Installation

This section describes how to install the plugin and get it working.

1. Upload subscribe-to-category to the /wp-content/plugins/ directory
2. Activate the plugin through the ‘Plugins’ menu in WordPress Admin
3. Save your settings ‘Settings > Subscribe’.
4. Create a page and add shortcode [stc-subscribe] or use the STC Widget to display stc form subscription.

Shortcode Attributes

‘category_in’ – Use this attribute if you only want one or several categories to be available for subscription. Value to be entered is the name of the category.
‘category_id_in’ – The difference to above is to use the category ID instead of category name.

‘category_not_in’ – Use this attribute if you want to exclude categories to be available for subscription. Value to be entered is the name of the category.
‘category_id_not_in’ – The difference to above is to use the category ID instead of category name.

‘hide_unsubscribe’ – Disables the unsubscribe feature is the shortcode attribuet is enabled at the admin setting

For the above attributes you can use a comma sign to separate multiple categories, like [stc-subscribe category_in=”news, article”].

Filter and hooks

Following filters and hooks can be used for customizing the email message.

<?php
// FILTERS
// Parameters: $value
add_filter( 'stc_message_length_sum_of_words', 'stc_message_length_sum_of_words', 10, 1 ); //set return value to a negative number to show the full content


// Parameters: $value, $post_id, $subscriber_post_id
add_filter( 'stc_message_title_html', 'my_stc_message_title_html', 10, 3 );
add_filter( 'stc_message_link_to_post_html', 'my_stc_message_link_to_post_html', 10, 3 );
add_filter( 'stc_message_unsubscribe_html', 'my_stc_message_unsubscribe_html', 10, 3 );
add_filter( 'stc_message_subscribe_html', 'my_stc_message_subscribe_html', 10, 3 );

// HOOKS
// Parameters: $post_id, $subscriber_post_id  
add_action( 'stc_before_message', 'my_stc_before_message', 10, 2 );
add_action( 'stc_before_message_title', 'my_stc_before_message_title', 10, 2 );
add_action( 'stc_after_message_title', 'my_stc_after_message_title', 10, 2 );
add_action( 'stc_before_message_content', 'my_stc_before_message_content', 10, 2 );
add_action( 'stc_after_message_content', 'my_stc_after_message_content', 10, 2 );
add_action( 'stc_after_message', 'my_stc_after_message', 10, 2 );

// Parameters: $subscriber_post_id, $categories, bool $all_categories
add_action( 'stc_after_update_subscriber', 'my_stc_after_update_subscriber', 10, 3 );
add_action( 'stc_after_insert_subscriber', 'my_stc_after_insert_subscriber', 10, 3 );

// Parameters: $subscriber_post_id, 
add_action( 'stc_before_unsubscribe', 'my_stc_before_unsubscribe', 10, 1 ); // runs before deleting a subscriber from database
add_action( 'stc_before_subscribe', 'my_stc_before_subscribe', 10, 1 ); // runs before adding a subscriber to the database


/**
 * Example for adding featured image to STC email
 */
function my_stc_after_message_title( $post_id ){
    echo get_the_post_thumbnail( $post_id, 'thumbnail' );
}
add_action( 'stc_after_message_title', 'my_stc_after_message_title', 10, 2 );

?>

Optionally but recommended

As WordPress Cron is depending on that you have visits on your website you should set up a cron job on your server to hit http://yourdomain.com/wp-cron.php at a regular interval to make sure that WP Cron is running as expected. In current version of Subscribe to Category the WP Cron is running once every hour, that might be an option that is changeable in future versions.
Therefore a suggested interval for your server cron could be once every 5 minutes.