How to Build a Basic Web Application with CodeIgniter 4

How to Build a Basic Web Application with CodeIgniter 4 - Are you looking to build a web application but don't know where to start? Look no further than CodeIgniter 4, a powerful PHP framework that simplifies web development by providing a solid foundation for building high-quality applications quickly and efficiently. In this article, we'll show you how to get started with CodeIgniter 4 and build a basic web application step by step.

1. Introduction to CodeIgniter 4

Before we dive into building our web application, let's take a quick look at what CodeIgniter 4 is and what it can do for us. CodeIgniter 4 is an open-source PHP web application framework that is fast, secure, and easy to use. It follows the Model-View-Controller (MVC) architectural pattern and comes with a robust set of features that make it an excellent choice for building web applications of any size.

2. Installation and Setup

To start building our web application, we first need to install and set up CodeIgniter 4 on our local machine. We can do this by following these steps:

2.1 Install Composer

CodeIgniter 4 uses Composer, a PHP dependency manager, to manage its dependencies. To install Composer, go to https://getcomposer.org/download/ and follow the installation instructions for your operating system.

2.2 Create a New Project

Once Composer is installed, we can create a new CodeIgniter 4 project by running the following command in the terminal:

composer create-project codeigniter4/appstarter myproject

This will create a new project called "myproject" in the current directory.

2.3 Configure Database

To configure the database, we need to modify the app/Config/Database.php file and add our database credentials. For example:

public $default = [

    'DSN'      => '',
    'hostname' => 'localhost',
    'username' => 'myusername',
    'password' => 'mypassword',
    'database' => 'mydatabase',
    'DBDriver' => 'MySQLi',
    'DBPrefix' => '',
    'pConnect' => false,
    'DBDebug'  => (ENVIRONMENT !== 'production'),
    'cacheOn'  => false,
    'cacheDir' => '',
    'charset'  => 'utf8',
    'DBCollat' => 'utf8_general_ci',
    'swapPre'  => '',
    'encrypt'  => false,
    'compress' => false,
    'strictOn' => false,
    'failover' => [],
    'port'     => 3306,
];

3. Creating the Application

Now that we have CodeIgniter 4 set up, we can start building our web application. In this example, we'll create a simple "Hello, World!" application that displays a greeting on the screen.

3.1 Create a Controller

The first step is to create a controller that will handle the logic for our application. To do this, we'll create a new file called Hello.php in the app/Controllers directory and add the following code:

namespace App\Controllers;

class Hello extends BaseController
{
    public function index()
    {
        echo "Hello, World!";
    }
}

3.2 Create a Route

Next, we need to create a route that maps the URL to our controller. We can do this by modifying the app/Config/Routes.php file and adding the following code:

$routes->get('/', 'Hello::index');

4. Views and Templates

Now that we have a basic controller and route set up, we can add a view to our application to display the "Hello, World!" greeting on the screen.

4.1 Create a View

To create a view, we'll create a new file called hello.php in the app/Views directory and add the following code:

<!DOCTYPE html>

<html>
    <head>
        <title>Hello, World!</title>
    </head>
    <body>
        <h1>Hello, World!</h1>
    </body>
</html>

4.2 Load the View

Finally, we need to modify the Hello controller to load the view instead of echoing the greeting. We can do this by adding the following code to the index() method:

public function index()
{
    return view('hello');
}

5. Conclusion

Congratulations, you have successfully built a basic web application with CodeIgniter 4! We covered the installation and setup process, creating a controller and route, and adding a view to display content on the screen. CodeIgniter 4 makes it easy to build powerful web applications quickly and efficiently.

FAQs

What is CodeIgniter 4? CodeIgniter 4 is an open-source PHP web application framework that simplifies web development by providing a solid foundation for building high-quality applications quickly and efficiently.
What is the Model-View-Controller (MVC) architectural pattern? The Model-View-Controller (MVC) architectural pattern is a design pattern that separates an application into three interconnected components: the model, the view, and the controller.
What is Composer? Composer is a PHP dependency manager that is used to manage the dependencies of CodeIgniter 4.
What is a route in CodeIgniter 4? A route in CodeIgniter 4 maps a URL to a specific controller method.
Can I use CodeIgniter 4 to build complex web applications? Yes, CodeIgniter 4 provides a robust set of features that make it an excellent choice for building web applications of any size and complexity.

How to Build a Basic Web Application with CodeIgniter 3 :Newer

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Author : parvezkhanats

For over the past decade, Parvez has developed a range of websites, web apps, custom CMS and CRM systems using PHP, MySQL, WordPress, Laravel, jQuery, HTML5, CSS3, XML, and Ajax for both startups and small businesses. His core expertise is in complete end-to-end management of new web development projects. Parvez joined WordPress to seek out opportunities to help clients build websites.

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How to Build a Basic Web Application with CodeIgniter 4