Node js CORS failure - node.js

Question

I have been trying to build a web application using NODE and React without Express router but I am getting a lot of issues with the CORS part since both node and react are running on different ports. I don't want to use express in this case since i want to use native http module provided by node, hence I am unable to use CORS middleware which is in the npm library.
I have tried every possible solution which would work for resolving the CORS issue but I am at a dead end now. I have shared my server side code below.
/*
* Main server file
*/
//Depenedencies
let https = require('https');
let url = require('url');
let fs = require('fs');
let handlers = require('./lib/handlers');
let stringDecoder = require('string_decoder').StringDecoder;
let decoder = new stringDecoder('utf-8');
//server object definition
let server = {};
//https certifications
server.certParams = {
'key': fs.readFileSync('../lib/Certificates/serverKey.key'),
'cert': fs.readFileSync('../lib/Certificates/serverCert.crt')
};
server.https = https.createServer(server.certParams, (req, res) => {
server.unifiedServer(req, res);
});
//main server
server.unifiedServer = (req, res) => {
//converting url to url object
let parsedUrl = url.parse("https://" + req.rawHeaders[1] + req.url, true);
//constructing required params for handlers
let method = req.method;
let route = parsedUrl.pathname;
let queryStringObject = parsedUrl.query;
let headers = req.headers;
//function specific params
let requestBodyString = "";
let chosenHandler;
let requestObject = {};
let responsePayload = {
'Payload': {},
'Status': ""
};
//streaming in the req body in case of post req
req.on("data", function(chunk) {
requestBodyString += chunk;
});
//this is called regardless of the method of the req
req.on("end", function() {
//this is specific to post req
requestBodyString += decoder.end();
requestBodyString = method == "POST" ? JSON.parse(requestBodyString) : {};
//the request object sent to the handlers
requestObject.method = method;
requestObject.reqBody = requestBodyString;
requestObject.queryObject = queryStringObject;
chosenHandler = server.handlers[route] ? server.handlers[route] : server.handlers.notFound;
let headers = {
"Access-Control-Allow-Origin" : "https://localhost:3000/",
"Access-Control-Allow-Methods" : "OPTIONS, POST, GET",
"Access-Control-Allow-Headers" : "Origin, Content-Type"
};
chosenHandler(requestObject)
.then((result) => {
//post handler call
responsePayload.Status = "SUCCESS";
responsePayload.Payload = result;
//send the data back
res.writeHead(200,headers);
res.write(JSON.stringify(responsePayload));
res.end();
}).catch((error) => {
//error handler
responsePayload.Status = "ERROR-->" + error;
//send the data back
res.writeHead(200,headers);
res.write(JSON.stringify(responsePayload));
res.end();
});
});
};
//router definition
server.handlers = {
'/login': handlers.login,
'/signup': handlers.signup,
'/checkUserName': handlers.checkUserName,
'/checkEmail': handlers.checkEmail,
'/notFound': handlers.notFound
};
//init function
server.init = () => {
//start the https server
//TODO--> Change this to handle changing port and env
server.https.listen(5000, function() {
console.log('The https server is listening on port 5000 in Development mode');
});
};
//export the module
module.exports = server;
I am making a post request to test the connection but I am getting this evertime:
Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://localhost:5000/login. (Reason: CORS request did not succeed).
Can anyone please tell me what am I doing wrong?

Answer 1

Set the "Access-Control-Allow-Origin" header in the response stream object.
Try with the below snippet -
server = http.createServer(function(req,res){
// Set CORS headers
res.setHeader('Access-Control-Allow-Origin', '*');
res.setHeader('Access-Control-Request-Method', '*');
res.setHeader('Access-Control-Allow-Methods', 'OPTIONS, GET');
res.setHeader('Access-Control-Allow-Headers', '*');
if ( req.method === 'OPTIONS' ) {
res.writeHead(200);
res.end();
return;
}
// ...
});
OR it that does not work, try using -
res.setHeader('Access-Control-Allow-Headers', req.header.origin);

Answer 2

Use this middle ware after let decoder = new stringDecoder('utf-8');
var express = require('express');
var app = express();
var allowCrossDomain = function (req, res, next) {
res.header('Access-Control-Allow-Origin', '*');
res.header('Access-Control-Allow-Methods', 'GET,PUT,POST,DELETE,OPTIONS');
res.header('Access-Control-Allow-Headers', 'Content-Type, Authorization, Content-Length, X-Requested-With');
res.header('Access-Control-Allow-Credentials', 'true');
// intercept OPTIONS method
if ('OPTIONS' == req.method) {
res.status(200).send();
} else {
next();
}
};
app.use(allowCrossDomain);
This is relevent for express framework.