http-mitm-proxy example

http-mitm-proxy-example.js

const Proxy = require('http-mitm-proxy');
const proxy = Proxy();
const port = 8081;
const host = '0.0.0.0';

function appendToBody(chunk, s) {
  return new Buffer(chunk.toString().replace(/<\/body>/g, s + '</body>'));
}

proxy.onError(function(ctx, err) {
  console.error('proxy error:', err);
});

proxy.onRequest(function(ctx, callback) {
  if (ctx.clientToProxyRequest.url.indexOf('/embed/stream') == 0) {
    ctx.use(Proxy.gunzip);

    ctx.onResponseData(function(ctx, chunk, callback) {
      chunk = appendToBody(chunk, "<script>document.body.addEventListener('touchstart', () => {});</script>");
      console.log(chunk.toString());
      return callback(null, chunk);
    });
  }
  return callback();
});

proxy.onResponse(function(ctx, callback) {
  // Disable caching
  ctx.serverToProxyResponse.headers['cache-control'] = 'no-cache, no-store, must-revalidate';
  ctx.serverToProxyResponse.headers['pragma'] = 'no-cache';
  ctx.serverToProxyResponse.headers['expires'] = '0';
  delete ctx.serverToProxyResponse.headers['age'];
  delete ctx.serverToProxyResponse.headers['etag'];
  delete ctx.serverToProxyResponse.headers['date'];
  return callback(null);
});

console.log(`Start listening on ${host}:${port}`);

// Once ran, you can find the CA certificate in .http-mitm-proxy/certs/ca.pem
// that you can install into your local machine and don't forget to trust it.
// Then change your settings to use this as a http proxy.
proxy.listen({port, host});