Add APICache trait for caching WC reports endpoints (#89)

Makefile

@@ -1,4 +1,4 @@
-VERSION := 3.30.3
+VERSION := 3.31.0
 PLUGINSLUG := woocart-defaults
 SRCPATH := $(shell pwd)/src
 

src/classes/CacheManager.php

@@ -18,6 +18,7 @@
 	class CacheManager {
 
 		use Extend\NavCache;
+		use Extend\APICache;
 
 		/**
 		 * FCGI Cache path.
@@ -98,6 +99,9 @@ public function __construct() {
 
 			// Nav-menu cache
 			add_action( 'init', array( $this, 'nav_init' ) );
+
+			// API cache
+			add_action( 'rest_api_init', array( $this, 'api_init' ) );
 		}
 
 		/**

src/classes/Extend/APICache.php

@@ -0,0 +1,162 @@
+<?php
+/**
+ * Cache WooCommerce API requests.
+ *
+ * @package Niteo\WooCart\Defaults
+ */
+
+namespace Niteo\WooCart\Defaults\Extend;
+
+trait APICache {
+
+	/**
+	 * Endpoint to cache.
+	 *
+	 * @var string
+	 */
+	private $endpoint_to_cache = 'wc/v3/reports';
+
+	/**
+	 * Unique identifier for the cache.
+	 *
+	 * @var string
+	 */
+	private $cache_key;
+
+	/**
+	 * Cache key prefix.
+	 *
+	 * @var string
+	 */
+	private $cache_key_prefix = 'wc_reports_';
+
+	/**
+	 * Initialize API cache.
+	 *
+	 * @return void
+	 */
+	public function api_init() : void {
+		// Build cache key using API url.
+		$this->create_cache_key();
+
+		// Check if cache needs to be skipped.
+		if ( ! $this->cache_key ) {
+			return;
+		}
+
+		add_filter( 'rest_pre_dispatch', array( $this, 'serve_cache' ), PHP_INT_MAX, 3 );
+		add_filter( 'rest_pre_echo_response', array( $this, 'set_cache' ), PHP_INT_MAX, 3 );
+	}
+
+	/**
+	 * Create cache key using the requested API url.
+	 *
+	 * @return void
+	 */
+	public function create_cache_key() : void {
+		// Requested API url which is used to create cache.
+		$request_url = sanitize_text_field( $_SERVER['REQUEST_URI'] );
+
+		if ( ! $request_url ) {
+			return;
+		}
+
+		// Parse URL to check for path and query args.
+		$parsed_url = wp_parse_url( $request_url );
+
+		if ( ! isset( $parsed_url['path'] ) || empty( $parsed_url['path'] ) ) {
+			return;
+		}
+
+		// Do nothing if not a cacheable endpoint.
+		if ( false === strpos( $parsed_url['path'], $this->endpoint_to_cache ) ) {
+			return;
+		}
+
+		// Check for query args.
+		$params = array();
+
+		if ( isset( $parsed_url['query'] ) && ! empty( $parsed_url['query'] ) ) {
+			$params = wp_parse_args( $parsed_url['query'] );
+		}
+
+		// Set cache key.
+		$this->cache_key = $this->cache_key_prefix . md5( $parsed_url['path'] . wp_json_encode( $params ) );
+	}
+
+	/**
+	 * Serve data from cache if key exists.
+	 *
+	 * @param null             $result  Response data to send to the client.
+	 * @param \WP_REST_Server  $server  Server instance.
+	 * @param \WP_REST_Request $request Request used to generate the response.
+	 *
+	 * @return null|array
+	 */
+	public function serve_cache( $result, \WP_REST_Server $server, \WP_REST_Request $request ) {
+		// Check if cache exists.
+		$output = \get_transient( $this->cache_key );
+
+		if ( $output ) {
+			// Set content type to JSON and output response.
+			$this->set_header( 'Content-Type: application/json' );
+			echo wp_json_encode( $output );
+
+			// Terminate as the request is complete.
+			$this->exit();
+		}
+
+		return $result;
+	}
+
+	/**
+	 * Set cache based on the endpoint and request type.
+	 *
+	 * @param array            $result  Response data to send to the client.
+	 * @param \WP_REST_Server  $server  Server instance.
+	 * @param \WP_REST_Request $request Request used to generate the response.
+	 *
+	 * @return array
+	 */
+	public function set_cache( $result, \WP_REST_Server $server, \WP_REST_Request $request ) : array {
+		// Ensure result is not empty.
+		if ( empty( $result ) ) {
+			return $result;
+		}
+
+		// Ignore any response other than 200.
+		if ( is_array( $result )
+		&& isset( $result['data']['status'] )
+		&& 200 !== (int) $result['data']['status']
+		) {
+			return $result;
+		}
+
+		// Set transient.
+		\set_transient( $this->cache_key, $result, HOUR_IN_SECONDS );
+
+		return $result;
+	}
+
+	/**
+	 * Wrapper for the header function.
+	 *
+	 * @param  string $header Header value to be set.
+	 * @return void
+	 * @codeCoverageIgnore
+	 */
+	protected function set_header( $header ) : void {
+		header( $header );
+	}
+
+	/**
+	 * Wrapper for the exit function.
+	 *
+	 * @return void
+	 * @codeCoverageIgnore
+	 */
+	protected function exit() : void {
+		exit;
+	}
+
+}