PHP Composer PSR-4 Basic

I had struggled to find basic example of php/composer/psr-4. Almost all example's have some kind of npm based frameworks. I wanted to create a basic tutorial using composer autoloader.

I hope this basic tutorial will be helpful to you to get started.

You can clone this git repository or follow along the below steps.

install php
install composer
read up Composer Autoloader at stackoverflow
add composer to environment variables path value
open bash/command prompt/power shell
create project folder
cd into project folder

composer init

update composer.json by adding following lines:

"autoload": {
    "psr-4": {
        "App\\": "app/"
    }
}

update composer

composer update

forward slash / signifies your project folder, not system root
create file /app/bootstrap.php and add following code in the file

<?php
    define('BASEPATH', __DIR__);
    
    $autoloader = require __DIR__ . '/../vendor/autoload.php';
    
    // https://phpocean.com/tutorials/back-end/php-frameworking-routing-autoloading-configuration-part-2/10
    require('Providers/Router.php');
    
    $router = new App\Providers\Router();

create file /app/routes.php and add following code in the file

<?php
$router->add('/',function(){
   $controller = new App\Http\Controllers\HomeController();
   echo $controller->show();
});

$router->add('/hello',function() use ($router){
    echo $router->view_display('hello.php');
});

create file /app/Http/Controllers/HomeController.php and add following code in the file

<?php
namespace App\Http\Controllers;
use App\Providers\Router;
class HomeController
{
    public function __construct()
    {
    }

    public function show()
    {
        $router = new Router();

        return $router->view_display('home.php');
        //return "Hello World!";
    }
}

create file /app/Providers/Router.php and add following code in the file

<?php
namespace App\Providers;

class Router
{
	private $routes = [];
	private $notFound;

	public function __construct()
	{
		$this->notFound = function ($url) {
			echo "404 - $url was not found!";
		};
	}

	public function add($url, $action)
	{
		$this->routes[$url] = $action;
	}

	public function setNotFound($action)
	{
		$this->notFound = $action;
	}

	public function dispatch()
	{
		if ( ! is_array($this->routes) || empty($this->routes))
		{
			return false;
		}

		foreach ($this->routes as $url => $action)
		{
			if ($url == $_SERVER['REQUEST_URI'])
			{
				return $action();
			}
		}
		call_user_func_array($this->notFound, [$_SERVER['REQUEST_URI']]);
	}

	public function view_load($view_path, $view_name)
	{
		if (file_exists($view_path . $view_name))
		{
			return file_get_contents($view_path . $view_name);
		}
		throw new Exception("View does not exist: " . $view_path . $view_name);
	}

	public function view_display($view_name)
	{
		$view_path = BASEPATH . '/../resources/views/';

		return $this->view_load($view_path, $view_name);
	}
}

create file /public/index.php and add following code in the file

<?php
require '../app/bootstrap.php';
require '../app/routes.php';

$router->dispatch();

run the composer command to generate autoload references

composer dumpautoload -o

if all is well, test the web site

php -S localhost:8080 -t public/

browser the url at http://localhost:8080

Appreciate if you mark the git repository with a star if this has been helpful or userful to you.

Checkout Modernize Your Legacy PHP Application for dependency injection concept.

My Blog @ WasaySyed.com

Previous releases: Version 1 on Mar 5, 2018

Version 1 does not have routes and views implemented.

nastanford/php-composer-psr4-hello-world

PHP Composer PSR-4 Basic