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NyholmNyholm
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Added a PSR6 cache plugin
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3 files changed

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‎composer.json

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"php-http/cookie": "^0.1@dev",
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"symfony/stopwatch": "^2.3",
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"psr/log": "^1.0",
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"psr/cache": "1.0.0",
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"php-http/encoding": "^0.1@dev"
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},
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"autoload": {
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"php-http/cookie": "Allow to use CookiePlugin",
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"symfony/stopwatch": "Allow to use the StopwatchPlugin",
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"psr/log-implementation": "Allow to use the LoggerPlugin",
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"psr/cache-implementation": "Allow to use the CachePlugin",
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"php-http/encoding": "Allow to use the Decoder and Encoder plugin"
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},
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"scripts": {

‎spec/CachePluginSpec.php

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<?php
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namespace spec\Http\Client\Plugin;
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use Http\Client\Tools\Promise\FulfilledPromise;
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use PhpSpec\ObjectBehavior;
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use Psr\Cache\CacheItemInterface;
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use Psr\Cache\CacheItemPoolInterface;
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use Psr\Http\Message\RequestInterface;
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use Psr\Http\Message\ResponseInterface;
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class CachePluginSpec extends ObjectBehavior
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{
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function let(CacheItemPoolInterface $pool)
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{
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$this->beConstructedWith($pool, ['default_ttl'=>60]);
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}
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function it_is_initializable(CacheItemPoolInterface $pool)
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{
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$this->shouldHaveType('Http\Client\Plugin\CachePlugin');
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}
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function it_is_a_plugin()
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{
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$this->shouldImplement('Http\Client\Plugin\Plugin');
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}
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function it_caches_responses(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
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{
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$request->getMethod()->willReturn('GET');
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$request->getUri()->willReturn('/');
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$response->getStatusCode()->willReturn(200);
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$response->getHeader('Cache-Control')->willReturn(array());
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$response->getHeader('Expires')->willReturn(array());
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$pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
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$item->isHit()->willReturn(false);
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$item->set($response)->willReturn($item)->shouldBeCalled();
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$item->expiresAfter(60)->willReturn($item)->shouldBeCalled();
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$pool->save($item)->shouldBeCalled();
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$next = function (RequestInterface $request) use ($response) {
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return new FulfilledPromise($response->getWrappedObject());
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};
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$this->handleRequest($request, $next, function () {});
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}
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function it_doesnt_store_failed_responses(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
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{
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$request->getMethod()->willReturn('GET');
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$request->getUri()->willReturn('/');
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$response->getStatusCode()->willReturn(400);
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$response->getHeader('Cache-Control')->willReturn(array());
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$response->getHeader('Expires')->willReturn(array());
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$pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
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$item->isHit()->willReturn(false);
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$next = function (RequestInterface $request) use ($response) {
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return new FulfilledPromise($response->getWrappedObject());
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};
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$this->handleRequest($request, $next, function () {});
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}
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function it_doesnt_store_post_requests(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
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{
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$request->getMethod()->willReturn('POST');
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$request->getUri()->willReturn('/');
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$next = function (RequestInterface $request) use ($response) {
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return new FulfilledPromise($response->getWrappedObject());
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};
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$this->handleRequest($request, $next, function () {});
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}
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function it_calculate_age_from_response(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
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{
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$request->getMethod()->willReturn('GET');
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$request->getUri()->willReturn('/');
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$response->getStatusCode()->willReturn(200);
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$response->getHeader('Cache-Control')->willReturn(array('max-age=40'));
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$response->getHeader('Age')->willReturn(array('15'));
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$response->getHeader('Expires')->willReturn(array());
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$pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
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$item->isHit()->willReturn(false);
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// 40-15 should be 25
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$item->set($response)->willReturn($item)->shouldBeCalled();
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$item->expiresAfter(25)->willReturn($item)->shouldBeCalled();
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$pool->save($item)->shouldBeCalled();
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$next = function (RequestInterface $request) use ($response) {
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return new FulfilledPromise($response->getWrappedObject());
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};
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$this->handleRequest($request, $next, function () {});
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}
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}

‎src/CachePlugin.php

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<?php
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namespace Http\Client\Plugin;
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use Http\Client\Tools\Promise\FulfilledPromise;
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use Psr\Cache\CacheItemPoolInterface;
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use Psr\Http\Message\RequestInterface;
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use Psr\Http\Message\ResponseInterface;
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/**
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* Allow for caching a response.
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*
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* @author Tobias Nyholm <[email protected]>
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*/
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class CachePlugin implements Plugin
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{
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/**
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* @var CacheItemPoolInterface
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*/
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private $pool;
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/**
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* Default time to store object in cache. This value is used if CachePlugin::respectCacheHeaders is false or
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* if cache headers are missing.
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*
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* @var int
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*/
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private $defaultTtl;
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/**
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* Look at the cache headers to know how long this response is going to be cached.
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*
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* @var bool
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*/
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private $respectCacheHeaders;
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/**
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* @param CacheItemPoolInterface $pool
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* @param array $options
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*/
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public function __construct(CacheItemPoolInterface $pool, array $options = [])
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{
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$this->pool = $pool;
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$this->defaultTtl = isset($options['default_ttl']) ? $options['default_ttl'] : null;
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$this->respectCacheHeaders = isset($options['respect_cache_headers']) ? $options['respect_cache_headers'] : true;
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}
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/**
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* {@inheritdoc}
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*/
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public function handleRequest(RequestInterface $request, callable $next, callable $first)
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{
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$method = strtoupper($request->getMethod());
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// if the request not is cachable, move to $next
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if ($method !== 'GET' && $method !== 'HEAD') {
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return $next($request);
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}
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// If we can cache the request
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$key = $this->createCacheKey($request);
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$cacheItem = $this->pool->getItem($key);
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if ($cacheItem->isHit()) {
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// return cached response
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return new FulfilledPromise($cacheItem->get());
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}
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return $next($request)->then(function (ResponseInterface $response) use ($cacheItem) {
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if ($this->isCacheable($response)) {
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$cacheItem->set($response)
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->expiresAfter($this->getMaxAge($response));
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$this->pool->save($cacheItem);
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}
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return $response;
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});
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}
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/**
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* Verify that we can cache this response.
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*
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* @param ResponseInterface $response
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*
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* @return bool
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*/
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protected function isCacheable(ResponseInterface $response)
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{
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if (!in_array($response->getStatusCode(), [200, 203, 300, 301, 302, 404, 410])) {
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return false;
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}
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if ($this->getCacheControlDirective($response, 'no-store') || $this->getCacheControlDirective($response, 'private')) {
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return false;
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}
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return true;
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}
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/**
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* Returns the value of a parameter in the cache control header. If not found we return false. If found with no
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* value return true.
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*
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* @param ResponseInterface $response
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* @param string $name
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*
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* @return bool|string
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*/
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private function getCacheControlDirective(ResponseInterface $response, $name)
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{
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$headers = $response->getHeader('Cache-Control');
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foreach ($headers as $header) {
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if (preg_match(sprintf('|%s=?([0-9]+)?|i', $name), $header, $matches)) {
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// return the value for $name if it exists
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if (isset($matches[1])) {
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return $matches[1];
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}
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return true;
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}
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}
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return false;
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}
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/**
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* @param RequestInterface $request
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*
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* @return string
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*/
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private function createCacheKey(RequestInterface $request)
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{
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return md5($request->getMethod().' '.$request->getUri());
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}
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/**
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* Get a ttl in seconds. It could return null if we do not respect cache headers and got no defaultTtl.
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*
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* @param ResponseInterface $response
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*
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* @return int|null
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*/
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private function getMaxAge(ResponseInterface $response)
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{
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if (!$this->respectCacheHeaders) {
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return $this->defaultTtl;
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}
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// check for max age in the Cache-Control header
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$maxAge = $this->getCacheControlDirective($response, 'max-age');
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if (!is_bool($maxAge)) {
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$ageHeaders = $response->getHeader('Age');
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foreach ($ageHeaders as $age) {
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return $maxAge - ((int) $age);
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}
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return $maxAge;
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}
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// check for ttl in the Expires header
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$headers = $response->getHeader('Expires');
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foreach ($headers as $header) {
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return (new \DateTime($header))->getTimestamp() - (new \DateTime())->getTimestamp();
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}
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return $this->defaultTtl;
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}
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}

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