class HeaderBag

HeaderBagTest.php in drupal/core/vendor/symfony/http-foundation/Symfony/Component/HttpFoundation/Tests/HeaderBagTest.php

RequestDataCollector.php in drupal/core/vendor/symfony/http-kernel/Symfony/Component/HttpKernel/DataCollector/RequestDataCollector.php

class HeaderBag implements \IteratorAggregate, \Countable {
  protected $headers;
  protected $cacheControl;

  /**
   * Constructor.
   *
   * @param array $headers An array of HTTP headers
   *
   * @api
   */
  public function __construct(array $headers = array()) {
    $this->cacheControl = array();
    $this->headers = array();
    foreach ($headers as $key => $values) {
      $this
        ->set($key, $values);
    }
  }

  /**
   * Returns the headers as a string.
   *
   * @return string The headers
   */
  public function __toString() {
    if (!$this->headers) {
      return '';
    }
    $max = max(array_map('strlen', array_keys($this->headers))) + 1;
    $content = '';
    ksort($this->headers);
    foreach ($this->headers as $name => $values) {
      $name = implode('-', array_map('ucfirst', explode('-', $name)));
      foreach ($values as $value) {
        $content .= sprintf("%-{$max}s %s\r\n", $name . ':', $value);
      }
    }
    return $content;
  }

  /**
   * Returns the headers.
   *
   * @return array An array of headers
   *
   * @api
   */
  public function all() {
    return $this->headers;
  }

  /**
   * Returns the parameter keys.
   *
   * @return array An array of parameter keys
   *
   * @api
   */
  public function keys() {
    return array_keys($this->headers);
  }

  /**
   * Replaces the current HTTP headers by a new set.
   *
   * @param array $headers An array of HTTP headers
   *
   * @api
   */
  public function replace(array $headers = array()) {
    $this->headers = array();
    $this
      ->add($headers);
  }

  /**
   * Adds new headers the current HTTP headers set.
   *
   * @param array $headers An array of HTTP headers
   *
   * @api
   */
  public function add(array $headers) {
    foreach ($headers as $key => $values) {
      $this
        ->set($key, $values);
    }
  }

  /**
   * Returns a header value by name.
   *
   * @param string  $key     The header name
   * @param mixed   $default The default value
   * @param Boolean $first   Whether to return the first value or all header values
   *
   * @return string|array The first header value if $first is true, an array of values otherwise
   *
   * @api
   */
  public function get($key, $default = null, $first = true) {
    $key = strtr(strtolower($key), '_', '-');
    if (!array_key_exists($key, $this->headers)) {
      if (null === $default) {
        return $first ? null : array();
      }
      return $first ? $default : array(
        $default,
      );
    }
    if ($first) {
      return count($this->headers[$key]) ? $this->headers[$key][0] : $default;
    }
    return $this->headers[$key];
  }

  /**
   * Sets a header by name.
   *
   * @param string       $key     The key
   * @param string|array $values  The value or an array of values
   * @param Boolean      $replace Whether to replace the actual value of not (true by default)
   *
   * @api
   */
  public function set($key, $values, $replace = true) {
    $key = strtr(strtolower($key), '_', '-');
    $values = array_values((array) $values);
    if (true === $replace || !isset($this->headers[$key])) {
      $this->headers[$key] = $values;
    }
    else {
      $this->headers[$key] = array_merge($this->headers[$key], $values);
    }
    if ('cache-control' === $key) {
      $this->cacheControl = $this
        ->parseCacheControl($values[0]);
    }
  }

  /**
   * Returns true if the HTTP header is defined.
   *
   * @param string $key The HTTP header
   *
   * @return Boolean true if the parameter exists, false otherwise
   *
   * @api
   */
  public function has($key) {
    return array_key_exists(strtr(strtolower($key), '_', '-'), $this->headers);
  }

  /**
   * Returns true if the given HTTP header contains the given value.
   *
   * @param string $key   The HTTP header name
   * @param string $value The HTTP value
   *
   * @return Boolean true if the value is contained in the header, false otherwise
   *
   * @api
   */
  public function contains($key, $value) {
    return in_array($value, $this
      ->get($key, null, false));
  }

  /**
   * Removes a header.
   *
   * @param string $key The HTTP header name
   *
   * @api
   */
  public function remove($key) {
    $key = strtr(strtolower($key), '_', '-');
    unset($this->headers[$key]);
    if ('cache-control' === $key) {
      $this->cacheControl = array();
    }
  }

  /**
   * Returns the HTTP header value converted to a date.
   *
   * @param string    $key     The parameter key
   * @param \DateTime $default The default value
   *
   * @return \DateTime The filtered value
   *
   * @api
   */
  public function getDate($key, \DateTime $default = null) {
    if (null === ($value = $this
      ->get($key))) {
      return $default;
    }
    if (false === ($date = \DateTime::createFromFormat(DATE_RFC2822, $value))) {
      throw new \RuntimeException(sprintf('The %s HTTP header is not parseable (%s).', $key, $value));
    }
    return $date;
  }
  public function addCacheControlDirective($key, $value = true) {
    $this->cacheControl[$key] = $value;
    $this
      ->set('Cache-Control', $this
      ->getCacheControlHeader());
  }
  public function hasCacheControlDirective($key) {
    return array_key_exists($key, $this->cacheControl);
  }
  public function getCacheControlDirective($key) {
    return array_key_exists($key, $this->cacheControl) ? $this->cacheControl[$key] : null;
  }
  public function removeCacheControlDirective($key) {
    unset($this->cacheControl[$key]);
    $this
      ->set('Cache-Control', $this
      ->getCacheControlHeader());
  }

  /**
   * Returns an iterator for headers.
   *
   * @return \ArrayIterator An \ArrayIterator instance
   */
  public function getIterator() {
    return new \ArrayIterator($this->headers);
  }

  /**
   * Returns the number of headers.
   *
   * @return int The number of headers
   */
  public function count() {
    return count($this->headers);
  }
  protected function getCacheControlHeader() {
    $parts = array();
    ksort($this->cacheControl);
    foreach ($this->cacheControl as $key => $value) {
      if (true === $value) {
        $parts[] = $key;
      }
      else {
        if (preg_match('#[^a-zA-Z0-9._-]#', $value)) {
          $value = '"' . $value . '"';
        }
        $parts[] = "{$key}={$value}";
      }
    }
    return implode(', ', $parts);
  }

  /**
   * Parses a Cache-Control HTTP header.
   *
   * @param string $header The value of the Cache-Control HTTP header
   *
   * @return array An array representing the attribute values
   */
  protected function parseCacheControl($header) {
    $cacheControl = array();
    preg_match_all('#([a-zA-Z][a-zA-Z_-]*)\\s*(?:=(?:"([^"]*)"|([^ \\t",;]*)))?#', $header, $matches, PREG_SET_ORDER);
    foreach ($matches as $match) {
      $cacheControl[strtolower($match[1])] = isset($match[2]) && $match[2] ? $match[2] : (isset($match[3]) ? $match[3] : true);
    }
    return $cacheControl;
  }

}