Skip to main content

​
Overview

The Application class is the heart of the MINI framework. It handles URL routing, controller instantiation, and method execution based on the request URL. Located at: application/core/application.php

​
Class Definition

application.php
class Application
{
    /** @var null The controller */
    private $url_controller = null;

    /** @var null The method (of the above controller), often also named "action" */
    private $url_action = null;

    /** @var array URL parameters */
    private $url_params = array();

    public function __construct()
    {
        // create array with URL parts in $url
        $this->splitUrl();
        // ... routing logic
    }
}

​
Properties

​
url_controller
string|null
required
The controller name extracted from the URL. This maps to a file in application/controller/.
​
url_action
string|null
required
The method name to call on the controller. Defaults to index() if not provided.
​
url_params
array
required
Additional URL segments passed as parameters to the controller method.

​
Constructor

​
__construct()

Initializes the application and processes the incoming request. Process Flow:
1

Parse URL

Calls splitUrl() to extract controller, action, and parameters from the URL.
2

Load Controller

Checks if the controller file exists in application/controller/. If no controller is specified, loads the default Home controller.
3

Instantiate Controller

Creates an instance of the controller class.
4

Execute Method

Checks if the requested method exists and calls it with any URL parameters.
5

Handle Errors

Redirects to the error page (problem controller) if the controller or method doesn’t exist.
Example: 
// In public/index.php
$app = new Application();

// For URL: example.com/songs/editsong/17
// 1. Loads application/controller/songs.php
// 2. Instantiates Songs class
// 3. Calls $songs->editsong(17)

​
Private Methods

​
splitUrl()

Parses the URL and extracts routing information. 
private function splitUrl()
{
    if (isset($_GET['url'])) {
        // split URL
        $url = trim($_GET['url'], '/');
        $url = filter_var($url, FILTER_SANITIZE_URL);
        $url = explode('/', $url);

        // Put URL parts into according properties
        $this->url_controller = isset($url[0]) ? $url[0] : null;
        $this->url_action = isset($url[1]) ? $url[1] : null;

        // Remove controller and action from the split URL
        unset($url[0], $url[1]);

        // Rebase array keys and store the URL params
        $this->url_params = array_values($url);
    }
}
URL Parsing Examples:
URLControllerActionParameters
/null → homenull → index[]
/songssongsnull → index[]
/songs/editsong/17songseditsong['17']
/user/profile/john/settingsuserprofile['john', 'settings']

​
Routing Logic

The complete routing logic from the constructor: 
if (!$this->url_controller) {
    // No controller: load home page
    require APP . 'controller/home.php';
    $page = new Home();
    $page->index();

} elseif (file_exists(APP . 'controller/' . $this->url_controller . '.php')) {
    // Controller exists: load and instantiate
    require APP . 'controller/' . $this->url_controller . '.php';
    $this->url_controller = new $this->url_controller();

    if (method_exists($this->url_controller, $this->url_action)) {
        // Method exists: call it with parameters
        if (!empty($this->url_params)) {
            call_user_func_array(
                array($this->url_controller, $this->url_action), 
                $this->url_params
            );
        } else {
            $this->url_controller->{$this->url_action}();
        }
    } else {
        if (strlen($this->url_action) == 0) {
            // No action: call default index() method
            $this->url_controller->index();
        } else {
            // Method doesn't exist: error page
            header('location: ' . URL . 'problem');
        }
    }
} else {
    // Controller doesn't exist: error page
    header('location: ' . URL . 'problem');
}

​
Error Handling

When a controller file doesn’t exist, MINI redirects to /problem:
header('location: ' . URL . 'problem');
This loads the Problem controller (formerly Error in PHP 5, renamed for PHP 7 compatibility).
When a controller exists but the method doesn’t:
  • If no action is specified, falls back to index()
  • If an action is specified but doesn’t exist, redirects to /problem

​
Usage Examples

​
Basic Routing

// URL: example.com/home
// Loads: application/controller/home.php
// Calls: Home::index()

public function index()
{
    require APP . 'view/_templates/header.php';
    require APP . 'view/home/index.php';
    require APP . 'view/_templates/footer.php';
}

​
Routing with Parameters

// URL: example.com/songs/editsong/17
// Loads: application/controller/songs.php
// Calls: Songs::editsong('17')

public function editsong($song_id)
{
    $song = $this->model->getSong($song_id);
    
    require APP . 'view/_templates/header.php';
    require APP . 'view/songs/edit.php';
    require APP . 'view/_templates/footer.php';
}

​
Multiple Parameters

// URL: example.com/blog/post/2024/03/hello-world
// Calls: Blog::post('2024', '03', 'hello-world')

public function post($year, $month, $slug)
{
    $post = $this->model->getPostBySlug($year, $month, $slug);
    // ... render view
}

​
Security Considerations

The URL is sanitized using filter_var($url, FILTER_SANITIZE_URL) before processing. However, you should still validate parameters in your controller methods.
All application logic outside the /public folder is protected by .htaccess, preventing direct access to controllers, models, and configuration files.

​
See Also

Controller Class

Learn about the base Controller class

Routing Concept

Deep dive into the routing system

Architecture

Understand the request lifecycle

Controllers Guide

How to create controllers

Build docs developers (and LLMs) love

Get started for freeTalk to us