Initial import.

vendor/guzzle/plugin-cache/Guzzle/Plugin/Cache/DefaultRevalidation.php

@@ -0,0 +1,174 @@
+<?php
+
+namespace Guzzle\Plugin\Cache;
+
+use Guzzle\Http\Message\RequestInterface;
+use Guzzle\Http\Message\Response;
+use Guzzle\Http\Exception\BadResponseException;
+
+/**
+ * Default revalidation strategy
+ */
+class DefaultRevalidation implements RevalidationInterface
+{
+    /** @var CacheStorageInterface Cache object storing cache data */
+    protected $storage;
+
+    /** @var CanCacheStrategyInterface */
+    protected $canCache;
+
+    /**
+     * @param CacheStorageInterface     $cache    Cache storage
+     * @param CanCacheStrategyInterface $canCache Determines if a message can be cached
+     */
+    public function __construct(CacheStorageInterface $cache, CanCacheStrategyInterface $canCache = null)
+    {
+        $this->storage = $cache;
+        $this->canCache = $canCache ?: new DefaultCanCacheStrategy();
+    }
+
+    public function revalidate(RequestInterface $request, Response $response)
+    {
+        try {
+            $revalidate = $this->createRevalidationRequest($request, $response);
+            $validateResponse = $revalidate->send();
+            if ($validateResponse->getStatusCode() == 200) {
+                return $this->handle200Response($request, $validateResponse);
+            } elseif ($validateResponse->getStatusCode() == 304) {
+                return $this->handle304Response($request, $validateResponse, $response);
+            }
+        } catch (BadResponseException $e) {
+            $this->handleBadResponse($e);
+        }
+
+        // Other exceptions encountered in the revalidation request are ignored
+        // in hopes that sending a request to the origin server will fix it
+        return false;
+    }
+
+    public function shouldRevalidate(RequestInterface $request, Response $response)
+    {
+        if ($request->getMethod() != RequestInterface::GET) {
+            return false;
+        }
+
+        $reqCache = $request->getHeader('Cache-Control');
+        $resCache = $response->getHeader('Cache-Control');
+
+        $revalidate = $request->getHeader('Pragma') == 'no-cache' ||
+            ($reqCache && ($reqCache->hasDirective('no-cache') || $reqCache->hasDirective('must-revalidate'))) ||
+            ($resCache && ($resCache->hasDirective('no-cache') || $resCache->hasDirective('must-revalidate')));
+
+        // Use the strong ETag validator if available and the response contains no Cache-Control directive
+        if (!$revalidate && !$resCache && $response->hasHeader('ETag')) {
+            $revalidate = true;
+        }
+
+        return $revalidate;
+    }
+
+    /**
+     * Handles a bad response when attempting to revalidate
+     *
+     * @param BadResponseException $e Exception encountered
+     *
+     * @throws BadResponseException
+     */
+    protected function handleBadResponse(BadResponseException $e)
+    {
+        // 404 errors mean the resource no longer exists, so remove from
+        // cache, and prevent an additional request by throwing the exception
+        if ($e->getResponse()->getStatusCode() == 404) {
+            $this->storage->delete($e->getRequest());
+            throw $e;
+        }
+    }
+
+    /**
+     * Creates a request to use for revalidation
+     *
+     * @param RequestInterface $request  Request
+     * @param Response         $response Response to revalidate
+     *
+     * @return RequestInterface returns a revalidation request
+     */
+    protected function createRevalidationRequest(RequestInterface $request, Response $response)
+    {
+        $revalidate = clone $request;
+        $revalidate->removeHeader('Pragma')->removeHeader('Cache-Control');
+
+        if ($response->getLastModified()) {
+            $revalidate->setHeader('If-Modified-Since', $response->getLastModified());
+        }
+
+        if ($response->getEtag()) {
+            $revalidate->setHeader('If-None-Match', $response->getEtag());
+        }
+
+        // Remove any cache plugins that might be on the request to prevent infinite recursive revalidations
+        $dispatcher = $revalidate->getEventDispatcher();
+        foreach ($dispatcher->getListeners() as $eventName => $listeners) {
+            foreach ($listeners as $listener) {
+                if (is_array($listener) && $listener[0] instanceof CachePlugin) {
+                    $dispatcher->removeListener($eventName, $listener);
+                }
+            }
+        }
+
+        return $revalidate;
+    }
+
+    /**
+     * Handles a 200 response response from revalidating. The server does not support validation, so use this response.
+     *
+     * @param RequestInterface $request          Request that was sent
+     * @param Response         $validateResponse Response received
+     *
+     * @return bool Returns true if valid, false if invalid
+     */
+    protected function handle200Response(RequestInterface $request, Response $validateResponse)
+    {
+        $request->setResponse($validateResponse);
+        if ($this->canCache->canCacheResponse($validateResponse)) {
+            $this->storage->cache($request, $validateResponse);
+        }
+
+        return false;
+    }
+
+    /**
+     * Handle a 304 response and ensure that it is still valid
+     *
+     * @param RequestInterface $request          Request that was sent
+     * @param Response         $validateResponse Response received
+     * @param Response         $response         Original cached response
+     *
+     * @return bool Returns true if valid, false if invalid
+     */
+    protected function handle304Response(RequestInterface $request, Response $validateResponse, Response $response)
+    {
+        static $replaceHeaders = array('Date', 'Expires', 'Cache-Control', 'ETag', 'Last-Modified');
+
+        // Make sure that this response has the same ETag
+        if ($validateResponse->getEtag() != $response->getEtag()) {
+            return false;
+        }
+
+        // Replace cached headers with any of these headers from the
+        // origin server that might be more up to date
+        $modified = false;
+        foreach ($replaceHeaders as $name) {
+            if ($validateResponse->hasHeader($name)) {
+                $modified = true;
+                $response->setHeader($name, $validateResponse->getHeader($name));
+            }
+        }
+
+        // Store the updated response in cache
+        if ($modified && $this->canCache->canCacheResponse($response)) {
+            $this->storage->cache($request, $response);
+        }
+
+        return true;
+    }
+}