mjj-bbp-subscription.php

<?php
/*
* Plugin Name: MJJ BBP Subscription
* Description: Custom subscribe to topic email with unsubscribe link. Cron job added using https://bbpress.org/forums/topic/hook-to-bbpress-notifications/#post-156426 by @korobochkin
* Author: Mary (JJ) Jay
* Version: 1.1
* License: GPLv2 or later: http://www.gnu.org/licenses/licenses.html
*/

class MJJ_BBP_Subscriptions{

	protected static $instance = null;

	public static function get_instance() {

		// If the single instance hasn't been set, set it now.
		if ( null == self::$instance ) {
			self::$instance = new self;
		} // end if

		return self::$instance;

	} // end get_instance

	private function __construct(){

		//this makes the salt for the check if needed. If there is one, it will not make one.
		register_activation_hook( __FILE__, array( 'MJJ_BBP_Subscriptions', 'mjj_salt_activate' ) );
		
		//custom topic subscription emails
		remove_action( 'bbp_new_reply',    'bbp_notify_subscribers', 11, 5 );
		remove_action( 'bbp_new_reply',    'bbp_notify_topic_subscribers', 11, 5 );
		remove_action( 'bbp_new_topic',    'bbp_notify_forum_subscribers', 11, 4 );
		
		// when a new reply is created, create the cron job
		add_action( 'bbp_new_reply',    array( 'MJJ_BBP_Subscriptions', 'mjj_bbp_notify_subscribers_cron' ), 11, 5 );
		// the hook in the cron is the notify subscription function itself
		add_action( 'mjj_bbp_notify_subscribers_callback',    array( 'MJJ_BBP_Subscriptions', 'mjj_bbp_notify_subscribers' ), 11, 5 );
		
		//add the one click unsubscribe on the topic itself
		add_action( 'bbp_template_before_single_topic', array( 'MJJ_BBP_Subscriptions', 'mjj_bbp_unsubscribe_notice' ) );

	}
	
	// the cron job setup
	public static function mjj_bbp_notify_subscribers_cron( $reply_id = 0, $topic_id = 0, $forum_id = 0, $anonymous_data = false, $reply_author = 0 ){
		wp_schedule_single_event (
			time(),
			'mjj_bbp_notify_subscribers_callback',
			array (
				$reply_id,
				$topic_id,
				$forum_id,
				$anonymous_data,
				$reply_author
			)
		);
	
		return true;
	}
	
	//I don't think activation hooks are allowed return values?
	public static function mjj_salt_activate(){
		self::mjj_get_salt();
		return;
	}
	
	//let's make a random value and add it to the database so it doesn't change and the links will always work
	private static function mjj_get_salt() {
	
		$salt = get_option( 'mjj_bbp_unsub_salt' );
		if( !$salt ){
			$salt = base64_encode( mcrypt_create_iv(12, MCRYPT_DEV_URANDOM) );
			//add the salt to the options table, it should not change
			add_option( 'mjj_bbp_unsub_salt', $salt );
		}
		return $salt;
	
	}
	
	
	private static function not_a_nonce( $uid, $tid ){
	//this is used for a quick check that the url hasn't been tampered with. It's not dependent on time or whether or not a user is logged in.
		$salt = self::mjj_get_salt();
		//because why not add a little string to it
		$string = $uid . $tid . "user and topic ids";
		$encrypted = hash_hmac( 'md5', $string, $salt );
		return $encrypted;
	
	}
	
	/**
	* from bbpress / includes / common / functions.php
	* this is taken from 2.5.3, except for the unsubsribe stuff
	**/
	public static function mjj_bbp_notify_subscribers( $reply_id = 0, $topic_id = 0, $forum_id = 0, $anonymous_data = false, $reply_author = 0 ) {
	
		// Bail if subscriptions are turned off
		if ( !bbp_is_subscriptions_active() ){
			return false;
		}
	
		/** Validation ************************************************************/
	
		$reply_id = bbp_get_reply_id( $reply_id );
		$topic_id = bbp_get_topic_id( $topic_id );
		$forum_id = bbp_get_forum_id( $forum_id );
	
	
		/** Reply *****************************************************************/
	
		// Bail if reply is not published
		if ( !bbp_is_reply_published( $reply_id ) ){
			return false;
		}
	
		/** Topic *****************************************************************/
	
		// Bail if topic is not published
		if ( !bbp_is_topic_published( $topic_id ) ){
			return false;
		}
	
		$topic_url = bbp_get_topic_permalink( $topic_id );
	
		/** User ******************************************************************/
	
		// Get topic subscribers and bail if empty
		$user_ids = bbp_get_topic_subscribers( $topic_id, true );
		if ( empty( $user_ids ) ){
			return false;
		}
	
		// Poster name
		$reply_author_name = bbp_get_reply_author_display_name( $reply_id );
	
		/** Mail ******************************************************************/
	
		do_action( 'bbp_pre_notify_subscribers', $reply_id, $topic_id, $user_ids );
	
		// Remove filters from reply content and topic title to prevent content
		// from being encoded with HTML entities, wrapped in paragraph tags, etc...
		remove_all_filters( 'bbp_get_reply_content' );
		remove_all_filters( 'bbp_get_topic_title'   );
	
		// Strip tags from text
		$topic_title   = strip_tags( bbp_get_topic_title( $topic_id ) );
		$reply_content = strip_tags( bbp_get_reply_content( $reply_id ) );
		$reply_url     = bbp_get_reply_url( $reply_id );
		$blog_name     = wp_specialchars_decode( get_option( 'blogname' ), ENT_QUOTES );
		$admin_email   = get_bloginfo( 'admin_email' );
	
		// Loop through users
		foreach ( (array) $user_ids as $user_id ) {
	
			$recipient     = get_userdata( $user_id );
			$recipient_name= $recipient->user_login;
	
			$nn_link 	   = self::not_a_nonce( $user_id, $topic_id );
			$unsubscribe_link = $topic_url . '?uid=' . $user_id . '&tid=' . $topic_id . '&nn=' . $nn_link;
	
			$user_sub_link = bbp_get_user_profile_url( $user_id ) . 'subscriptions/';
	
			// Don't send notifications to the person who made the post
			if ( !empty( $reply_author ) && (int) $user_id === (int) $reply_author )
				continue;
	
			// For plugins to filter messages per reply/topic/user
			$message = sprintf( __( 'Hi %8$s,
	
	You are receiving this email because you have subscribed to the topic <a href="%3$s">%6$s</a>. Links to unsubscribe are below.
	
	You can\'t reply to the topics via email, so you\'ll need to go to the topic on the site here: <a href="%3$s">%3$s</a>
	======
	
	%1$s wrote on %6$s:
	
	%2$s
	
	======
	
	Unsubscribe in one click here: <a href="%4$s">%4$s</a>
	Manage all your subscriptions: <a href="%5$s">%5$s</a>
	If you have any issues, please email <a href="mailto:%7$s">%7$s</a>
	', 'bbpress' ),
	
				$reply_author_name,
				$reply_content,
				$reply_url,
				$unsubscribe_link,
				$user_sub_link,
				$topic_title,
				$admin_email,
				$recipient_name
			);
	
			$message = apply_filters( 'bbp_subscription_mail_message', $message, $reply_id, $topic_id, $user_id );
			if ( empty( $message ) )
				continue;
	
			// For plugins to filter titles per reply/topic/user
			$subject = apply_filters( 'bbp_subscription_mail_title', '[' . $blog_name . '] ' . $topic_title, $reply_id, $topic_id, $user_id );
			if ( empty( $subject ) )
				continue;
	
			// Custom headers
			$headers = apply_filters( 'bbp_subscription_mail_headers', array() );
	
			// Get user data of this user
			$user = get_userdata( $user_id );
	
			// Send notification email
			wp_mail( $user->user_email, $subject, $message, $headers );
		}
	
		do_action( 'bbp_post_notify_subscribers', $reply_id, $topic_id, $user_ids );
	
		return true;
	}
	
	//this function does the work of the unsubscribing and also gives a little template notice. It's on the topic in question - I thought about putting it on the user profile page 	but don't want to give out that info if the url is shared
	public static function mjj_bbp_unsubscribe_notice(){
	
		global $post;
	
		$topic_id = ( isset( $_GET['tid'] ) && !empty($_GET['tid'] ) ? $_GET['tid'] : '' );
		$user_id = ( isset( $_GET['uid'] ) && !empty($_GET['uid'] ) ? $_GET['uid'] : '' );
		$to_check = ( isset( $_GET['nn'] ) && !empty($_GET['nn'] ) ? $_GET['nn'] : '' );
		$check = self::not_a_nonce( $user_id, $topic_id );
	
		$current_user = is_user_logged_in() ? wp_get_current_user() : false;
	
		//are there any of the query vars? If not, return
		if( !$topic_id && !$user_id && !$to_check ){
			return;
		}
		//if you fail the check, it  doesn't work. Also it has to be on the right topic.
		elseif( ! hash_equals( $check, $to_check ) || (int)$post->ID !== (int)$topic_id  ){
			$admin_email   = get_bloginfo( 'admin_email' );
			$message = "Something has gone wrong. You can manage your subscriptions from your profile. If you need assistance, 
				please email <a href='mailto:{$admin_email}'>{$admin_email}</a>";
		}
		//if you are logged in and using someone else's link, it won't work for you (or unsubscribe them) so you get a link to your subscriptions page
		elseif( is_user_logged_in() && (int)$current_user->ID !== (int)$user_id ){
	
			$subscriptions_link = bbp_get_user_profile_url( $current_user->ID ) . 'subscriptions/';
			$message = "Unsubscribe links are unique to each user of the forum.<br />This link can&rsquo;t be used for you to unsubscribe, but you can manage all your subscriptions <a href='{$subscriptions_link}'>here</a>";
	
		}
		//what else haven't I thought about? add anything I've forgotten here. If you are not logged in, you can still unsubscribe. That's ok. Better accidental unsubscriptions than people not being able to unsubscribe.
		else{
	
			bbp_remove_user_subscription( (int)$user_id, (int)$topic_id );
			$message = 'You have been unsubscribed from this topic.';
	
		}
	
		echo '<div class="notice good">';
		echo $message;
		echo '</div>';
	
		return;
	
	}
}

MJJ_BBP_Subscriptions::get_instance();