Adding Merge Tags to existing Triggers

Sometimes it's needed to add your own Merge Tag to already defined Trigger. In example you can add a custom meta Merge Tag to default Post Published Trigger.

To do this simply hook into the action and add your Merge Tag:

// Hook into an action when Merge Tags are attached to Trigger.
add_action( 'notification/trigger/merge_tags', function( $trigger ) {
​
// Check if registered Trigger is the one you need.
if ( 'post/post/updated' !== $trigger->get_slug() ) {
return;
}
​
// Pay attention to the Tag type you are defining.
// If you want to output an HTML, use HtmlTag instead.
$trigger->add_merge_tag( new BracketSpace\Notification\Defaults\MergeTag\StringTag( [
'slug' => 'new_merge_tag',
'name' => __( 'New Merge Tag', 'textdomain' ),
'resolver' => function( $trigger ) {
return get_post_meta( $trigger->post->ID, '_my_meta_key', true );
},
] ) );
​
} );

Targeting all Post Type Triggers

You can target all the Post Type Triggers like this:

add_action( 'notification/trigger/merge_tags', function( $trigger ) {
​
if ( ! preg_match( '/post\/(.*)\/(updated|trashed|published|drafted|added|pending|scheduled)/', $trigger->get_slug() )
return;
}
​
// Add your Tag.
​
} );

Global Merge Tags

The Notification plugin also supports global Merge Tags which are added to all Triggers. You can use this nifty function to create one:

notification_add_global_merge_tag( new BracketSpace\Notification\Defaults\MergeTag\StringTag( [
'slug' => 'option_value',
'name' => __( 'Site title', 'textdomain' ),
'resolver' => function( $trigger ) {
return get_option( 'your_option_name', 'Default' );
},
] ) );

Before using any property of the Trigger make sure it's avaible. Global Merge Tags are intended to be loosly connected with any Trigger.