Create Database

 
CREATE TABLE `users` (
  `id` int(11) NOT NULL PRIMARY KEY AUTO_INCREMENT,

  `username` varchar(255) NOT NULL,
  `password` varchar(255) NOT NULL,
  `created` timestamp NOT NULL DEFAULT CURRENT_TIMESTAMP ON UPDATE CURRENT_TIMESTAMP
) 

Koneksi Database

 
class Database{
 
    // specify your own database credentials
    private $host = "localhost";
    private $db_name = "PHPLearning";
    private $username = "root";
    private $password = "";
    public $conn;
 
    // get the database connection
    public function getConnection(){
 
        $this->conn = null;
 
        try{
            $this->conn = new PDO("mysql:host=" . $this->host . ";dbname=" . $this->db_name, $this->username, $this->password);
            $this->conn->exec("set names utf8");
        }catch(PDOException $exception){
            echo "Connection error: " . $exception->getMessage();
        }
 
        return $this->conn;
    }
}

Fungsi User

 
class User{
 
    // database connection and table name
    private $conn;
    private $table_name = "users";
 
    // object properties
    public $id;
    public $username;
    public $password;
    public $created;
 
    // constructor with $db as database connection
    public function __construct($db){
        $this->conn = $db;
    }
    // signup user
    function signup(){
    
        if($this->isAlreadyExist()){
            return false;
        }
        // query to insert record
        $query = "INSERT INTO
                    " . $this->table_name . "
                SET
                    username=:username, password=:password, created=:created";
    
        // prepare query
        $stmt = $this->conn->prepare($query);
    
        // sanitize
        $this->username=htmlspecialchars(strip_tags($this->username));
        $this->password=htmlspecialchars(strip_tags($this->password));
        $this->created=htmlspecialchars(strip_tags($this->created));
    
        // bind values
        $stmt->bindParam(":username", $this->username);
        $stmt->bindParam(":password", $this->password);
        $stmt->bindParam(":created", $this->created);
    
        // execute query
        if($stmt->execute()){
            $this->id = $this->conn->lastInsertId();
            return true;
        }
    
        return false;
        
    }
    // login user
    function login(){
        // select all query
        $query = "SELECT
                    `id`, `username`, `password`, `created`
                FROM
                    " . $this->table_name . " 
                WHERE
                    username='".$this->username."' AND password='".$this->password."'";
        // prepare query statement
        $stmt = $this->conn->prepare($query);
        // execute query
        $stmt->execute();
        return $stmt;
    }
    function isAlreadyExist(){
        $query = "SELECT *
            FROM
                " . $this->table_name . " 
            WHERE
                username='".$this->username."'";
        // prepare query statement
        $stmt = $this->conn->prepare($query);
        // execute query
        $stmt->execute();
        if($stmt->rowCount() > 0){
            return true;
        }
        else{
            return false;
        }
    }
}

Login.php

 
// include database and object files
include_once '../config/database.php';
include_once '../objects/user.php';
 
// get database connection
$database = new Database();
$db = $database->getConnection();
 
// prepare user object
$user = new User($db);
// set ID property of user to be edited
$user->username = isset($_GET['username']) ? $_GET['username'] : die();
$user->password = base64_encode(isset($_GET['password']) ? $_GET['password'] : die());
// read the details of user to be edited
$stmt = $user->login();
if($stmt->rowCount() > 0){
    // get retrieved row
    $row = $stmt->fetch(PDO::FETCH_ASSOC);
    // create array
    $user_arr=array(
        "status" => true,
        "message" => "Successfully Login!",
        "id" => $row['id'],
        "username" => $row['username']
    );
}
else{
    $user_arr=array(
        "status" => false,
        "message" => "Invalid Username or Password!",
    );
}
// make it json format
print_r(json_encode($user_arr));

Signup.php

// get database connection
include_once '../config/database.php';
 
// instantiate user object
include_once '../objects/user.php';
 
$database = new Database();
$db = $database->getConnection();
 
$user = new User($db);
 
// set user property values
$user->username = $_POST['username'];
$user->password = base64_encode($_POST['password']);
$user->created = date('Y-m-d H:i:s');
 
// create the user
if($user->signup()){
    $user_arr=array(
        "status" => true,
        "message" => "Successfully Signup!",
        "id" => $user->id,
        "username" => $user->username
    );
}
else{
    $user_arr=array(
        "status" => false,
        "message" => "Username already exists!"
    );
}
print_r(json_encode($user_arr));