refactor: log error when payload too large

error.go

@@ -363,12 +363,13 @@ func gatewayTimeout(rw http.ResponseWriter, r *http.Request) {
 func payloadTooLarge(rw http.ResponseWriter, r *http.Request) {
 	responseError(rw, r,
 		413,
-		"<br>The page you have requested is unavailable."+
-			"<br>Perhaps you are here because:"+
-			"<br><br><ul>"+
-			"<br>The request entity is larger than limits defined by server"+
-			"<br>Please change the request entity and try again."+
-			"</ul>",
+		`<br>The page you have requested is unavailable.
+		 <br>Perhaps you are here because:<br><br>
+		 <ul>
+			<br>The request entity is larger than limits defined by server.
+			<br>Please change the request entity and try again.
+		 </ul>
+		`,
 	)
 }
 

router.go

@@ -707,7 +707,9 @@ func (p *ControllerRegister) ServeHTTP(rw http.ResponseWriter, r *http.Request)
 
 	if r.Method != http.MethodGet && r.Method != http.MethodHead {
 		if BConfig.CopyRequestBody && !context.Input.IsUpload() {
+			// connection will close if the incoming data are larger (RFC 7231, 6.5.11)
 			if r.ContentLength > BConfig.MaxMemory {
+				logs.Error(errors.New("payload too large"))
 				exception("413", context)
 				goto Admin
 			}

router_test.go

@@ -726,7 +726,7 @@ func TestRouterEntityTooLargeCopyBody(t *testing.T) {
 	BConfig.CopyRequestBody = _CopyRequestBody
 	BConfig.MaxMemory = _MaxMemory
 
-	if w.Code != 413 {
+	if w.Code != http.StatusRequestEntityTooLarge {
 		t.Errorf("TestRouterRequestEntityTooLarge can't run")
 	}
 }