CacheBustingWorker.php

<?php

/*
 * This file is part of the Assetic package, an OpenSky project.
 *
 * (c) 2010-2013 OpenSky Project Inc
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Assetic\Factory\Worker;

use Assetic\Asset\AssetCollectionInterface;
use Assetic\Asset\AssetInterface;
use Assetic\Factory\LazyAssetManager;

/**
 * Adds cache busting code
 *
 * @author Kris Wallsmith <kris.wallsmith@gmail.com>
 */
class CacheBustingWorker implements WorkerInterface {
  protected $am;
  private $separator;
  public function __construct(LazyAssetManager $am, $separator = '-') {
    $this->am = $am;
    $this->separator = $separator;
  }
  public function process(AssetInterface $asset) {
    if (!($path = $asset
      ->getTargetPath())) {

      // no path to work with
      return;
    }
    if (!($search = pathinfo($path, PATHINFO_EXTENSION))) {

      // nothing to replace
      return;
    }
    $replace = $this->separator . $this
      ->getHash($asset) . '.' . $search;
    if (preg_match('/' . preg_quote($replace, '/') . '$/', $path)) {

      // already replaced
      return;
    }
    $asset
      ->setTargetPath(preg_replace('/\\.' . preg_quote($search, '/') . '$/', $replace, $path));
  }
  protected function getHash(AssetInterface $asset) {
    $hash = hash_init('sha1');
    hash_update($hash, $this->am
      ->getLastModified($asset));
    if ($asset instanceof AssetCollectionInterface) {
      foreach ($asset as $i => $leaf) {
        $sourcePath = $leaf
          ->getSourcePath();
        hash_update($hash, $sourcePath ?: $i);
      }
    }
    return substr(hash_final($hash), 0, 7);
  }

}