Login and register system using PHP with PDO

Certainly! If you want to implement a login and register system using PHP with PDO (PHP Data Objects) and Object-Oriented Programming (OOP) principles, you can follow the steps below. I’ll provide a simple example to get you started.

Let’s create a basic class for database connection (DbConnection), a class for user operations (User), and a simple login/register script.

1. DbConnection.php:

<?php

class DbConnection
{
    private $host = 'your_host';
    private $db_name = 'your_database';
    private $username = 'your_username';
    private $password = 'your_password';
    private $conn;

    public function connect()
    {
        $this->conn = null;

        try {
            $this->conn = new PDO(
                'mysql:host=' . $this->host . ';dbname=' . $this->db_name,
                $this->username,
                $this->password
            );
            $this->conn->setAttribute(PDO::ATTR_ERRMODE, PDO::ERRMODE_EXCEPTION);
        } catch (PDOException $e) {
            echo 'Connection Error: ' . $e->getMessage();
        }

        return $this->conn;
    }
}
?>

2. User.php:

<?php

class User
{
    private $conn;

    public function __construct($db)
    {
        $this->conn = $db;
    }

    public function register($username, $password)
    {
        $hashed_password = password_hash($password, PASSWORD_DEFAULT);

        $query = 'INSERT INTO users (username, password) VALUES (:username, :password)';
        $stmt = $this->conn->prepare($query);

        $stmt->bindParam(':username', $username);
        $stmt->bindParam(':password', $hashed_password);

        if ($stmt->execute()) {
            return true;
        } else {
            return false;
        }
    }

    public function login($username, $password)
    {
        $query = 'SELECT id, username, password FROM users WHERE username = :username';
        $stmt = $this->conn->prepare($query);

        $stmt->bindParam(':username', $username);
        $stmt->execute();

        $row = $stmt->fetch(PDO::FETCH_ASSOC);
        if ($row) {
            $hashed_password = $row['password'];
            if (password_verify($password, $hashed_password)) {
                return $row;
            } else {
                return false;
            }
        } else {
            return false;
        }
    }
}
?>

3. index.php:

<?php
require_once 'DbConnection.php';
require_once 'User.php';

// Database connection
$database = new DbConnection();
$db = $database->connect();

// User object
$user = new User($db);

// Example usage for registration
$username = 'example_user';
$password = 'example_password';

if ($user->register($username, $password)) {
    echo 'Registration successful!';
} else {
    echo 'Registration failed!';
}

// Example usage for login
$login_username = 'example_user';
$login_password = 'example_password';

$logged_in_user = $user->login($login_username, $login_password);

if ($logged_in_user) {
    echo 'Login successful! Welcome, ' . $logged_in_user['username'] . '!';
} else {
    echo 'Login failed!';
}
?>

Remember to replace the placeholders (your_host, your_database, your_username, your_password) with your actual database connection details.

This is a basic example, and you might want to enhance it by adding features such as session management, error handling, input validation, etc., based on your specific requirements.