4 * This file is part of the Symfony package.
6 * (c) Fabien Potencier <fabien@symfony.com>
8 * For the full copyright and license information, please view the LICENSE
9 * file that was distributed with this source code.
12 namespace Symfony\Component\HttpFoundation\File\MimeType;
15 * A singleton mime type to file extension guesser.
17 * A default guesser is provided.
18 * You can register custom guessers by calling the register()
19 * method on the singleton instance:
21 * $guesser = ExtensionGuesser::getInstance();
22 * $guesser->register(new MyCustomExtensionGuesser());
24 * The last registered guesser is preferred over previously registered ones.
26 class ExtensionGuesser implements ExtensionGuesserInterface
29 * The singleton instance.
31 * @var ExtensionGuesser
33 private static $instance = null;
36 * All registered ExtensionGuesserInterface instances.
40 protected $guessers = array();
43 * Returns the singleton instance.
47 public static function getInstance()
49 if (null === self::$instance) {
50 self::$instance = new self();
53 return self::$instance;
57 * Registers all natively provided extension guessers.
59 private function __construct()
61 $this->register(new MimeTypeExtensionGuesser());
65 * Registers a new extension guesser.
67 * When guessing, this guesser is preferred over previously registered ones.
69 public function register(ExtensionGuesserInterface $guesser)
71 array_unshift($this->guessers, $guesser);
75 * Tries to guess the extension.
77 * The mime type is passed to each registered mime type guesser in reverse order
78 * of their registration (last registered is queried first). Once a guesser
79 * returns a value that is not NULL, this method terminates and returns the
82 * @param string $mimeType The mime type
84 * @return string The guessed extension or NULL, if none could be guessed
86 public function guess($mimeType)
88 foreach ($this->guessers as $guesser) {
89 if (null !== $extension = $guesser->guess($mimeType)) {