How to use CI4 framework in php?

PHP is a widely used server-side scripting language, and CodeIgniter4 (CI4) is a popular PHP framework that provides a fast and excellent way to build web applications. In this article, we will get you started using the CI4 framework to develop outstanding web applications by walking you through how to use it.

1. Download and install CI4

First, you need to download the CI4 framework from the official website (https://codeigniter.com/download) and unzip it. Then, copy the files from the framework into your web server's working directory. Make sure you have PHP 7.2 and above installed.

2. Create a new project

In CI4, you can use the "spark" tool to create a new project, just open the terminal and enter the following command:

. /spark new myproject

Where, "myproject" is the name of the new project. This command will create a new folder called "My project" containing default files and folders related to the CI4 framework.

3. Set up routing

CI4 provides flexible routing capabilities so you can easily manage URLs in your web application. You can set routes in the '/app/Config/Routes.php' file.

For example:

$routes->get('users', 'UserController::index');

In this case, when the user accesses 'localhost /myproject/users', the 'index' method in the 'UserController' controller will be called.

4. Create a Controller

In CI4, you can easily create a controller. You just need to create a new PHP file in the '/app/Controllers' folder and embed your controller using the following code:

class UserController extends BaseController {

public function index()
{
    echo 'User index controller';
}

}

In this case, we created a controller called 'UserController.php' and defined a controller called 'index' in it method, which simply outputs the "User index controller" text. You can define other controllers and methods yourself to handle different parts of your web application.

5. Create models

Models are an important part of CI4 applications, they are used to handle interactions with the database. Fortunately, creating models in CI4 is also very simple. You just create a new PHP file in the '/app/Models' folder and embed your model using the following code:

use CodeIgniterModel;

class UserModel extends Model
{

protected $table = 'users';

protected $allowedFields = ['firstname', 'lastname', 'email'];

}

In this case, we create a model called "UserModel.php" and define A property called "$table" points to the "users" table in our database. We also define "$allowedFields", which tells the CI4 model which fields are available for database interaction.

6. Create views

Views are a common way to present data in web applications. In CI4 you can create a new PHP file in the '/app/Views' folder and embed your view using the following code:

<title>Users</title>

<?php foreach ($users as $user): ?>
    <div>
        <p><?php echo $user['firstname'].' '.$user['lastname']; ?></p>
        <p><?php echo $user['email']; ?></p>
    </div>
<?php endforeach; ?>

In this case, we Created a view called "users.php" and used a loop to iterate over the users data in the database to create a list containing user names and emails.

7. Execute the Web application

After completing all settings, you can open the web browser and enter the following URL: 'http://localhost/myproject/users', that's it Run the web application. If everything is fine, you will see the user view you created previously.

The above are some basic knowledge of the CI4 framework. If you want to know more, you can visit the CI4 official website, which contains more detailed documentation and tutorials. I believe this article has begun to provide you with the basic knowledge of writing web applications based on the CI4 framework.

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