Add cached HTTP client (#589)

* Adding cached http client support

* Rector fix

* Include headers

CHANGELOG.md

@@ -17,9 +17,11 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 - Added dynamic creation of post type/taxonomy factories.
 - Added `Reset_Server` trait to reset the server between tests.
 - Add `with_https()` to control if the request being tested is over HTTPS.
+- Add cached HTTP response support using the `cache()` method.
 
 ### Changed
 
+- **Breaking:** Http Client pools should now be built using `->method()` and `->url()` instead.
 - Dropped support for Redis as a cache backend in favor of the default object
   cache drop-in.
 - Allow returning falsey from `Collection::map_to_dictionary()`.

src/mantle/http-client/autoload.php

@@ -12,6 +12,8 @@
 
 declare( strict_types=1 );
 
+namespace Mantle\Http_Client;
+
 use Mantle\Http_Client\Pending_Request;
 use Mantle\Http_Client\Response;
 

src/mantle/http-client/class-cache-middleware.php

@@ -0,0 +1,95 @@
+<?php
+/**
+ * Cache_Middleware class
+ *
+ * @package Mantle
+ */
+
+namespace Mantle\Http_Client;
+
+use Closure;
+use DateTimeInterface;
+
+/**
+ * Cache Middleware for Http Client.
+ *
+ * Allows for simple caching of HTTP requests.
+ */
+class Cache_Middleware {
+	/**
+	 * Cache group.
+	 */
+	public const CACHE_GROUP = 'httpclient';
+
+	/**
+	 * Constructor.
+	 *
+	 * @param int|DateTimeInterface|callable $ttl Time to live for the cache.
+	 */
+	public function __construct( protected mixed $ttl ) {}
+
+	/**
+	 * Invoke the middleware.
+	 *
+	 * @param Pending_Request $request Request to process.
+	 * @param Closure         $next Next middleware in the stack.
+	 * @return Response Response from the request.
+	 */
+	public function __invoke( Pending_Request $request, Closure $next ): Response {
+		$cache_key = $this->get_cache_key( $request );
+		$cache     = wp_cache_get( $cache_key, self::CACHE_GROUP );
+
+		if ( $cache && $cache instanceof Response ) {
+			return $cache;
+		}
+
+		$response = $next( $request );
+
+		wp_cache_set( $cache_key, $response, self::CACHE_GROUP, $this->calculate_ttl( $request ) ); // phpcs:ignore WordPressVIPMinimum.Performance.LowExpiryCacheTime.CacheTimeUndetermined
+
+		return $response;
+	}
+
+	/**
+	 * Purge the cache for a request.
+	 *
+	 * @param Pending_Request $request Request to purge the cache for.
+	 */
+	public function purge( Pending_Request $request ): bool {
+		return wp_cache_delete( $this->get_cache_key( $request ), self::CACHE_GROUP );
+	}
+
+	/**
+	 * Retrieve the cache key for the request.
+	 *
+	 * @param Pending_Request $request Request to retrieve the cache key for.
+	 */
+	protected function get_cache_key( Pending_Request $request ): string {
+		return md5( json_encode( [ // phpcs:ignore WordPress.WP.AlternativeFunctions.json_encode_json_encode
+			$request->base_url(),
+			$request->url(),
+			$request->method(),
+			$request->body(),
+			$request->headers(),
+		] ) );
+	}
+
+	/**
+	 * Calculate the time to live for the cache in seconds.
+	 *
+	 * @param Pending_Request $request Request to calculate the TTL for.
+	 */
+	protected function calculate_ttl( Pending_Request $request ): int {
+		if ( is_int( $this->ttl ) ) {
+			return $this->ttl;
+		}
+
+		if ( $this->ttl instanceof DateTimeInterface ) {
+			return $this->ttl->getTimestamp() - time();
+		}
+
+		$callback = $this->ttl;
+
+		return (int) $callback( $request );
+	}
+}