Building a high scalable chat application using rabbitmq

In this blog post, we will explore how to build a high scalable chat application using RabbitMQ.

Understanding RabbitMQ

RabbitMQ is an open-source message-broker software that allows applications to communicate with each other through a message queue. It uses AMQP (Advanced Message Queuing Protocol) as its messaging protocol, which enables reliable messaging between applications.

RabbitMQ provides several features that make it an ideal choice for building scalable chat applications:

It supports multiple messaging patterns such as point-to-point, publish-subscribe, and request-response. It provides message durability and persistence, which ensures that messages are not lost even in the event of a system failure. It supports clustering, which enables horizontal scaling of the messaging system. Designing the Chat Application The chat application will consist of three components:

A messaging server that will handle incoming and outgoing messages. A backend server that will store chat messages and handle user authentication. A frontend client that will allow users to connect to the chat application. The messaging server will be implemented using RabbitMQ, while the backend server and frontend client will be built using Node.js.

Implementing the Messaging Server

The messaging server will consist of two RabbitMQ exchanges: one for incoming messages and another for outgoing messages. Each exchange will have its own queue, which will store messages until they are consumed by the backend server.

When a user sends a message, it will be published to the incoming messages exchange, and the messaging server will route the message to the appropriate queue based on the recipient's ID.

When the backend server consumes a message from the incoming messages queue, it will process the message and store it in the database. Then, it will publish the message to the outgoing messages exchange, which will route the message to the appropriate queue based on the recipient's ID.

When the frontend client connects to the chat application, it will create a RabbitMQ queue for receiving messages and subscribe to the outgoing messages exchange. When a message is published to the outgoing messages exchange, it will be routed to the appropriate queue, and the frontend client will receive the message.

Implementing the Backend Server

The backend server will be responsible for storing chat messages and handling user authentication. It will expose a REST API for creating and retrieving chat messages, as well as for user authentication.

When a user sends a message, the frontend client will make a POST request to the backend server's API with the message content and recipient's ID. The backend server will validate the user's authentication credentials and store the message in the database. Then, it will publish the message to the incoming messages exchange.

When the backend server consumes a message from the outgoing messages queue, it will retrieve the recipient's information from the database and publish the message to the appropriate user's RabbitMQ queue.

Implementing the Frontend Client

The frontend client will be built using React.js and will connect to the chat application using WebSockets. When a user sends a message, the frontend client will make a POST request to the backend server's API to send the message. It will also create a RabbitMQ queue for receiving messages and subscribe to the outgoing messages exchange.

When the frontend client receives a message from RabbitMQ, it will update the chat window with the new message.

Conclusion

Building a high scalable chat application using RabbitMQ is a powerful solution for handling large volumes of messages and users. With its support for messaging patterns, message durability, persistence, and clustering, RabbitMQ provides a reliable messaging backbone for building distributed applications.