runTest_Middleware(t, handler, encoder.Encode, r)
 
 		require.True(t, handler.Called)
 		require.False(t, encoder.Called)
@@ -593,7 +647,7 @@ func TestValidationHandler_ServeHTTP(t *testing.T) {
 
 		handler := &testHandler{}
 		encoder := &ValidationErrorEncoder{Encoder: (ErrorEncoder)(DefaultErrorEncoder)}
-		resp := runTest(t, handler, encoder.Encode, r)
+		resp := runTest_Middleware(t, handler, encoder.Encode, r)
 
 		body, err := ioutil.ReadAll(resp.Body)
 		require.NoError(t, err)

openapi3filter/validation_handler.go

@@ -41,14 +41,32 @@ func (h *ValidationHandler) Load() error {
 }
 
 func (h *ValidationHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
-	if err := h.validateRequest(r); err != nil {
-		h.ErrorEncoder(r.Context(), err, w)
+	if handled := h.before(w, r); handled {
 		return
 	}
 	// TODO: validateResponse
 	h.Handler.ServeHTTP(w, r)
 }
 
+// Middleware implements gorilla/mux MiddlewareFunc
+func (h *ValidationHandler) Middleware(next http.Handler) http.Handler {
+	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if handled := h.before(w, r); handled {
+			return
+		}
+		// TODO: validateResponse
+		next.ServeHTTP(w, r)
+	})
+}
+
+func (h *ValidationHandler) before(w http.ResponseWriter, r *http.Request) (handled bool) {
+	if err := h.validateRequest(r); err != nil {
+		h.ErrorEncoder(r.Context(), err, w)
+		return true
+	}
+	return false
+}
+
 func (h *ValidationHandler) validateRequest(r *http.Request) error {
 	// Find route
 	route, pathParams, err := h.router.FindRoute(r.Method, r.URL)