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system/Cache/ResponseCache.php

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+<?php
+
+declare(strict_types=1);
+
+/**
+ * This file is part of CodeIgniter 4 framework.
+ *
+ * (c) CodeIgniter Foundation <admin@codeigniter.com>
+ *
+ * For the full copyright and license information, please view
+ * the LICENSE file that was distributed with this source code.
+ */
+
+namespace CodeIgniter\Cache;
+
+use CodeIgniter\HTTP\CLIRequest;
+use CodeIgniter\HTTP\Header;
+use CodeIgniter\HTTP\IncomingRequest;
+use CodeIgniter\HTTP\ResponseInterface;
+use Config\Cache as CacheConfig;
+use Exception;
+
+/**
+ * Web Page Caching
+ *
+ * @see \CodeIgniter\Cache\ResponseCacheTest
+ */
+final class ResponseCache
+{
+    /**
+     * Whether to take the URL query string into consideration when generating
+     * output cache files. Valid options are:
+     *
+     *    false      = Disabled
+     *    true       = Enabled, take all query parameters into account.
+     *                 Please be aware that this may result in numerous cache
+     *                 files generated for the same page over and over again.
+     *    array('q') = Enabled, but only take into account the specified list
+     *                 of query parameters.
+     *
+     * @var bool|list<string>
+     */
+    private $cacheQueryString = false;
+
+    /**
+     * Cache time to live.
+     *
+     * @var int seconds
+     */
+    private int $ttl = 0;
+
+    public function __construct(CacheConfig $config, private readonly CacheInterface $cache)
+    {
+        $this->cacheQueryString = $config->cacheQueryString;
+    }
+
+    /**
+     * @return $this
+     */
+    public function setTtl(int $ttl)
+    {
+        $this->ttl = $ttl;
+
+        return $this;
+    }
+
+    /**
+     * Generates the cache key to use from the current request.
+     *
+     * @param CLIRequest|IncomingRequest $request
+     *
+     * @internal for testing purposes only
+     */
+    public function generateCacheKey($request): string
+    {
+        if ($request instanceof CLIRequest) {
+            return md5($request->getPath());
+        }
+
+        $uri = clone $request->getUri();
+
+        $query = $this->cacheQueryString
+            ? $uri->getQuery(is_array($this->cacheQueryString) ? ['only' => $this->cacheQueryString] : [])
+            : '';
+
+        return md5($request->getMethod() . ':' . $uri->setFragment('')->setQuery($query));
+    }
+
+    /**
+     * Caches the response.
+     *
+     * @param CLIRequest|IncomingRequest $request
+     */
+    public function make($request, ResponseInterface $response): bool
+    {
+        if ($this->ttl === 0) {
+            return true;
+        }
+
+        $headers = [];
+
+        foreach ($response->headers() as $name => $value) {
+            if ($value instanceof Header) {
+                $headers[$name] = $value->getValueLine();
+            } else {
+                foreach ($value as $header) {
+                    $headers[$name][] = $header->getValueLine();
+                }
+            }
+        }
+
+        return $this->cache->save(
+            $this->generateCacheKey($request),
+            serialize(['headers' => $headers, 'output' => $response->getBody()]),
+            $this->ttl
+        );
+    }
+
+    /**
+     * Gets the cached response for the request.
+     *
+     * @param CLIRequest|IncomingRequest $request
+     */
+    public function get($request, ResponseInterface $response): ?ResponseInterface
+    {
+        if ($cachedResponse = $this->cache->get($this->generateCacheKey($request))) {
+            $cachedResponse = unserialize($cachedResponse);
+
+            if (
+                ! is_array($cachedResponse)
+                || ! isset($cachedResponse['output'])
+                || ! isset($cachedResponse['headers'])
+            ) {
+                throw new Exception('Error unserializing page cache');
+            }
+
+            $headers = $cachedResponse['headers'];
+            $output  = $cachedResponse['output'];
+
+            // Clear all default headers
+            foreach (array_keys($response->headers()) as $key) {
+                $response->removeHeader($key);
+            }
+
+            // Set cached headers
+            foreach ($headers as $name => $value) {
+                $response->setHeader($name, $value);
+            }
+
+            $response->setBody($output);
+
+            return $response;
+        }
+
+        return null;
+    }
+}