CodeIgniter middleware: implement custom processing of requests and responses

CodeIgniter middleware: Implementing custom processing of requests and responses

Introduction:
When developing web applications, we often need to process requests and responses. The CodeIgniter framework provides a middleware mechanism that allows us to customize the logic for processing requests and responses. Middleware is a piece of code that executes before the request reaches the controller or before the response is sent to the client. In this article, we will learn how to use CodeIgniter middleware to implement custom handling of requests and responses.

1. Install CodeIgniter
First, we need to install the CodeIgniter framework. You can install CodeIgniter by defining a composer.json file and running the "composer update" command. The following is a sample composer.json file:

{

"require": {
    "codeigniter4/framework": "^4.1"
}

}

2. Create middleware
In CodeIgniter, we can customize it by creating middleware Handle requests and responses. Middleware is usually stored in the app/Middleware directory. We can create a middleware called LogMiddleware using the following command:

php spark make:middleware LogMiddleware

This will create a file called LogMiddleware.php in the app/Middleware directory.

3. Implement request processing logic
In the LogMiddleware.php file, we can define the code logic that needs to be executed before the request reaches the controller. Here is an example:

namespace AppMiddleware;

use CodeIgniterHTTPRequestInterface;
use CodeIgniterHTTPResponseInterface;
use PsrLogLoggerInterface;
use PsrLogLogLevel ;

class LogMiddleware implements CodeIgniterHTTPMiddlewareInterface
{

protected $logger;

public function __construct(LoggerInterface $logger)
{
    $this->logger = $logger;
}

public function before(RequestInterface $request, $arguments = null)
{
    $this->logger->log(LogLevel::INFO, 'Request received: ' . $request->getMethod() . ' ' . $request->getUri()->getPath());
}

public function after(RequestInterface $request, ResponseInterface $response, $arguments = null)
{
    $this->logger->log(LogLevel::INFO, 'Response sent with status: ' . $response->getStatusCode());
}

}

The LogMiddleware class in the above code example implements the MiddlewareInterface interface. In the before() method, we log the details of the request received, including the request method and URI path. In the after() method, we record the status code of the response.

4. Register middleware
To use middleware, we need to register them in the application's configuration file config/App.php. Find the following code and add LogMiddleware to the $middlewareGroups array:

'groups' => [

'web' => [
    // ...
    AppMiddlewareLogMiddleware::class,
],
// ...

],

Now, LogMiddleware will be in the middle of "web" are automatically applied in the component group.

5. Test middleware
We can create a simple example in the controller to test our middleware. In the app/Controllers directory, create a file called Home.php and add the following code:

namespace AppControllers;

use CodeIgniterController;

class Home extends Controller
{

public function index()
{
    return "Hello World!";
}

}

6. Access the application in the browser
Now, access the application in the browser , we can view the effect of the middleware in real time. Enter the application's URL into your browser and observe the request and response information in the logs.

Summary:
CodeIgniter’s middleware mechanism provides us with the ability to customize requests and responses. By creating middleware, we can apply custom code logic before the request reaches the controller or before the response is sent to the client. In this article, we learned how to create a simple middleware and register it for use in your application. I hope this article was helpful and allowed you to better master the use of CodeIgniter middleware.

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