Protect PowerPress Podcast Feeds, but let members access them with their custom RSS key. Requires both BluBrry PowerPress plugin, and the PMPro Member RSS add-on.

e20r-pmpro-powerpress-feed-protection.php

<?php
/*
Plugin Name: E20R - PowerPress Podcast Feed Protection for Paid Memberships Pro
Plugin URI: https://eighty20results.com/paid-memberships-pro/do-it-for-me/
Description: Verify PMPro RSS Member Key when accessing PowerPress feed
Version: 1.2
Author: Eighty / 20 Results by Wicked Strong Chicks, LLC <thomas@eighty20results.com>
Author URI: https://eighty20results.com/thomas-sjolshagen/
License URI: https://www.gnu.org/licenses/old-licenses/gpl-2.0.html
License: GPLv2 or later

 * Copyright (C) 2017-2018  Thomas Sjolshagen - Eighty / 20 Results by Wicked Strong Chicks, LLC
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
 */

class pmproPowerPress {
	
	/**
	 * @var null|pmproPowerPress
	 */
	private static $instance = null;
	
	/**
	 * @var array $error_msg Error Messages
	 */
	private $error_msg = array();
	
	/**
	 * @var array $error_class - CSS class (notice- prefixed) for the error message type
	 */
	private $error_class = array();
	
	/**
	 * pmproPowerPress constructor.
	 */
	private function __construct() {
	}
	
	/**
	 * Load action and filter hooks for the plugin
	 */
	public function loadHooks() {
		add_action( 'admin_init', array( $this, 'checkDependencies' ), 10 );
		add_action( 'admin_notices', array( $this, 'loadAdminNotices' ), 10 );
        	add_action( 'init', array( $this, 'addFeedHandlers' ), - 999 );
		
		add_filter( 'pmpromrss_feeds', array( $this, 'addFeedsToRSSLinks' ), 10, 1 );
		add_filter( 'rss_enclosure', array( $this, 'rssEnclosure' ), 20, 1 );
		add_filter( 'pmpro_rss_text_filter', array( $this, 'setAccessDeniedMessage' ), 5, 1 );
		add_filter( 'plugin_row_meta', array( $this, 'pluginRowMeta' ), 10, 2 );		
	}
	
	/**
	 * Fetch list of Podcast Feeds from PowerPress's settings
	 *
	 * @return array
	 *
	 * @access private
	 */
	private function getPowerPressFeeds() {
		
		$settings = get_option( 'powerpress_general' );
		$feeds    = array_merge( $settings['custom_feeds'],
			array_merge(
				$settings['custom_feeds'],
				array(
					'podcast' => apply_filters(
						'pmpro_powerpress_default_feed_label',
						__( 'Default PowerPress Podcast Feed', 'pmpro-powerpress-feed-protection' )
					),
				)
			)
		);
		
		return $feeds;
	}
 
	/**
	 * Include PowerPress feeds in listing on PMPro Account page
	 *
	 * @param array $feeds
	 *
	 * @return array
	 */
	public function addFeedsToRSSLinks( $feeds ) {
		
		$default_url = get_bloginfo_rss( 'url' );
		
		foreach ( $this->getPowerPressFeeds() as $slug => $name ) {
			$feeds[ $name ] = "{$default_url}/{$slug}/";
		}
		
		return $feeds;
	}
	
	/**
	 * Using the "Message for RSS Feed" message as a template, create the appropriate (expanded) error message when
	 * a user should NOT have access to a feed.
	 *
	 * @param string $text
	 *
	 * @return string
	 */
	public function setAccessDeniedMessage( $text ) {
		
		global $powerpress_feed;
		global $current_user;
		global $pmpromrss_user_id;
		global $post;
		
		$post_id = null;
		if ( ! empty( $post->ID ) ) {
			$post_id = $post->ID;
		}
		
		if ( is_user_logged_in() ) {
			$user_id = $current_user->ID;
		} else {
			$user_id = $pmpromrss_user_id;
		}
		
		// Process PowerPress feeds
		$feeds = $this->getPowerPressFeeds();
		
		// Check access to the podcast post/page
		$access = pmpro_has_membership_access( $post_id, $user_id, true );
		
		// Grab the default text for the RSS Text PMPro Advanced Settings page
		$denied_text                = stripslashes( pmpro_getOption( "rsstext" ) );
		$pmpro_content_message_pre  = '<div class="pmpro_content_message">';
		$pmpro_content_message_post = '</div>';
		
		$sr_search  = array( "!!login_url!!", "!!levels!!", "!!referrer!!", "!!podcast_feed!!" );
		$sr_replace = array(
			wp_login_url(),
			!empty($access[2]) ? pmpro_implodeToEnglish( $access[2] ) : '',
			urlencode( site_url( $_SERVER['REQUEST_URI'] ) ),
			$feeds[ $powerpress_feed['feed-slug'] ],
		);
		
		$access_denied_message = $pmpro_content_message_pre . str_replace( $sr_search, $sr_replace, $denied_text ) . $pmpro_content_message_post;
		
		if ( empty( $user_id ) || false == $access[0] ) {
			$text = $access_denied_message;
		}
		
		return $text;
	}
	
	/**
	 * Process the PowerPress podcast feed for access
	 *
	 * @param mixed  $var1
	 * @param string $feed_slug
	 */
	public function processFeeds( $var1, $feed_slug ) {
		
		global $current_user;
		global $pmpromrss_user_id;
		global $post;
		
		$post_id = null;
		if ( isset( $post->ID ) ) {
			$post_id = $post->ID;
		}
		
		if ( is_user_logged_in() ) {
			$user_id = $current_user->ID;
		} else {
			$user_id = $pmpromrss_user_id;
		}
		
		$access = pmpro_has_membership_access( $post_id, $user_id, true );
		
		if ( ! is_array( $access ) && true == $access ) {
			return;
		}
  
		if ( empty( $user_id ) || ( is_array( $access ) && false == $access[0] ) ) {
			
			// Remove the default PMPro Membership RSS access denied message handler
			remove_filter( 'pmpro_rss_text_filter', 'pmprorss_pmpro_rss_text_filter' );
			
			// Apply any/all other filters
			$denied_text = apply_filters( "pmpro_rss_text_filter", stripslashes( pmpro_getOption( "rsstext" ) ) );
			
			wp_die( $denied_text );
		}
	}
	
	
	/**
	 * Add handlers for each of the PowerPress feeds configured
	 */
	public function addFeedHandlers() {
		
		// Only process if PowerPress is active
		if ( ! function_exists( 'powerpress_is_podcast_feed' ) ) {
			return;
		}
		
		foreach ( $this->getPowerPressFeeds() as $feed_slug => $feed_name ) {
			add_action( "do_feed_{$feed_slug}", array( $this, 'processFeeds' ), 10, 2 );
		}
	}
	
	/**
	 * Remove the enclosure setting if not able to access post/page/feed
	 * (Should never get there)
	 *
	 * @param string $enclosure
	 *
	 * @return string
	 */
	public function rssEnclosure( $enclosure ) {
		
		global $current_user;
		global $pmpromrss_user_id;
		global $post;
		
		$post_id = null;
		if ( isset( $post->ID ) ) {
			$post_id = $post->ID;
		}
		
		if ( is_user_logged_in() ) {
			$user_id = $current_user->ID;
		} else {
			$user_id = $pmpromrss_user_id;
		}
		
		$has_access = pmpro_has_membership_access( $post_id, $user_id );
		
		if ( false == $has_access ) {
			$enclosure = "";
		}
		
		return $enclosure;
	}
	
	/**
	 * Load any admin notices/warnings/errors
	 */
	public function loadAdminNotices() {
		
		if ( ! empty( $this->error_msg ) && ! empty( $this->error_class ) ) {
			
			foreach ( $this->error_msg as $key => $msg ) {
				?>
                <div class="notice notice-<?php esc_attr_e( $this->error_class[ $key ] ); ?> is-dismissible">
                    <p><?php echo $msg; ?></p>
                </div>
				<?php
			}
		}
		
		$this->error_class = array();
		$this->error_msg   = array();
	}
	
	/**
	 * Check dependencies for this site
	 */
	public function checkDependencies() {
		
		$has_PowerPress = function_exists( 'powerpress_premium_content_authorized_filter' );
		$has_PMProRSS   = function_exists( 'pmpromrss_pmpro_has_membership_access_filter' );
		$has_PMPro      = function_exists( 'pmpro_has_membership_access' );
		
		if ( is_admin() ) {
			
			if ( false === $has_PowerPress ) {
				$this->error_msg[]   = sprintf(
					__( "Error: The Blubrry '<a href=\"%s\" target=\"_blank\">PowerPress</a>' plug-in must be installed and active!", "pmpro-powerpress-feed-protection" ),
					'https://wordpress.org/plugins/powerpress/'
				);
				$this->error_class[] = 'error';
			}
			
			if ( false === $has_PMPro ) {
				$this->error_msg[]   = sprintf(
					__( "Error: The  '<a href=\"%s\" target=\"_blank\">Paid Memberships Pro</a>' plugin must be installed and active!", "pmpro-powerpress-feed-protection" ),
					'https://wordpress.org/plugins/paid-memberships-pro/'
				);
				$this->error_class[] = 'error';
			}
			if ( false === $has_PMProRSS ) {
				$this->error_msg[]   = sprintf(
					__( "Error: The Paid Memberships Pro '<a href=\"%s\" target=\"_blank\">Member RSS</a>' Add-on must be installed and active!", "pmpro-powerpress-feed-protection" ),
					'https://www.paidmembershipspro.com/add-ons/pmpro-member-rss/'
				);
				$this->error_class[] = 'error';
			}
		}
	}
	
	/**
	 * Add Link to PMPro Support Forum on Plugins page
	 *
	 * @param array $links
	 * @param string $file
	 *
	 * @return array
	 */
	public function pluginRowMeta( $links, $file ) {
		
		if ( false !== strpos( $file, 'pmpro-powerpress-feed-protection.php' ) ) {
			
			$links[] = sprintf( '<a href="%s" title="%s" target="_blank">%s</a>',
				esc_url( 'https://paidmembershipsorp.com/support/' ),
				__( 'Visit the Customer Support Forum', 'paid-memberships-pro' ),
				__( 'Support', 'paid-memberships-pro' )
			);
		}
		
		return $links;
	}
	
	/**
	 * Get or create instance of this class (pmproPowerPress)
	 *
	 * @return pmproPowerPress
	 */
	public static function getInstance() {
		
		if ( is_null( self::$instance ) ) {
			self::$instance = new self;
		}
		
		return self::$instance;
	}
}

add_action( 'plugins_loaded', array( pmproPowerPress::getInstance(), ''loadHooks ) );