RocketChat/Rocket.Chat

import type { IncomingMessage, RequestOptions, ServerResponse } from 'http';
import http from 'http';
import url from 'url';

import type polka from 'polka';

const isProdEnv = process.env.NODE_ENV === 'production';

const skipProxyPaths = [/^\/sockjs\/info\?cb=/, /^\/health/];

export function proxy(): (req: IncomingMessage, res: ServerResponse, next: polka.Next) => void {
    if (isProdEnv) {
        return (_req, _res, next) => next();
    }

    return (req, res, next) => {
        if (skipProxyPaths.some((regex) => regex.test(req.url || ''))) {
            return next();
        }

        req.pause();

        const options: RequestOptions = url.parse(req.url || '');
        options.headers = req.headers;
        options.method = req.method;
        options.agent = false;
        options.hostname = 'localhost';
        options.port = 3000;

        const connector = http.request(options, function (serverResponse) {
            serverResponse.pause();
            if (serverResponse.statusCode) {
                res.writeHead(serverResponse.statusCode, serverResponse.headers);
            }
            serverResponse.pipe(res);
            serverResponse.resume();
        });
        req.pipe(connector);
        req.resume();
    };
}