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<?php
/*
* This file is part of the Symfony package.
*
* (c) Fabien Potencier <fabien@symfony.com>
*
* This code is partially based on the Rack-Cache library by Ryan Tomayko,
* which is released under the MIT license.
*
* For the full copyright and license information, please view the LICENSE
* file that was distributed with this source code.
*/
namespace Symfony\Component\HttpKernel\HttpCache;
use Symfony\Component\HttpFoundation\Request;
use Symfony\Component\HttpFoundation\Response;
/**
* Store implements all the logic for storing cache metadata (Request and Response headers).
*
* @author Fabien Potencier <fabien@symfony.com>
*/
class Store implements StoreInterface
{
protected $root;
private $keyCache;
private $locks;
/**
* Constructor.
*
* @param string $root The path to the cache directory
*/
public function __construct($root)
{
$this->root = $root;
if (!is_dir($this->root)) {
mkdir($this->root, 0777, true);
}
$this->keyCache = new \SplObjectStorage();
$this->locks = array();
}
/**
* Cleanups storage.
*/
public function cleanup()
{
// unlock everything
foreach ($this->locks as $lock) {
if (file_exists($lock)) {
@unlink($lock);
}
}
$error = error_get_last();
if (1 === $error['type'] && false === headers_sent()) {
// send a 503
header('HTTP/1.0 503 Service Unavailable');
header('Retry-After: 10');
echo '503 Service Unavailable';
}
}
/**
* Locks the cache for a given Request.
*
* @param Request $request A Request instance
*
* @return Boolean|string true if the lock is acquired, the path to the current lock otherwise
*/
public function lock(Request $request)
{
$path = $this->getPath($this->getCacheKey($request).'.lck');
if (!is_dir(dirname($path)) && false === @mkdir(dirname($path), 0777, true)) {
return false;
}
$lock = @fopen($path, 'x');
if (false !== $lock) {
fclose($lock);
$this->locks[] = $path;
return true;
}
return !file_exists($path) ?: $path;
}
/**
* Releases the lock for the given Request.
*
* @param Request $request A Request instance
*
* @return Boolean False if the lock file does not exist or cannot be unlocked, true otherwise
*/
public function unlock(Request $request)
{
$file = $this->getPath($this->getCacheKey($request).'.lck');
return is_file($file) ? @unlink($file) : false;
}
public function isLocked(Request $request)
{
return is_file($this->getPath($this->getCacheKey($request).'.lck'));
}
/**
* Locates a cached Response for the Request provided.
*
* @param Request $request A Request instance
*
* @return Response|null A Response instance, or null if no cache entry was found
*/
public function lookup(Request $request)
{
$key = $this->getCacheKey($request);
if (!$entries = $this->getMetadata($key)) {
return null;
}
// find a cached entry that matches the request.
$match = null;
foreach ($entries as $entry) {
if ($this->requestsMatch(isset($entry[1]['vary'][0]) ? $entry[1]['vary'][0] : '', $request->headers->all(), $entry[0])) {
$match = $entry;
break;
}
}
if (null === $match) {
return null;
}
list($req, $headers) = $match;
if (is_file($body = $this->getPath($headers['x-content-digest'][0]))) {
return $this->restoreResponse($headers, $body);
}
// TODO the metaStore referenced an entity that doesn't exist in
// the entityStore. We definitely want to return nil but we should
// also purge the entry from the meta-store when this is detected.
return null;
}
/**
* Writes a cache entry to the store for the given Request and Response.
*
* Existing entries are read and any that match the response are removed. This
* method calls write with the new list of cache entries.
*
* @param Request $request A Request instance
* @param Response $response A Response instance
*
* @return string The key under which the response is stored
*
* @throws \RuntimeException
*/
public function write(Request $request, Response $response)
{
$key = $this->getCacheKey($request);
$storedEnv = $this->persistRequest($request);
// write the response body to the entity store if this is the original response
if (!$response->headers->has('X-Content-Digest')) {
$digest = $this->generateContentDigest($response);
if (false === $this->save($digest, $response->getContent())) {
throw new \RuntimeException('Unable to store the entity.');
}
$response->headers->set('X-Content-Digest', $digest);
if (!$response->headers->has('Transfer-Encoding')) {
$response->headers->set('Content-Length', strlen($response->getContent()));
}
}
// read existing cache entries, remove non-varying, and add this one to the list
$entries = array();
$vary = $response->headers->get('vary');
foreach ($this->getMetadata($key) as $entry) {
if (!isset($entry[1]['vary'][0])) {
$entry[1]['vary'] = array('');
}
if ($vary != $entry[1]['vary'][0] || !$this->requestsMatch($vary, $entry[0], $storedEnv)) {
$entries[] = $entry;
}
}
$headers = $this->persistResponse($response);
unset($headers['age']);
array_unshift($entries, array($storedEnv, $headers));
if (false === $this->save($key, serialize($entries))) {
throw new \RuntimeException('Unable to store the metadata.');
}
return $key;
}
/**
* Returns content digest for $response.
*
* @param Response $response
*
* @return string
*/
protected function generateContentDigest(Response $response)
{
return 'en'.hash('sha256', $response->getContent());
}
/**
* Invalidates all cache entries that match the request.
*
* @param Request $request A Request instance
*
* @throws \RuntimeException
*/
public function invalidate(Request $request)
{
$modified = false;
$key = $this->getCacheKey($request);
$entries = array();
foreach ($this->getMetadata($key) as $entry) {
$response = $this->restoreResponse($entry[1]);
if ($response->isFresh()) {
$response->expire();
$modified = true;
$entries[] = array($entry[0], $this->persistResponse($response));
} else {
$entries[] = $entry;
}
}
if ($modified) {
if (false === $this->save($key, serialize($entries))) {
throw new \RuntimeException('Unable to store the metadata.');
}
}
}
/**
* Determines whether two Request HTTP header sets are non-varying based on
* the vary response header value provided.
*
* @param string $vary A Response vary header
* @param array $env1 A Request HTTP header array
* @param array $env2 A Request HTTP header array
*
* @return Boolean true if the two environments match, false otherwise
*/
private function requestsMatch($vary, $env1, $env2)
{
if (empty($vary)) {
return true;
}
foreach (preg_split('/[\s,]+/', $vary) as $header) {
$key = strtr(strtolower($header), '_', '-');
$v1 = isset($env1[$key]) ? $env1[$key] : null;
$v2 = isset($env2[$key]) ? $env2[$key] : null;
if ($v1 !== $v2) {
return false;
}
}
return true;
}
/**
* Gets all data associated with the given key.
*
* Use this method only if you know what you are doing.
*
* @param string $key The store key
*
* @return array An array of data associated with the key
*/
private function getMetadata($key)
{
if (false === $entries = $this->load($key)) {
return array();
}
return unserialize($entries);
}
/**
* Purges data for the given URL.
*
* @param string $url A URL
*
* @return Boolean true if the URL exists and has been purged, false otherwise
*/
public function purge($url)
{
if (is_file($path = $this->getPath($this->getCacheKey(Request::create($url))))) {
unlink($path);
return true;
}
return false;
}
/**
* Loads data for the given key.
*
* @param string $key The store key
*
* @return string The data associated with the key
*/
private function load($key)
{
$path = $this->getPath($key);
return is_file($path) ? file_get_contents($path) : false;
}
/**
* Save data for the given key.
*
* @param string $key The store key
* @param string $data The data to store
*
* @return Boolean
*/
private function save($key, $data)
{
$path = $this->getPath($key);
if (!is_dir(dirname($path)) && false === @mkdir(dirname($path), 0777, true)) {
return false;
}
$tmpFile = tempnam(dirname($path), basename($path));
if (false === $fp = @fopen($tmpFile, 'wb')) {
return false;
}
@fwrite($fp, $data);
@fclose($fp);
if ($data != file_get_contents($tmpFile)) {
return false;
}
if (false === @rename($tmpFile, $path)) {
return false;
}
@chmod($path, 0666 & ~umask());
}
public function getPath($key)
{
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);
}
/**
* Generates a cache key for the given Request.
*
* This method should return a key that must only depend on a
* normalized version of the request URI.
*
* If the same URI can have more than one representation, based on some
* headers, use a Vary header to indicate them, and each representation will
* be stored independently under the same cache key.
*
* @param Request $request A Request instance
*
* @return string A key for the given Request
*/
protected function generateCacheKey(Request $request)
{
return 'md'.hash('sha256', $request->getUri());
}
/**
* Returns a cache key for the given Request.
*
* @param Request $request A Request instance
*
* @return string A key for the given Request
*/
private function getCacheKey(Request $request)
{
if (isset($this->keyCache[$request])) {
return $this->keyCache[$request];
}
return $this->keyCache[$request] = $this->generateCacheKey($request);
}
/**
* Persists the Request HTTP headers.
*
* @param Request $request A Request instance
*
* @return array An array of HTTP headers
*/
private function persistRequest(Request $request)
{
return $request->headers->all();
}
/**
* Persists the Response HTTP headers.
*
* @param Response $response A Response instance
*
* @return array An array of HTTP headers
*/
private function persistResponse(Response $response)
{
$headers = $response->headers->all();
$headers['X-Status'] = array($response->getStatusCode());
return $headers;
}
/**
* Restores a Response from the HTTP headers and body.
*
* @param array $headers An array of HTTP headers for the Response
* @param string $body The Response body
*
* @return Response
*/
private function restoreResponse($headers, $body = null)
{
$status = $headers['X-Status'][0];
unset($headers['X-Status']);
if (null !== $body) {
$headers['X-Body-File'] = array($body);
}
return new Response($body, $status, $headers);
}
}
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