Step‑by‑Step Guide to Building a PHP MVC Framework from Scratch

MVC (Model‑View‑Controller) is a software architecture pattern that separates data, user interface, and control logic to improve maintainability and scalability of web applications.

1. Define core files and directories – create folders such as controllers/, models/, views/, and core/ to hold the main components of the framework.

- controllers/
- models/
- views/
- core/

2. Create routing – map URLs to controller actions. Example routes are defined in routes.php:

// routes.php
$routes = [
    '/' => 'HomeController@index',
    '/user' => 'UserController@index',
    '/user/create' => 'UserController@create',
    '/user/store' => 'UserController@store',
    '/user/edit/{id}' => 'UserController@edit',
    '/user/update/{id}' => 'UserController@update',
    '/user/delete/{id}' => 'UserController@delete',
];

3. Create controllers – handle requests and invoke models and views. Example UserController.php shows typical CRUD actions:

// controllers/UserController.php
class UserController {
    public function index() {
        $users = UserModel::all();
        View::render('users/index', $users);
    }

    public function create() {
        View::render('users/create');
    }

    public function store() {
        $user = new UserModel($_POST);
        $user->save();
        redirectTo('/user');
    }

    public function edit($id) {
        $user = UserModel::getById($id);
        View::render('users/edit', $user);
    }

    public function update($id) {
        $user = UserModel::getById($id);
        $user->fill($_POST);
        $user->save();
        redirectTo('/user');
    }

    public function delete($id) {
        $user = UserModel::getById($id);
        $user->delete();
        redirectTo('/user');
    }
}

4. Create models – interact with the database. Example UserModel.php provides static methods for fetching data and instance methods for persisting changes:

// models/UserModel.php
class UserModel {
    public static function all() {
        $result = DB::query('SELECT * FROM users');
        return $result;
    }

    public static function getById($id) {
        $result = DB::query('SELECT * FROM users WHERE id = ?', [$id]);
        return $result[0];
    }

    public function fill($data) {
        $this->name = $data['name'];
        $this->email = $data['email'];
        $this->password = $data['password'];
    }

    public function save() {
        if ($this->id) {
            DB::execute('UPDATE users SET name = ?, email = ?, password = ? WHERE id = ?', [$this->name, $this->email, $this->password, $this->id]);
        } else {
            DB::execute('INSERT INTO users (name, email, password) VALUES (?, ?, ?)', [$this->name, $this->email, $this->password]);
        }
    }

    public function delete() {
        DB::execute('DELETE FROM users WHERE id = ?', [$this->id]);
    }
}

5. Create views – render HTML for the user interface. Example views/users/index.php displays a table of users:

<!-- views/users/index.php -->
<h1>Users List</h1>
<table>
    <thead>
        <tr><th>Name</th><th>Email</th><th>Action</th></tr>
    </thead>
    <tbody>
        <?php foreach ($users as $user): ?>
            <tr>
                <td><?php echo $user['name']; ?></td>
                <td><?php echo $user['email']; ?></td>
                <td>
                    <a href="/user/edit/<?php echo $user['id']; ?>">Edit</a>
                    <a href="/user/delete/<?php echo $user['id']; ?>">Delete</a>
                </td>
            </tr>
        <?php endforeach; ?>
    </tbody>
</table>

6. Create core utilities – router, database wrapper, view renderer, and helper functions. Sample implementations are provided for Router.php, DB.php, View.php, and Helpers.php to handle request dispatching, PDO connections, template rendering, and redirects.

// core/Router.php
class Router {
    private static $routes = [];
    public static function addRoute($uri, $handler) { self::$routes[$uri] = $handler; }
    public static function dispatch($uri) {
        if (isset(self::$routes[$uri])) {
            $handler = self::$routes[$uri];
            list($controller, $action) = explode('@', $handler);
            $controller = 'controllers\' . $controller;
            $controller = new $controller;
            $controller->$action();
        } else {
            http_response_code(404);
            echo "404 Not Found";
        }
    }
}

// core/DB.php
class DB {
    private static $conn = null;
    public static function connect() {
        if (self::$conn === null) {
            self::$conn = new PDO('mysql:host=localhost;dbname=myapp', 'root', '');
        }
    }
    public static function query($sql, $params = []) {
        self::connect();
        $stmt = self::$conn->prepare($sql);
        $stmt->execute($params);
        return $stmt->fetchAll(PDO::FETCH_ASSOC);
    }
    public static function execute($sql, $params = []) {
        self::connect();
        $stmt = self::$conn->prepare($sql);
        $stmt->execute($params);
    }
}

// core/View.php
class View {
    public static function render($view, $data = []) {
        extract($data);
        include "views/$view.php";
    }
}

// core/Helpers.php
function redirectTo($uri) { header("Location: $uri"); }

7. Deploy the application – upload all files to a server with PHP and MySQL, configure the web server (Apache or Nginx) to redirect all requests to index.php using an .htaccess file:

# .htaccess
RewriteEngine On
RewriteBase /
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^(.+)$ index.php [QSA,L]

After deployment, URLs are routed to index.php, which dispatches them to the appropriate controller actions, invoking models and views to generate responses.

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