Example for protocol.interceptStreamProtocol()

example.js

const r = require('request');
const zlib = require('zlib');
const text = require('text-encoding');
const stream = require('stream');

var interceptCallback = async (request: any, callback: any) => {
  console.log(`intercepted ${request.method} ${request.url}`);

  // TODO: support multiple upload data's
  var options = {
    method: request.method,
    url: request.url,
    headers: request.headers,
    body: (request.uploadData && request.uploadData[0]) ? request.uploadData[0].bytes : undefined,
    encoding: null,
    gzip: false,
    followRedirect: false,
  };

  r(options, async (error: any, response: any, body: any) => {
    const contentType = response ? (response.headers['Content-Type'] || response.headers['content-type']) : undefined;
    if (!contentType || (contentType.indexOf('text/javascript') < 0 && contentType.indexOf('application/javascript') < 0)) {
      console.log(`ignoring 'callback', used 'response'`);
      return;
    }

    const contentEncoding = response ? (response.headers['Content-Encoding'] || response.headers['content-encoding']) : undefined;

    let source = body;
    if (!error && response.statusCode === 200 && contentType) {
      if (contentEncoding === 'gzip') {
        console.log(`decoding GZIP response`);
        body = zlib.gunzipSync(body);
      }

      if (contentType.indexOf('text/javascript') >= 0 || contentType.indexOf('application/javascript') >= 0) {
        source = (new text.TextDecoder()).decode(body);
        // make changes
      }

      if (contentEncoding === 'gzip') {
        source = zlib.gzipSync(source);
      }
    }
    else {
      console.log(`did not modify response (error, non-200 status code, or no content type)`);
    }

    var s = new stream.PassThrough();
    s.end(source);

    callback({
      statusCode: response ? response.statusCode : undefined,
      headers: response ? response.headers : undefined,
      data: s,
    });
  })
  .on('response', (response: any) => {
    const contentType = response ? (response.headers['Content-Type'] || response.headers['content-type']) : undefined;
    if (contentType && (contentType.indexOf('text/javascript') >= 0 || contentType.indexOf('application/javascript') >= 0)) {
      console.log(`ignoring 'on response', will use 'callback'`);
      return;
    }

    callback({
      statusCode: response ? response.statusCode : undefined,
      headers: response ? response.headers : undefined,
      data: response,
    });
  })
  .on('error', (error: any) => {
    console.error(`'on error': ${error.message}`);
  });
};

protocol.interceptStreamProtocol('http', interceptCallback, (error: any) => {
  if (error) console.error('failed to register protocol handler for HTTP');
});
protocol.interceptStreamProtocol('https', interceptCallback, (error: any) => {
  if (error) console.error('failed to register protocol handler for HTTPS');
});