Angular `CORS` policy Eroro - node.js

Question

I’m using the MEAN stack (MongoDB, Express, Angular, and NodeJS).
There is a simple function to get data from an external API like this:
let api = 'https://thongtindoanhnghiep.co/api/city';
return this.http.get<any>(api).subscribe(res => { this.data = res; });
But whenever it sends a request, I get the following error:
"OPTIONS https://thongtindoanhnghiep.co/api/city 405 (Method Not Allowed)
Access to XMLHttpRequest at 'https://thongtindoanhnghiep.co/api/city' from origin 'http://localhost:4040' has been blocked by CORS policy: Response to preflight request doesn't pass access control check: It does not have HTTP ok status."
My Chrome has web security disabled, with the CORS extension installed, and my app is configured to enable CORS on the server side.
When I use Postman to do this, it is working well.

Answer 1

In node js you have fix this issue in 2 type
Type 1
install cors
npm install cors
var express = require('express')
var cors = require('cors')
var app = express()
app.use(cors())
// cors config
app.use(function (req, res, next) {
res.header("Access-Control-Allow-Origin", "*");
res.header("Access-Control-Allow-Methods", "GET,HEAD,OPTIONS,POST,PUT,DELETE");
res.header("Access-Control-Allow-Headers", "*");
next();
});
app.listen(8083, () => {
console.log('Server connected with 8083');
})
Type 2
npm install browser-sync --save
var fs = require('fs');
var http = require('http');
var https = require('https');
var privateKey = fs.readFileSync('node_modules/browser-sync/certs/server.key', 'utf8');
var certificate = fs.readFileSync('node_modules/browser-sync/certs/server.crt', 'utf8');
var credentials = {key: privateKey, cert: certificate};
var httpServer = http.createServer(app);
var httpsServer = https.createServer(credentials, app);
httpServer.listen(8080,()=>{
console.log('Server connected with 8080');
});
httpsServer.listen(8081,()=>{
console.log('Server connected with 8081');
});
In that way you provide express middleware to the native http/https server
If you want your app running on ports below 1024, you will need to use sudo command (not recommended) or use a reverse proxy (e.g. nginx, haproxy).

Answer 2

You can use this in your Node.js application entry point
var cors = require('cors')
app.use(cors())
Or
You can use response object to set the header
response.setHeader("Access-Control-Allow-Origin", "*");
response.setHeader("Access-Control-Allow-Headers", "Origin, X-Requested-With, Content-Type, Accept");
Hopefully this should solve the problem.