Wordpress Actions & Filters<!-- --> | <!-- -->IORoot

Wordpress Simple Actions & Filters

Curse the gods, this simple functionality can seem complicated. I think its a combination of the terminology and word choice being so unhelpful. Do I add , apply or do a filter or action? What is a hook here? Or maybe I need to register it? It's all very vague, and I constantly forget.

Anyway, here's some pretty pictures instead. I've made it as basic as possible, more for remembering which one to use and where.

🧗🏻‍♀️ Basic Actions (does a task, returns nothing)

Plug in new code at a specific point.

Normal code flow
Registered Action
add_action( 'my_action_name', 'run_this_function', $priority, $number_of_args)
do_action( 'my_action_name', $arguments )
Registered Callback Function
  1. Once you've registered your action with a my_action_name in functions.php or a plugin, you can now call it.
  2. Whenever the code gets to a do_action('my_action_name'), it'll run the associated callback function run_this_function.
  3. No need to return anything.

🔗 Action Links:



🔍 Basic Filters (returns filtered data)

Pass in a value, change the value, pass new value back.

Normal code flow
Registered Callback Function
run_this_function($value, $arguments){ return 'hi! '. $value; }
$value_to_be_filtered = 'Andrew'
$new_value = apply_filters( 'my_filter_name', $value_to_be_filtered, $arguments )
echo $new_value
Registered Filter
add_filter( 'my_filter_name', 'run_this_function', $priority, $number_of_args)
  1. Registered your filter with an add_filter referencing a callback function.
  2. Run the filter with the apply_filter function.
  3. The callback function will take the passed value, change it and return it back. (filtering it)
  4. MUST return something (the new value).