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[CachePlugin] Streams are not cached #21

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Merged
merged 4 commits into from
Dec 25, 2015
Merged

[CachePlugin] Streams are not cached #21

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63c3f5f
Make sure we cache the message body
Nyholm Dec 18, 2015
7b9ae72
Added options resolver
Nyholm Dec 19, 2015
ddd69ba
Make sure to rewind the stream or create a new one if needed
Nyholm Dec 21, 2015
5a6cbb1
minor
Nyholm Dec 22, 2015
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4 changes: 3 additions & 1 deletion composer.json
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Original file line number Diff line number Diff line change
Expand Up @@ -13,7 +13,9 @@
"require": {
"php": ">=5.4",
"php-http/httplug": "1.0.0-beta",
"php-http/client-tools": "^0.1@dev"
"php-http/client-tools": "^0.1@dev",
"php-http/message-factory": "^1.0",
"symfony/options-resolver": "^2.6|^3.0"
},
"require-dev": {
"phpspec/phpspec": "^2.4-alpha",
Expand Down
22 changes: 16 additions & 6 deletions spec/CachePluginSpec.php
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Expand Up @@ -3,17 +3,19 @@
namespace spec\Http\Client\Plugin;

use Http\Client\Tools\Promise\FulfilledPromise;
use Http\Message\StreamFactory;
use PhpSpec\ObjectBehavior;
use Psr\Cache\CacheItemInterface;
use Psr\Cache\CacheItemPoolInterface;
use Psr\Http\Message\RequestInterface;
use Psr\Http\Message\ResponseInterface;
use Psr\Http\Message\StreamInterface;

class CachePluginSpec extends ObjectBehavior
{
function let(CacheItemPoolInterface $pool)
function let(CacheItemPoolInterface $pool, StreamFactory $streamFactory)
{
$this->beConstructedWith($pool, ['default_ttl'=>60]);
$this->beConstructedWith($pool, $streamFactory, ['default_ttl'=>60]);
}

function it_is_initializable(CacheItemPoolInterface $pool)
Expand All @@ -26,17 +28,21 @@ function it_is_a_plugin()
$this->shouldImplement('Http\Client\Plugin\Plugin');
}

function it_caches_responses(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
function it_caches_responses(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response, StreamInterface $stream)
{
$httpBody = 'body';
$stream->__toString()->willReturn($httpBody);

$request->getMethod()->willReturn('GET');
$request->getUri()->willReturn('/');
$response->getStatusCode()->willReturn(200);
$response->getBody()->willReturn($stream);
$response->getHeader('Cache-Control')->willReturn(array());
$response->getHeader('Expires')->willReturn(array());

$pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
$item->isHit()->willReturn(false);
$item->set($response)->willReturn($item)->shouldBeCalled();
$item->set(['response' => $response, 'body' => $httpBody])->willReturn($item)->shouldBeCalled();
$item->expiresAfter(60)->willReturn($item)->shouldBeCalled();
$pool->save($item)->shouldBeCalled();

Expand Down Expand Up @@ -78,11 +84,15 @@ function it_doesnt_store_post_requests(CacheItemPoolInterface $pool, CacheItemIn
}


function it_calculate_age_from_response(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
function it_calculate_age_from_response(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response, StreamInterface $stream)
{
$httpBody = 'body';
$stream->__toString()->willReturn($httpBody);

$request->getMethod()->willReturn('GET');
$request->getUri()->willReturn('/');
$response->getStatusCode()->willReturn(200);
$response->getBody()->willReturn($stream);
$response->getHeader('Cache-Control')->willReturn(array('max-age=40'));
$response->getHeader('Age')->willReturn(array('15'));
$response->getHeader('Expires')->willReturn(array());
Expand All @@ -91,7 +101,7 @@ function it_calculate_age_from_response(CacheItemPoolInterface $pool, CacheItemI
$item->isHit()->willReturn(false);

// 40-15 should be 25
$item->set($response)->willReturn($item)->shouldBeCalled();
$item->set(['response' => $response, 'body' => $httpBody])->willReturn($item)->shouldBeCalled();
$item->expiresAfter(25)->willReturn($item)->shouldBeCalled();
$pool->save($item)->shouldBeCalled();

Expand Down
65 changes: 44 additions & 21 deletions src/CachePlugin.php
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Original file line number Diff line number Diff line change
Expand Up @@ -3,9 +3,11 @@
namespace Http\Client\Plugin;

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

/**
* Allow for caching a response.
Expand All @@ -20,33 +22,32 @@ class CachePlugin implements Plugin
private $pool;

/**
* Default time to store object in cache. This value is used if CachePlugin::respectCacheHeaders is false or
* if cache headers are missing.
*
* @var int
* @var StreamFactory
*/
private $defaultTtl;
private $streamFactory;

/**
* Look at the cache headers to know whether this response may be cached and to
* decide how it can be cached.
*
* @var bool Defaults to true
* @var array
*/
private $respectCacheHeaders;
private $config;

/**
* Available options are
* - respect_cache_headers: Whether to look at the cache directives or ignore them.
*
* - default_ttl: If we do not respect cache headers or can't calculate a good ttl, use this value.
*
* @param CacheItemPoolInterface $pool
* @param array $options
* @param StreamFactory $streamFactory
* @param array $config
*/
public function __construct(CacheItemPoolInterface $pool, array $options = [])
public function __construct(CacheItemPoolInterface $pool, StreamFactory $streamFactory, array $config = [])
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What's the problem with options? 😛

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None, but SocketHttpClient was using $config so I thought I would be consistent.

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Okay, makes sense

{
$this->pool = $pool;
$this->defaultTtl = isset($options['default_ttl']) ? $options['default_ttl'] : null;
$this->respectCacheHeaders = isset($options['respect_cache_headers']) ? $options['respect_cache_headers'] : true;
$this->streamFactory = $streamFactory;

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

/**
Expand All @@ -67,12 +68,16 @@ public function handleRequest(RequestInterface $request, callable $next, callabl

if ($cacheItem->isHit()) {
// return cached response
return new FulfilledPromise($cacheItem->get());
$data = $cacheItem->get();
$response = $data['response'];
$response = $response->withBody($this->streamFactory->createStream($data['body']));
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does it make sense that the body is always a stream? should we keep what it was when we had a cache miss?

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Yes, The body has to be a stream, always. That is part of PSR-7.

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Actually, I think it can be null as well, can't it?

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Hm, I might be wrong. But getBody should always return a stream.

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You are right. Initially, it was the plan to return null when the body is empty. All these PSR7 versions in my head sometimes make me wonder about the REAL interfaces.


return new FulfilledPromise($response);
}

return $next($request)->then(function (ResponseInterface $response) use ($cacheItem) {
if ($this->isCacheable($response)) {
$cacheItem->set($response)
$cacheItem->set(['response' => $response, 'body' => $response->getBody()->__toString()])
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We need to have some sort of buffered stream, as some implementations provide a unbuffered stream, so reading a stream once will certainly make it not available afterwards.

Also even if the stream is buffered by the implementation, it must be rewind here.

Concretly we must add something like, if stream is seekable just rewind this, if not buffer it into a new stream.

We may face memory problem if big file are downloaded, but don't know if we can avoid that

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what happens with a stream body when setting the cache? what happens without a stream body? duplicated data in cache? maybe we could check if the body is a stream and if so set it to the cache item, otherwise only set the response? and when restoring check if we have a body in the cache and if we do create the stream from that?

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@dbu dbu Dec 21, 2015 via email

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Thank you for the comments.

Concretly we must add something like, if stream is seekable just rewind this, if not buffer it into a new stream.

Hm, okey. I think I understand what you mean.. Give me a minute and I'll update

We may face memory problem if big file are downloaded, but don't know if we can avoid that

sounds like a warning for the cache plugin doc: if you handle large
downloads, make sure the implementation works as expected. or contribute
to make it better.

Agreed.

->expiresAfter($this->getMaxAge($response));
$this->pool->save($cacheItem);
}
Expand All @@ -93,7 +98,7 @@ protected function isCacheable(ResponseInterface $response)
if (!in_array($response->getStatusCode(), [200, 203, 300, 301, 302, 404, 410])) {
return false;
}
if (!$this->respectCacheHeaders) {
if (!$this->config['respect_cache_headers']) {
return true;
}
if ($this->getCacheControlDirective($response, 'no-store') || $this->getCacheControlDirective($response, 'private')) {
Expand Down Expand Up @@ -148,8 +153,8 @@ private function createCacheKey(RequestInterface $request)
*/
private function getMaxAge(ResponseInterface $response)
{
if (!$this->respectCacheHeaders) {
return $this->defaultTtl;
if (!$this->config['respect_cache_headers']) {
return $this->config['default_ttl'];
}

// check for max age in the Cache-Control header
Expand All @@ -169,6 +174,24 @@ private function getMaxAge(ResponseInterface $response)
return (new \DateTime($header))->getTimestamp() - (new \DateTime())->getTimestamp();
}

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

/**
* Configure an options resolver.
*
* @param OptionsResolver $resolver
*
* @return array
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It does not return anything.

*/
private function configureOptions(OptionsResolver $resolver)
{
$resolver->setDefaults([
'default_ttl' => null,
'respect_cache_headers' => true,
]);

$resolver->setAllowedTypes('default_ttl', ['int', 'null']);
$resolver->setAllowedTypes('respect_cache_headers', 'bool');
}
}