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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;
/**
* @throws \RuntimeException
*/
public function __construct(string $root)
{
$this->root = $root;
if (!file_exists($this->root) && !@mkdir($this->root, 0777, true) && !is_dir($this->root)) {
throw new \RuntimeException(sprintf('Unable to create the store directory (%s).', $this->root));
}
$this->keyCache = new \SplObjectStorage();
$this->locks = [];
}
/**
* Cleanups storage.
*/
public function cleanup()
{
// unlock everything
foreach ($this->locks as $lock) {
flock($lock, LOCK_UN);
fclose($lock);
}
$this->locks = [];
}
/**
* Tries to lock the cache for a given Request, without blocking.
*
* @return bool|string true if the lock is acquired, the path to the current lock otherwise
*/
public function lock(Request $request)
{
$key = $this->getCacheKey($request);
if (!isset($this->locks[$key])) {
$path = $this->getPath($key);
if (!file_exists(\dirname($path)) && false === @mkdir(\dirname($path), 0777, true) && !is_dir(\dirname($path))) {
return $path;
}
$h = fopen($path, 'cb');
if (!flock($h, LOCK_EX | LOCK_NB)) {
fclose($h);
return $path;
}
$this->locks[$key] = $h;
}
return true;
}
/**
* Releases the lock for the given Request.
*
* @return bool False if the lock file does not exist or cannot be unlocked, true otherwise
*/
public function unlock(Request $request)
{
$key = $this->getCacheKey($request);
if (isset($this->locks[$key])) {
flock($this->locks[$key], LOCK_UN);
fclose($this->locks[$key]);
unset($this->locks[$key]);
return true;
}
return false;
}
public function isLocked(Request $request)
{
$key = $this->getCacheKey($request);
if (isset($this->locks[$key])) {
return true; // shortcut if lock held by this process
}
if (!file_exists($path = $this->getPath($key))) {
return false;
}
$h = fopen($path, 'rb');
flock($h, LOCK_EX | LOCK_NB, $wouldBlock);
flock($h, LOCK_UN); // release the lock we just acquired
fclose($h);
return (bool) $wouldBlock;
}
/**
* Locates a cached Response for the Request provided.
*
* @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]) ? implode(', ', $entry[1]['vary']) : '', $request->headers->all(), $entry[0])) {
$match = $entry;
break;
}
}
if (null === $match) {
return null;
}
$headers = $match[1];
if (file_exists($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.
*
* @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 (!$this->save($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 = [];
$vary = $response->headers->get('vary');
foreach ($this->getMetadata($key) as $entry) {
if (!isset($entry[1]['vary'][0])) {
$entry[1]['vary'] = [''];
}
if ($entry[1]['vary'][0] != $vary || !$this->requestsMatch($vary ?? '', $entry[0], $storedEnv)) {
$entries[] = $entry;
}
}
$headers = $this->persistResponse($response);
unset($headers['age']);
array_unshift($entries, [$storedEnv, $headers]);
if (!$this->save($key, serialize($entries))) {
throw new \RuntimeException('Unable to store the metadata.');
}
return $key;
}
/**
* Returns content digest for $response.
*
* @return string
*/
protected function generateContentDigest(Response $response)
{
return 'en'.hash('sha256', $response->getContent());
}
/**
* Invalidates all cache entries that match the request.
*
* @throws \RuntimeException
*/
public function invalidate(Request $request)
{
$modified = false;
$key = $this->getCacheKey($request);
$entries = [];
foreach ($this->getMetadata($key) as $entry) {
$response = $this->restoreResponse($entry[1]);
if ($response->isFresh()) {
$response->expire();
$modified = true;
$entries[] = [$entry[0], $this->persistResponse($response)];
} else {
$entries[] = $entry;
}
}
if ($modified && !$this->save($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|null $vary A Response vary header
* @param array $env1 A Request HTTP header array
* @param array $env2 A Request HTTP header array
*/
private function requestsMatch(?string $vary, array $env1, array $env2): bool
{
if (empty($vary)) {
return true;
}
foreach (preg_split('/[\s,]+/', $vary) as $header) {
$key = str_replace('_', '-', strtolower($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.
*/
private function getMetadata(string $key): array
{
if (!$entries = $this->load($key)) {
return [];
}
return unserialize($entries);
}
/**
* Purges data for the given URL.
*
* This method purges both the HTTP and the HTTPS version of the cache entry.
*
* @return bool true if the URL exists with either HTTP or HTTPS scheme and has been purged, false otherwise
*/
public function purge(string $url)
{
$http = preg_replace('#^https:#', 'http:', $url);
$https = preg_replace('#^http:#', 'https:', $url);
$purgedHttp = $this->doPurge($http);
$purgedHttps = $this->doPurge($https);
return $purgedHttp || $purgedHttps;
}
/**
* Purges data for the given URL.
*/
private function doPurge(string $url): bool
{
$key = $this->getCacheKey(Request::create($url));
if (isset($this->locks[$key])) {
flock($this->locks[$key], LOCK_UN);
fclose($this->locks[$key]);
unset($this->locks[$key]);
}
if (file_exists($path = $this->getPath($key))) {
unlink($path);
return true;
}
return false;
}
/**
* Loads data for the given key.
*/
private function load(string $key): ?string
{
$path = $this->getPath($key);
return file_exists($path) && false !== ($contents = file_get_contents($path)) ? $contents : null;
}
/**
* Save data for the given key.
*/
private function save(string $key, string $data): bool
{
$path = $this->getPath($key);
if (isset($this->locks[$key])) {
$fp = $this->locks[$key];
@ftruncate($fp, 0);
@fseek($fp, 0);
$len = @fwrite($fp, $data);
if (\strlen($data) !== $len) {
@ftruncate($fp, 0);
return false;
}
} else {
if (!file_exists(\dirname($path)) && false === @mkdir(\dirname($path), 0777, true) && !is_dir(\dirname($path))) {
return false;
}
$tmpFile = tempnam(\dirname($path), basename($path));
if (false === $fp = @fopen($tmpFile, 'wb')) {
@unlink($tmpFile);
return false;
}
@fwrite($fp, $data);
@fclose($fp);
if ($data != file_get_contents($tmpFile)) {
@unlink($tmpFile);
return false;
}
if (false === @rename($tmpFile, $path)) {
@unlink($tmpFile);
return false;
}
}
@chmod($path, 0666 & ~umask());
return true;
}
public function getPath(string $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.
*
* @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.
*/
private function getCacheKey(Request $request): string
{
if (isset($this->keyCache[$request])) {
return $this->keyCache[$request];
}
return $this->keyCache[$request] = $this->generateCacheKey($request);
}
/**
* Persists the Request HTTP headers.
*/
private function persistRequest(Request $request): array
{
return $request->headers->all();
}
/**
* Persists the Response HTTP headers.
*/
private function persistResponse(Response $response): array
{
$headers = $response->headers->all();
$headers['X-Status'] = [$response->getStatusCode()];
return $headers;
}
/**
* Restores a Response from the HTTP headers and body.
*/
private function restoreResponse(array $headers, string $body = null): Response
{
$status = $headers['X-Status'][0];
unset($headers['X-Status']);
if (null !== $body) {
$headers['X-Body-File'] = [$body];
}
return new Response($body, $status, $headers);
}
}
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