Access to XMLHttpRequest at 'localhost:3000/users' from origin 'http://localhost:6252-CodePudding

I am getting this error even though I have allowed CORS in my code. This one is in Node js:

app.use(cors());

app.get('/users', (req, res) => {
    res.set({
        'Access-Control-Allow-Headers': '*',
        'Access-Control-Allow-Methods': 'POST,GET,DELETE,PUT,OPTIONS'
    });

    User.find({}, function(err, users){
        

        if(err)
        {
            return res.status(500).send({err});
        }
        return res.send(users);
    });
});

I am just trying to do a GET request from http://localhost:3000/users using Flutter:

import 'package:retrofit/http.dart' as head;

@head.RestApi(baseUrl: "http://localhost:3000")
abstract class ApiClient {
  factory ApiClient(Dio dio, {String baseUrl}) = _ApiClient;

  @head.GET("/users")
  Future<User> getUsers();
}

Doing this GET request works just fine in Postman but it doesn't work in Flutter because of the CORS. Can anyone help with this?

CodePudding user response：

You only allowed Headers and Method, try adding Access-Control-Allow-Origin and assigning it to * or website URLs.

res.set({
        'Access-Control-Allow-Origin': '*',
        'Access-Control-Allow-Headers': '*',
        'Access-Control-Allow-Methods': 'POST,GET,DELETE,PUT,OPTIONS'
});