WordPress Email, Custom Post types and Email Subscriptions

Question

I have something a client wants me to build, and I can with wp_mail, but I am wondering if how it should be built is fessable - no they dont want to use third party websites or software.

Essentially a widget will take in the clients email address, with this we can:

Have some kind of interface so we can say that send out 5, 10, 15 posts of category x, y, x on a daily, weekly or monthly basis

Thats not hard, but the question is: how would I store the emails that come in? a new column?

Use these emails and a custom post type to create email templates, newsletters and so on that could be sent to a set of emails (in this case all emails stored for now) at a specified time.

This one isn't hard either, its the custom post type part, how would I create a custom post type that when a post is published the post is not published the same way a post is, or a page. but instead its stored like one, but I can use its content in an email body instead of displaying it like a post or page.

essentially I shouldn't be able to go to: site.come/email_templates/post_id

So the second one is a bit more complicated but I am wondering how you guys might approach this situation or idea.

rafiki_rafi rafiki_rafi · Accepted Answer · 2012-11-09T04:27:19

Here are some thoughts when it comes to the e-mail subscription part. As for the custom post types - I don't have much experience with those, sorry :)

If you want a quick and easy solution for the e-mail subscriptions, create a wp option (see http://codex.wordpress.org/Function_Reference/add_option) that is essentially a hash table that maps categories to keys in the table.

For each category in the hash table, store an array of userIDs and/or e-mails of the users that are subscribed to that category.

Once you have this data structure in place, it's fairly easy to manipulate and use in with wp_mail. Here is some example code that I've written for one of my plugins:

        $subscribers = get_option('subscribers');
        $categories = get_the_category($post->ID);

        if( !empty($categories) && !empty($subscribers)){
            $emails = array();
            //Go through each category and accumulate the necessary e-mail addresses
            foreach($categories as $category){
                $catID = $category->term_id;
                if( !empty($subscribers[$catID]) ){
                    foreach($subscribers[$catID] as $userID => $trash){
                        $user      = get_userdata($userID);
                        $userEmail = array( $userID => $user->user_email );
                        if( !in_array($userEmail, $emails) ){
                            $emails   = $emails + $userEmail; 
                            //you can use something like implode(", ", $emails)
                            //in the Bcc: part when you send out the e-mail.
                        }
                    }
                }
            }
        }

Some things to note:

This is a quick and dirty solution. If the number of categories and number of subscribers grows big, you're better of creating a table in the database and maintaining it that way
Make sure to think of situations when categories are deleted (i.e. hook into actions when categories are deleted) and how that will affect your datastructure
The hash table approach works well assuming categories are NOT deleted/added frequently

Good luck!

WordPress Email, Custom Post types and Email Subscriptions

1 Answers