3.0) Hooks

Hooks

The PHP Hooks Class is a fork of the WordPress filters hook system rolled in to a class to be ported into any php based system

• This class is heavily based on the WordPress plugin API and most (if not all) of the code comes from there.

How to use?

We start with a simple example ...

<?php

$hooks = Hooks::getInstance();

$hooks->add_action('header_action','echo_this_in_header');

function echo_this_in_header(){
   echo 'this came from a hooked function';
}

then all that is left for you is to call the hooked function when you want anywhere in your application, EX:

<?php

$hooks = Hooks::getInstance();

echo '<div id="extra_header">';
$hooks->do_action('header_action');
echo '</div>';

and you output will be: <div id="extra_header">this came from a hooked function</div>

PS: you can also use method from a class for a hook e.g.: $hooks->add_action('header_action', array($this, 'echo_this_in_header_via_method');

Hooks List

https://github.com/marcocesarato/Database-Web-API/wiki/3.2)-Hooks:-List

Methods

ACTIONS:

add_action Hooks a function on to a specific action.

 - @access public
 - @since 0.1
 - @param string $tag The name of the action to which the $function_to_add is hooked.
 - @param callback $function_to_add The name of the function you wish to be called.
 - @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
 - @param int $accepted_args optional. The number of arguments the function accept (default 1).

do_action Execute functions hooked on a specific action hook.

 - @access public
 - @since 0.1
 - @param string $tag The name of the action to be executed.
 - @param mixed $arg,... Optional additional arguments which are passed on to the functions hooked to the action.
 - @return null Will return null if $tag does not exist

remove_action Removes a function from a specified action hook.

 - @access public
 - @since 0.1
 - @param string $tag The action hook to which the function to be removed is hooked.
 - @param callback $function_to_remove The name of the function which should be removed.
 - @param int $priority optional The priority of the function (default: 10).
 - @return boolean Whether the function is removed.

has_action Check if any action has been registered for a hook.

 -  @access public
 -  @since 0.1
 -  @param string $tag The name of the action hook.
 -  @param callback $function_to_check optional.
 -  @return mixed If $function_to_check is omitted, returns boolean for whether the hook has anything registered.
  When checking a specific function, the priority of that hook is returned, or false if the function is not attached.
  When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false (e.g.) 0, so use the === operator for testing the return value.

did_action Retrieve the number of times an action is fired.

 - @access public
 - @since 0.1
 - @param string $tag The name of the action hook.
 - @return int The number of times action hook <tt>$tag</tt> is fired

FILTERS:

add_filter Hooks a function or method to a specific filter action.

 - @access public
 - @since 0.1
 - @param string $tag The name of the filter to hook the $function_to_add to.
 - @param callback $function_to_add The name of the function to be called when the filter is applied.
 - @param int $priority optional. Used to specify the order in which the functions associated with a particular action are executed (default: 10). Lower numbers correspond with earlier execution, and functions with the same priority are executed in the order in which they were added to the action.
 - @param int $accepted_args optional. The number of arguments the function accept (default 1).
 - @return boolean true

remove_filter Removes a function from a specified filter hook.

 - @access public
 - @since 0.1
 - @param string $tag The filter hook to which the function to be removed is hooked.
 - @param callback $function_to_remove The name of the function which should be removed.
 - @param int $priority optional. The priority of the function (default: 10).
 - @param int $accepted_args optional. The number of arguments the function accepts (default: 1).
 - @return boolean Whether the function existed before it was removed.

has_filter Check if any filter has been registered for a hook.

 - @access public
 - @since 0.1
 - @param string $tag The name of the filter hook.
 - @param callback $function_to_check optional.
 - @return mixed If $function_to_check is omitted, returns boolean for whether the hook has anything registered.
   When checking a specific function, the priority of that hook is  returned, or false if the function is not attached.
   When using the $function_to_check argument, this function may return a non-boolean value that evaluates to false (e.g.) 0, so use the === operator for testing the return value.

apply_filters Call the functions added to a filter hook.

 - @access public
 - @since 0.1
 - @param string $tag The name of the filter hook.
 - @param mixed $value The value on which the filters hooked to <tt>$tag</tt> are applied on.
 - @param mixed $var,... Additional variables passed to the functions hooked to <tt>$tag</tt>.
 - @return mixed The filtered value after all hooked functions are applied to it.