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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   * This code is partially based on the Rack-Cache library by Ryan Tomayko,
   9   * which is released under the MIT license.
  10   *
  11   * For the full copyright and license information, please view the LICENSE
  12   * file that was distributed with this source code.
  13   */
  14  
  15  namespace Symfony\Component\HttpKernel\HttpCache;
  16  
  17  use Symfony\Component\HttpFoundation\Request;
  18  use Symfony\Component\HttpFoundation\Response;
  19  
  20  /**
  21   * Store implements all the logic for storing cache metadata (Request and Response headers).
  22   *
  23   * @author Fabien Potencier <fabien@symfony.com>
  24   */
  25  class Store implements StoreInterface
  26  {
  27      protected $root;
  28      private $keyCache;
  29      private $locks;
  30  
  31      /**
  32       * @param string $root The path to the cache directory
  33       *
  34       * @throws \RuntimeException
  35       */
  36      public function __construct($root)
  37      {
  38          $this->root = $root;
  39          if (!file_exists($this->root) && !@mkdir($this->root, 0777, true) && !is_dir($this->root)) {
  40              throw new \RuntimeException(sprintf('Unable to create the store directory (%s).', $this->root));
  41          }
  42          $this->keyCache = new \SplObjectStorage();
  43          $this->locks = array();
  44      }
  45  
  46      /**
  47       * Cleanups storage.
  48       */
  49      public function cleanup()
  50      {
  51          // unlock everything
  52          foreach ($this->locks as $lock) {
  53              flock($lock, LOCK_UN);
  54              fclose($lock);
  55          }
  56  
  57          $this->locks = array();
  58      }
  59  
  60      /**
  61       * Tries to lock the cache for a given Request, without blocking.
  62       *
  63       * @return bool|string true if the lock is acquired, the path to the current lock otherwise
  64       */
  65      public function lock(Request $request)
  66      {
  67          $key = $this->getCacheKey($request);
  68  
  69          if (!isset($this->locks[$key])) {
  70              $path = $this->getPath($key);
  71              if (!file_exists(\dirname($path)) && false === @mkdir(\dirname($path), 0777, true) && !is_dir(\dirname($path))) {
  72                  return $path;
  73              }
  74              $h = fopen($path, 'cb');
  75              if (!flock($h, LOCK_EX | LOCK_NB)) {
  76                  fclose($h);
  77  
  78                  return $path;
  79              }
  80  
  81              $this->locks[$key] = $h;
  82          }
  83  
  84          return true;
  85      }
  86  
  87      /**
  88       * Releases the lock for the given Request.
  89       *
  90       * @return bool False if the lock file does not exist or cannot be unlocked, true otherwise
  91       */
  92      public function unlock(Request $request)
  93      {
  94          $key = $this->getCacheKey($request);
  95  
  96          if (isset($this->locks[$key])) {
  97              flock($this->locks[$key], LOCK_UN);
  98              fclose($this->locks[$key]);
  99              unset($this->locks[$key]);
 100  
 101              return true;
 102          }
 103  
 104          return false;
 105      }
 106  
 107      public function isLocked(Request $request)
 108      {
 109          $key = $this->getCacheKey($request);
 110  
 111          if (isset($this->locks[$key])) {
 112              return true; // shortcut if lock held by this process
 113          }
 114  
 115          if (!file_exists($path = $this->getPath($key))) {
 116              return false;
 117          }
 118  
 119          $h = fopen($path, 'rb');
 120          flock($h, LOCK_EX | LOCK_NB, $wouldBlock);
 121          flock($h, LOCK_UN); // release the lock we just acquired
 122          fclose($h);
 123  
 124          return (bool) $wouldBlock;
 125      }
 126  
 127      /**
 128       * Locates a cached Response for the Request provided.
 129       *
 130       * @return Response|null A Response instance, or null if no cache entry was found
 131       */
 132      public function lookup(Request $request)
 133      {
 134          $key = $this->getCacheKey($request);
 135  
 136          if (!$entries = $this->getMetadata($key)) {
 137              return;
 138          }
 139  
 140          // find a cached entry that matches the request.
 141          $match = null;
 142          foreach ($entries as $entry) {
 143              if ($this->requestsMatch(isset($entry[1]['vary'][0]) ? implode(', ', $entry[1]['vary']) : '', $request->headers->all(), $entry[0])) {
 144                  $match = $entry;
 145  
 146                  break;
 147              }
 148          }
 149  
 150          if (null === $match) {
 151              return;
 152          }
 153  
 154          $headers = $match[1];
 155          if (file_exists($body = $this->getPath($headers['x-content-digest'][0]))) {
 156              return $this->restoreResponse($headers, $body);
 157          }
 158  
 159          // TODO the metaStore referenced an entity that doesn't exist in
 160          // the entityStore. We definitely want to return nil but we should
 161          // also purge the entry from the meta-store when this is detected.
 162      }
 163  
 164      /**
 165       * Writes a cache entry to the store for the given Request and Response.
 166       *
 167       * Existing entries are read and any that match the response are removed. This
 168       * method calls write with the new list of cache entries.
 169       *
 170       * @return string The key under which the response is stored
 171       *
 172       * @throws \RuntimeException
 173       */
 174      public function write(Request $request, Response $response)
 175      {
 176          $key = $this->getCacheKey($request);
 177          $storedEnv = $this->persistRequest($request);
 178  
 179          // write the response body to the entity store if this is the original response
 180          if (!$response->headers->has('X-Content-Digest')) {
 181              $digest = $this->generateContentDigest($response);
 182  
 183              if (false === $this->save($digest, $response->getContent())) {
 184                  throw new \RuntimeException('Unable to store the entity.');
 185              }
 186  
 187              $response->headers->set('X-Content-Digest', $digest);
 188  
 189              if (!$response->headers->has('Transfer-Encoding')) {
 190                  $response->headers->set('Content-Length', \strlen($response->getContent()));
 191              }
 192          }
 193  
 194          // read existing cache entries, remove non-varying, and add this one to the list
 195          $entries = array();
 196          $vary = $response->headers->get('vary');
 197          foreach ($this->getMetadata($key) as $entry) {
 198              if (!isset($entry[1]['vary'][0])) {
 199                  $entry[1]['vary'] = array('');
 200              }
 201  
 202              if ($entry[1]['vary'][0] != $vary || !$this->requestsMatch($vary, $entry[0], $storedEnv)) {
 203                  $entries[] = $entry;
 204              }
 205          }
 206  
 207          $headers = $this->persistResponse($response);
 208          unset($headers['age']);
 209  
 210          array_unshift($entries, array($storedEnv, $headers));
 211  
 212          if (false === $this->save($key, serialize($entries))) {
 213              throw new \RuntimeException('Unable to store the metadata.');
 214          }
 215  
 216          return $key;
 217      }
 218  
 219      /**
 220       * Returns content digest for $response.
 221       *
 222       * @return string
 223       */
 224      protected function generateContentDigest(Response $response)
 225      {
 226          return 'en'.hash('sha256', $response->getContent());
 227      }
 228  
 229      /**
 230       * Invalidates all cache entries that match the request.
 231       *
 232       * @throws \RuntimeException
 233       */
 234      public function invalidate(Request $request)
 235      {
 236          $modified = false;
 237          $key = $this->getCacheKey($request);
 238  
 239          $entries = array();
 240          foreach ($this->getMetadata($key) as $entry) {
 241              $response = $this->restoreResponse($entry[1]);
 242              if ($response->isFresh()) {
 243                  $response->expire();
 244                  $modified = true;
 245                  $entries[] = array($entry[0], $this->persistResponse($response));
 246              } else {
 247                  $entries[] = $entry;
 248              }
 249          }
 250  
 251          if ($modified && false === $this->save($key, serialize($entries))) {
 252              throw new \RuntimeException('Unable to store the metadata.');
 253          }
 254      }
 255  
 256      /**
 257       * Determines whether two Request HTTP header sets are non-varying based on
 258       * the vary response header value provided.
 259       *
 260       * @param string $vary A Response vary header
 261       * @param array  $env1 A Request HTTP header array
 262       * @param array  $env2 A Request HTTP header array
 263       *
 264       * @return bool true if the two environments match, false otherwise
 265       */
 266      private function requestsMatch($vary, $env1, $env2)
 267      {
 268          if (empty($vary)) {
 269              return true;
 270          }
 271  
 272          foreach (preg_split('/[\s,]+/', $vary) as $header) {
 273              $key = str_replace('_', '-', strtolower($header));
 274              $v1 = isset($env1[$key]) ? $env1[$key] : null;
 275              $v2 = isset($env2[$key]) ? $env2[$key] : null;
 276              if ($v1 !== $v2) {
 277                  return false;
 278              }
 279          }
 280  
 281          return true;
 282      }
 283  
 284      /**
 285       * Gets all data associated with the given key.
 286       *
 287       * Use this method only if you know what you are doing.
 288       *
 289       * @param string $key The store key
 290       *
 291       * @return array An array of data associated with the key
 292       */
 293      private function getMetadata($key)
 294      {
 295          if (!$entries = $this->load($key)) {
 296              return array();
 297          }
 298  
 299          return unserialize($entries);
 300      }
 301  
 302      /**
 303       * Purges data for the given URL.
 304       *
 305       * This method purges both the HTTP and the HTTPS version of the cache entry.
 306       *
 307       * @param string $url A URL
 308       *
 309       * @return bool true if the URL exists with either HTTP or HTTPS scheme and has been purged, false otherwise
 310       */
 311      public function purge($url)
 312      {
 313          $http = preg_replace('#^https:#', 'http:', $url);
 314          $https = preg_replace('#^http:#', 'https:', $url);
 315  
 316          $purgedHttp = $this->doPurge($http);
 317          $purgedHttps = $this->doPurge($https);
 318  
 319          return $purgedHttp || $purgedHttps;
 320      }
 321  
 322      /**
 323       * Purges data for the given URL.
 324       *
 325       * @param string $url A URL
 326       *
 327       * @return bool true if the URL exists and has been purged, false otherwise
 328       */
 329      private function doPurge($url)
 330      {
 331          $key = $this->getCacheKey(Request::create($url));
 332          if (isset($this->locks[$key])) {
 333              flock($this->locks[$key], LOCK_UN);
 334              fclose($this->locks[$key]);
 335              unset($this->locks[$key]);
 336          }
 337  
 338          if (file_exists($path = $this->getPath($key))) {
 339              unlink($path);
 340  
 341              return true;
 342          }
 343  
 344          return false;
 345      }
 346  
 347      /**
 348       * Loads data for the given key.
 349       *
 350       * @param string $key The store key
 351       *
 352       * @return string The data associated with the key
 353       */
 354      private function load($key)
 355      {
 356          $path = $this->getPath($key);
 357  
 358          return file_exists($path) ? file_get_contents($path) : false;
 359      }
 360  
 361      /**
 362       * Save data for the given key.
 363       *
 364       * @param string $key  The store key
 365       * @param string $data The data to store
 366       *
 367       * @return bool
 368       */
 369      private function save($key, $data)
 370      {
 371          $path = $this->getPath($key);
 372  
 373          if (isset($this->locks[$key])) {
 374              $fp = $this->locks[$key];
 375              @ftruncate($fp, 0);
 376              @fseek($fp, 0);
 377              $len = @fwrite($fp, $data);
 378              if (\strlen($data) !== $len) {
 379                  @ftruncate($fp, 0);
 380  
 381                  return false;
 382              }
 383          } else {
 384              if (!file_exists(\dirname($path)) && false === @mkdir(\dirname($path), 0777, true) && !is_dir(\dirname($path))) {
 385                  return false;
 386              }
 387  
 388              $tmpFile = tempnam(\dirname($path), basename($path));
 389              if (false === $fp = @fopen($tmpFile, 'wb')) {
 390                  @unlink($tmpFile);
 391  
 392                  return false;
 393              }
 394              @fwrite($fp, $data);
 395              @fclose($fp);
 396  
 397              if ($data != file_get_contents($tmpFile)) {
 398                  @unlink($tmpFile);
 399  
 400                  return false;
 401              }
 402  
 403              if (false === @rename($tmpFile, $path)) {
 404                  @unlink($tmpFile);
 405  
 406                  return false;
 407              }
 408          }
 409  
 410          @chmod($path, 0666 & ~umask());
 411      }
 412  
 413      public function getPath($key)
 414      {
 415          return $this->root.\DIRECTORY_SEPARATOR.substr($key, 0, 2).\DIRECTORY_SEPARATOR.substr($key, 2, 2).\DIRECTORY_SEPARATOR.substr($key, 4, 2).\DIRECTORY_SEPARATOR.substr($key, 6);
 416      }
 417  
 418      /**
 419       * Generates a cache key for the given Request.
 420       *
 421       * This method should return a key that must only depend on a
 422       * normalized version of the request URI.
 423       *
 424       * If the same URI can have more than one representation, based on some
 425       * headers, use a Vary header to indicate them, and each representation will
 426       * be stored independently under the same cache key.
 427       *
 428       * @return string A key for the given Request
 429       */
 430      protected function generateCacheKey(Request $request)
 431      {
 432          return 'md'.hash('sha256', $request->getUri());
 433      }
 434  
 435      /**
 436       * Returns a cache key for the given Request.
 437       *
 438       * @return string A key for the given Request
 439       */
 440      private function getCacheKey(Request $request)
 441      {
 442          if (isset($this->keyCache[$request])) {
 443              return $this->keyCache[$request];
 444          }
 445  
 446          return $this->keyCache[$request] = $this->generateCacheKey($request);
 447      }
 448  
 449      /**
 450       * Persists the Request HTTP headers.
 451       *
 452       * @return array An array of HTTP headers
 453       */
 454      private function persistRequest(Request $request)
 455      {
 456          return $request->headers->all();
 457      }
 458  
 459      /**
 460       * Persists the Response HTTP headers.
 461       *
 462       * @return array An array of HTTP headers
 463       */
 464      private function persistResponse(Response $response)
 465      {
 466          $headers = $response->headers->all();
 467          $headers['X-Status'] = array($response->getStatusCode());
 468  
 469          return $headers;
 470      }
 471  
 472      /**
 473       * Restores a Response from the HTTP headers and body.
 474       *
 475       * @param array  $headers An array of HTTP headers for the Response
 476       * @param string $body    The Response body
 477       *
 478       * @return Response
 479       */
 480      private function restoreResponse($headers, $body = null)
 481      {
 482          $status = $headers['X-Status'][0];
 483          unset($headers['X-Status']);
 484  
 485          if (null !== $body) {
 486              $headers['X-Body-File'] = array($body);
 487          }
 488  
 489          return new Response($body, $status, $headers);
 490      }
 491  }