Easy CORS/Reverse Proxy

ecrp.js

#!/usr/bin/env node
// ecrp.js - Easy CORS/Reverse Proxy
// SPDX-License-Identifier: MIT (https://ncurl.xyz/s/o_o6DVqIR)
// https://gist.github.com/supersonictw/cf01a30ed886c8763bdd8329c1115f8c
"use strict";

const cookieEncoder = (data) => {
  const cookies = [];
  for (const key in data) {
    const value = encodeURIComponent(data[key]);
    cookies.push(`${key}=${value}`);
  }
  return cookies.join("; ");
};

const config = {
  connection: {
    scheme: 'https',
    host: 'example.com',
  },
  reqOrigin: 'https://example.com',
  resOrigin: 'http://example.com',
  extendReqHeaders: {
    cookie: cookieEncoder({
      lang: "en",
    }),
    "x-requested-with": "ECRP",
  },
  extendResHeaders: {
    "x-powered-by": "ECRP",
  },
};

const http = require("node:http");
const https = require("node:https");

http.createServer((req, rsp) => {
  const options = {
    ...config.connection,
    path: req.url,
    method: req.method,
    headers: {
      ...req.headers,
      host: config.connection.host,
      origin: config.reqOrigin,
      referer: config.reqOrigin,
      connection: "close",
      ...config.extendReqHeaders
    },
    port: config.connection.port ||
      (config.connection.scheme === 'https' ? 443 : 80),
  };

  const client = config.connection.scheme === 'https' ? https : http;
  const proxy = client.request(options, (response) => {
    rsp.writeHead(response.statusCode, {
      ...response.headers,
      "access-control-allow-origin": config.resOrigin,
      "access-control-allow-credentials": "true",
      ...config.extendResHeaders
    });
    response.on("data", (chunk) => {
      rsp.write(chunk);
    });
    response.on("end", () => {
      rsp.end();
    });
  });

  proxy.once("error", (e) => {
    console.error(e);
    rsp.writeHead(500);
    rsp.end();
  });

  req.pipe(proxy);

  req.on('end', () => {
    proxy.end()
  });
}).listen(8000);

console.info("Proxy server running at http://localhost:8000/");