Library as Singleton in Codeigniter? - php

Question

I've created a custom library using singleton pattern. Why by this way? because I need to be able to call my functions without $this-> reference, for example, I could execute the code below:
function foo() {
MyLibrary::instance()->foo();
}
then I could call my functions in controllers like this:
function foo();
instead of
$this->mylibrary->foo();
I am in trouble because CodeIgniter try to instantiate my library when the best way to do is "read" the static instance.
Why I need to do this?
My custom library must register "hooks" from external php files located in /plugins directory outside of application folder. Look:
/application
/plugins
/plugins/helloworld.php
This is my Loader library:
class Loader{
public static $instance;
protected $hooks;
private function __construct($params = array()){
$this->hooks= array();
$this->includePlugins();
}
public static function instance()
{
if (!self::$instance)
{
self::$instance = new Loader();
}
return self::$instance;
}
public function includePlugins()
{
include_once "/plugins/helloworld.php";
}
public function do_action($hook= "after")
{
foreach ($this->actions[$hook] as $function)
{
call_user_func_array($function, array());
}
}
public function add_action($hook, $function, $priority)
{
if ($hooks !== false)
{
$this->actions[$hook][] = $function;
}
else
{
echo "hook name is unavalaible";
}
}
}
/**
* Functions using the Singleton instance !!!
*/
function do_action($hook)
{
Loader::instance()->do_action($hook);
}
function add_action($hook, $function, $priority)
{
Loader::instance()->add_action($hook, $function, $priority);
}
No, my helloworld.php (plugin) looks like this:
add_action('right_here', 'show_message', 11);
function show_message()
{
echo "hello world!";
}
Finally, I could call my the function do_action in my controller/view in order to print the message, like this:
do_action('right_here');
Note that all my important functions are called by a global function that allow me to use the singleton instance. But I am experiencing two issues:
Codeigniter needs that my contruct be public in order to
instantiate. Here I need to take my singleton.
If I let it public, several instances will be created and the library
will no longer works as expected.

Answer 1

I've solved the problem :)
In order to create a singleton library you must:
Include your library at system/core/Codeigniter.php like this:
require_once("/path/to/library.php");
Make your instance return with & symbol, like this:
Singleton:
public static function &instance()
{
if (!self::$instance)
{
self::$instance = new Loader();
}
return self::$instance;
}
Ready to uses your functions as well. Also, you can include th CI
object in you library.