Most Important Laravel Interview Questions and Answers
Laravel is an open-source widely used PHP framework. The platform was intended to develop web applications by using MVC architectural patterns. Laravel is released under the MIT license.
Therefore, its source code is hosted on GitHub. It is a reliable PHP framework as it follows explicit and accurate language rules.
It is an application-level package manager for PHP. It provides a standard format for managing PHP software dependencies and libraries.
HTTP middleware is a technique for filtering HTTP requests. Laravel includes a middleware that checks whether the application user is authenticated or not.
Aggregates methods of query builder are: 1) max(), 2) min(), 3) sum(), 4) avg(), and 5) count().
A route is basically an endpoint specified by a URI (Uniform Resource Identifier). It acts as a pointer in the Laravel application.
Most commonly, a route simply points to a method on a controller and dictates which HTTP methods can hit that URI.
Routes are stored inside files under the /routes folder inside the project’s root directory. By default, there are a few different files corresponding to the different “sides” of the application (“sides” comes from the hexagonal architecture methodology).
In Laravel, bundles are referred to as packages. These packages are used to increase the functionality of Laravel. A package can have views, configuration, migrations, routes, and tasks.
A controller is the “C” in the “MVC” (Model-View-Controller) architecture, which is what Laravel is based on.
Reverse routing is a method of generating URLs based on symbols or names. It makes your Laravel application flexible.
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 concrete class.
They are a set of interfaces of the Laravel framework. These contracts provide core services. Contracts defined in Laravel include the corresponding implementation of the framework.
You can register service providers in the config/app.php configuration file that contains an array where you can mention the service provider class name.
All facades of Laravel have been defined in Illuminate\Support\Facades namespace.
Get method allows you to send a limited amount of data in the header. Post allows you to send a large amount of data in the body.
A service container is a tool used for performing dependency injection in Laravel.
You can use enableQueryLog method to enable query log in Laravel.
An event is an occurrence or action that helps you to subscribe and listen for events that occur in the Laravel application. Some of the events are fired automatically by Laravel when any activity occurs.
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, and 3) interface injection.
Validations are an important concept while designing any Laravel application. It ensures that the data is always in an expected format before it stores in the database. Laravel provides many ways to validate your data.
Base controller trait uses a ValidatesRequests class which provides a useful method to validate requests coming from the client machine.
ORM stands for Object Relational Mapping
While processing a large amount of data, you can use the cursor method in order to reduce memory usage.
Types of relationships in Laravel Eloquent are: 1) One To One 2) One To Many 3) Many To Many 4) Has Many Through, and 5) Polymorphic Relations.
Blade is a powerful template engine utilized by Laravel.
Laravel supports the following databases:
Migrations are important because it allows you to share application by maintaining database consistency. Without migration, it is difficult to share any Laravel application. It also allows you to sync the database.
Lumen is a micro-framework. It is a smaller, and faster, version of building Laravel based services, and REST API’s.
An artisan is a command-line tool of Laravel. It provides commands that help you to build Laravel applications without any hassle.
Laravel has helpers to generate URLs. This is helpful when you build links in your templates and API response.
Laravel exceptions are handled by App\Exceptions\Handler class.
The most common HTTP error codes are:
I. Error 404 – Displays when Page is not found.
ii. Error- 401 – Displays when an error is not authorized
It is a database query builder that provides a convenient, faster interface to create and run database queries.
This function is used to dump the contents of a variable to the browser. The full form of dd is Dump and Die.
PHP artisan serve –port=8080
PHP artisan down;
PHP artisan up;
PHP artisan make:controller;
PHP artisan make:model;
PHP artisan make:migration;
PHP artisan make:middleware;
It is a method of identifying a user’s login credentials with a password. In Laravel it can be managed with a session which takes two parameters 1) username and 2) password.
i. delete(): remove all records from the database table.
ii. softDeletes(): It does not remove the data from the table. It is used to flag any record as deleted.
You can create all web pages of a website to tell the search engine about the organizing site content. The crawlers of search engines read this file intelligently to crawl a website.
It is a type of module or package which are used to create fake data. This data can be used for testing purposes.
It can also be used to generate: 1) Numbers, 2) Addresses, 3) DateTime, 4) Payments, and 5) Lorem text.
Use hasTable() Laravel function to check whether the desired table exists in the database or not.
Insert(): This function is simply used to insert a record into the database. It is not necessary that ID should be autoincremented.
InsertGetId(): This function also inserts a record into the table, but it is used when the ID field is auto-increment.
In active record, class map to your database table. It helps you to deal with CRUD operations.
The following are basic concepts used in Laravel:
Implicit Controllers help you to define a proper route to handle controller action. You can define them in the route.php file with the Route:: controller() method.
In order to use a custom table, you can override the property of the protected variable $table.
It is Model, View, and Controller:
-Model: The model defines the logic to write Laravel applications.
-View: It covers the UI logic of the Laravel application.
-Controller: It works as an interface between Model, and View. It is a way how the user interacts with an application.
@include is used to load more than one template view file. It helps you to include a view within another view. Users can also load multiple files in one view.
Cookies are small files sent from a particular website and stored on a PC by the user’s browser while the user is browsing.
To create a connection with the database, you can use the .env file.
Eloquent is an ORM used in Laravel. It provides simple active record implementation working with the database. Each database table has its Model, which is used to interact with the table.
Laravel guard is a special component that is used to find authenticated users. The incoming request is initially routed through this guard to validate credentials entered by users. Guards are defined in the ../config/auth.php file.
It is a feature of Laravel. It provides handle throttling. Rate limiting helps Laravel developers to develop a secure application and prevent DOS attacks.
Collections is a wrapper class to work with arrays. Laravel Eloquent queries use a set of the most common functions to return database results.
DB facade is used to run SQL queries like create, select, update, insert, and delete.
Object Relational Mapping is a technique that helps developers address, access, and manipulate objects without considering the relation between object and their data sources.
It allows routing all your application requests to the controller. Laravel routing acknowledges and accepts a Uniform Resource Identifier with a closure.
The session is used to pass user information from one web page to another. Laravel provides various drivers like a cookie, array, file, Memcached, and Redis to handle session data.
Session data be accessed by creating an instance of the session in the HTTP request. Once you get the instance, use the get() method with a “Key” as a parameter to get the session details.
Authentication means confirming user identities through credentials, while authorization refers to gathering access to the system.
Listeners are used to handling events and exceptions. The most common listener in Laravel for login events is LoginListener.
Policies classes include the authorization logic of the Laravel application. These classes are used for a particular model or resource.
Use need to use the artisan command to rollback the last migration.
Laravel developers can use the make method to bind an interface to concreate class. This method returns an instance of the class or interface. Laravel automatically injects dependencies defined in the class constructor.
All controllers and routes should return a response to be sent back to the web browser. Laravel provides various ways to return this response. The most basic response is returning a string from the controller or route.
It is a feature of Laravel where we can reuse similar queries. We do not require to write the same types of queries again in the Laravel project. Once the scope is defined, just call the scope method when querying the model.
Laravel homestead is the official, disposable, and pre-packaged Vagrant box that is a powerful development environment without installing HHVM, a web server, and PHP on your computer.
A namespace allows a user to group the functions, classes, and constants under a specific name.
Laravel Forge helps in organizing and designing a web application. Although the manufacturers of the Laravel framework developed this toll, it can automate the deployment of every web application that works on a PHP server.
Model Observers is a feature of Laravel. It is used to make clusters of event listeners for a model. Method names of these classes depict the Eloquent event. Observer’s class methods receive the model as an argument.
It is used to initialize a Laravel project. This bootstrap directory contains the app.php file that is responsible for bootstrapping the framework.
The default Laravel session timeout duration is 2 hours.
Use the clear-compiled command to remove the compiled class file.
Robot.txt file is placed in the Public directory.
Its routes correspond to an API cluster. It has API middleware which is enabled by default in Laravel. These routes do not have any state and cross-request memory or have no sessions.
Name route is a method of generating a routing path. The chaining of these routes can be selected by applying the name method to the description of the route.
Open-source software is software in which source code is freely available. The source code can be shared and modified according to the user’s requirements.
It is a technique in which the system logs generated errors. Loggin is helpful to increase the reliability of the system. Laravel supports various logging modes like Syslog, daily, single, and error log modes.
It is a feature of Laravel that supports various languages to be used in the application. A developer can store strings of different languages in a file, and these files are stored in the resources/views folder. Developers should create a separate folder for each supported language.
It is the method of converting text into a key that shows the original text. Laravel uses the Hash facade to store the password securely in a hashed manner.
It is a process of transforming any message using some algorithms in such a way that the third user cannot read information. Encryption is quite helpful to protect your sensitive information from an intruder.
Encryption is performed using a Cryptography process. The message which is to be encrypted is called a plain message. The message obtained after the encryption is referred to as cipher message. When you convert cypher text to plain text or message, this process is called decryption.
To pass data to all views in Laravel use a method called to share(). This method takes two arguments, key, and value.
Generally, the share() method is called from the boot method of the Laravel application service provider. A developer can use any service provider, AppServiceProvider, or our own service provider.
Web.php is the public-facing “browser” based route. This route is the most common and is what gets hit by the web browser. They run through the web middleware group and also contain facilities for CSRF protection (which helps defend against form-based malicious attacks and hacks) and generally contain a degree of “state” (by this I mean they utilize sessions).
Use the following artisan command in Laravel to generate a request:
PHP artisan make:request UploadFileRequest