POST AJAX request denied - CORS?

Question

I have setup CORS on my node.js server on port 5000 as follows:

var app = express();

app.use(cors()); //normal CORS
app.options('*', cors()); //preflight 

app.post('/connect', function(req, res) { 
    console.log("Connection request received !")
});

var port = 5000;
app.listen(port, function () {
    console.log('Listening on port '+port);
});

I am now trying to send AJAX POST requests using JQuery like so, in a static web page open from my hard disk :

var xhr = $.post({
            url: 'http://localhost:5000/connect',
            complete: function() {
                console.log("done !")
            },
            crossDomain: true
        });

xhr.fail(function(xhr, status, error){
    alert(error)
})

The complete function is never called, and the only alert I get is an alert from the XHR fail handler, containing the following error :

NS_ERROR_DOM_BAD_URI: Access to restricted URI denied

I think CORS is well-configured, what am I missing ?

---

EDIT : for those in my case, the best solution I could find was to send the page from the server :

app.use(express.static('web'))

app.get("/", function(req, res) {
    res.sendFile(__dirname + '/web/HTML/index.html');
});

Answer 1

This is the code I am using. It is located in my app.js file

app.all("/*", function (req, res, next) {

  res.header("Access-Control-Allow-Origin", req.headers.origin);
  res.header("Access-Control-Allow-Credentials",true);
  res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
  res.header('Access-Control-Allow-Headers', 'Content-Type,Accept,X-Access-Token,X-Key,Authorization,X-Requested-With,Origin,Access-Control-Allow-Origin,Access-Control-Allow-Credentials');
  if (req.method === 'OPTIONS') {
    res.status(200).end();
  } else {
    next();
  }
});

Answer 2

I've never used cors() so I can't speak to that piece. But you could manually allow cross origin resource sharing by setting up the node.js headers.

Add This Pre-Route on All Requests

app.route('*')
   .all(function(req, res, next) {
     res.header('Access-Control-Allow-Methods', 'POST, GET, PUT, DELETE, OPTIONS');
     res.header('Access-Control-Allow-Origin', '*');
     res.header('Access-Control-Allow-Headers', 'X-API-TOKEN, Content-Type, Authorization, Content-Length, X-Requested-Wit
h');
   next();
})

This should work.

Answer 3

CORS doesn't work using the file protocol because there is no server there to send back the requisite headers. Your solution of using a server is the only way to get CORS to work.

Answer 4

I have a project that use cors.

The node code used is just:

const cors = require('cors');
const express = require('express');
const app = express();

app.use(cors());

/* Connect/other routes here */

The jquery code look a litte different:

$.post('http://localhost:5000/connect', {}).done( () => {
  // Request complete
}).fail((jqXHR) => {
  // Request failed 
});