Request life cycle of Laravel (How laravel works under the hoods)

Hey there! I have been developing a laravel based application for more than a year now. I know a thing or two about how to write code on Laravel but truth to be told; I know very less about how Laravel handles all the executions under the hood. Recently I & some of my colleagues have decided to learn how laravel works its magic. So as a part of that, I studied “Laravel Request Lifecycle” today. And I am going to share what I learned from it. Yes, I know you can read about that on laravel documentation, but in this blog, I am going to break it down step by step.

But first, let me give you a quick example of why you should learn about that. Take riding a motorcycle, for example. It’s not mandatory to learn how the motorcycle engine works, simply learning how to ride a bike is enough. But when you know about its engine, how it works, what kind of oil it requires, it’s capabilities, then you become more confident while riding it. Because you know everything about and that gives you more confidence utilizing its full potential. Learning what happens under the hood of the Laravel framework is almost same. In my opinion, It’s essential to understand the inner workings of any tool you are given to work with, a complete understanding of that tool will enable you to use all the power that comes with the tool.

Auto loader

The entry point (Eg: https://https://shoroborno.com or any other URL) for all requests to a Laravel application is the public/index.php file. All requests are directed to this file by your web server (Apache / Nginx) configuration. If you are familiar with Laravel, I think you have seen the file. It doesn’t have much code in it. It’s simply an entry point which loads all the necessary files to handle the request you submitted from your web browser. 

HTTP / Console Kernels

The next step occurs on the Kernel part of the application. There are two kinds of Kernel request HTTP or Console.

The request is sent to either HTTP or Console Kernels based on the request which has been sent to the application. These two Kernels acts as a central location that all requests flow through. For this blog, let’s focus on the HTTP part of Kernels which handles the requests sent to your application via HTTP method which is located in app/Http/Kernel.php .

It receives a request and returns a response. All of this is accomplished by the handle method available to the Kernel class. Once the handle method recognizes an HTTP request, it returns an HTTP response. The Kernel class extends the Illuminate\Foundation\HTTP\Kernel class, which contains a bootstrap method. This method checks if our application has been bootstrapped (the process of starting or resetting ) already. If not, the bootstrap method runs on a bunch of classes to bootstrap the application. It loads the configuration file, also loads the environment variables, handles exceptions, registers facades and also registers the application’s service providers. The application’s default service providers are stored in the app/Providers directory.

The Kernel also defines a list of HTTP middleware that requests needs to pass through before being handled by your application. So what middleware does? It merely filters your requests that are trying to enter your application. For instance, you don’t want to give the user access to some page without being logged in. You can handle that by using middleware in your route files.

Service Providers

One of the most important Kernels 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 parts, such as the database, queue, validation, and routing components. Since it configures all the features offered by Laravel, it’s the essential component of your Laravel application.

Dispatch Request

Once the service providers bootstrap the application, the request is now passed to the router for dispatching. The router will dispatch the request to a route file or to a controller to handle the further process. For instance, getting data from database and showing them on a page or storing data to the database.

Now let me give you a step by step request life cycle that will help you visualize the steps mentioned above.

Step 1

The user input https://shoroborno.com/ in the browser and hits ‘enter’.

Step 2

Once the user hit this URL, the browser will send the page request over the Internet to the web server (Apache or Nginx).

Step 3

The web server will receive the request and analyze the request information. In the web server’s configuration file, the site’s root path is specified. Based on that, the web server will look for index.php file in that root directory, since URL doesn’t contain any subdirectory or any other routes.

Step 4

Web server will direct the request to public/index.php file of laravel application.

Step 5

In this step, PHP Interpreter is executing the code contained in the index.php file from the request. During this step, auto loader files which are generated by composer will be loaded.

Step 6

Then it will create the laravel instance and bootstrapping the components of laravel.

Step 7

The kernel will receive the request, load the service providers and will be redirected to router.

Step 8

Router will render the view file content and return back to web server.

Step 9

Web server receives the output from PHP and sends it back over the Internet to a user’s web browser.

Step 10

The user’s web browser receives the response from the server, and renders the web page on user’s computer.

I hope this helps you understand the request life cycle. You can also learn more about it from the Laravel documentation.

In the last blog, we installed our first Laravel application on our local machine and served it using php artisan serve. But we didn’t connect any database or anything. So today we are going to do that. Instead of serving our Laravel application with php artisan serve command on local machine, we are going to serve our application using Vagrant a virtual machine that take cares of all the dependencies for your application. I don’t want to go in the details of what the Homestead or virtual machine or vagrant is. You can simply just google about them or visit Laravel official documentation for that. So without farther a due let’s get started- “Installing Homestead”.

Installation Process

As we are going to install a virtual machine first, you need to enable virtualization from your local PC BIOS settings. After that download any virtualization software that you prefer. In my case, I used Virtual box. So just go to their website download the one which suits your PC configuration and install. After installing Virtual box, you need to install vagrant for your PC. To do that visit https://www.vagrantup.com/downloads.html . After that download the one which suits your PC configuration. As I am Ubuntu user, I downloaded the Debian package.

Adding Laravel/Homestead box to vagrant installation

Now, we need to add Laravel/homestead box to our vagrant installation. So to do that open up your terminal type in this command vagrant box add Laravel/homestead and hit enter. After that type in 3, if you are using virtual box and press enter. Depending on your internet speed, it may take 30-45 minutes to download.

If you are following correctly till now, you are ready to install Homestead.

So just copy git clone https://github.com/laravel/homestead.git ~/Homestead this git command and clone this repository by typing in this line in terminal. After cloning this repository cd into this directory from your terminal by cd Homestead. After that inside Homestead directory on your terminal, enter bash init.sh ( for Ubuntu/Linux/Mac) or init.bat (For windows) .

Connecting Our Application with Homestead

Now all the installations steps are done. Finally we are ready to serve our application. But first let’s make some necessary changes to connect our application with Homestead. So go to your homestead directory on your PC from file explorer or any GUI application.

Open Homestead.yaml file in any text editor.

In this file on the folders section

-map: ( Type the directory of your project folder)

to:( location of your application in vagrant virtual machine)

Sites section: -map: (any domain you want for your application except .com domain for instance for my crud app I used crud.test)

to: (location of the index.php file which is in public folder of your project) we need to map inside the public folder inside vagrant.

databases: just type the database name you prefer for your application. I used crud for my project. After doing all of that save the file and open your hosts file.

For ubuntu open your terminal cd into etc folder ,

cd /etc .

Open hosts file by sudo nano hosts in your terminal from etc directory. And, add the domain name, you added in Homestead.yaml crud.test . After that press ctrx+x to exit and Y to save and hit enter to save the modified hosts file.

Fire Up Vagrant to Serve Our Application

We are almost done for now. Time to fire up vagrant and serve our application. So go to your terminal, cd into Homestead folder type and enter vagrant up to fire up vagrant/our virtual machine.

Now our application should be running on localhost on this domain crud.test. Just verify that by opening your browser and visiting this address crud.test

Now let’s connect our database with our application and check if everything is working perfectly as should. So to do that first lets use php artisan make:auth command to create Laravel default authentication/login system. To do that ssh into your vagrant machine from terminal. cd Homestead -> vagrant ssh -> cd crud . Now if you are inside crud project folder inside vagrant, run auth command and create default authentication method.

Now open your project folder. Copy .env.example file to .env and open the .env file.

For DB_Database = your database name for this project
DB_USERNAME = homestead

DB_PASSWORD = secret.

And, everything is done. Now run php artisan migrate to migrate your database columns to your database you created from your virtual machine.

And, everything is done. You might be wondering why going through all of these hassle. Well, at first to make our project encapsulated from OS dependencies to easily manage project. Also connecting to individual databases for individual application and many more. We are done for today. In the next tutorial, we will learn about Model, Controllers, route view and all of the fun stuffs.

My Previous Blogs on Laravel:

Getting Started with LARAVEL ( Chapter 01)

Things you need to know about Laravel in 2019

In the previous blog ( Things you need to know about Laravel in 2019) I talked about Laravel and its origin, current and future position in the Web Application/Software development field. This is going to be a small series on Laravel where I will start from the basics and in the end you will have a ready to deploy small CRUD application. As you are following the tutorial I expect you have a basic understanding of Object-Oriented Programming PHP & MySQL. So in this tutorial series, we will follow the official laravel documentation. The documentation will help guide you through if you face any difficulties. So let’s begin.

In this tutorial, we’ll learn the basics of Laravel application installation and running your first Laravel starter application.

Installation:

To start building your first Laravel application you’ll need to install some dependencies first. As the Laravel framework has few requirements So Homestead comes with all the requirements you need to work on your Laravel application. Homestead is an official virtual machine for Laravel. In the next tutorial of this series, I’ll discuss everything you need to know about it. So, for now, will just stick to the most simple one. I am using Ubuntu but You may use any OS you prefer. Because Everything is almost the same. So there’s no need to panic.

As we are not using Homestead for this part of the tutorial, So you need to make sure you have PHP and its extensions installed on your local computer. Therefore I am assuming you have a basic understanding of PHP you should have PHP and its extensions installed on your system.

Now you need to install Composer on your machine. So to install composer just open up your terminal, type in the following command and press enter.

Installing composer:


php -r "copy('https://getcomposer.org/installer', 'composer-setup.php');"

php -r "if (hash_file('sha384', 'composer-setup.php') === '48e3236262b34d30969dca3c37281b3b4bbe3221bda826ac6a9a62d6444cdb0dcd0615698a5cbe587c3f0fe57a54d8f5') { echo 'Installer verified'; } else { echo 'Installer corrupt'; unlink('composer-setup.php'); } echo PHP_EOL;"

php composer-setup.php

php -r "unlink('composer-setup.php');"

After installing composer run the command below to install composer for Laravel globally on your system.

Run composer to check whether the composer is installed properly or not.

composer global require laravel/installer

Once you are done installing composer you are ready to create your first Laravel starter application.

To create your first Laravel application run composer create-project --prefer-dist laravel/laravel crud. On this command “crud” is the name of the application. You can type any name you prefer instead of crud. As I prefer to create all my applications inside a folder to keep everything organized, So For me it’s inside the Documents/projects folder. So I will CD into the folder and run the command to create the application.

After successfully running the command composer will start setting up a fresh Laravel application in your Documents/projects folder. And it will look like this.

The next thing we need to do is to generate a unique application id for your Laravel application. To do that first you need to open up your GUI file explorer go inside your folder and copy .env.example to .env . It should look like this.

Now run php artisan key:generate from CLI tool/ terminal inside your project directory.

Now you are ready to run your application. And to do that type and enter php artisan serve from your terminal.

And voila! your app is running on this local IP address. On my case which it’s running on http://127.0.0.1:8000 . Now open up your favorite browser and type in the url http://127.0.0.1:8000 .

Congratulations! your application is ready to rock and roll.

This is just a basic laravel application so there’s not much to it. So in the next tutorial, we’ll Install Homestead and discuss how to use homestead with your laravel application. Connecting MySQL database and folder structure of laravel.

Taylor Otwell created Laravel mainly for web application development. Laravel provides an amazing experience while developing a web-based application. In order to understand Laravel, we’ll have to understand what PHP is.

PHP

At first, let’s talk about PHP. PHP which stands for Hypertext Preprocessor. PHP was introduced back in 1994 which is one of the most used programming languages over the internet. More than 80% of web applications are developed with PHP because of the combination of PHP & MYSQL. Till now PHP & MYSQL are one of the most rock-solid combinations in the web application development world and this combination is going to stay as rock-solid as it is right now. One of the most used web application Facebook is developed with PHP and now billions of people use it. If you have little bit idea about web applications, you might have heard about WordPress which is one of the most dominating technology for web applications developed using PHP. Learning PHP is a very easy task and it offers a whole lot of detailed documentation that helps the newbies to grasp everything easily. PHP provides all of the functionality that you need to develop a modern web application. To learn more about PHP, visit-https://en.wikipedia.org/wiki/PHP

Laravel

Now let’s talk about Laravel. As we have mentioned earlier that Laravel is a PHP framework. Now you may have a question what is framework? To simply put it, take making noodles as an example. You need to buy raw noodles pack, mix them with other ingredients, boil those things and cook and finally serve. That’s what basic programming language is. On the other hand, the framework is like a 2 minutes’ instant noodles pack, that means all ingredients are ready, all you have to do is just put some boiled water into the cup with some flavors and it’s ready to serve.

Laravel has been in the web application development game for a while now. Many developers all over the globe love it for its outstanding performance & easy to integration technique with other systems. It serves with many features that made this framework so popular over the last few years. Laravel follows MVC architecture which makes one of the most attractive framework to develop web applications. As it’s an open-source platform, there are thousands of contributors who are contributing to making this framework even more powerful. Laravel also comes with many packages which provide hundreds of important functionality to develop applications faster than before.

Current and Future Position of Laravel and PHP

Now let’s talk about its current and future position in the tech world. PHP and its framework are dominating the web world. PHP and frameworks built more than 80% web applications. As it’s getting more & more features and performance improvements in each update, Laravel & PHP will keep on dominating the web world in the upcoming future. Few people think that PHP is a dying language. It’s simply a myth & nothing else. PHP is not going anywhere in the recent future. As we have discussed earlier PHP & MySQL combination which is a rock-solid combination, and no other combination has come closer to this one. Until then there’s no possibility of any language taking the lead.

Should you learn PHP in 2019 and why?

Absolutely yes. There’s no harm in learning PHP right now. If you want to become a web application developer or you want to develop your career in the freelancing world, you can’t ignore PHP & it’s frameworks. Laravel makes it even easier to integrate with other famous front end technologies like VUE js, Node and many more. So If you are passionate about being a web application developer, Laravel is definitely a good choice to start with.

Finally, let me introduce you with a great team “Augnitive” experienced team of passionate engineers working with Laravel and they have been developing an application for the competitive industry for quite a while now. To learn more visit: https://augnitive.com/.

Next Blog on Laravel Tutorial Series: Getting Started with LARAVEL ( Chapter 01)