Proxy Server

proxy-server.js

#!/usr/bin/env node

const path = require('path');
const bin = path.basename(process.argv[1]);

const chalk = require('chalk');
const debug = require('debug')(bin);
const program = require('commander');
const httpProxy = require('http-proxy');

const defaultListenPort = 0;
const defaultTargetHost = 'localhost';
const defaultTargetPort = 80;

program
    .usage('[options]')
    .option('--listen-port <port>', 'listen port', defaultListenPort)
    .option('--target-host <host>', 'target host', defaultTargetHost)
    .option('--target-port <port>', 'target port', defaultTargetPort);

program.on('--help', () => {
    console.log('');
    console.log('  Examples:');
    console.log('');
    console.log(`    $ ${bin} --listen-port 8080 --target-host 127.0.0.1 --target-port 80`);
});

program.parse(process.argv);

const { listenPort, targetHost, targetPort } = program;

const proxy = httpProxy.createProxyServer({
    target: {
        host: targetHost,
        port: targetPort
    },
    localAddress: '127.0.0.1'
}).listen(listenPort);

const proxyServerAddress = proxy._server.address();

console.info(`Starting the proxy server at ${chalk.blueBright(proxyServerAddress.port)} and proxy requests to ${chalk.blueBright(`${targetHost}:${targetPort}`)}`);

proxy.on('proxyRes', function(proxyRes, req, res) {
    //if (req.headers.origin) {
    res.setHeader('access-control-allow-origin', '*');
    res.setHeader('access-control-allow-credentials', 'true');
    res.setHeader('access-control-max-age', 86400);
    //}

    if (req.headers['access-control-request-method']) {
        res.setHeader('access-control-allow-methods', req.headers['access-control-request-method']);
    }

    if (req.headers['access-control-request-headers']) {
        res.setHeader('access-control-allow-headers', req.headers['access-control-request-headers']);
    }

    if (req.method === 'OPTIONS') {
        res.send(200);
        res.end();
    }
});