How should I design and use an User class? - php

Question

When I worked in procedural PHP programming, I would have a login page, where user's session would be created, and stored. Then, on every page, I just displayed the name of the user and retrieved the information I needed.
But I am helpless, how would you achieve this in object programming?
So, procedural (login.php):
if ( $_POST['password'] != '' && $_POST['username'] != '' ) {
// check if password&username combination exists in database etc.
$_SESSION['user_id'] = $user_id;
$_SESSION['username'] = $username;
}
I assume it would be done like this in OOP:
// include user class
if ( $_POST['password'] != '' && $_POST['username'] != '' ) {
// check if password&username combination exists in database etc.
$user = new User();
$user->id = $userId;
$user->username = $username;
But here is the problem: Where do I create session? And this object is not going to exist outside of this "login.php" page, since I create it there. How do I make this information accessible everywhere?
And how would you get information from the database, using a special class ( let's say PDO ) without putting the queries into the user class?
Thank you very much, I just cannot understand the structure

Answer 1

You would do something along the lines:
class User{
private $id;
private $username;
function __construct($userId, $username) {
$this->$id = $userId;
$this->$username = $username;
}
}
if ( $_POST['password'] != '' && $_POST['username'] != '' ) {
// check if password&username combination exists in database etc.
//......
//Store your session
$_SESSION['user_id'] = $user_id;
$_SESSION['username'] = $username;
//Create user instance
$user = new User($user_id, $username );
}
You can also put your data access layer in the user constructor, that way you just need to worry about storing the id session.
User.php:
class User{
private $id;
private $username, $first_name, $last_name;
function __construct($userId) {
$this->$id = $userId;
//get user data from db using $id
$this->$username = $row['username'];
$this->$first_name = $row['first_name'];
$this->$last_name = $row['last_name'];
}
}
Login.php:
function get_userId($username, $password)
// check if password&username combination exists in database etc.
//then return Id
//......
return $userId
}
Then use the function like the following:
if ( $_POST['password'] != '' && $_POST['username'] != '' ) {
$username = $_POST['username'];
$password = $_POST['password'];
$user_id = get_userId($username, $password);
$_SESSION['user_id'] = $user_id;
}
then you would create the user instance using the id like this:
session_start();
$user_id = $_SESSION['user_id'];
$user = new User($user_id);

Answer 2

Try this you are nearly there
// include user class
session_start();
if ( $_POST['password'] != '' && $_POST['username'] != '' ) {
// check if password&username combination exists in database etc.
$user = new User();
$user->id = $userId;
$user->username = $username;
$_SESSION['user_obj'] = serialize($user);
Then when you want to access it again in another page:
// include user class
session_start();
$user = new User();
if ( isset( $_SESSION['user_obj'] ) {
$user = unserialize($_SESSION['user_obj'];
}

Answer 3

At first you need to use official documentation
For all my experiance I can tell you that only you are decide how to use classes and OOP at all. There are many models and stadarts that gives you some structure but it is personal choices.
But in your case i can suggest to you using an regulary class that will check and store information.
class User {
private $id = null;
private $username = null;
private $isLoggedIn = false;
public function __construct() {
if (isset($_SESSION['userData']) && !empty($_SESSION['userData'])) {
// I want to think that you have more complex check for user session
$this->id = $_SESSION['userData']['userId'];
$this->username = $_SESSION['userData']['username'];
$this->isLoggedIn = true;
}
}
public function auth() {
$_SESSION['userData'] = array()
$result = false;
// Here can be an password check
if ($this->id && $this->username) {
$_SESSION['userData']['userId'] = $this->id;
$_SESSION['userData']['username'] = $this->username ;
$this->isLoggedIn = true;
$result = true;
}
return $result;
}
public function isLoggedIn() {
return $this->isLoggedIn;
}
public function userId($id = null) {
if ($id != null) {
$this->id = $id;
}
return $this->id;
}
public function userName($name = null) {
if ($name != null) {
$this->name = $name;
}
return $this->name;
}
}
And usage for this class will be short and easy
// include user class
session_start();
$user = new User();
if ($user->isLoggedIn()) {
// user is Logged In
} elseif ( $_POST['password'] != '' && $_POST['username'] != '' ) {
// check if password&username combination exists in database etc.
$user->userId($userId);
$user->userName($username);
$user->auth();
} else {
echo 'Auth failed';
die();
}
echo 'Hello, ' . $user->userName();