Crystal Web Dev

Web Development

Crystal WebSockets

Using WebSockets

Crystal WebSockets use kemal-websocket for real-time apps.

Introduction to Crystal WebSockets

WebSockets provide a full-duplex communication channel over a single TCP connection, enabling real-time data transfer between a client and server. In Crystal, the kemal-websocket shard is used to implement WebSocket functionality, allowing you to build responsive, real-time applications.

Setting Up Your Environment

Before you start coding with Crystal WebSockets, ensure that you have Crystal installed on your system. You can install Crystal from the official website. Additionally, you will need to add the kemal-websocket shard to your project.

Creating a Basic WebSocket Server

Let's create a simple WebSocket server using Crystal and kemal-websocket. This server will echo messages back to the client.

Understanding the Code

  • require "kemal" and require "kemal-websocket" are importing the necessary libraries.
  • The ws "/echo" block defines a WebSocket route at /echo.
  • The socket.on_message block listens for incoming messages and echoes them back using socket.send.
  • Kemal.run starts the Kemal web server to handle incoming WebSocket connections.

Testing Your WebSocket Server

To test your WebSocket server, you can use a tool like WebSocket Echo Test or a WebSocket client in your browser's console.

Conclusion

By following the steps outlined in this guide, you can set up a basic WebSocket server using Crystal and kemal-websocket. This forms the foundation for building more complex real-time applications. Experiment with different message types and WebSocket events to expand your application's capabilities.

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