Compressed responses

[limadm]

Hello,

When using ajax-request to download static assets from a cdn, some of the proxies/mirrors compress the response body, signaling so in the content-encoding response header (MDN docs).
It would be great if ajax-request could detect and uncompress these responses, or at least provide a pipeline callback for the users to uncompress the response body on-the-fly before writing to disk.

For now I have been rewriting the destination in simple scenarios (only one content-encoding) in the download callback, somewhat like:

const ajaxRequest = require('ajax-request');
const fs = require('fs');
const zlib = require('zlib');

ajaxRequest.download({
  url: 'https://my.cdn.org/lib/file.js',
  destPath: () => './js/assets/file.js',
}, (err, res, body, destpath) => {
  if (err) {
    console.log('Download failed!', err);
  } else {
    var supported = ['gzip','x-gzip','deflate'];
    var encoding = res.headers['content-encoding'];
    if (supported.includes(encoding)) {
      fs.createWriteStream(destpath).pipe(zlib.createUnzip()).pipe(body);
    }
  }
});

Thanks.