Added some specs

Author: Nyholm

spec/CachePluginSpec.php

@@ -0,0 +1,102 @@
+<?php
+
+namespace spec\Http\Client\Plugin;
+
+use Http\Client\Utils\Promise\FulfilledPromise;
+use PhpSpec\ObjectBehavior;
+use Psr\Cache\CacheItemInterface;
+use Psr\Cache\CacheItemPoolInterface;
+use Psr\Http\Message\RequestInterface;
+use Psr\Http\Message\ResponseInterface;
+
+class CachePluginSpec extends ObjectBehavior
+{
+    function let(CacheItemPoolInterface $pool)
+    {
+        $this->beConstructedWith($pool);
+    }
+
+    function it_is_initializable(CacheItemPoolInterface $pool)
+    {
+        $this->shouldHaveType('Http\Client\Plugin\CachePlugin');
+    }
+
+    function it_is_a_plugin()
+    {
+        $this->shouldImplement('Http\Client\Plugin\Plugin');
+    }
+
+    function it_caches_responses(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
+    {
+        $request->getMethod()->willReturn('GET');
+        $request->getUri()->willReturn('/');
+        $response->getStatusCode()->willReturn(200);
+        $response->getHeader('Cache-Control')->willReturn(array());
+        $response->getHeader('Expires')->willReturn(array());
+
+        $pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
+        $item->exists()->willReturn(false);
+        $item->set($response, 60)->shouldBeCalled();
+        $pool->save($item)->shouldBeCalled();
+
+        $next = function (RequestInterface $request) use ($response) {
+            return new FulfilledPromise($response->getWrappedObject());
+        };
+
+        $this->handleRequest($request, $next, function () {});
+    }
+
+    function it_doesnt_store_failed_responses(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
+    {
+        $request->getMethod()->willReturn('GET');
+        $request->getUri()->willReturn('/');
+        $response->getStatusCode()->willReturn(400);
+        $response->getHeader('Cache-Control')->willReturn(array());
+        $response->getHeader('Expires')->willReturn(array());
+
+        $pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
+        $item->exists()->willReturn(false);
+
+        $next = function (RequestInterface $request) use ($response) {
+            return new FulfilledPromise($response->getWrappedObject());
+        };
+
+        $this->handleRequest($request, $next, function () {});
+    }
+
+    function it_doesnt_store_post_requests(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
+    {
+        $request->getMethod()->willReturn('POST');
+        $request->getUri()->willReturn('/');
+
+        $next = function (RequestInterface $request) use ($response) {
+            return new FulfilledPromise($response->getWrappedObject());
+        };
+
+        $this->handleRequest($request, $next, function () {});
+    }
+
+
+    function it_calculate_age_from_response(CacheItemPoolInterface $pool, CacheItemInterface $item, RequestInterface $request, ResponseInterface $response)
+    {
+        $request->getMethod()->willReturn('GET');
+        $request->getUri()->willReturn('/');
+        $response->getStatusCode()->willReturn(200);
+        $response->getHeader('Cache-Control')->willReturn(array('max-age=40'));
+        $response->getHeader('Age')->willReturn(array('15'));
+        $response->getHeader('Expires')->willReturn(array());
+
+        $pool->getItem('e3b717d5883a45ef9493d009741f7c64')->shouldBeCalled()->willReturn($item);
+        $item->exists()->willReturn(false);
+
+        // 40-15 should be 25
+        $item->set($response, 25)->shouldBeCalled();
+        $pool->save($item)->shouldBeCalled();
+
+        $next = function (RequestInterface $request) use ($response) {
+            return new FulfilledPromise($response->getWrappedObject());
+        };
+
+        $this->handleRequest($request, $next, function () {});
+    }
+}

src/CachePlugin.php

@@ -147,6 +147,11 @@ private function getMaxAge(ResponseInterface $response)
         // 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 $maxAge;
         }