Added CacheKeyGenerator (#35)

* Added CacheKeyGenerator

Also added a default generator

* cs fix

* Support PSR-4

* Added test to make sure cache_key_generator works

* cs

* Changes according to feedback.

* Make plugin final

* Bugfixes

* Remove final

* typo

Author: Nyholm

spec/Cache/Generator/SimpleGeneratorSpec.php

@@ -0,0 +1,38 @@
+<?php
+
+namespace spec\Http\Client\Common\Plugin\Cache\Generator;
+
+use PhpSpec\ObjectBehavior;
+use Psr\Http\Message\RequestInterface;
+
+class SimpleGeneratorSpec extends ObjectBehavior
+{
+    public function it_is_initializable()
+    {
+        $this->shouldHaveType('Http\Client\Common\Plugin\Cache\Generator\SimpleGenerator');
+    }
+
+    public function it_is_a_key_generator()
+    {
+        $this->shouldImplement('Http\Client\Common\Plugin\Cache\Generator\CacheKeyGenerator');
+    }
+
+    public function it_generates_cache_from_request(RequestInterface $request)
+    {
+        $request->getMethod()->shouldBeCalled()->willReturn('GET');
+        $request->getUri()->shouldBeCalled()->willReturn('http://example.com/foo');
+        $request->getBody()->shouldBeCalled()->willReturn('bar');
+
+        $this->generate($request)->shouldReturn('GET http://example.com/foo bar');
+    }
+
+    public function it_generates_cache_from_request_with_no_body(RequestInterface $request)
+    {
+        $request->getMethod()->shouldBeCalled()->willReturn('GET');
+        $request->getUri()->shouldBeCalled()->willReturn('http://example.com/foo');
+        $request->getBody()->shouldBeCalled()->willReturn('');
+
+        // No extra space after uri
+        $this->generate($request)->shouldReturn('GET http://example.com/foo');
+    }
+}

spec/CachePluginSpec.php

@@ -2,6 +2,7 @@
 
 namespace spec\Http\Client\Common\Plugin;
 
+use Http\Client\Common\Plugin\Cache\Generator\SimpleGenerator;
 use Prophecy\Argument;
 use Http\Message\StreamFactory;
 use Http\Promise\FulfilledPromise;
@@ -400,6 +401,47 @@ function it_caches_private_responses_when_allowed(
     }
 
 
+    function it_can_be_initialized_with_custom_cache_key_generator(
+        CacheItemPoolInterface $pool,
+        CacheItemInterface $item,
+        StreamFactory $streamFactory,
+        RequestInterface $request,
+        ResponseInterface $response,
+        StreamInterface $stream,
+        SimpleGenerator $generator
+    ) {
+        $this->beConstructedThrough('clientCache', [$pool, $streamFactory, [
+            'cache_key_generator' => $generator,
+        ]]);
+
+        $generator->generate($request)->shouldBeCalled()->willReturn('foo');
+
+        $stream->isSeekable()->willReturn(true);
+        $stream->rewind()->shouldBeCalled();
+        $streamFactory->createStream(Argument::any())->willReturn($stream);
+
+        $request->getMethod()->willReturn('GET');
+        $request->getUri()->willReturn('/');
+        $response->withBody(Argument::any())->willReturn($response);
+
+        $pool->getItem(Argument::any())->shouldBeCalled()->willReturn($item);
+        $item->isHit()->willReturn(true);
+        $item->get()->willReturn([
+            'response' => $response->getWrappedObject(),
+            'body' => 'body',
+            'expiresAt' => null,
+            'createdAt' => 0,
+            'etag' => []
+        ]);
+
+        $next = function (RequestInterface $request) use ($response) {
+            return new FulfilledPromise($response->getWrappedObject());
+        };
+
+        $this->handleRequest($request, $next, function () {});
+    }
+
+
     /**
      * Private function to match cache item data.
      *

src/Cache/Generator/CacheKeyGenerator.php

@@ -0,0 +1,22 @@
+<?php
+
+namespace Http\Client\Common\Plugin\Cache\Generator;
+
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * An interface for generate a cache key.
+ *
+ * @author Tobias Nyholm <tobias.nyholm@gmail.com>
+ */
+interface CacheKeyGenerator
+{
+    /**
+     * Generate a cache key from a Request.
+     *
+     * @param RequestInterface $request
+     *
+     * @return string
+     */
+    public function generate(RequestInterface $request);
+}

src/Cache/Generator/SimpleGenerator.php

@@ -0,0 +1,23 @@
+<?php
+
+namespace Http\Client\Common\Plugin\Cache\Generator;
+
+use Psr\Http\Message\RequestInterface;
+
+/**
+ * Generate a cache key from the request method, URI and body.
+ *
+ * @author Tobias Nyholm <tobias.nyholm@gmail.com>
+ */
+class SimpleGenerator implements CacheKeyGenerator
+{
+    public function generate(RequestInterface $request)
+    {
+        $body = (string) $request->getBody();
+        if (!empty($body)) {
+            $body = ' '.$body;
+        }
+
+        return $request->getMethod().' '.$request->getUri().$body;
+    }
+}

src/CachePlugin.php

@@ -4,6 +4,8 @@
 
 use Http\Client\Common\Plugin;
 use Http\Client\Common\Plugin\Exception\RewindStreamException;
+use Http\Client\Common\Plugin\Cache\Generator\CacheKeyGenerator;
+use Http\Client\Common\Plugin\Cache\Generator\SimpleGenerator;
 use Http\Message\StreamFactory;
 use Http\Promise\FulfilledPromise;
 use Psr\Cache\CacheItemInterface;
@@ -55,7 +57,8 @@ final class CachePlugin implements Plugin
      *              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.
      *     @var array $methods list of request methods which can be cached
-     *     @var array $respect_response_cache_directives list of cache directives this plugin will respect while caching responses.
+     *     @var array $respect_response_cache_directives list of cache directives this plugin will respect while caching responses
+     *     @var CacheKeyGenerator $cache_key_generator a class to generate the cache key. Defaults to SimpleGenerator
      * }
      */
     public function __construct(CacheItemPoolInterface $pool, StreamFactory $streamFactory, array $config = [])
@@ -73,6 +76,10 @@ public function __construct(CacheItemPoolInterface $pool, StreamFactory $streamF
         $optionsResolver = new OptionsResolver();
         $this->configureOptions($optionsResolver);
         $this->config = $optionsResolver->resolve($config);
+
+        if (null === $this->config['cache_key_generator']) {
+            $this->config['cache_key_generator'] = new SimpleGenerator();
+        }
     }
 
     /**
@@ -282,12 +289,9 @@ private function getCacheControlDirective(ResponseInterface $response, $name)
      */
     private function createCacheKey(RequestInterface $request)
     {
-        $body = (string) $request->getBody();
-        if (!empty($body)) {
-            $body = ' '.$body;
-        }
+        $key = $this->config['cache_key_generator']->generate($request);
 
-        return hash($this->config['hash_algo'], $request->getMethod().' '.$request->getUri().$body);
+        return hash($this->config['hash_algo'], $key);
     }
 
     /**
@@ -338,12 +342,14 @@ private function configureOptions(OptionsResolver $resolver)
             'hash_algo' => 'sha1',
             'methods' => ['GET', 'HEAD'],
             'respect_response_cache_directives' => ['no-cache', 'private', 'max-age', 'no-store'],
+            'cache_key_generator' => null,
         ]);
 
         $resolver->setAllowedTypes('cache_lifetime', ['int', 'null']);
         $resolver->setAllowedTypes('default_ttl', ['int', 'null']);
         $resolver->setAllowedTypes('respect_cache_headers', 'bool');
         $resolver->setAllowedTypes('methods', 'array');
+        $resolver->setAllowedTypes('cache_key_generator', ['null', 'Http\Client\Common\Plugin\Cache\Generator\CacheKeyGenerator']);
         $resolver->setAllowedValues('hash_algo', hash_algos());
         $resolver->setAllowedValues('methods', function ($value) {
             /* RFC7230 sections 3.1.1 and 3.2.6 except limited to uppercase characters. */