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Real-time Communication Using WebSockets

WebSockets enable real-time communication between a server and client by maintaining an open connection, allowing data to be sent and received instantly without repeated requests.

Details

URL: 🔗 https://docs.vapor.codes/4.0/websockets/

Source: 🔗 Book: Server-Side Swift

Author: [Author Name]

Tags:
WebSockets, Vapor, Swift, Real-time Communication

Platforms Supported: macOS, Linux

Swift Version: 5.x

Implementing WebSockets in Vapor​

Step 1: Create a WebSocket Endpoint​

In Routes.swift, add a WebSocket route:

app.webSocket("talk-back") { req, ws in
    ws.onText { ws, text in
        if text.lowercased() == "hello" {
            ws.send("Is it me you're looking for...?")
        }
    }
}

This route listens for WebSocket connections and responds with a message when "hello" is received.

Step 2: Connect with an iOS Client​

Using the Starscream library, connect an iOS app to the WebSocket server:

guard let url = URL(string: "ws://127.0.0.1:8080/talk-back") else { return }

let socket = WebSocket(url: url)
socket.connect()

Add an action to send a message:

@IBAction func onSendRequest(_ sender: Any) {
    socket.write(string: "Hello")
}

Step 3: Test the WebSocket Communication​

Run the Vapor server and iOS app. When the message "Hello" is sent from the app, the server will respond with "Is it me you're looking for...?"

How it Works​

WebSockets maintain a continuous, open connection, unlike traditional HTTP requests. This allows real-time communication between a client and server without the need for repeated requests or polling.

Advanced WebSocket Handling​

Monitoring Connection Health​

Use onPing and onPong to monitor the connection:

ws.onPing { ws in }
ws.onPong { ws in }

Sending and Receiving Data​

Send text or binary data:

ws.send("Message text")
ws.send([1, 2, 3]) // Binary data

Handle completion with an event loop promise:

let promise = eventLoop.makePromise(of: Void.self)
ws.send("Message", promise: promise)
promise.futureResult.whenComplete { result in
    // Handle result
}

Closing the Connection​

Close the WebSocket connection gracefully:

ws.close()
ws.onClose.whenComplete { result in
    // Handle closure
}

Conclusion​

WebSockets in Vapor enable efficient real-time communication for use cases like chat applications, live dashboards, and more.

Learn More about Vapor WebSockets→