WC 401: Playing Well With Others

WordCamp Phoenix 2013

Erick Hitter

Design Engineer @ Automattic

Design Engineer at Automattic, the company behind WordPress.com
Formerly a Senior WordPress Developer with Oomph, Inc. working on the WordPress.com VIP platform
3+ years developing WordPress themes and plugins
WordPress Core Contributor
WordCamp Boston Organizer
Plugin Author

Arguably, hooks are one of WordPress' most powerful, and most important, features.

While there are always places in Core where an action or filter would be useful, this is much moreso the case in our plugins.

Don't take my word for it. What does Brad Williams think?

@helenhousandi @simpledream filters everywhere!Need one of the Sharing label at the moment
— Brad Williams (@williamsba) January 3, 2013

Brad was talking specifically about Jetpack, but it is hardly the only plugin that lacks sufficient hooks.

We're all probably familiar with add_action() and add_filter().

Their counterparts aren't much more complicated.

Arguments:
- $tag – the name of the action that other code can hook to.
- $arg – datum made available to the function that executes when this action is called.
Important! – a hook can accept multiple arguments.

Example:

<?php
do_action( 'after_setup_theme' );
?>

Arguments:
- $tag – the name of the filter to hook to.
- $value – the value to be filtered.
Important! A filter can provide more arguments, which contain additional data useful to the filter.

Example:

<?php
$excerpt_length = apply_filters('excerpt_length', 55);
?>