AcceptHeader.php

<?php

/*
 * This file is part of the Symfony package.
 *
 * (c) Fabien Potencier <fabien@symfony.com>
 *
 * For the full copyright and license information, please view the LICENSE
 * file that was distributed with this source code.
 */
namespace Symfony\Component\HttpFoundation;


/**
 * Represents an Accept-* header.
 *
 * An accept header is compound with a list of items,
 * sorted by descending quality.
 *
 * @author Jean-François Simon <contact@jfsimon.fr>
 */
class AcceptHeader {

  /**
   * @var AcceptHeaderItem[]
   */
  private $items = array();

  /**
   * @var bool
   */
  private $sorted = true;

  /**
   * Constructor.
   *
   * @param AcceptHeaderItem[] $items
   */
  public function __construct(array $items) {
    foreach ($items as $item) {
      $this
        ->add($item);
    }
  }

  /**
   * Builds an AcceptHeader instance from a string.
   *
   * @param string $headerValue
   *
   * @return AcceptHeader
   */
  public static function fromString($headerValue) {
    $index = 0;
    return new self(array_map(function ($itemValue) use (&$index) {
      $item = AcceptHeaderItem::fromString($itemValue);
      $item
        ->setIndex($index++);
      return $item;
    }, preg_split('/\\s*(?:,*("[^"]+"),*|,*(\'[^\']+\'),*|,+)\\s*/', $headerValue, 0, PREG_SPLIT_NO_EMPTY | PREG_SPLIT_DELIM_CAPTURE)));
  }

  /**
   * Returns header value's string representation.
   *
   * @return string
   */
  public function __toString() {
    return implode(',', $this->items);
  }

  /**
   * Tests if header has given value.
   *
   * @param string $value
   *
   * @return Boolean
   */
  public function has($value) {
    return isset($this->items[$value]);
  }

  /**
   * Returns given value's item, if exists.
   *
   * @param string $value
   *
   * @return AcceptHeaderItem|null
   */
  public function get($value) {
    return isset($this->items[$value]) ? $this->items[$value] : null;
  }

  /**
   * Adds an item.
   *
   * @param AcceptHeaderItem $item
   *
   * @return AcceptHeader
   */
  public function add(AcceptHeaderItem $item) {
    $this->items[$item
      ->getValue()] = $item;
    $this->sorted = false;
    return $this;
  }

  /**
   * Returns all items.
   *
   * @return AcceptHeaderItem[]
   */
  public function all() {
    $this
      ->sort();
    return $this->items;
  }

  /**
   * Filters items on their value using given regex.
   *
   * @param string $pattern
   *
   * @return AcceptHeader
   */
  public function filter($pattern) {
    return new self(array_filter($this->items, function (AcceptHeaderItem $item) use ($pattern) {
      return preg_match($pattern, $item
        ->getValue());
    }));
  }

  /**
   * Returns first item.
   *
   * @return AcceptHeaderItem|null
   */
  public function first() {
    $this
      ->sort();
    return !empty($this->items) ? reset($this->items) : null;
  }

  /**
   * Sorts items by descending quality
   */
  private function sort() {
    if (!$this->sorted) {
      uasort($this->items, function ($a, $b) {
        $qA = $a
          ->getQuality();
        $qB = $b
          ->getQuality();
        if ($qA === $qB) {
          return $a
            ->getIndex() > $b
            ->getIndex() ? 1 : -1;
        }
        return $qA > $qB ? -1 : 1;
      });
      $this->sorted = true;
    }
  }

}