HttpRequest (web client) and HttpRequest (server): method and contentType doesn't exchange

Issue

The method and contentType parameters doesn’t exchange in HttpRequest (web client) and HttpRequest (server) in Dart.

I have the following code:

(Web Client)

var url = "http://127.0.0.1:8087";
String jsonString = JSON.encode(dadosRegistro[id]);
HttpRequest.request(url, method: "DELETE", sendData: jsonString, mimeType:  "application/json")
  .then((HttpRequest resp) {
     window.console.log(resp.response);
  }).catchError(tratarErro);

(Server)

HttpServer.bind('127.0.0.1', 8087).then((server) {
server.listen((HttpRequest request) {
  print(request.method);
  print(request.headers.contentType);
});

When the Web Client calls server, the result is the following:

OPTIONS
null

My expectative was:

DELETE
application/json

Am I doing anything wrong?

Thanks!

Solution

This is a CORS issue. The request you are receiving is actually the pre-flight request, sent by the browser to verify if the server can receive the actual request. You can see more about CORS here: http://www.html5rocks.com/en/tutorials/cors/

To see the expected result, you can change your server code to handle the pre-flight request:

 HttpServer.bind('127.0.0.1', 8087).then((server) {
 server.listen((HttpRequest request) {
   request.response.headers.add("Access-Control-Allow-Origin", "*");
   request.response.headers.add("Access-Control-Allow-Methods", "POST,GET,DELETE,PUT,OPTIONS");
   request.response.statusCode = HttpStatus.OK;
   if (request.method == "OPTIONS") {
     //pre-flight request
     request.response.close();
   } else {
     print(request.method);
     print(request.headers.contentType);
     request.response.close();
   }
 });

Answered By – luizmineo

Answer Checked By – Candace Johnson (FlutterFixes Volunteer)