CachePlugin::isCacheable() - Code Metrics - Inspection of "Optionally enable caching of POST requests" - php-http/cache-plugin - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#24)

unknown

created 2017-02-11 05:58 UTC

CachePlugin::isCacheable() B

↳ Parent: CachePlugin

Complexity

Conditions	5
Paths	4

Size

Total Lines	14
Code Lines	8

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	6
CRAP Score	5.3906

Importance

Changes

Metric	Value
dl	0
loc	14
ccs	6
cts	8
cp	0.75
rs	8.8571
c	0
b	0
f	0
cc	5
eloc	8
nc	4
nop	1
crap	5.3906

<?php

namespace Http\Client\Common\Plugin;

use Http\Client\Common\Plugin;
use Http\Message\StreamFactory;
use Http\Promise\FulfilledPromise;
use Psr\Cache\CacheItemInterface;
use Psr\Cache\CacheItemPoolInterface;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
use Symfony\Component\OptionsResolver\OptionsResolver;

/**
 * Allow for caching a response.
 *
 * @author Tobias Nyholm <[email protected]>
 */
final class CachePlugin implements Plugin
{
    /**
     * @var CacheItemPoolInterface
     */
    private $pool;

    /**
     * @var StreamFactory
     */
    private $streamFactory;

    /**
     * @var array
     */
    private $config;

    /**
     * @param CacheItemPoolInterface $pool
     * @param StreamFactory          $streamFactory
     * @param array                  $config        {
     *
     *     @var bool $respect_cache_headers Whether to look at the cache directives or ignore them
     *     @var int $default_ttl (seconds) If we do not respect cache headers or can't calculate a good ttl, use this
     *              value
     *     @var string $hash_algo The hashing algorithm to use when generating cache keys
     *     @var int $cache_lifetime (seconds) To support serving a previous stale response when the server answers 304
     *              we have to store the cache for a longer time than the server originally says it is valid for.
     *              We store a cache item for $cache_lifetime + max age of the response.
     * }
     */
    public function __construct(CacheItemPoolInterface $pool, StreamFactory $streamFactory, array $config = [])
    {
        $this->pool = $pool;
        $this->streamFactory = $streamFactory;

        $optionsResolver = new OptionsResolver();
        $this->configureOptions($optionsResolver);
        $this->config = $optionsResolver->resolve($config);
    }

    /**
     * {@inheritdoc}
     */
    public function handleRequest(RequestInterface $request, callable $next, callable $first)
    {
        $method = strtoupper($request->getMethod());
        // if the request not is cachable, move to $next
        if (!in_array($method, $this->config['methods'])) {
            return $next($request);
        }

        // If we can cache the request
        $key = $this->createCacheKey($request);
        $cacheItem = $this->pool->getItem($key);

        if ($cacheItem->isHit()) {
            $data = $cacheItem->get();
            // The array_key_exists() is to be removed in 2.0.
            if (array_key_exists('expiresAt', $data) && ($data['expiresAt'] === null || time() < $data['expiresAt'])) {
                // This item is still valid according to previous cache headers
                return new FulfilledPromise($this->createResponseFromCacheItem($cacheItem));
            }

            // Add headers to ask the server if this cache is still valid
            if ($modifiedSinceValue = $this->getModifiedSinceHeaderValue($cacheItem)) {
                $request = $request->withHeader('If-Modified-Since', $modifiedSinceValue);
            }

            if ($etag = $this->getETag($cacheItem)) {
                $request = $request->withHeader('If-None-Match', $etag);
            }
        }

        return $next($request)->then(function (ResponseInterface $response) use ($cacheItem) {
            if (304 === $response->getStatusCode()) {
                if (!$cacheItem->isHit()) {
                    /*
                     * We do not have the item in cache. This plugin did not add If-Modified-Since
                     * or If-None-Match headers. Return the response from server.
                     */
                    return $response;
                }

                // The cached response we have is still valid
                $data = $cacheItem->get();
                $maxAge = $this->getMaxAge($response);
                $data['expiresAt'] = $this->calculateResponseExpiresAt($maxAge);
                $cacheItem->set($data)->expiresAfter($this->calculateCacheItemExpiresAfter($maxAge));
                $this->pool->save($cacheItem);

                return $this->createResponseFromCacheItem($cacheItem);
            }

            if ($this->isCacheable($response)) {
                $bodyStream = $response->getBody();
                $body = $bodyStream->__toString();
                if ($bodyStream->isSeekable()) {
                    $bodyStream->rewind();
                } else {
                    $response = $response->withBody($this->streamFactory->createStream($body));
                }

                $maxAge = $this->getMaxAge($response);
                $cacheItem
                    ->expiresAfter($this->calculateCacheItemExpiresAfter($maxAge))
                    ->set([
                        'response' => $response,
                        'body' => $body,
                        'expiresAt' => $this->calculateResponseExpiresAt($maxAge),
                        'createdAt' => time(),
                        'etag' => $response->getHeader('ETag'),
                    ]);
                $this->pool->save($cacheItem);
            }

            return $response;
        });
    }

    /**
     * Calculate the timestamp when this cache item should be dropped from the cache. The lowest value that can be
     * returned is $maxAge.
     *
     * @param int|null $maxAge
     *
     * @return int|null Unix system time passed to the PSR-6 cache
     */
    private function calculateCacheItemExpiresAfter($maxAge)
    {
        if ($this->config['cache_lifetime'] === null && $maxAge === null) {
            return;
        }

        return $this->config['cache_lifetime'] + $maxAge;
    }

    /**
     * Calculate the timestamp when a response expires. After that timestamp, we need to send a
     * If-Modified-Since / If-None-Match request to validate the response.
     *
     * @param int|null $maxAge
     *
     * @return int|null Unix system time. A null value means that the response expires when the cache item expires
     */
    private function calculateResponseExpiresAt($maxAge)
    {
        if ($maxAge === null) {
            return;
        }

        return time() + $maxAge;
    }

    /**
     * Verify that we can cache this response.
     *
     * @param ResponseInterface $response
     *
     * @return bool
     */
    protected function isCacheable(ResponseInterface $response)
    {
        if (!in_array($response->getStatusCode(), [200, 203, 300, 301, 302, 404, 410])) {
            return false;
        }
        if (!$this->config['respect_cache_headers']) {
            return true;
        }
        if ($this->getCacheControlDirective($response, 'no-store') || $this->getCacheControlDirective($response, 'private')) {
            return false;
        }

        return true;
    }

    /**
     * Get the value of a parameter in the cache control header.
     *
     * @param ResponseInterface $response
     * @param string            $name     The field of Cache-Control to fetch
     *
     * @return bool|string The value of the directive, true if directive without value, false if directive not present
     */
    private function getCacheControlDirective(ResponseInterface $response, $name)
    {
        $headers = $response->getHeader('Cache-Control');
        foreach ($headers as $header) {
            if (preg_match(sprintf('|%s=?([0-9]+)?|i', $name), $header, $matches)) {
                // return the value for $name if it exists
                if (isset($matches[1])) {
                    return $matches[1];
                }

                return true;
            }
        }

        return false;
    }

    /**
     * @param RequestInterface $request
     *
     * @return string
     */
    private function createCacheKey(RequestInterface $request)
    {
        if ('POST' === $request->getMethod()) {
            return hash($this->config['hash_algo'], $request->getMethod().' '.$request->getUri().' '.$request->getBody());
        }

        return hash($this->config['hash_algo'], $request->getMethod().' '.$request->getUri());
    }

    /**
     * Get a ttl in seconds. It could return null if we do not respect cache headers and got no defaultTtl.
     *
     * @param ResponseInterface $response
     *
     * @return int|null
     */
    private function getMaxAge(ResponseInterface $response)
    {
        if (!$this->config['respect_cache_headers']) {
            return $this->config['default_ttl'];
        }

        // check for max age in the Cache-Control header
        $maxAge = $this->getCacheControlDirective($response, 'max-age');
        if (!is_bool($maxAge)) {
            $ageHeaders = $response->getHeader('Age');
            foreach ($ageHeaders as $age) {
                return $maxAge - ((int) $age);
            }

            return (int) $maxAge;
        }

        // check for ttl in the Expires header
        $headers = $response->getHeader('Expires');
        foreach ($headers as $header) {
            return (new \DateTime($header))->getTimestamp() - (new \DateTime())->getTimestamp();
        }

        return $this->config['default_ttl'];
    }

    /**
     * Configure an options resolver.
     *
     * @param OptionsResolver $resolver
     */
    private function configureOptions(OptionsResolver $resolver)
    {
        $resolver->setDefaults([
            'cache_lifetime' => 86400 * 30, // 30 days
            'default_ttl' => 0,
            'respect_cache_headers' => true,
            'hash_algo' => 'sha1',
            'methods' => ['GET', 'HEAD'],
        ]);

        $resolver->setAllowedTypes('cache_lifetime', ['int', 'null']);
        $resolver->setAllowedTypes('default_ttl', ['int', 'null']);
        $resolver->setAllowedTypes('respect_cache_headers', 'bool');
        $resolver->setAllowedTypes('methods', 'array');
        $resolver->setAllowedValues('hash_algo', hash_algos());
        $resolver->setAllowedValues('methods', function ($value) {
            return 0 === count(array_diff($value, ['GET', 'HEAD', 'POST']));
        });
    }

    /**
     * @param CacheItemInterface $cacheItem
     *
     * @return ResponseInterface
     */
    private function createResponseFromCacheItem(CacheItemInterface $cacheItem)
    {
        $data = $cacheItem->get();

        /** @var ResponseInterface $response */
        $response = $data['response'];
        $response = $response->withBody($this->streamFactory->createStream($data['body']));

        return $response;
    }

    /**
     * Get the value of the "If-Modified-Since" header.
     *
     * @param CacheItemInterface $cacheItem
     *
     * @return string|null
     */
    private function getModifiedSinceHeaderValue(CacheItemInterface $cacheItem)
    {
        $data = $cacheItem->get();
        // The isset() is to be removed in 2.0.
        if (!isset($data['createdAt'])) {
            return;
        }

        $modified = new \DateTime('@'.$data['createdAt']);
        $modified->setTimezone(new \DateTimeZone('GMT'));

        return sprintf('%s GMT', $modified->format('l, d-M-y H:i:s'));
    }

    /**
     * Get the ETag from the cached response.
     *
     * @param CacheItemInterface $cacheItem
     *
     * @return string|null
     */
    private function getETag(CacheItemInterface $cacheItem)
    {
        $data = $cacheItem->get();
        // The isset() is to be removed in 2.0.
        if (!isset($data['etag'])) {
            return;
        }

        if (!is_array($data['etag'])) {
            return $data['etag'];
        }

        foreach ($data['etag'] as $etag) {
            if (!empty($etag)) {
                return $etag;
            }
        }
    }
}


1		<?php
2
3		namespace Http\Client\Common\Plugin;
4
5		use Http\Client\Common\Plugin;
6		use Http\Message\StreamFactory;
7		use Http\Promise\FulfilledPromise;
8		use Psr\Cache\CacheItemInterface;
9		use Psr\Cache\CacheItemPoolInterface;
10		use Psr\Http\Message\RequestInterface;
11		use Psr\Http\Message\ResponseInterface;
12		use Symfony\Component\OptionsResolver\OptionsResolver;
13
14		/**
15		* Allow for caching a response.
16		*
17		* @author Tobias Nyholm <[email protected]>
18		*/
19		final class CachePlugin implements Plugin
20		{
21		/**
22		* @var CacheItemPoolInterface
23		*/
24		private $pool;
25
26		/**
27		* @var StreamFactory
28		*/
29		private $streamFactory;
30
31		/**
32		* @var array
33		*/
34		private $config;
35
36		/**
37		* @param CacheItemPoolInterface $pool
38		* @param StreamFactory $streamFactory
39		* @param array $config {
40		*
41		* @var bool $respect_cache_headers Whether to look at the cache directives or ignore them
42		* @var int $default_ttl (seconds) If we do not respect cache headers or can't calculate a good ttl, use this
43		* value
44		* @var string $hash_algo The hashing algorithm to use when generating cache keys
45		* @var int $cache_lifetime (seconds) To support serving a previous stale response when the server answers 304
46		* we have to store the cache for a longer time than the server originally says it is valid for.
47		* We store a cache item for $cache_lifetime + max age of the response.
48		* }
49		*/
50	11	public function __construct(CacheItemPoolInterface $pool, StreamFactory $streamFactory, array $config = [])
51		{
52	11	$this->pool = $pool;
53	11	$this->streamFactory = $streamFactory;
54
55	11	$optionsResolver = new OptionsResolver();
56	11	$this->configureOptions($optionsResolver);
57	11	$this->config = $optionsResolver->resolve($config);
58	11	}
59
60		/**
61		* {@inheritdoc}
62		*/
63	9	public function handleRequest(RequestInterface $request, callable $next, callable $first)
64	1	{
65	9	$method = strtoupper($request->getMethod());
66		// if the request not is cachable, move to $next
67	9	if (!in_array($method, $this->config['methods'])) {
68	1	return $next($request);
69		}
70
71		// If we can cache the request
72	8	$key = $this->createCacheKey($request);
73	8	$cacheItem = $this->pool->getItem($key);
74
75	8	if ($cacheItem->isHit()) {
76	3	$data = $cacheItem->get();
77		// The array_key_exists() is to be removed in 2.0.
78	3	if (array_key_exists('expiresAt', $data) && ($data['expiresAt'] === null \|\| time() < $data['expiresAt'])) {
79		// This item is still valid according to previous cache headers
80	1	return new FulfilledPromise($this->createResponseFromCacheItem($cacheItem));
81		}
82
83		// Add headers to ask the server if this cache is still valid
84	2	if ($modifiedSinceValue = $this->getModifiedSinceHeaderValue($cacheItem)) {
85	2	$request = $request->withHeader('If-Modified-Since', $modifiedSinceValue);
86	2	}
87
88	2	if ($etag = $this->getETag($cacheItem)) {
89	2	$request = $request->withHeader('If-None-Match', $etag);
90	2	}
91	2	}
92
93		return $next($request)->then(function (ResponseInterface $response) use ($cacheItem) {
94	7	if (304 === $response->getStatusCode()) {
95	2	if (!$cacheItem->isHit()) {
96		/*
97		* We do not have the item in cache. This plugin did not add If-Modified-Since
98		* or If-None-Match headers. Return the response from server.
99		*/
100	1	return $response;
101		}
102
103		// The cached response we have is still valid
104	1	$data = $cacheItem->get();
105	1	$maxAge = $this->getMaxAge($response);
106	1	$data['expiresAt'] = $this->calculateResponseExpiresAt($maxAge);
107	1	$cacheItem->set($data)->expiresAfter($this->calculateCacheItemExpiresAfter($maxAge));
108	1	$this->pool->save($cacheItem);
109
110	1	return $this->createResponseFromCacheItem($cacheItem);
111		}
112
113	5	if ($this->isCacheable($response)) {
114	4	$bodyStream = $response->getBody();
115	4	$body = $bodyStream->__toString();
116	4	if ($bodyStream->isSeekable()) {
117	4	$bodyStream->rewind();
118	4	} else {
119		$response = $response->withBody($this->streamFactory->createStream($body));
120		}
121
122	4	$maxAge = $this->getMaxAge($response);
123		$cacheItem
124	4	->expiresAfter($this->calculateCacheItemExpiresAfter($maxAge))
125	4	->set([
126	4	'response' => $response,
127	4	'body' => $body,
128	4	'expiresAt' => $this->calculateResponseExpiresAt($maxAge),
129	4	'createdAt' => time(),
130	4	'etag' => $response->getHeader('ETag'),
131	4	]);
132	4	$this->pool->save($cacheItem);
133	4	}
134
135	5	return $response;
136	7	});
137		}
138
139		/**
140		* Calculate the timestamp when this cache item should be dropped from the cache. The lowest value that can be
141		* returned is $maxAge.
142		*
143		* @param int\|null $maxAge
144		*
145		* @return int\|null Unix system time passed to the PSR-6 cache
146		*/
147	5	private function calculateCacheItemExpiresAfter($maxAge)
148		{
149	5	if ($this->config['cache_lifetime'] === null && $maxAge === null) {
150		return;
151		}
152
153	5	return $this->config['cache_lifetime'] + $maxAge;
154		}
155
156		/**
157		* Calculate the timestamp when a response expires. After that timestamp, we need to send a
158		* If-Modified-Since / If-None-Match request to validate the response.
159		*
160		* @param int\|null $maxAge
161		*
162		* @return int\|null Unix system time. A null value means that the response expires when the cache item expires
163		*/
164	5	private function calculateResponseExpiresAt($maxAge)
165		{
166	5	if ($maxAge === null) {
167		return;
168		}
169
170	5	return time() + $maxAge;
171		}
172
173		/**
174		* Verify that we can cache this response.
175		*
176		* @param ResponseInterface $response
177		*
178		* @return bool
179		*/
180	5	protected function isCacheable(ResponseInterface $response)
181		{
182	5	if (!in_array($response->getStatusCode(), [200, 203, 300, 301, 302, 404, 410])) {
183	1	return false;
184		}
185	4	if (!$this->config['respect_cache_headers']) {
186		return true;
187		}
188	4	if ($this->getCacheControlDirective($response, 'no-store') \|\| $this->getCacheControlDirective($response, 'private')) {
189		return false;
190		}
191
192	4	return true;
193		}
194
195		/**
196		* Get the value of a parameter in the cache control header.
197		*
198		* @param ResponseInterface $response
199		* @param string $name The field of Cache-Control to fetch
200		*
201		* @return bool\|string The value of the directive, true if directive without value, false if directive not present
202		*/
203	5	private function getCacheControlDirective(ResponseInterface $response, $name)
204		{
205	5	$headers = $response->getHeader('Cache-Control');
206	5	foreach ($headers as $header) {
207	1	if (preg_match(sprintf('\|%s=?([0-9]+)?\|i', $name), $header, $matches)) {
208		// return the value for $name if it exists
209	1	if (isset($matches[1])) {
210	1	return $matches[1];
211		}
212
213		return true;
214		}
215	5	}
216
217	5	return false;
218		}
219
220		/**
221		* @param RequestInterface $request
222		*
223		* @return string
224		*/
225	8	private function createCacheKey(RequestInterface $request)
226		{
227	8	if ('POST' === $request->getMethod()) {
228	1	return hash($this->config['hash_algo'], $request->getMethod().' '.$request->getUri().' '.$request->getBody());
229		}
230
231	7	return hash($this->config['hash_algo'], $request->getMethod().' '.$request->getUri());
232		}
233
234		/**
235		* Get a ttl in seconds. It could return null if we do not respect cache headers and got no defaultTtl.
236		*
237		* @param ResponseInterface $response
238		*
239		* @return int\|null
240		*/
241	5	private function getMaxAge(ResponseInterface $response)
242		{
243	5	if (!$this->config['respect_cache_headers']) {
244		return $this->config['default_ttl'];
245		}
246
247		// check for max age in the Cache-Control header
248	5	$maxAge = $this->getCacheControlDirective($response, 'max-age');
249	5	if (!is_bool($maxAge)) {
250	1	$ageHeaders = $response->getHeader('Age');
251	1	foreach ($ageHeaders as $age) {
252	1	return $maxAge - ((int) $age);
253		}
254
255		return (int) $maxAge;
256		}
257
258		// check for ttl in the Expires header
259	4	$headers = $response->getHeader('Expires');
260	4	foreach ($headers as $header) {
261		return (new \DateTime($header))->getTimestamp() - (new \DateTime())->getTimestamp();
262	4	}
263
264	4	return $this->config['default_ttl'];
265		}
266
267		/**
268		* Configure an options resolver.
269		*
270		* @param OptionsResolver $resolver
271		*/
272	11	private function configureOptions(OptionsResolver $resolver)
273		{
274	11	$resolver->setDefaults([
275	11	'cache_lifetime' => 86400 * 30, // 30 days
276	11	'default_ttl' => 0,
277	11	'respect_cache_headers' => true,
278	11	'hash_algo' => 'sha1',
279	11	'methods' => ['GET', 'HEAD'],
280	11	]);
281
282	11	$resolver->setAllowedTypes('cache_lifetime', ['int', 'null']);
283	11	$resolver->setAllowedTypes('default_ttl', ['int', 'null']);
284	11	$resolver->setAllowedTypes('respect_cache_headers', 'bool');
285	11	$resolver->setAllowedTypes('methods', 'array');
286	11	$resolver->setAllowedValues('hash_algo', hash_algos());
287	11	$resolver->setAllowedValues('methods', function ($value) {
288	11	return 0 === count(array_diff($value, ['GET', 'HEAD', 'POST']));
289	11	});
290	11	}
291
292		/**
293		* @param CacheItemInterface $cacheItem
294		*
295		* @return ResponseInterface
296		*/
297	2	private function createResponseFromCacheItem(CacheItemInterface $cacheItem)
298		{
299	2	$data = $cacheItem->get();
300
301		/** @var ResponseInterface $response */
302	2	$response = $data['response'];
303	2	$response = $response->withBody($this->streamFactory->createStream($data['body']));
304
305	2	return $response;
306		}
307
308		/**
309		* Get the value of the "If-Modified-Since" header.
310		*
311		* @param CacheItemInterface $cacheItem
312		*
313		* @return string\|null
314		*/
315	2	private function getModifiedSinceHeaderValue(CacheItemInterface $cacheItem)
316		{
317	2	$data = $cacheItem->get();
318		// The isset() is to be removed in 2.0.
319	2	if (!isset($data['createdAt'])) {
320		return;
321		}
322
323	2	$modified = new \DateTime('@'.$data['createdAt']);
324	2	$modified->setTimezone(new \DateTimeZone('GMT'));
325
326	2	return sprintf('%s GMT', $modified->format('l, d-M-y H:i:s'));
327		}
328
329		/**
330		* Get the ETag from the cached response.
331		*
332		* @param CacheItemInterface $cacheItem
333		*
334		* @return string\|null
335		*/
336	2	private function getETag(CacheItemInterface $cacheItem)
337		{
338	2	$data = $cacheItem->get();
339		// The isset() is to be removed in 2.0.
340	2	if (!isset($data['etag'])) {
341		return;
342		}
343
344	2	if (!is_array($data['etag'])) {
345		return $data['etag'];
346		}
347
348	2	foreach ($data['etag'] as $etag) {
349	2	if (!empty($etag)) {
350	2	return $etag;
351		}
352		}
353		}
354		}
355

php-http / cache-plugin

Pull Request — master (#24)

CachePlugin::isCacheable() B

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