[#127] WordPress 5.6/SimplePie Compatibility: Dealing with deprecated…

… WP_Feed_Cache with replacement FeedWordPie_Cache class. (Should resolve PHP warnings: 'Deprecated: class-wp-feed-cache.php is <strong>deprecated</strong> since version 5.6.0', 'Message: ./cache is not writable. Make sure you've set the correct relative or absolute path, and that the location is server-writable.')

extend/SimplePie/feedwordpie_cache.class.php

@@ -0,0 +1,177 @@
+<?php
+/**
+ * FeedWordPie_Cache class. Provides customized feed caching for FeedWordPress.
+ * This is derived (currently, just copied and combined) from WordPress Core
+ * wp-includes/class-wp-feed-cache.php ("Feed API: WP_Feed_Cache_Transient class")
+ * and from wp-includes/SimplePie/Cache.php ("SimplePie_Cache"), pursuant to the
+ * terms of the GPL.
+ *
+ * The wrapper class WP_Feed_Cache was deprecated in WordPress 5.6, but its intended
+ * replacement, WP_Feed_Cache_Transient, is currently NOT a subclass of SimplePie_Cache
+ * which causes problems registering it as a cache class in some versions of SimplePie.
+ * Solution: For now, let's copy the class over under a new name, but this time, inherit
+ * from SimplePie_Cache. (I am doing it this way because I might want to make some real
+ * changs to the implementation of caching, in order to better support typical FeedWordPress
+ * use cases. In the meantime, this should at least stop the PHP warnings and the failure
+ * to correctly cache feed contents that users are encountering with WordPress 5.6.)
+ *
+ * @version 2021.0118
+ */
+
+/**
+ * Core class used to implement feed cache transients.
+ *
+ * @since 2.8.0
+ */
+class FeedWordPie_Cache extends SimplePie_Cache {
+
+	/**
+	 * Holds the transient name.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $name;
+
+	/**
+	 * Holds the transient mod name.
+	 *
+	 * @since 2.8.0
+	 * @var string
+	 */
+	public $mod_name;
+
+	/**
+	 * Holds the cache duration in seconds.
+	 *
+	 * Defaults to 43200 seconds (12 hours).
+	 *
+	 * @since 2.8.0
+	 * @var int
+	 */
+	public $lifetime = 43200;
+
+	/**
+	 * Constructor.
+	 *
+	 * @since 2.8.0
+	 * @since 3.2.0 Updated to use a PHP5 constructor.
+	 *
+	 * @param string $location  URL location (scheme is used to determine handler).
+	 * @param string $filename  Unique identifier for cache object.
+	 * @param string $extension 'spi' or 'spc'.
+	 */
+	public function __construct( $location, $filename, $extension ) {
+		$this->name     = 'feed_' . $filename;
+		$this->mod_name = 'feed_mod_' . $filename;
+
+		$lifetime = $this->lifetime;
+		/**
+		 * Filters the transient lifetime of the feed cache.
+		 *
+		 * @since 2.8.0
+		 *
+		 * @param int    $lifetime Cache duration in seconds. Default is 43200 seconds (12 hours).
+		 * @param string $filename Unique identifier for the cache object.
+		 */
+		$this->lifetime = apply_filters( 'wp_feed_cache_transient_lifetime', $lifetime, $filename );
+	}
+
+	/**
+	 * Sets the transient.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @param SimplePie $data Data to save.
+	 * @return true Always true.
+	 */
+	public function save( $data ) {
+		if ( $data instanceof SimplePie ) {
+			$data = $data->data;
+		}
+
+		set_transient( $this->name, $data, $this->lifetime );
+		set_transient( $this->mod_name, time(), $this->lifetime );
+		return true;
+	}
+
+	/**
+	 * Gets the transient.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @return mixed Transient value.
+	 */
+	public function load() {
+		return get_transient( $this->name );
+	}
+
+	/**
+	 * Gets mod transient.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @return mixed Transient value.
+	 */
+	public function mtime() {
+		return get_transient( $this->mod_name );
+	}
+
+	/**
+	 * Sets mod transient.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @return bool False if value was not set and true if value was set.
+	 */
+	public function touch() {
+		return set_transient( $this->mod_name, time(), $this->lifetime );
+	}
+
+	/**
+	 * Deletes transients.
+	 *
+	 * @since 2.8.0
+	 *
+	 * @return true Always true.
+	 */
+	public function unlink() {
+		delete_transient( $this->name );
+		delete_transient( $this->mod_name );
+		return true;
+	}
+
+	/**
+	 * Create a new SimplePie_Cache object
+	 *
+	 * @param string $location URL location (scheme is used to determine handler)
+	 * @param string $filename Unique identifier for cache object
+	 * @param string $extension 'spi' or 'spc'
+	 * @return SimplePie_Cache_Base Type of object depends on scheme of `$location`
+	 */
+	public static function get_handler($location, $filename, $extension)
+	{
+
+		$type = explode(':', $location, 2);
+		$type = $type[0];
+		if (!empty(self::$handlers[$type]))
+		{
+			$class = self::$handlers[$type];
+			return $class($location, $filename, $extension);
+		}
+
+		return new FeedWordPie_Cache($location, $filename, $extension);
+	}
+
+	/**
+	 * Create a new SimplePie_Cache object
+	 *
+	 * @deprecated Use {@see get_handler} instead
+	 */
+	public function create($location, $filename, $extension)
+	{
+		trigger_error('Cache::create() has been replaced with Cache::get_handler(). Switch to the registry system to use this.', E_USER_DEPRECATED);
+		return self::get_handler($location, $filename, $extension);
+	}
+
+}

feedwordpress.php

@@ -3,7 +3,7 @@
 Plugin Name: FeedWordPress
 Plugin URI: http://feedwordpress.radgeek.com/
 Description: simple and flexible Atom/RSS syndication for WordPress
-Version: 2020.0818
+Version: 2021.0118
 Author: C. Johnson
 Author URI: https://feedwordpress.radgeek.com/contact/
 License: GPL
@@ -96,8 +96,6 @@
 // Dependencies: modules packaged with WordPress core
 $wpCoreDependencies = array(
 "class:SimplePie" => "class-simplepie",
-"class:WP_Feed_Cache" => "class-wp-feed-cache",
-"class:WP_Feed_Cache_Transient" => "class-wp-feed-cache-transient",
 "class:WP_SimplePie_File" => "class-wp-simplepie-file",
 "class:WP_SimplePie_Sanitize_KSES" => "class-wp-simplepie-sanitize-kses",
 "function:wp_insert_user" => "registration",
@@ -141,6 +139,7 @@
 require_once("${dir}/inspectpostmeta.class.php");
 require_once("${dir}/syndicationdataqueries.class.php");
 require_once("${dir}/extend/SimplePie/feedwordpie.class.php");
+require_once("${dir}/extend/SimplePie/feedwordpie_cache.class.php");
 require_once("${dir}/extend/SimplePie/feedwordpie_item.class.php");
 require_once("${dir}/extend/SimplePie/feedwordpie_file.class.php");
 require_once("${dir}/extend/SimplePie/feedwordpie_parser.class.php");
@@ -1928,15 +1927,15 @@ static function fetch ($url, $params = array()) {
 		$timeout = intval($timeout);
 
 		$pie_class = apply_filters('feedwordpress_simplepie_class', 'FeedWordPie');
-		$cache_class = apply_filters('feedwordpress_cache_class', 'WP_Feed_Cache');
+		$cache_class = apply_filters('feedwordpress_cache_class', 'FeedWordPie_Cache');
 		$file_class = apply_filters('feedwordpress_file_class', 'FeedWordPie_File');
 		$parser_class = apply_filters('feedwordpress_parser_class', 'FeedWordPie_Parser');
 		$item_class = apply_filters('feedwordpress_item_class', 'FeedWordPie_Item');
 		$sniffer_class = apply_filters('feedwordpress_sniffer_class', 'FeedWordPie_Content_Type_Sniffer');
 
 		$feed = new $pie_class;
 		$feed->set_feed_url($url);
-		$feed->set_cache_class($cache_class);
+		$feed->registry->register('Cache', $cache_class);
 		$feed->set_timeout($timeout);
 
 		$feed->set_content_type_sniffer_class($sniffer_class);