Question

There are users with different privileges in the system. They privileges are hierarchical

class User{//abstract user not logged in
    //function signIn(){}
}

class Guest extends User{

}

class FullUser extends Guest{
    static function signUp(){}//create an account
    function signOut(){}
}

class Moderator extends FullUser{
          function edit(){}//some new method introduced here,never introduced before
}

class Admin extends Moderator{
           //can do everything
}

//can use
FullUser::signUP()

Is my architecture good?
Can you advice me anything else?
I was wondering which is the best way to create a user – write a constructor? Or let it be a “factory” function.

function signIn($username, $password)

I’m new to OOP in php, so I accept wise advices, links, etc.

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EDIT:
I’m planning to use this role – checking system:

if(!method_exists($user->addComment())) die('Access denied')

What do you think of it?

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EDIT 2:
should I create a role table with ROLE in axis X and METHOD in axis Y?

            comment | post |  editPost | kill
guest          0        0        0         0
fullUser       1        0        0         0
moderator      1        1        1         0
admin          1        1        1         1

And later I should write something like this

function addComment($user){
if(!$ROLES [$this->$role][__FUNCTION__])return;
....
}

Is that better than OOP, wise programmers?

Answer 1

Roles are definitely the way to go.

You can do something simple like letting each user have a public $role attribute where $role is just a number (e.g. 9 = admin, 6 = fulluser, 3 = guest).

The database table would look like this

Users
id  username    password    role
1   admin       somePass    9
2   someUser    somePass    3

In the code you do stuff like ´if ($user->role >= 9)´.

If you want, you can have a role table instead of using just numbers – like this:

Roles
id  role
1   admin
2   fulluser
3   user
4   guest

You could also make it more advanced where one user can have an array of roles.