download vscode extensions from settings sync's cloudSettings file

download.js

const fs = require('fs');
const { promisify } = require('util');
const child = require('child_process');

const statAsync = promisify(fs.stat);
const unlinkAsync = promisify(fs.unlink);

const UA = 'Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_5) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/83.0.4103.97 Safari/537.36';

async function main() {
  try {
    fs.mkdirSync('ext-downloads');
  } catch {}

  const extensions = require('./extensions.json');

  let downloaded = 0;

  for (const extension of extensions) {
    const [ publisher ] = extension.metadata.publisherId.split('.', 1);

    const destination = `ext-downloads/${extension.name}-${extension.version}.vsix`;

    try {
      if ((await statAsync(destination)).size > 0) {
        console.info('SKIP');
        downloaded += 1;
        continue;
      } else {
        await unlinkAsync(destination);
      }
    } catch {}

    const url = `https://${publisher}.gallery.vsassets.io/_apis/public/gallery/publisher/${publisher}/extension/${extension.name}/${extension.version}/assetbyname/Microsoft.VisualStudio.Services.VSIXPackage`;

    const downloader = child.spawn('wget', [
      '--no-dns-cache',
      '--retry-on-http-error=429',
      '-t=10',
      '--waitretry=5',
      '-U',
      UA,
      '-O',
      destination,
      url,
    ]);

    downloader.stdout.pipe(process.stdout);
    downloader.stderr.pipe(process.stderr);

    await new Promise((resolve) => {
      downloader.on('exit', resolve);
    });

    try {
      if ((await statAsync(destination)).size === 0) {
        throw new Error();
      }

      console.info('OK');
      downloaded += 1;
    } catch {
      await unlinkAsync(destination).catch(() => {});
      console.info('ERROR');
    }
  }

  console.info(downloaded, '/', extensions.length);
}

main();