Top 30+ Laravel interview questions and their answer

Question List:

  1. What is Laravel?
  2. What are the features of Laravel?
  3. What is a view in Laravel?
  4. How to create a canonical URL in laravel?
  5. How to check laravel version, composer version, and PHP version?
  6. How to rename, and resize an image  and upload it in laravel?
  7. how to create and run specific migration in laravel?
  8. List down of Aggregates function with Laravel Eloquent, Query Builder?
  9. How to publish all laravel default error-related blade files?
  10. How to Enable Maintenance Mode in Laravel 9?
  11. How many databases laravel support?
  12. How many default actions are handled by the restful resource controllers in laravel?
  13. What are the default main routing files in Laravel?
  14. How many router methods are available in Laravel?
  15. What is the CSRF token in laravel and how to use it?
  16. How to install laravel specific version?
  17. What does the "composer dump-autoload" command?
  18. composer update vs composer install, When to install, and when to update?
  19. __() in laravel used for?
  20. What is {{ }} and {!! !!} in laravel blade files?
  21. What is migration in Laravel?
  22. What is the controller in laravel?
  23. What is the model in Laravel?
  24. What is the artisan in Laravel?
  25. How to ignore other dependencies while installing any new package in Laravel?
  26. How to Display Index Numbers in Laravel Pagination Views?




What is Laravel?

Laravel is a free, open-source PHP web application framework designed for building web applications using the model-view-controller (MVC) architectural pattern. It was created by Taylor Otwell in 2011 and is now one of the most popular PHP frameworks available.

Some of the key features of Laravel include its expressive syntax, elegant and intuitive syntax, robust routing system, powerful dependency injection container, and support for various relational databases and popular cache backends. Additionally, Laravel provides a wide range of tools and features for handling common web application development tasks, such as authentication, security, session management, and caching, making it a popular choice for building web applications of all sizes and complexities.

What are the features of Laravel?

The key features of Laravel are:

  • MVC Architecture: Laravel follows the Model-View-Controller (MVC) architectural pattern, which helps to organize the codebase in a structured and maintainable way.
  • Artisan CLI: Laravel provides a powerful command-line interface called Artisan, which can be used to automate various tasks like database migration, code generation, and testing.
  • Blade Template Engine: Laravel's Blade templating engine provides an easy-to-use syntax for creating views and templates, which helps to keep the application's presentation layer separate from the business logic.
  • Eloquent ORM: Laravel's Eloquent ORM provides a simple and expressive way to interact with databases, reducing the boilerplate code required for CRUD operations.
  • Middleware: Laravel's middleware feature provides a flexible way to filter HTTP requests and responses, which can be used for tasks like authentication, input validation, and logging.
  • Routing: Laravel's routing system provides a simple and expressive way to define application routes, which can be used to handle different
  • Security: Laravel provides various security features like encryption, hashing, and CSRF protection, which help to prevent common web application vulnerabilities.
  • Testing: Laravel has built-in support for testing, which makes it easy to make, it easy to write unit and functional tests for different application parts
  • Task Scheduling: Laravel's task scheduling feature provides a way to schedule tasks to run at specific times or intervals, which can be used for tasks like sending emails, generating reports, and cleaning up data.
  • Community: Laravel has a large and active community of developers, which provides support, documentation, and various open-source packages to extend the framework's functionality.


What is a view in Laravel?

A view in Laravel is a way to render HTML templates. It contains the HTML markup for your application and can be used to display data passed from the controller.

Example:

        
        // Define a view in a controller
public function show($id)
{
$post = Post::find($id);
return view('posts.show', ['post' => $post]);
}

// Render the view in a Blade template

<h1>{{ $post->title }}</h1>
<p>{{ $post->body }}</p>

How to install laravel specific version?

We can run different commands to install different laravel versions. Before installing laravel you must have composer installed in your system. then run the bellow command to install a specific laravel version or the latest one.

        
        //it will install current version of laravel
composer create-project --prefer-dist laravel/laravel project_name

//it will install laravel 7 latest one
composer create-project --prefer-dist laravel/laravel project_name "7.*"

//it will install laravel 8 latest one
composer create-project --prefer-dist laravel/laravel project_name "8.*"

//it will install laravel 8.2 latest one
composer create-project --prefer-dist laravel/laravel project_name "8.2"

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What does the "composer dump-autoload" command?

composer dump-autoload scan all the file directories mentioned (in the composer.json file), create an array of namespace and regenerate the autoload.php file with these arrays.

composer update vs composer install, When to install, and when to update?

composer update:

composer update command will update your dependencies which are specified in composer.json.

In detail:

  • Read the composer.json file
  • Remove installed packages that are no more required in composer.json
  • Check the availability of the latest versions of required packages
  • Install the latest versions of your packages and
  • finally, it updates the composer.lock to store the version of the installed package


composer install

composer install command will not update any package or dependencies, it will just install all the package dependencies which is specified in the composer.lock file.

In detail:

  • it will check if the composer.lock file exists (if the composer.lock file not exists, it will run composer update and create it)
  • Read the composer.lock file
  • and it will install all the packages or dependencies specified in the composer.lock file


__() in laravel used for?

In Laravel, the __() helper function is used for localization and translation. 

It is a shorthand function that is equivalent to calling the trans() function.

  1. $key: The translation key, is used to look up the translation string in the translation files.
  2. $replace: An optional array of replacement values for placeholders in the translation string.


For example, if you have a translation file located at "resources/lang/en/messages.php" with the following contents:

        
        return [
    'welcome' => 'Welcome to our website!',
];

You can use the __() hleper function to translate the "welcome" key in your views or controllers like this:

        
        {{__('messages.welcome')}}   //for view
echo __('messages.welcome')     // for controller or view

This will output "Welcome to our website!" to the browser. Laravel uses a package called "Symfony Translation" to handle translations, and it allows you to define translations in different languages and switch between them.

What is {{ }} and {!! !!} in laravel blade files?

By default, In Laravel's blade templates, {{ }} statements are automatically sent through PHP's htmlentities function to prevent XSS attacks and is used to escape and print the output to the HTML. The double curly braces {{ }} ensure that any malicious code or content is escaped before it is displayed on the page.

While {!! !!} is used to print the output as it is without escaping any HTML content. If you do not want your data to be escaped, you may print your data inside {!! !!}. The double exclamation marks {!! !!} allow unescaped output, which can be dangerous if the data comes from untrusted sources.  

{{ }} statements use the laravel echo e() function which is the shorthand for the PHP's "htmlentities" function, which is used to encode HTML entities to protect against malicious code. The e function returns a string with HTML characters properly encoded, so that they can be safely displayed on a web page without risking any malicious code execution. This helps to prevent cross-site scripting (XSS) attacks.

Example:

        
        This is unescaped description {!! $data->description !!}

This is escaped description {{ $data->description }}

What is migration in Laravel?

A migration in Laravel is a way to modify database schema using code. It provides a convenient way to modify your database schema over time, without having to manually update the database.

Example:

        
        // Create a new migration file
php artisan make:migration create_posts_table

// Edit the migration file to add a 'title' and 'body' column to the 'posts' table
Schema::create('posts', function (Blueprint $table) {
$table->id();
$table->string('title');
$table->text('body');
$table->timestamps();
});

// Run the migration to update the database schema
php artisan migrate

What is controller in laravel?

In Laravel, a controller is a class that handles HTTP requests and returns an appropriate HTTP response. It is responsible for processing user input and returning a view, redirecting the user to another page, or returning data as a JSON response.

In Laravel, controllers are located in the app/Http/Controllers directory and are responsible for receiving HTTP requests and processing the logic needed to satisfy those requests. They typically contain methods that map to specific HTTP routes and are used to perform database operations, call services, or run any other custom business logic that is required to fulfill the request.

Example of a simple Laravel controller:

        
        namespace App\Http\Controllers;

use Illuminate\Http\Request;

class UserController extends Controller
{
    public function index()
    {
        // Retrieve all users from the database
        $users = User::all();

        // Render a view to display the users
        return view('users.index', ['users' => $users]);
    }
}

What is model in Laravel?

In Laravel, a model represents the data and the rules around that data. It is a PHP class that represents a database table and provides an abstraction layer for working with the database.

In Laravel 8 and above, Models are generally located in the app/Models directory and contain properties and methods that allow you to interact with the database table it represents. For example, you can use a model to retrieve data from a table, insert new data, update existing data, and delete data.

for creating a new model file in the command line run the bellow command:

php artisan make:model ModelName


Example of a simple model in Laravel:

        
        <?php

namespace App\Models;

use Illuminate\Database\Eloquent\Model;

class User extends Model
{
    protected $table = 'users';
    protected $fillable = ['name', 'email', 'password'];
}

What is the artisan in Laravel?

Artisan is a command-line interface included in the Laravel framework that provides various helpful commands for tasks such as generating boilerplate code, managing the database, and running tests. The Artisan CLI is designed to simplify and speed up many of the common tasks involved in building a Laravel application.

With Artisan, you can generate the basic structure of your Laravel application, create and manage database migrations, run database seeds, create controllers and models, and much more. Some of the most commonly used Artisan commands include:

  • php artisan serve: Starts the Laravel development server.
  • php artisan make:controller: Generates a new controller class.
  • php artisan make:model: Generates a new Eloquent model class.
  • php artisan make:middleware: Generates a new middleware class.
  • php artisan migrate: Runs all pending database migrations.
  • php artisan tinker: Opens an interactive console for your Laravel application.

How to ignore other dependencies while installing any new package in Laravel?

To ignore other dependencies while installing any Laravel package using Composer, you can use the

--ignore-platform-reqs option with the composer require command. This option tells Composer to ignore the PHP version and extensions requirements for the package and its dependencies.

Example:

composer require package-name --ignore-platform-reqs

some more examples:

composer require package-name --no-scripts

This command will install the package and skip running any post-install scripts. This can be useful when you don't want to execute certain scripts that might cause problems or take too much time.

composer require package-name --no-update:

This command will install the package without updating the existing dependencies. This can be useful when you want to install a specific version of a package without updating other dependencies to their latest versions.

How to Display Index Numbers in Laravel Pagination Views?

        
        @foreach ($posts as $item)
    {{-- Calculate the continuous index --}}
    {{ ($posts->currentPage() - 1) * $posts->perPage() + $loop->index + 1 }}

    {{-- Rest of your loop logic --}}
    {{ $item->name }}
@endforeach

{{-- Display pagination links --}}
{{ $posts->links() }}
But if you are using Datatable or you need a separate record number for every separate page then you can go with the below approach.
        
        @foreach ($posts as $item)
    {{ $loop->iteration }} {{-- This prints the index starting from 1 --}}
    {{ $item->name }}
@endforeach


////OR

@foreach ($posts as $item)
    {{ $loop->index + 1 }} {{-- This prints the index starting from 1 --}}
    {{ $item->name }}
@endforeach

How to create a canonical URL in laravel?

A canonical URL is helpful for SEO purposes and the canonical is the current URL of the page. this answer will also resolve, how we can dynamically get the current URL of the page.

Just go to your master layout page and inside the head section just paste the below Example 01 code. 

Or if it is returning the URL with www and you want a URL without www then paste the below Example 02 code.

        
        {{-- Example 01 --}}
    <link rel="canonical" href="{{ url()->current() }}">

{{-- Example 02 --}}
@if (Str::startsWith($current = url()->current(), 'https://www'))
        <link rel="canonical" href="{{ str_replace('https://www.', 'https://', $current) }}">
@else
        <link rel="canonical" href="{{ str_replace('https://', 'https://www.', $current) }}">
@endif

How to check laravel version, composer version, and PHP version?

we can check the Laravel version via an artisan command. This is the easiest way if we are familiar with artisan commands. open command line and enter 

php artisan -v   

or 

 php artisan --version

for more detail to check the laravel version go through this tutorial How to check Laravel version of our application

another way we can check the laravel version is via the app helper function in the blade file:

{{ app()->version() }}

we can also check the composer version via the command line using below command 

composer -v

or 

composer --version

we can check the PHP version via the command line using the below command:

php -v

//or

php --version

List for checking versions of laravel, composer, and PHP:

        
        //check the laravel version via command line 
php artisan -v
//or
php artisan --version

//check the laravel version via the blade file
{{ app()->version() }}

//check the composer version via the command line
composer -v
//or
composer --version

//check the PHP version via the command line
php -v
//or
php --version

How to rename, and resize an image and upload it in laravel?

        
        $image_tmp = $request->file('product_image');

//rename image
$extension = $image_tmp->getClientOriginalExtension();
$imageName = rand(111,99999).'.'.$extension;

//define upload path
$imagePath = 'upload/'.$imageName;


//resize the image 500*500 and upload
Image::make($image_tmp)->resize(500, 500)->save( $imagePath );

// resize the image to a width of 500 and constrain aspect ratio (auto height)
Image::make($image_tmp)->resize(500, null, function ($constraint) {
    $constraint->aspectRatio();
})->save( $imagePath );   

// resize the image to a height of 500 and constrain aspect ratio (auto width) and upload
Image::make($image_tmp)->resize(null, 500, function ($constraint) {
    $constraint->aspectRatio();
})->save( $imagePath );

How to create and run specific migrations in laravel

        
        //for creating a migration
php artisan make:migration create_posts_table

//run the specific migration
php artisan migrate --path=/database/migrations/migrationfileName.php

//run the specific migration if the table already exist
php artisan migrate:refresh --path=/database/migrations/migrationfileName.php

List down of Aggregates function with Laravel Eloquent, Query Builder?

Laravel Aggregate function use for calculating in numeric values if we want to calculate the number of record,  we want to calculate average or maximum and minimum price of product.

Once have have created a Eloquent model and the associated table in the database database, Then we can start retrieving/fetching data from Our database.

Some important Aggregates function list

  • count();
  • max();
  • min();
  • sum();
  • avg();


How to use it?

        
        $count = Product::where('status', 1)->count();
$max = Product::where('status', 1)->max('price');
$min = Product::where('status', 1)->min('price');
$sum = Product::where('status', 1)->sum('price');
$avg = Product::where('status', 1)->avg('price');

How to publish all laravel default error-related blade files?

Just open your project folder and run the below command in cmd. It will publish all default error pages of laravel and will locate inside resources>views>errors

        
        php artisan vendor:publish --tag=laravel-errors

How to Enable Maintenance Mode in Laravel 9?

Laravel has some artisan commands with the help of these commands we can down our laravel application for sometimes and we can display the 503 pages or the coming soon page.

we can also set a password so that we can access the application using that password and other users can't access it.

        
        //To enable laravel project maintenance mode run bellow artisan command
php artisan down

//To enable laravel project maintenance mode run bellow artisan command
php artisan up

//Automatically refresh the page after a specified number of seconds
php artisan down --refresh=60

Retry option to the down command, although browsers generally ignore this header
php artisan down --retry=60

//setup password during downmode 
php artisan down --secret="yourpassword"

//access application by passing your password in url
http://127.0.0.1:8000/yourpassword

//pre-render a template of your choice using the down command's render option:
php artisan down --render="errors::503"

//Redirect webiste to another url during maintance mode
php artisan down --redirect=/

Laravel supports the following listed databases:

  • MySQL 5.6+
  • PostgreSQL (Postgres) 9.4+
  • SQLite 3.8.8+
  • SQL Server 2017+


How many default actions are handled by the restful resource controllers in laravel? 

There are seven default actions handled by restful resource controllers in Laravel.

The following default actions are handled by the resource controllers in  Laravel.

Method Path Action Route Name Use
GET /posts index posts.index get all posts
GET /posts/create create posts.create create a new user
POST /posts store posts.store store post details
GET /posts/{post} show posts.show get post details
GET /posts/{post}/edit edit posts.edit edit post
PUT/PATCH /posts/{post} update posts.update update post
DELETE /posts/{post} destroy posts.destroy delete post


What are the default main routing files in Laravel?

There are two main routing file available in laravel which is located inside the routes folder.

  1. web.php file in the routes folder.
  2. api.php file in the routes folder.


How many router methods are available in Laravel?

The Bellow mentioned list shows the router methods available in Laravel:

  • Route::get($uri, $callback);
  • Route::post($uri, $callback);
  • Route::put($uri, $callback);
  • Route::patch($uri, $callback);
  • Route::delete($uri, $callback);
  • Route::options($uri, $callback);


What is the CSRF token in laravel and how to use it?

CSRF stands for Cross-Site Request Forgery. A CSRF token is generated by the server side and a unique value that is sent to the client, we can store it in a form hidden field using @csrf or we can store it in the meta tag.

Generally, a CSRF token uses for protecting web applications from attackers (commonly known as CSRF attacks). The following code shows how we can generate and use a CSRF token when creating a form in Laravel.

        
        //in meta tag it helps while using ajax request
<meta name="csrf-token" content="{{ csrf_token() }}">

//inside form hidden field
<form action="/post" method="POST"> 
@csrf 
... 
</form>

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