zyAdmin/node_modules/unzipper/lib/extract.js

module.exports = Extract;

var Parse = require('./parse');
var Writer = require('fstream').Writer;
var path = require('path');
var stream = require('stream');
var duplexer2 = require('duplexer2');
var Promise = require('bluebird');

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

  var parser = new Parse(opts);

  var outStream = new stream.Writable({objectMode: true});
  outStream._write = function(entry, encoding, cb) {

    if (entry.type == 'Directory') return 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.
    var extractPath = path.join(opts.path, entry.path);
    if (extractPath.indexOf(opts.path) != 0) {
      return cb();
    }

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

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

  var extract = duplexer2(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;
}