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   1  <?php
   2  
   3  /*
   4   * This file is part of the Symfony package.
   5   *
   6   * (c) Fabien Potencier <fabien@symfony.com>
   7   *
   8   * For the full copyright and license information, please view the LICENSE
   9   * file that was distributed with this source code.
  10   */
  11  
  12  namespace Symfony\Component\HttpKernel\HttpCache;
  13  
  14  use Symfony\Component\HttpFoundation\Request;
  15  use Symfony\Component\HttpFoundation\Response;
  16  use Symfony\Component\HttpKernel\HttpKernelInterface;
  17  
  18  /**
  19   * Esi implements the ESI capabilities to Request and Response instances.
  20   *
  21   * For more information, read the following W3C notes:
  22   *
  23   *  * ESI Language Specification 1.0 (http://www.w3.org/TR/esi-lang)
  24   *
  25   *  * Edge Architecture Specification (http://www.w3.org/TR/edge-arch)
  26   *
  27   * @author Fabien Potencier <fabien@symfony.com>
  28   */
  29  class Esi implements SurrogateInterface
  30  {
  31      private $contentTypes;
  32      private $phpEscapeMap = array(
  33          array('<?', '<%', '<s', '<S'),
  34          array('<?php echo "<?"; ?>', '<?php echo "<%"; ?>', '<?php echo "<s"; ?>', '<?php echo "<S"; ?>'),
  35      );
  36  
  37      /**
  38       * @param array $contentTypes An array of content-type that should be parsed for ESI information
  39       *                            (default: text/html, text/xml, application/xhtml+xml, and application/xml)
  40       */
  41      public function __construct(array $contentTypes = array('text/html', 'text/xml', 'application/xhtml+xml', 'application/xml'))
  42      {
  43          $this->contentTypes = $contentTypes;
  44      }
  45  
  46      public function getName()
  47      {
  48          return 'esi';
  49      }
  50  
  51      /**
  52       * Returns a new cache strategy instance.
  53       *
  54       * @return ResponseCacheStrategyInterface A ResponseCacheStrategyInterface instance
  55       */
  56      public function createCacheStrategy()
  57      {
  58          return new ResponseCacheStrategy();
  59      }
  60  
  61      /**
  62       * Checks that at least one surrogate has ESI/1.0 capability.
  63       *
  64       * @return bool true if one surrogate has ESI/1.0 capability, false otherwise
  65       */
  66      public function hasSurrogateCapability(Request $request)
  67      {
  68          if (null === $value = $request->headers->get('Surrogate-Capability')) {
  69              return false;
  70          }
  71  
  72          return false !== strpos($value, 'ESI/1.0');
  73      }
  74  
  75      /**
  76       * Checks that at least one surrogate has ESI/1.0 capability.
  77       *
  78       * @param Request $request A Request instance
  79       *
  80       * @return bool true if one surrogate has ESI/1.0 capability, false otherwise
  81       *
  82       * @deprecated since version 2.6, to be removed in 3.0. Use hasSurrogateCapability() instead
  83       */
  84      public function hasSurrogateEsiCapability(Request $request)
  85      {
  86          @trigger_error('The '.__METHOD__.' method is deprecated since Symfony 2.6 and will be removed in 3.0. Use the hasSurrogateCapability() method instead.', E_USER_DEPRECATED);
  87  
  88          return $this->hasSurrogateCapability($request);
  89      }
  90  
  91      /**
  92       * Adds ESI/1.0 capability to the given Request.
  93       */
  94      public function addSurrogateCapability(Request $request)
  95      {
  96          $current = $request->headers->get('Surrogate-Capability');
  97          $new = 'symfony2="ESI/1.0"';
  98  
  99          $request->headers->set('Surrogate-Capability', $current ? $current.', '.$new : $new);
 100      }
 101  
 102      /**
 103       * Adds ESI/1.0 capability to the given Request.
 104       *
 105       * @param Request $request A Request instance
 106       *
 107       * @deprecated since version 2.6, to be removed in 3.0. Use addSurrogateCapability() instead
 108       */
 109      public function addSurrogateEsiCapability(Request $request)
 110      {
 111          @trigger_error('The '.__METHOD__.' method is deprecated since Symfony 2.6 and will be removed in 3.0. Use the addSurrogateCapability() method instead.', E_USER_DEPRECATED);
 112  
 113          $this->addSurrogateCapability($request);
 114      }
 115  
 116      /**
 117       * Adds HTTP headers to specify that the Response needs to be parsed for ESI.
 118       *
 119       * This method only adds an ESI HTTP header if the Response has some ESI tags.
 120       */
 121      public function addSurrogateControl(Response $response)
 122      {
 123          if (false !== strpos($response->getContent(), '<esi:include')) {
 124              $response->headers->set('Surrogate-Control', 'content="ESI/1.0"');
 125          }
 126      }
 127  
 128      /**
 129       * Checks that the Response needs to be parsed for ESI tags.
 130       *
 131       * @return bool true if the Response needs to be parsed, false otherwise
 132       */
 133      public function needsParsing(Response $response)
 134      {
 135          if (!$control = $response->headers->get('Surrogate-Control')) {
 136              return false;
 137          }
 138  
 139          return (bool) preg_match('#content="[^"]*ESI/1.0[^"]*"#', $control);
 140      }
 141  
 142      /**
 143       * Checks that the Response needs to be parsed for ESI tags.
 144       *
 145       * @param Response $response A Response instance
 146       *
 147       * @return bool true if the Response needs to be parsed, false otherwise
 148       *
 149       * @deprecated since version 2.6, to be removed in 3.0. Use needsParsing() instead
 150       */
 151      public function needsEsiParsing(Response $response)
 152      {
 153          @trigger_error('The '.__METHOD__.' method is deprecated since Symfony 2.6 and will be removed in 3.0. Use the needsParsing() method instead.', E_USER_DEPRECATED);
 154  
 155          return $this->needsParsing($response);
 156      }
 157  
 158      /**
 159       * Renders an ESI tag.
 160       *
 161       * @param string $uri          A URI
 162       * @param string $alt          An alternate URI
 163       * @param bool   $ignoreErrors Whether to ignore errors or not
 164       * @param string $comment      A comment to add as an esi:include tag
 165       *
 166       * @return string
 167       */
 168      public function renderIncludeTag($uri, $alt = null, $ignoreErrors = true, $comment = '')
 169      {
 170          $html = sprintf('<esi:include src="%s"%s%s />',
 171              $uri,
 172              $ignoreErrors ? ' onerror="continue"' : '',
 173              $alt ? sprintf(' alt="%s"', $alt) : ''
 174          );
 175  
 176          if (!empty($comment)) {
 177              return sprintf("<esi:comment text=\"%s\" />\n%s", $comment, $html);
 178          }
 179  
 180          return $html;
 181      }
 182  
 183      /**
 184       * Replaces a Response ESI tags with the included resource content.
 185       *
 186       * @return Response
 187       */
 188      public function process(Request $request, Response $response)
 189      {
 190          $type = $response->headers->get('Content-Type');
 191          if (empty($type)) {
 192              $type = 'text/html';
 193          }
 194  
 195          $parts = explode(';', $type);
 196          if (!\in_array($parts[0], $this->contentTypes)) {
 197              return $response;
 198          }
 199  
 200          // we don't use a proper XML parser here as we can have ESI tags in a plain text response
 201          $content = $response->getContent();
 202          $content = preg_replace('#<esi\:remove>.*?</esi\:remove>#s', '', $content);
 203          $content = preg_replace('#<esi\:comment[^>]+>#s', '', $content);
 204  
 205          $chunks = preg_split('#<esi\:include\s+(.*?)\s*(?:/|</esi\:include)>#', $content, -1, PREG_SPLIT_DELIM_CAPTURE);
 206          $chunks[0] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[0]);
 207  
 208          $i = 1;
 209          while (isset($chunks[$i])) {
 210              $options = array();
 211              preg_match_all('/(src|onerror|alt)="([^"]*?)"/', $chunks[$i], $matches, PREG_SET_ORDER);
 212              foreach ($matches as $set) {
 213                  $options[$set[1]] = $set[2];
 214              }
 215  
 216              if (!isset($options['src'])) {
 217                  throw new \RuntimeException('Unable to process an ESI tag without a "src" attribute.');
 218              }
 219  
 220              $chunks[$i] = sprintf('<?php echo $this->surrogate->handle($this, %s, %s, %s) ?>'."\n",
 221                  var_export($options['src'], true),
 222                  var_export(isset($options['alt']) ? $options['alt'] : '', true),
 223                  isset($options['onerror']) && 'continue' === $options['onerror'] ? 'true' : 'false'
 224              );
 225              ++$i;
 226              $chunks[$i] = str_replace($this->phpEscapeMap[0], $this->phpEscapeMap[1], $chunks[$i]);
 227              ++$i;
 228          }
 229          $content = implode('', $chunks);
 230  
 231          $response->setContent($content);
 232          $response->headers->set('X-Body-Eval', 'ESI');
 233  
 234          // remove ESI/1.0 from the Surrogate-Control header
 235          if ($response->headers->has('Surrogate-Control')) {
 236              $value = $response->headers->get('Surrogate-Control');
 237              if ('content="ESI/1.0"' == $value) {
 238                  $response->headers->remove('Surrogate-Control');
 239              } elseif (preg_match('#,\s*content="ESI/1.0"#', $value)) {
 240                  $response->headers->set('Surrogate-Control', preg_replace('#,\s*content="ESI/1.0"#', '', $value));
 241              } elseif (preg_match('#content="ESI/1.0",\s*#', $value)) {
 242                  $response->headers->set('Surrogate-Control', preg_replace('#content="ESI/1.0",\s*#', '', $value));
 243              }
 244          }
 245      }
 246  
 247      /**
 248       * Handles an ESI from the cache.
 249       *
 250       * @param HttpCache $cache        An HttpCache instance
 251       * @param string    $uri          The main URI
 252       * @param string    $alt          An alternative URI
 253       * @param bool      $ignoreErrors Whether to ignore errors or not
 254       *
 255       * @return string
 256       *
 257       * @throws \RuntimeException
 258       * @throws \Exception
 259       */
 260      public function handle(HttpCache $cache, $uri, $alt, $ignoreErrors)
 261      {
 262          $subRequest = Request::create($uri, 'get', array(), $cache->getRequest()->cookies->all(), array(), $cache->getRequest()->server->all());
 263  
 264          try {
 265              $response = $cache->handle($subRequest, HttpKernelInterface::SUB_REQUEST, true);
 266  
 267              if (!$response->isSuccessful()) {
 268                  throw new \RuntimeException(sprintf('Error when rendering "%s" (Status code is %s).', $subRequest->getUri(), $response->getStatusCode()));
 269              }
 270  
 271              return $response->getContent();
 272          } catch (\Exception $e) {
 273              if ($alt) {
 274                  return $this->handle($cache, $alt, '', $ignoreErrors);
 275              }
 276  
 277              if (!$ignoreErrors) {
 278                  throw $e;
 279              }
 280          }
 281      }
 282  }