Integrating CodeIgniter4 with RabbitMQ

CodeIgniter4 is a PHP web application framework, while RabbitMQ is a message broker that allows you to send and receive messages between different applications or components. Integrating CodeIgniter4 with RabbitMQ involves setting up a messaging system for communication. Below, is a basic example of how you might achieve this integration. Please note that this example assumes you have both CodeIgniter4 and RabbitMQ installed and configured.

Step 1: Install Required Libraries
In your CodeIgniter4 project, you’ll need to install the php-amqplib/php-amqplib library, which provides a PHP implementation of the AMQP protocol used by RabbitMQ. You can use Composer to install it:

composer require php-amqplib/php-amqplib

Step 2: Configuration
In your CodeIgniter4 project, open the app/Config/RabbitMQ.php configuration file (you might need to create it) and add the following configuration settings:

<?php

namespace Config;

use PhpAmqpLib\Connection\AMQPStreamConnection;

class RabbitMQ
{
    public $connection;

    public function __construct()
    {
        $this->connection = new AMQPStreamConnection(
            'localhost',  // RabbitMQ server hostname
            5672,         // RabbitMQ server port
            'guest',      // RabbitMQ username
            'guest'       // RabbitMQ password
        );
    }
}

Step 3: Sending Messages
Now, let’s create a controller method in CodeIgniter that sends a message to RabbitMQ:

<?php

namespace App\Controllers;

use App\Config\RabbitMQ;
use CodeIgniter\Controller;

class RabbitMQController extends Controller
{
    public function sendMessage()
    {
        $rabbitMQConfig = new RabbitMQ();
        $connection = $rabbitMQConfig->connection;

        $channel = $connection->channel();

        $channel->queue_declare('hello', false, false, false, false);

        $message = 'Hello, RabbitMQ!';
        $channel->basic_publish(new \PhpAmqpLib\Message\AMQPMessage($message), '', 'hello');

        $channel->close();
        $connection->close();

        return 'Message sent to RabbitMQ.';
    }
}

Step 4: Receiving Messages
Let’s create another controller method that receives messages from RabbitMQ:

<?php

namespace App\Controllers;

use App\Config\RabbitMQ;
use CodeIgniter\Controller;

class RabbitMQController extends Controller
{
    public function receiveMessage()
    {
        $rabbitMQConfig = new RabbitMQ();
        $connection = $rabbitMQConfig->connection;

        $channel = $connection->channel();

        $channel->queue_declare('hello', false, false, false, false);

        echo "Waiting for messages. To exit, press Ctrl+C\n";

        $callback = function ($msg) {
            echo "Received: ", $msg->body, "\n";
        };

        $channel->basic_consume('hello', '', false, true, false, false, $callback);

        while ($channel->is_consuming()) {
            $channel->wait();
        }
    }
}

Step 5: Accessing the Controller Methods
You can access the sendMessage and receiveMessage methods by navigating to the respective URLs in your web browser.

• To send a message, visit: http://your_domain/rabbitmq/sendMessage
• To receive messages, visit: http://your_domain/rabbitmq/receiveMessage

Please note that this example is a basic introduction to integrating CodeIgniter4 with RabbitMQ. In a production environment, you’d likely want to handle exceptions, implement better error handling, and perhaps encapsulate the RabbitMQ functionality into a separate service class for better code organization.