Creating CodeIgniter4 (CI4) CRUD (Create, Read, Update, Delete) application with Apache Kafka

Creating a full CodeIgniter 4 (CI4) CRUD (Create, Read, Update, Delete) application with Apache Kafka involves several steps, from setting up the development environment to integrating Kafka for event-based communication. Here’s a step-by-step tutorial to guide you through the process:

Prerequisites:

1. PHP and CodeIgniter4 installed.
2. Apache Kafka installed and running.
3. Composer installed.

Installing the rdkafka extension on Windows
Precompiled binaries for each release are available from » PECL for a variety of combinations of versions, thread safety, and VC libraries. Extract the archive and put librdkafka.dll in the root PHP directory (same level as php.exe) and the php_rdkfaka.dll file in your PHP extension directory (“ext” by default).

Note:
Each precompiled binary works only for a specific PHP build. Please make sure to download the right one after opening the DLL link on » PECL.

Add the following line to your php.ini file:

extension=php_rdkafka.dll

---

Step 1: Set Up CodeIgniter4 Project:

1. Create a new CI4 project if you haven’t already:

   composer create-project codeigniter4/appstarter ci4-kafka-crud

2. Navigate to your project directory:

   cd ci4-kafka-crud

Step 2: Install Dependencies:

1. Install the Kafka library using Composer:

   composer require edenhill/phpkafka

Step 3: Create Kafka Configuration:

1. Create a file named KafkaConfig.php in app/Config directory:

<?php namespace Config;

use CodeIgniter\Config\BaseConfig;

class KafkaConfig extends BaseConfig
{
    public $brokers = ['localhost:9092']; // Update with your Kafka broker(s)

    public $topic = 'ci4_crud_events'; // Update with your Kafka topic
}

Step 4: Create Controller and Views:

1. Generate a controller named Users:

   php spark make:controller Users

2. In the Users.php controller, create methods for CRUD operations (create, read, update, delete).

Step 5: Integrate Kafka:

1. Modify the Users controller to send Kafka events after successful CRUD operations:

use App\Config\KafkaConfig;
use PHPEasykafka\KafkaProducer;

class Users extends BaseController
{
    public function create()
    {
        // ... Create user logic ...

        // Send Kafka event
        $producer = new KafkaProducer(KafkaConfig::$brokers);
        $producer->produce(KafkaConfig::$topic, json_encode(['event' => 'user_created', 'data' => $user]));

        // ... Redirect or display success message ...
    }

    // Repeat similar steps for read, update, and delete methods.
}

Step 6: Consume Kafka Events:

1. Create a Kafka consumer script to handle events. This can be a separate PHP file or a part of your CI4 project.

use App\Config\KafkaConfig;
use PHPEasykafka\KafkaConsumer;
use RdKafka\Message;

$consumer = new KafkaConsumer(
    KafkaConfig::$brokers,
    KafkaConfig::$topic,
    'consumer_group' // Update with your consumer group
);

$consumer->consume(function (Message $message) {
    $payload = json_decode($message->payload, true);

    // Handle different events
    switch ($payload['event']) {
        case 'user_created':
            // Process user created event
            break;
        // Handle other events...
    }
});

Step 7: Configure Routes:
Define your CRUD routes in the app/Config/Routes.php file.

Step 8: Run the Application:

1. Start the Kafka consumer script in a terminal to listen for events.
2. Start the CodeIgniter development server:

   php spark serve

Step 9: Test the Application:
Access the CRUD operations from your browser or an API testing tool.

That’s it! You’ve successfully created a CodeIgniter4 CRUD application integrated with Apache Kafka for event-based communication. Remember that this is a high-level overview, and you may need to adapt the steps to fit your specific application structure and requirements.