使用先前在其他类中声明的对象

Question

This is my general php page:

<?php
require_once('includes.php');
require_once('cms.class.php');
.....
rest of the page
?>

in includes.php an pro object called $db is initiated which I want to use in the class specified in the cms.class.php

includes.php:

$db = new PDO('mysql:host=localhost;dbname=xxxxx','xxxxx','xxxxxx'); 
$db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
$db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);

How can I use this database object in my classes without having multiple places where my credentials are stored?

Answer 1

You need want a dependency manager or a bootstrapper or whatever you want to call it.

class Dependency_Manager {

    private $db;

    public function __construct($settings) {
        $this->db = new PDO('mysql:host=localhost;dbname=' . settings["dbname"],settings["username"],$setings["password"]); 
        $db->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION); 
        $db->setAttribute(PDO::ATTR_DEFAULT_FETCH_MODE, PDO::FETCH_ASSOC);
    }

    public function getDB() {
        return $db;
    }

}

class CMS {
    public function __construct(PDO $db) {
        /* .. */
    }
}

$setting = array(/* etc */);

$dm = new Dependency_Manager($settings);
$cms = new CMS($dm->getDB());

This approach scales very well and can handle any dependecy. It also aims to put all the settings in one place so you don't have configuration settings littered everywhere. The $dm is the only one who knows the settings, if you need to construct something based on the settings, put it in the $dm.