How Laravel Works?

Laravel is a free, open-source PHP framework. It is intended for the development of web application using MVC architectural pattern and based on Symfony.

Whenever I code application in Laravel, one question would pop-up to my mind was how it works?. Today, through this article we are gonna explore that.

If you have Laravel application then go to index.php file in public folder. This is where all the magic happens.

<?php

/**
 * Laravel - A PHP Framework For Web Artisans
 *
 * @package  Laravel
 * @author   Taylor Otwell <taylorotwell@gmail.com>
 */

/*
|--------------------------------------------------------------------------
| Register The Auto Loader
|--------------------------------------------------------------------------
|
| Composer provides a convenient, automatically generated class loader for
| our application. We just need to utilize it! We'll simply require it
| into the script here so that we don't have to worry about manual
| loading any of our classes later on. It feels nice to relax.
|
*/

require __DIR__.'/../bootstrap/autoload.php';

/*
|--------------------------------------------------------------------------
| Turn On The Lights
|--------------------------------------------------------------------------
|
| We need to illuminate PHP development, so let us turn on the lights.
| This bootstraps the framework and gets it ready for use, then it
| will load up this application so that we can run it and send
| the responses back to the browser and delight our users.
|
*/

$app = require_once __DIR__.'/../bootstrap/app.php';

/*
|--------------------------------------------------------------------------
| Run The Application
|--------------------------------------------------------------------------
|
| Once we have the application, we can handle the incoming request
| through the kernel, and send the associated response back to
| the client's browser allowing them to enjoy the creative
| and wonderful application we have prepared for them.
|
*/

$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);

$response = $kernel->handle(
    $request = Illuminate\Http\Request::capture()
);

$response->send();

$kernel->terminate($request, $response);

All requests into your application are directed through the public/index.php script.

The index.php file loads the Composer generated autoloader definition and then retrieves an instance of the Laravel application from the script. The first action taken by Laravel itself is to create an instance of the application.

Next, the incoming request is sent to either the HTTP kernel. The kernel serves as the central location that all requests flow through.

The HTTP kernel extends the Illuminate\Foundation\Http\Kernel class, which defines an array of bootstrappers that will be run before the request is executed. These bootstrappers configure error handling, configure logging, detect the application environment, and perform other tasks that need to be done before the request is actually handled.

The HTTP kernel also defines a list of HTTP middleware that all requests must pass through before being handled by the application. These middleware handle reading and writing the HTTP session, determine if the application is in maintenance mode, verifying the CSRF token, and more.

The method signature for the HTTP kernel’s handle method is quite simple: receive a Requestand return a Response. Think of the Kernel as being a big black box that represents your entire application. Feed it HTTP requests and it will return HTTP responses.

One of the most important kernel bootstrapping actions is loading the service providers for your application. All of the service providers for the application are configured in the config/app.php configuration file's providers array. First, the register method will be called on all providers, then, once all providers have been registered, the boot method will be called.

Service providers are responsible for bootstrapping all of the framework’s various components, such as the database, queue, validation, and routing components. Since they bootstrap and configure every feature offered by the framework, service providers are the most important aspect of the entire Laravel bootstrap process.

Once the application has been bootstrapped and all service providers have been registered, the Request will be handed off to the router for dispatching. The router will dispatch the request to a route or controller, as well as run any route specific middleware.

Once the request is handled by the controller, the response is sent back. Before returning the response, terminate function on all middlewares are run and the process is completed.

This is how the Laravel’s request life cycle works.

Refer to the Diving cycle and Laravel Core Adventures to get a fair idea of Laravel framework and its core packages.

Thanks!!Happy Reading!!