WordPress hooks are functions that allow you to manipulate a procedure without changing a file in WordPress core. A hook can be applied to both an event (action hook) and a filter (filter hook).
Let’s create our first hook
For example, go to the file header.php our WordPress theme. Open the file and add a new hook:
<?php
do_action('my_first_hook')
?>
This code calls the my_first_hook action. Actions (hooks) in PHP allow you to execute specific code at specific times within your program. In this case, the code do_action(‘my_first_hook’) tells PHP to execute all the functions that were bound to the my_first_hook hook.
To do this, go to yours function.php, and add:
<?php
//Our usual function is to display text
function mycustom() {
echo 'This text add by hook';
}
//add_action attaches this function to the hook we created
add_action('my_first_hook', 'mycustom');
?>
We will add more text to our hook:
And now we will change the text in places, for this purpose we will use priority of hooks, it is set by 3 parameters:
Pass the variables $ var, $ var2 to our hook
<?php
do_action('my_first_hook', $var, $var2)
?>
<?php
function mycustom2($var, $var2) {
echo $var . $var2;
}
add_action('my_first_hook', 'mycustom2', 1,2);
?>
Сreate a filter
Now let’s talk about the filter, its functionality is very similar to the hook, but created to change values:
<?php
$color = 'red';
$color = apply_filters('my_first_filter', $color);
?>
in functions.php we will add
<?php
function myfilter($name) {
$color = 'black';
return $color;
}
add_filter('my_first_filter', 'myfilter');
?>
The values that will pass through this filter will change to = ‘black’
Remove hooks and filters?
Sometimes a hook or filter may not be created by you. If it interferes with you by disrupting your theme or plugin, you can easily turn it off using the functions remove_filter and remove_hook
remove_hook
<?php
remove_hook('my_first_hook', 'mycustom');
?>
This code removes the mycustom function, which was bound to the my_first_hook hook.
remove filter
<?php
remove_filter('mycustom2', 'myfilter');
?>
This code removes the myfilter filter that was bound to the mycustom2 hook. The remove_filter() function is used to remove bound filters from a specific hook in PHP.