unzipper-esm/lib/extract.js

Unzip cross-platform streaming API

import fs from 'fs'; // 'node:fs'
import path from 'path'; // 'node:path'
import { Writable } from 'stream'; // 'node:stream'

import DuplexStream from './DuplexStream.js';
import Parse from './parse.js';
import ensureDir from './ensureDir.js';

export default function Extract (opts) {
  // make sure path is normalized before using it
  opts.path = path.resolve(path.normalize(opts.path));

  const parser = Parse(opts);

  const outStream = new Writable({
    objectMode: true,
    write: async function(entry, encoding, cb) {
      // to avoid zip slip (writing outside of the destination), we resolve
      // the target path, and make sure it's nested in the intended
      // destination, or not extract it otherwise.
      // NOTE: Need to normalize to forward slashes for UNIX OS's to properly
      // ignore the zip slipped file entirely
      const extractPath = path.join(opts.path, entry.path.replace(/\\/g, '/'));
      if (extractPath.indexOf(opts.path) != 0) {
        return cb();
      }

      if (entry.type == 'Directory') {
        await ensureDir(extractPath);
        return cb();
      }

      await ensureDir(path.dirname(extractPath));

      const writer = opts.getWriter ? opts.getWriter({path: extractPath}) : fs.createWriteStream(extractPath);

      entry.pipe(writer)
        .on('error', cb)
        .on('close', cb);
    }
  });

  // Create a combined stream
  const extract = new DuplexStream(parser, outStream);

  parser.once('crx-header', function(crxHeader) {
    extract.crxHeader = crxHeader;
  });

  parser
    .pipe(outStream)
    .on('finish', function() {
      extract.emit('close');
    });

  extract.promise = function() {
    return new Promise(function(resolve, reject) {
      extract.on('close', resolve);
      extract.on('error', reject);
    });
  };

  return extract;
}