Top Laravel Interview Questions and Answer

Laravel is a free, open-source PHP-based web framework that is used for building web applications using the MVC architectural pattern. Laravel was created with the aim to offer features that are not offered in CodeIgniter framework. These provide features such as in-built support for authorization and user authentication. Most framework releases are done in the first quarter of the year. Laravel provides bug fixes for 18 months and security fixes for two years.

Some of the main features of Laravel are:

• Eloquent ORM
• Query builder
• Reverse Routing
• Restful Controllers
• Migrations
• Database Seeding
• Unit Testing
• Homestead

The latest Laravel version is 9. It was launched on February 8th, 2022.

Laravel is a popular web application framework that allows you to build dynamic websites and applications.

A composer is a tool that includes all the dependencies and libraries. It helps the user to develop a project concerning the mentioned framework. Third-party libraries can be installed easily using composer.

Composer is used to managing its dependencies, which are noted in the composer.json file and placed in the source folder.

The Laravel Blade templating engine is a powerful piece of the framework that allows you to easily create powerful templates with a syntax that's simple and intuitive.

The Blade templating engine provides structure, such as conditional statements and loops. To create a blade template, you just need to create a view file and save it with a .blade.PHP extension instead of a .php extension. The blade templates are stored in the /resources/view directory. The main advantage of using the blade template is that we can create the master template, which other files can extend.

Some common directories include the following: 

• App/: This source folder holds the application’s primary code, including controllers and models. This directory represents the architectural pattern of a web app in development. 

• Public/: This directory contains publicly accessible files, including various assets, such as the index.php file. This PHP code file is the first to be loaded and executed when a user visits a website. 

• Database/: This directory holds database-related files and configurations, including migrations, seeders, and factories.

• Config/: The configuration folder holds configuration files for the website or application that enable developers to define its behavior. 

• Extensive community and documentation
• Robust security features
• Easy third-party integrations
• Expressive and elegant syntax
• MVC architecture
• Artisan command-line interface
• Testing and debugging

Yes, it is useful for full stack development as it can help in building scalable applications. Developers can use blade files for frontend and Laravel for backend.

Web developers prefer Laravel framework since it has many inbuilt modules and libraries that expedite the development process. It also has the inbuilt facility to support unit tests. With the help of Eloquent ORM, developers can handle database operations.

Laravel supports four database systems: MySQL, Postgres, SQLite, and SQL Server.

The artisan script is a command-line interface included with Laravel. It's the first thing you'll see when you run composer create-project, or PHP artisan serve.

Artisan is made up of commands and is one of your best friends for developing and managing your Laravel applications. You can view a list of all available Artisan commands by running PHP artisan list.

Following are the common PHP artisan commands:

1. php artisan route:list: for listing all registered routes
2. php artisan migrate: for running database migrations
3. php artisan tinker: for interacting with the application
4. php artisan make:seeder Seeder_Name: for creating a seeder
5. php artisan make:model Model_Name: for creating a model
6. php artisan make:mail Mail_Class_Name: for creating a mail class
7. php artisan make:controller Controller_Name: for creating a controller
8. php artisan make:middleware Middleware_Name: for creating a middleware
9. php artisan make:migration create_table-name_table: for creating a migration

dd() stands for Dump and Die. It is a helper function is used for dumping a variable’s contents to the browser and stop further script execution. It is used to dump the variable/object and then die the script execution. 

You will require an instance session to access session data. An instance of session can be accessed via HTTP request. To access the data, you can use either get() method that requires ‘key’ (argument).

$value = $request->session()->get(‘key’);

To delete session data, you have the following different ways:

1. forget() method: To delete single item 

2. flush() method: To delete all session data  

3. pull() method: To retrieve and then delete session data

CSRF protection stands for Cross-Site Request Forgery protection. CSRF detects unauthorized attacks on web applications by the unauthorized users of a system. The built-in CSRF plug-in is used to create CSRF tokens so that it can verify all the operations and requests sent by an active authenticated user.

To turn off CSRF protection for a specific route, we can add that specific URL or Route in $except variable which is present in the app\Http\Middleware\VerifyCsrfToken.phpfile.

You can generate CSRF tokens by either directly using csrf_token() method or by using $request→session()→token()

You can define Laravel routes in your routes/web.php file or create a separate file for other types of routes.

All routes are defined in your route files, located in the routes directory. The Laravel framework automatically loads these files. The routes/web.php file defines routes for your web interface. These routes are assigned to the web middleware group, providing features like session state and CSRF protection. The routes in routes/api.php are stateless and set in the API middleware group.

For most applications, you will begin by defining routes in your routes/web.php file. You may access the routes described in routes/web.php by entering the designated route's URL in your browser or through one of your controllers' actions or methods (explained later).

There are some official packages provided by Laravel which are given below:

Cashier

Laravel cashier implements an expressive, fluent interface to Stripe's and Braintree's subscription billing services. It controls almost all of the boilerplate subscription billing code you are dreading writing. Moreover, the cashier can also control coupons, subscription quantities, swapping subscription, cancellation grace periods, and even generate invoice PDFs.

Envoy

Laravel Envoy is responsible for providing a clean, minimal syntax for defining frequent tasks that we run on our remote servers. Using Blade style syntax, one can quickly arrange tasks for deployment, Artisan commands, and more. Envoy only provides support for Mac and Linux.

Passport

Laravel is used to create API authentication to act as a breeze with the help of Laravel passport. It further provides a full Oauth2 server implementation for Laravel application in a matter of minutes. Passport is usually assembled on top of League OAuth2 server which is maintained by Alex Bilbie.

Scout

Laravel Scout is used for providing a simple, driver-based solution for adding full-text search to the eloquent models. Using model observers, Scout automatically keeps search indexes in sync with eloquent records.

Socialite

Laravel Socialite is used for providing an expressive, fluent interface to OAuth authentication with Facebook, Twitter, Google, and Linkedln, etc. It controls almost all the boilerplate social authentication code that you are dreading writing.

HTTP middleware is used to filter HTTP requests. There is a middleware present in Laravel that is responsible for checking if an application user is authenticated.

 

Middleware provides a convenient mechanism for inspecting and filtering HTTP requests entering your application.

For example, Laravel includes a middleware that verifies the user of your application is authenticated. If the user is not authenticated, the middleware will redirect the user to your application’s login screen. However, if the user is authenticated, the middleware will allow the request to proceed further into the application.

Some query builder aggregates methods are: 1max(), min(), sum(), avg(), and count()

Before understanding eloquent let’s first understand ORM - Object Relational Mapping, it’s a programming technique for converting data between a relational database and object-oriented programming, we can say it an object-relational mapper as well.

Eloquent is an ORM used in Laravel. It provides simple Active record implementation working with the database. Each database table has their Model which used to interact with the table.  Eloquent provides many types of relationships:

• One to One
• Many to one
• One to Many
• Many to Many
• Has one through
• Has many through

A staple in Laravel technical interview questions and answers, be prepared to answer this one using your hands-on experience.

A migration in Laravel is a PHP file that defines the structure of the database schema. Migrations are used to create, modify, and drop database tables and columns.

Migrations are like version control for your database, allowing your team to define and share the application’s database schema definition.

 

The Laravel Schema facade provides database agnostic support for creating and manipulating tables across all of Laravel's supported database systems.

Laravel's database seeding feature allows you to quickly insert data into your database. It is helpful for development environments where you may not have access to your production database.

Laravel includes the ability to seed your database with data. By default, a Database seeder class is defined for you. You may use the call method from this class to run other seed classes. All seed classes are stored in the database/seeders directory.

A seeder class only contains one method: run. This method is called when the db:seed Artisan command is executed. You may use the query builder to insert data or Eloquent model factories.

Reverse routing is the process used to generate the URLs based on the names or symbols. It is also known as backtracking or reverse mapping.

You can do reverse routing in two ways:

1. Using route parameters in routes
2. Using route names in routes

When you use the URL structure, you can simply add a symbol or name at the end of your URL. It will let you create more readable URLs in your application and make it easier for users to understand them.

Route:: get(‘list’, ‘blog@list’);

{{ HTML::link_to_action('blog@list') }}

Service providers can be defined as the central place to configure all the entire Laravel applications. Applications, as well as Laravel's core services, are bootstrapped via service providers. These are powerful tools for maintaining class dependencies and performing dependency injection. Service providers also instruct Laravel to bind various components into the Laravel's Service Container.

An artisan command is given here which can be used to generate a service provider:

1. php artisan make: provider ClientsServiceProvider  

Almost, all the service providers extend the Illuminate\Support\ServiceProviderclass. Most of the service providers contain below-listed functions in its file:

• Register() Function

• Boot() Function

Within the Register() method, one should only bind things into the service container. One should never attempt to register any event listeners, routes, or any other piece of functionality within the Register() method.

Service container in Laravel is one of the most powerful features. It is an important, powerful tool for resolving class dependencies and performing dependency injection in Laravel. It is also known as IoC container.

Advantages of Service Container

• It can handle class dependencies on object creation.

• It can combine interfaces to concrete classes.

Laravel's Query Builder provides more direct access to the database, alternative to the Eloquent ORM. It doesn't require SQL queries to be written directly. Instead, it offers a set of classes and methods which are capable of building queries programmatically. It also allows specific caching of the results of the executed queries.

Requests in Laravel are a way to interact with incoming HTTP requests along with sessions, cookies, and even files if submitted with the request.

The class responsible for doing this is Illuminate\Http\Request.

When any request is submitted to a laravel route, it goes through to the controller method, and with the help of dependency Injection, the request object is available within the method. We can do all kinds of things with the request like validating or authorizing the request, etc.

Laravel traits are a group of functions that you include within another class. A trait is like an abstract class. You cannot instantiate directly, but its methods can be used in concreate class.

It is a technique in which one object is dependent on another object.

 

There are three types of dependency injection:

1) Constructor injection

2) setter injection

3) interface injection