738 lines
25 KiB
PHP
738 lines
25 KiB
PHP
<?php
|
|
|
|
/*
|
|
* This file is part of the Symfony package.
|
|
*
|
|
* (c) Fabien Potencier <fabien@symfony.com>
|
|
*
|
|
* For the full copyright and license information, please view the LICENSE
|
|
* file that was distributed with this source code.
|
|
*/
|
|
|
|
/*
|
|
* This code is partially based on the Rack-Cache library by Ryan Tomayko,
|
|
* which is released under the MIT license.
|
|
* (based on commit 02d2b48d75bcb63cf1c0c7149c077ad256542801)
|
|
*/
|
|
|
|
namespace Symfony\Component\HttpKernel\HttpCache;
|
|
|
|
use Symfony\Component\HttpFoundation\Request;
|
|
use Symfony\Component\HttpFoundation\Response;
|
|
use Symfony\Component\HttpKernel\HttpKernelInterface;
|
|
use Symfony\Component\HttpKernel\TerminableInterface;
|
|
|
|
/**
|
|
* Cache provides HTTP caching.
|
|
*
|
|
* @author Fabien Potencier <fabien@symfony.com>
|
|
*/
|
|
class HttpCache implements HttpKernelInterface, TerminableInterface
|
|
{
|
|
private $kernel;
|
|
private $store;
|
|
private $request;
|
|
private $surrogate;
|
|
private $surrogateCacheStrategy;
|
|
private $options = [];
|
|
private $traces = [];
|
|
|
|
/**
|
|
* Constructor.
|
|
*
|
|
* The available options are:
|
|
*
|
|
* * debug If true, exceptions are thrown when things go wrong. Otherwise, the cache
|
|
* will try to carry on and deliver a meaningful response.
|
|
*
|
|
* * trace_level May be one of 'none', 'short' and 'full'. For 'short', a concise trace of the
|
|
* main request will be added as an HTTP header. 'full' will add traces for all
|
|
* requests (including ESI subrequests). (default: 'full' if in debug; 'none' otherwise)
|
|
*
|
|
* * trace_header Header name to use for traces. (default: X-Symfony-Cache)
|
|
*
|
|
* * default_ttl The number of seconds that a cache entry should be considered
|
|
* fresh when no explicit freshness information is provided in
|
|
* a response. Explicit Cache-Control or Expires headers
|
|
* override this value. (default: 0)
|
|
*
|
|
* * private_headers Set of request headers that trigger "private" cache-control behavior
|
|
* on responses that don't explicitly state whether the response is
|
|
* public or private via a Cache-Control directive. (default: Authorization and Cookie)
|
|
*
|
|
* * allow_reload Specifies whether the client can force a cache reload by including a
|
|
* Cache-Control "no-cache" directive in the request. Set it to ``true``
|
|
* for compliance with RFC 2616. (default: false)
|
|
*
|
|
* * allow_revalidate Specifies whether the client can force a cache revalidate by including
|
|
* a Cache-Control "max-age=0" directive in the request. Set it to ``true``
|
|
* for compliance with RFC 2616. (default: false)
|
|
*
|
|
* * stale_while_revalidate Specifies the default number of seconds (the granularity is the second as the
|
|
* Response TTL precision is a second) during which the cache can immediately return
|
|
* a stale response while it revalidates it in the background (default: 2).
|
|
* This setting is overridden by the stale-while-revalidate HTTP Cache-Control
|
|
* extension (see RFC 5861).
|
|
*
|
|
* * stale_if_error Specifies the default number of seconds (the granularity is the second) during which
|
|
* the cache can serve a stale response when an error is encountered (default: 60).
|
|
* This setting is overridden by the stale-if-error HTTP Cache-Control extension
|
|
* (see RFC 5861).
|
|
*/
|
|
public function __construct(HttpKernelInterface $kernel, StoreInterface $store, SurrogateInterface $surrogate = null, array $options = [])
|
|
{
|
|
$this->store = $store;
|
|
$this->kernel = $kernel;
|
|
$this->surrogate = $surrogate;
|
|
|
|
// needed in case there is a fatal error because the backend is too slow to respond
|
|
register_shutdown_function([$this->store, 'cleanup']);
|
|
|
|
$this->options = array_merge([
|
|
'debug' => false,
|
|
'default_ttl' => 0,
|
|
'private_headers' => ['Authorization', 'Cookie'],
|
|
'allow_reload' => false,
|
|
'allow_revalidate' => false,
|
|
'stale_while_revalidate' => 2,
|
|
'stale_if_error' => 60,
|
|
'trace_level' => 'none',
|
|
'trace_header' => 'X-Symfony-Cache',
|
|
], $options);
|
|
|
|
if (!isset($options['trace_level'])) {
|
|
$this->options['trace_level'] = $this->options['debug'] ? 'full' : 'none';
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Gets the current store.
|
|
*
|
|
* @return StoreInterface
|
|
*/
|
|
public function getStore()
|
|
{
|
|
return $this->store;
|
|
}
|
|
|
|
/**
|
|
* Returns an array of events that took place during processing of the last request.
|
|
*
|
|
* @return array
|
|
*/
|
|
public function getTraces()
|
|
{
|
|
return $this->traces;
|
|
}
|
|
|
|
private function addTraces(Response $response)
|
|
{
|
|
$traceString = null;
|
|
|
|
if ('full' === $this->options['trace_level']) {
|
|
$traceString = $this->getLog();
|
|
}
|
|
|
|
if ('short' === $this->options['trace_level'] && $masterId = array_key_first($this->traces)) {
|
|
$traceString = implode('/', $this->traces[$masterId]);
|
|
}
|
|
|
|
if (null !== $traceString) {
|
|
$response->headers->add([$this->options['trace_header'] => $traceString]);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Returns a log message for the events of the last request processing.
|
|
*
|
|
* @return string
|
|
*/
|
|
public function getLog()
|
|
{
|
|
$log = [];
|
|
foreach ($this->traces as $request => $traces) {
|
|
$log[] = sprintf('%s: %s', $request, implode(', ', $traces));
|
|
}
|
|
|
|
return implode('; ', $log);
|
|
}
|
|
|
|
/**
|
|
* Gets the Request instance associated with the main request.
|
|
*
|
|
* @return Request
|
|
*/
|
|
public function getRequest()
|
|
{
|
|
return $this->request;
|
|
}
|
|
|
|
/**
|
|
* Gets the Kernel instance.
|
|
*
|
|
* @return HttpKernelInterface
|
|
*/
|
|
public function getKernel()
|
|
{
|
|
return $this->kernel;
|
|
}
|
|
|
|
/**
|
|
* Gets the Surrogate instance.
|
|
*
|
|
* @return SurrogateInterface
|
|
*
|
|
* @throws \LogicException
|
|
*/
|
|
public function getSurrogate()
|
|
{
|
|
return $this->surrogate;
|
|
}
|
|
|
|
/**
|
|
* {@inheritdoc}
|
|
*/
|
|
public function handle(Request $request, int $type = HttpKernelInterface::MAIN_REQUEST, bool $catch = true)
|
|
{
|
|
// FIXME: catch exceptions and implement a 500 error page here? -> in Varnish, there is a built-in error page mechanism
|
|
if (HttpKernelInterface::MAIN_REQUEST === $type) {
|
|
$this->traces = [];
|
|
// Keep a clone of the original request for surrogates so they can access it.
|
|
// We must clone here to get a separate instance because the application will modify the request during
|
|
// the application flow (we know it always does because we do ourselves by setting REMOTE_ADDR to 127.0.0.1
|
|
// and adding the X-Forwarded-For header, see HttpCache::forward()).
|
|
$this->request = clone $request;
|
|
if (null !== $this->surrogate) {
|
|
$this->surrogateCacheStrategy = $this->surrogate->createCacheStrategy();
|
|
}
|
|
}
|
|
|
|
$this->traces[$this->getTraceKey($request)] = [];
|
|
|
|
if (!$request->isMethodSafe()) {
|
|
$response = $this->invalidate($request, $catch);
|
|
} elseif ($request->headers->has('expect') || !$request->isMethodCacheable()) {
|
|
$response = $this->pass($request, $catch);
|
|
} elseif ($this->options['allow_reload'] && $request->isNoCache()) {
|
|
/*
|
|
If allow_reload is configured and the client requests "Cache-Control: no-cache",
|
|
reload the cache by fetching a fresh response and caching it (if possible).
|
|
*/
|
|
$this->record($request, 'reload');
|
|
$response = $this->fetch($request, $catch);
|
|
} else {
|
|
$response = $this->lookup($request, $catch);
|
|
}
|
|
|
|
$this->restoreResponseBody($request, $response);
|
|
|
|
if (HttpKernelInterface::MAIN_REQUEST === $type) {
|
|
$this->addTraces($response);
|
|
}
|
|
|
|
if (null !== $this->surrogate) {
|
|
if (HttpKernelInterface::MAIN_REQUEST === $type) {
|
|
$this->surrogateCacheStrategy->update($response);
|
|
} else {
|
|
$this->surrogateCacheStrategy->add($response);
|
|
}
|
|
}
|
|
|
|
$response->prepare($request);
|
|
|
|
$response->isNotModified($request);
|
|
|
|
return $response;
|
|
}
|
|
|
|
/**
|
|
* {@inheritdoc}
|
|
*/
|
|
public function terminate(Request $request, Response $response)
|
|
{
|
|
if ($this->getKernel() instanceof TerminableInterface) {
|
|
$this->getKernel()->terminate($request, $response);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Forwards the Request to the backend without storing the Response in the cache.
|
|
*
|
|
* @param bool $catch Whether to process exceptions
|
|
*
|
|
* @return Response
|
|
*/
|
|
protected function pass(Request $request, bool $catch = false)
|
|
{
|
|
$this->record($request, 'pass');
|
|
|
|
return $this->forward($request, $catch);
|
|
}
|
|
|
|
/**
|
|
* Invalidates non-safe methods (like POST, PUT, and DELETE).
|
|
*
|
|
* @param bool $catch Whether to process exceptions
|
|
*
|
|
* @return Response
|
|
*
|
|
* @throws \Exception
|
|
*
|
|
* @see RFC2616 13.10
|
|
*/
|
|
protected function invalidate(Request $request, bool $catch = false)
|
|
{
|
|
$response = $this->pass($request, $catch);
|
|
|
|
// invalidate only when the response is successful
|
|
if ($response->isSuccessful() || $response->isRedirect()) {
|
|
try {
|
|
$this->store->invalidate($request);
|
|
|
|
// As per the RFC, invalidate Location and Content-Location URLs if present
|
|
foreach (['Location', 'Content-Location'] as $header) {
|
|
if ($uri = $response->headers->get($header)) {
|
|
$subRequest = Request::create($uri, 'get', [], [], [], $request->server->all());
|
|
|
|
$this->store->invalidate($subRequest);
|
|
}
|
|
}
|
|
|
|
$this->record($request, 'invalidate');
|
|
} catch (\Exception $e) {
|
|
$this->record($request, 'invalidate-failed');
|
|
|
|
if ($this->options['debug']) {
|
|
throw $e;
|
|
}
|
|
}
|
|
}
|
|
|
|
return $response;
|
|
}
|
|
|
|
/**
|
|
* Lookups a Response from the cache for the given Request.
|
|
*
|
|
* When a matching cache entry is found and is fresh, it uses it as the
|
|
* response without forwarding any request to the backend. When a matching
|
|
* cache entry is found but is stale, it attempts to "validate" the entry with
|
|
* the backend using conditional GET. When no matching cache entry is found,
|
|
* it triggers "miss" processing.
|
|
*
|
|
* @param bool $catch Whether to process exceptions
|
|
*
|
|
* @return Response
|
|
*
|
|
* @throws \Exception
|
|
*/
|
|
protected function lookup(Request $request, bool $catch = false)
|
|
{
|
|
try {
|
|
$entry = $this->store->lookup($request);
|
|
} catch (\Exception $e) {
|
|
$this->record($request, 'lookup-failed');
|
|
|
|
if ($this->options['debug']) {
|
|
throw $e;
|
|
}
|
|
|
|
return $this->pass($request, $catch);
|
|
}
|
|
|
|
if (null === $entry) {
|
|
$this->record($request, 'miss');
|
|
|
|
return $this->fetch($request, $catch);
|
|
}
|
|
|
|
if (!$this->isFreshEnough($request, $entry)) {
|
|
$this->record($request, 'stale');
|
|
|
|
return $this->validate($request, $entry, $catch);
|
|
}
|
|
|
|
if ($entry->headers->hasCacheControlDirective('no-cache')) {
|
|
return $this->validate($request, $entry, $catch);
|
|
}
|
|
|
|
$this->record($request, 'fresh');
|
|
|
|
$entry->headers->set('Age', $entry->getAge());
|
|
|
|
return $entry;
|
|
}
|
|
|
|
/**
|
|
* Validates that a cache entry is fresh.
|
|
*
|
|
* The original request is used as a template for a conditional
|
|
* GET request with the backend.
|
|
*
|
|
* @param bool $catch Whether to process exceptions
|
|
*
|
|
* @return Response
|
|
*/
|
|
protected function validate(Request $request, Response $entry, bool $catch = false)
|
|
{
|
|
$subRequest = clone $request;
|
|
|
|
// send no head requests because we want content
|
|
if ('HEAD' === $request->getMethod()) {
|
|
$subRequest->setMethod('GET');
|
|
}
|
|
|
|
// add our cached last-modified validator
|
|
if ($entry->headers->has('Last-Modified')) {
|
|
$subRequest->headers->set('If-Modified-Since', $entry->headers->get('Last-Modified'));
|
|
}
|
|
|
|
// Add our cached etag validator to the environment.
|
|
// We keep the etags from the client to handle the case when the client
|
|
// has a different private valid entry which is not cached here.
|
|
$cachedEtags = $entry->getEtag() ? [$entry->getEtag()] : [];
|
|
$requestEtags = $request->getETags();
|
|
if ($etags = array_unique(array_merge($cachedEtags, $requestEtags))) {
|
|
$subRequest->headers->set('If-None-Match', implode(', ', $etags));
|
|
}
|
|
|
|
$response = $this->forward($subRequest, $catch, $entry);
|
|
|
|
if (304 == $response->getStatusCode()) {
|
|
$this->record($request, 'valid');
|
|
|
|
// return the response and not the cache entry if the response is valid but not cached
|
|
$etag = $response->getEtag();
|
|
if ($etag && \in_array($etag, $requestEtags) && !\in_array($etag, $cachedEtags)) {
|
|
return $response;
|
|
}
|
|
|
|
$entry = clone $entry;
|
|
$entry->headers->remove('Date');
|
|
|
|
foreach (['Date', 'Expires', 'Cache-Control', 'ETag', 'Last-Modified'] as $name) {
|
|
if ($response->headers->has($name)) {
|
|
$entry->headers->set($name, $response->headers->get($name));
|
|
}
|
|
}
|
|
|
|
$response = $entry;
|
|
} else {
|
|
$this->record($request, 'invalid');
|
|
}
|
|
|
|
if ($response->isCacheable()) {
|
|
$this->store($request, $response);
|
|
}
|
|
|
|
return $response;
|
|
}
|
|
|
|
/**
|
|
* Unconditionally fetches a fresh response from the backend and
|
|
* stores it in the cache if is cacheable.
|
|
*
|
|
* @param bool $catch Whether to process exceptions
|
|
*
|
|
* @return Response
|
|
*/
|
|
protected function fetch(Request $request, bool $catch = false)
|
|
{
|
|
$subRequest = clone $request;
|
|
|
|
// send no head requests because we want content
|
|
if ('HEAD' === $request->getMethod()) {
|
|
$subRequest->setMethod('GET');
|
|
}
|
|
|
|
// avoid that the backend sends no content
|
|
$subRequest->headers->remove('If-Modified-Since');
|
|
$subRequest->headers->remove('If-None-Match');
|
|
|
|
$response = $this->forward($subRequest, $catch);
|
|
|
|
if ($response->isCacheable()) {
|
|
$this->store($request, $response);
|
|
}
|
|
|
|
return $response;
|
|
}
|
|
|
|
/**
|
|
* Forwards the Request to the backend and returns the Response.
|
|
*
|
|
* All backend requests (cache passes, fetches, cache validations)
|
|
* run through this method.
|
|
*
|
|
* @param bool $catch Whether to catch exceptions or not
|
|
* @param Response|null $entry A Response instance (the stale entry if present, null otherwise)
|
|
*
|
|
* @return Response
|
|
*/
|
|
protected function forward(Request $request, bool $catch = false, Response $entry = null)
|
|
{
|
|
if ($this->surrogate) {
|
|
$this->surrogate->addSurrogateCapability($request);
|
|
}
|
|
|
|
// always a "master" request (as the real master request can be in cache)
|
|
$response = SubRequestHandler::handle($this->kernel, $request, HttpKernelInterface::MAIN_REQUEST, $catch);
|
|
|
|
/*
|
|
* Support stale-if-error given on Responses or as a config option.
|
|
* RFC 7234 summarizes in Section 4.2.4 (but also mentions with the individual
|
|
* Cache-Control directives) that
|
|
*
|
|
* A cache MUST NOT generate a stale response if it is prohibited by an
|
|
* explicit in-protocol directive (e.g., by a "no-store" or "no-cache"
|
|
* cache directive, a "must-revalidate" cache-response-directive, or an
|
|
* applicable "s-maxage" or "proxy-revalidate" cache-response-directive;
|
|
* see Section 5.2.2).
|
|
*
|
|
* https://tools.ietf.org/html/rfc7234#section-4.2.4
|
|
*
|
|
* We deviate from this in one detail, namely that we *do* serve entries in the
|
|
* stale-if-error case even if they have a `s-maxage` Cache-Control directive.
|
|
*/
|
|
if (null !== $entry
|
|
&& \in_array($response->getStatusCode(), [500, 502, 503, 504])
|
|
&& !$entry->headers->hasCacheControlDirective('no-cache')
|
|
&& !$entry->mustRevalidate()
|
|
) {
|
|
if (null === $age = $entry->headers->getCacheControlDirective('stale-if-error')) {
|
|
$age = $this->options['stale_if_error'];
|
|
}
|
|
|
|
/*
|
|
* stale-if-error gives the (extra) time that the Response may be used *after* it has become stale.
|
|
* So we compare the time the $entry has been sitting in the cache already with the
|
|
* time it was fresh plus the allowed grace period.
|
|
*/
|
|
if ($entry->getAge() <= $entry->getMaxAge() + $age) {
|
|
$this->record($request, 'stale-if-error');
|
|
|
|
return $entry;
|
|
}
|
|
}
|
|
|
|
/*
|
|
RFC 7231 Sect. 7.1.1.2 says that a server that does not have a reasonably accurate
|
|
clock MUST NOT send a "Date" header, although it MUST send one in most other cases
|
|
except for 1xx or 5xx responses where it MAY do so.
|
|
|
|
Anyway, a client that received a message without a "Date" header MUST add it.
|
|
*/
|
|
if (!$response->headers->has('Date')) {
|
|
$response->setDate(\DateTime::createFromFormat('U', time()));
|
|
}
|
|
|
|
$this->processResponseBody($request, $response);
|
|
|
|
if ($this->isPrivateRequest($request) && !$response->headers->hasCacheControlDirective('public')) {
|
|
$response->setPrivate();
|
|
} elseif ($this->options['default_ttl'] > 0 && null === $response->getTtl() && !$response->headers->getCacheControlDirective('must-revalidate')) {
|
|
$response->setTtl($this->options['default_ttl']);
|
|
}
|
|
|
|
return $response;
|
|
}
|
|
|
|
/**
|
|
* Checks whether the cache entry is "fresh enough" to satisfy the Request.
|
|
*
|
|
* @return bool
|
|
*/
|
|
protected function isFreshEnough(Request $request, Response $entry)
|
|
{
|
|
if (!$entry->isFresh()) {
|
|
return $this->lock($request, $entry);
|
|
}
|
|
|
|
if ($this->options['allow_revalidate'] && null !== $maxAge = $request->headers->getCacheControlDirective('max-age')) {
|
|
return $maxAge > 0 && $maxAge >= $entry->getAge();
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Locks a Request during the call to the backend.
|
|
*
|
|
* @return bool true if the cache entry can be returned even if it is staled, false otherwise
|
|
*/
|
|
protected function lock(Request $request, Response $entry)
|
|
{
|
|
// try to acquire a lock to call the backend
|
|
$lock = $this->store->lock($request);
|
|
|
|
if (true === $lock) {
|
|
// we have the lock, call the backend
|
|
return false;
|
|
}
|
|
|
|
// there is already another process calling the backend
|
|
|
|
// May we serve a stale response?
|
|
if ($this->mayServeStaleWhileRevalidate($entry)) {
|
|
$this->record($request, 'stale-while-revalidate');
|
|
|
|
return true;
|
|
}
|
|
|
|
// wait for the lock to be released
|
|
if ($this->waitForLock($request)) {
|
|
// replace the current entry with the fresh one
|
|
$new = $this->lookup($request);
|
|
$entry->headers = $new->headers;
|
|
$entry->setContent($new->getContent());
|
|
$entry->setStatusCode($new->getStatusCode());
|
|
$entry->setProtocolVersion($new->getProtocolVersion());
|
|
foreach ($new->headers->getCookies() as $cookie) {
|
|
$entry->headers->setCookie($cookie);
|
|
}
|
|
} else {
|
|
// backend is slow as hell, send a 503 response (to avoid the dog pile effect)
|
|
$entry->setStatusCode(503);
|
|
$entry->setContent('503 Service Unavailable');
|
|
$entry->headers->set('Retry-After', 10);
|
|
}
|
|
|
|
return true;
|
|
}
|
|
|
|
/**
|
|
* Writes the Response to the cache.
|
|
*
|
|
* @throws \Exception
|
|
*/
|
|
protected function store(Request $request, Response $response)
|
|
{
|
|
try {
|
|
$this->store->write($request, $response);
|
|
|
|
$this->record($request, 'store');
|
|
|
|
$response->headers->set('Age', $response->getAge());
|
|
} catch (\Exception $e) {
|
|
$this->record($request, 'store-failed');
|
|
|
|
if ($this->options['debug']) {
|
|
throw $e;
|
|
}
|
|
}
|
|
|
|
// now that the response is cached, release the lock
|
|
$this->store->unlock($request);
|
|
}
|
|
|
|
/**
|
|
* Restores the Response body.
|
|
*/
|
|
private function restoreResponseBody(Request $request, Response $response)
|
|
{
|
|
if ($response->headers->has('X-Body-Eval')) {
|
|
ob_start();
|
|
|
|
if ($response->headers->has('X-Body-File')) {
|
|
include $response->headers->get('X-Body-File');
|
|
} else {
|
|
eval('; ?>'.$response->getContent().'<?php ;');
|
|
}
|
|
|
|
$response->setContent(ob_get_clean());
|
|
$response->headers->remove('X-Body-Eval');
|
|
if (!$response->headers->has('Transfer-Encoding')) {
|
|
$response->headers->set('Content-Length', \strlen($response->getContent()));
|
|
}
|
|
} elseif ($response->headers->has('X-Body-File')) {
|
|
// Response does not include possibly dynamic content (ESI, SSI), so we need
|
|
// not handle the content for HEAD requests
|
|
if (!$request->isMethod('HEAD')) {
|
|
$response->setContent(file_get_contents($response->headers->get('X-Body-File')));
|
|
}
|
|
} else {
|
|
return;
|
|
}
|
|
|
|
$response->headers->remove('X-Body-File');
|
|
}
|
|
|
|
protected function processResponseBody(Request $request, Response $response)
|
|
{
|
|
if (null !== $this->surrogate && $this->surrogate->needsParsing($response)) {
|
|
$this->surrogate->process($request, $response);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* Checks if the Request includes authorization or other sensitive information
|
|
* that should cause the Response to be considered private by default.
|
|
*/
|
|
private function isPrivateRequest(Request $request): bool
|
|
{
|
|
foreach ($this->options['private_headers'] as $key) {
|
|
$key = strtolower(str_replace('HTTP_', '', $key));
|
|
|
|
if ('cookie' === $key) {
|
|
if (\count($request->cookies->all())) {
|
|
return true;
|
|
}
|
|
} elseif ($request->headers->has($key)) {
|
|
return true;
|
|
}
|
|
}
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* Records that an event took place.
|
|
*/
|
|
private function record(Request $request, string $event)
|
|
{
|
|
$this->traces[$this->getTraceKey($request)][] = $event;
|
|
}
|
|
|
|
/**
|
|
* Calculates the key we use in the "trace" array for a given request.
|
|
*/
|
|
private function getTraceKey(Request $request): string
|
|
{
|
|
$path = $request->getPathInfo();
|
|
if ($qs = $request->getQueryString()) {
|
|
$path .= '?'.$qs;
|
|
}
|
|
|
|
return $request->getMethod().' '.$path;
|
|
}
|
|
|
|
/**
|
|
* Checks whether the given (cached) response may be served as "stale" when a revalidation
|
|
* is currently in progress.
|
|
*/
|
|
private function mayServeStaleWhileRevalidate(Response $entry): bool
|
|
{
|
|
$timeout = $entry->headers->getCacheControlDirective('stale-while-revalidate');
|
|
|
|
if (null === $timeout) {
|
|
$timeout = $this->options['stale_while_revalidate'];
|
|
}
|
|
|
|
return abs($entry->getTtl()) < $timeout;
|
|
}
|
|
|
|
/**
|
|
* Waits for the store to release a locked entry.
|
|
*/
|
|
private function waitForLock(Request $request): bool
|
|
{
|
|
$wait = 0;
|
|
while ($this->store->isLocked($request) && $wait < 100) {
|
|
usleep(50000);
|
|
++$wait;
|
|
}
|
|
|
|
return $wait < 100;
|
|
}
|
|
}
|