In my swift code I have opened a websocket connection with eleven labs and am sending it text and getting back chunks of audio data in stream that I want to play continuously and start the playback as soon as the first chunk arrives.

But it only plays a very small part of the text and then stops abruptly and I see the error :

WebSocket receive error: Error Domain=NSPOSIXErrorDomain Code=57 “Socket is not connected”

Audio player error: Error Domain=NSOSStatusErrorDomain Code=1954115647 “(null)”

My code is :

class WebSocketViewModel: NSObject, ObservableObject, URLSessionWebSocketDelegate {
private var webSocketTask: URLSessionWebSocketTask?
private var player: AVAudioPlayer?
private var audioBuffer = Data()

func connectAndPlay() {
    let urlString = "wss://api.elevenlabs.io/v1/text-to-speech/voice-id/stream-input?model_id=eleven_turbo_v2"
       guard let url = URL(string: urlString) else {
           print("Invalid URL")
           return
       }
       
       var request = URLRequest(url: url)

    let session = URLSession(configuration: .default, delegate: self, delegateQueue: OperationQueue())
    webSocketTask = session.webSocketTask(with: request)
    webSocketTask?.resume()
    sendInitialMessages(apiKey: apiKey)
}

private func sendInitialMessages(apiKey: String) {
    let bosMessage: [String: Any] = [
        "text": " ",
        "voice_settings": [
            "stability": 0.5,
            "similarity_boost": 0.8
        ],
        "xi_api_key": apiKey
    ]

    sendMessage(bosMessage)

    let textMessage: [String: Any] = [
        "text": "Hello World this is just a random message for testing purposes",
    ]

    sendMessage(textMessage)

    let eosMessage: [String: Any] = [
        "text": ""
    ]

    sendMessage(eosMessage)
}

private func sendMessage(_ message: [String: Any]) {
    do {
        let messageData = try JSONSerialization.data(withJSONObject: message, options: [])
        let messageString = String(data: messageData, encoding: .utf8) ?? ""
        let webSocketMessage = URLSessionWebSocketTask.Message.string(messageString)
        webSocketTask?.send(webSocketMessage) { error in
            if let error = error {
                print("WebSocket send error: (error)")
            }
        }
    } catch {
        print("JSON serialization error: (error)")
    }
}


func urlSession(_ session: URLSession, webSocketTask: URLSessionWebSocketTask, didOpenWithProtocol protocol: String?) {
    print("WebSocket connection opened")
    receiveMessages()
}

func urlSession(_ session: URLSession, webSocketTask: URLSessionWebSocketTask, didCloseWith closeCode: URLSessionWebSocketTask.CloseCode, reason: Data?) {
    print("WebSocket connection closed")
}

private func receiveMessages() {
    webSocketTask?.receive { [weak self] result in
        switch result {
        case .failure(let error):
            print("WebSocket receive error: (error)")
        case .success(let message):
            switch message {
            case .string(let text):
                self?.handleMessage(text)
            default:
                break
            }
            self?.receiveMessages()
        }
    }
}

private func handleMessage(_ text: String) {
    guard let data = text.data(using: .utf8),
          let response = try? JSONSerialization.jsonObject(with: data, options: []) as? [String: Any] else { return }

    if let audioBase64 = response["audio"] as? String {
                addToAudioBuffer(audioBase64)
                if player == nil || !player!.isPlaying {
                    playAudio()
                }
            }

    if let isFinal = response["isFinal"] as? Bool, isFinal {
        print("Audio generation is complete.")
    }

}

private func addToAudioBuffer(_ base64String: String) {
       guard let audioData = Data(base64Encoded: base64String) else {
           print("Failed to decode base64 audio data")
           return
       }
       audioBuffer.append(audioData)
   }

private func playAudio() {
    guard !audioBuffer.isEmpty else {
                print("Audio buffer is empty")
                return
            }

            do {
                player = try AVAudioPlayer(data: audioBuffer)
                player?.play()
            } catch {
                print("Audio player error: (error)")
            }

            audioBuffer.removeAll()
}

}