The OOP way of doing things (in PHP)
Marcos’s Question:
I’m still trying to wrap my head around OOP, having been brought up in procedural coding a long time ago. Been stretching my legs in PHP for a while now.
So I’ve read a lot about best practices and paradigms and such. Especially SOLID. And I’ve tried to do things in a number of different ways. MVC-style, I ended up with extremely long, convoluted models that were either tightly couple to everything else, or had to be injected with half a dozen dependencies. Then I swung back to fat controllers, who did pretty much all the work and the models were only like helpers.
Now, I need a judgement on my current approach. Would this be a valid (SOLID) OOP way of doing a user-account-management system:
class PDO_Wrapper { # wraps PHP's PDO functions nicely
public function select(...);
public function insert(...);
public function delete(...);
public function update(...);
}
class ORM extends PDO_Wrapper { # very basic
public function load($id); # assigns everything in row $id to object paramters
public function save(); # writes all object parameters to db
}
class User extends ORM { # some User specific functions
public function hashPassword($password);
public function sendConfirmationMail();
...
}
class Login extends User { # one model for each User action (login, register, forgot password...)
public function login($input);
}
Well, I dont know which one of SOLID priniciples are you following:
Lets break down your code
class ORM extends PDO_Wrapper { # very basic
public function load($id); # assigns everything in row $id to object paramters
public function save(); # writes all object parameters to db
}
This class, is extending PDO_Wrapper. Now lets ask, does it provide an extension of PDO_Wrapper? Actually It does, so its kind of correct. But for this:
class User extends ORM { # some User specific functions
public function hashPassword($password);
public function sendConfirmationMail();
...
}
Does User extend the ORM in some way? NO, it uses it! So very wrong. You have to create an object of it inside the class and use it like:
class User {
private $orm_db;
function __construct() {
$this -> orm_db = new ORM();
}
}
Now for this:
class Login extends User { # one model for each User action (login, register, forgot password...)
public function login($input);
}
Login is an action done by the object of User class. So it is a method of User Class, not a sub class.
class User {
private $orm_db;
function __construct() {
$this -> orm_db = new ORM();
}
public function login($input) {
//...
}
}
I hope it clears some concept about OOP.
