Ticket #2707: mjj-bbp-subscription.php

<?php
/*
Plugin Name: MJJ BBP Subscription
Description: Custom subscribe to topic email with unsubscribe link 
Author: Mary (JJ) Jay
Version: 1
*/

//this makes the salt for the check if needed. If there is one, it will not make one.
register_activation_hook( __FILE__, 'mjj_salt_activate' );

//custom topic subscription emails
remove_action( 'bbp_new_reply',    'bbp_notify_subscribers', 11, 5 );
add_action( 'bbp_new_reply',    'mjj_bbp_notify_subscribers', 11, 5 );

//add the one click unsubscribe on the topic itself
add_action( 'bbp_template_before_single_topic', 'mjj_bbp_unsubscribe_notice' );

//I don't think activation hooks are allowed return values?
function mjj_salt_activate(){
        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
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;
        
}


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 = mjj_get_salt();
        //because why not add a little string to it
        $string = $uid . $tid . "user and topic ids";
        $encrypted = crypt( $string, $salt );
        return $encrypted;      

}

/** 
* from bbpress / includes / common / functions.php
* this is taken from 2.5.3, except for the unsubsribe stuff
**/
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     = $topic_url . '#the-reply-form';
        $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 ) {
        
                $nn_link           = 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,

You are receiving this email because you have subscribed to the topic "%6$s." Links to unsubscribe are below.

Please note that unfortunately, you can\'t reply to the topics via email, so you\'ll need to go to the topic on the website here:
%3$s
======

%1$s wrote on %6$s:

%2$s

======

Unsubscribe in one click here: %4$s
Manage all your subscriptions: %5$s
If you have any issues, please email %7$s  
', 'bbpress' ),

                        $reply_author_name,
                        $reply_content,
                        $reply_url,
                        $unsubscribe_link,
                        $user_sub_link,
                        $topic_title,
                        $admin_email
                );

                $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
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 = not_a_nonce( $user_id, $topic_id );
        
        $current_user = wp_get_current_user();

        //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( $to_check != $check || $post->ID != $topic_id  ){
                $message = 'Something has gone wrong. You can manage your subscriptions from your profile.'; 
        }
        //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( $current_user && $current_user-> ID != $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( $user_id, $topic_id );
                $message = 'You have been unsubscribed from this topic.';
        
        }
        
        echo '<div class="bbp-template-notice">';
        echo $message;
        echo '</div>';  
        
        return;

}