XSockets support sending text data together with binary data over websockets. Event though the protocol does no support it... Try that with somethingR ;)

CombinedMessage.js

//Create a new XSockets text message.... the event is foo... The data is {lion:'grrr', p:Date()}
var myJson = new XSockets.Message("foo", { lion: 'grrr', p: Date() });

//Create a XSockets binary message and attach the text to it... (we call canvasToBuffer() to get hold of some data)
var binaryMessage = new XSockets.BinaryMessage(myJson, canvasToBuffer(),
    //The callback where we have data in the arrayBuffer...
    function (arrayBuffer) {
        // Okey, the buffer is created and wrapped in our simple "subprotocol".... send it!
        ws.send(arrayBuffer.buffer);
    });

csharp.cs

using System.Diagnostics;
using XSockets.Core.Common.Socket.Event.Interface;
using XSockets.Core.XSocket;
using XSockets.Core.XSocket.Helpers;

namespace XSockets.Test.Controllers
{
    //A custom object that reflect the JSON being sent...
    public class CustomData
    {
        public string lion { get; set; }
        public string p { get; set; }
    }

    public class MyBinaryController : XSocketController
    {
        //Override the method where the binary data will arrive...
        public override void OnMessage(IBinaryArgs binaryArgs)
        {
            //Convert the binaryArgs to a combinedMessage (will contain both ITextArgs and IBinaryArgs)
            var bm = binaryArgs.AsCombinedMessage();
            
            //Get the IBinaryArgs (the arraybuffer from the canvas)
            //bm.BinaryArgs

            //Get the ITextArgs (the JSON attached with the binary message)
            //bm.TextArgs

            //The interesting part... Get the strongly typed object passed with the arraybuffer
            var myCustomObject = bm.Extract<CustomData>();
            Debug.WriteLine(myCustomObject.lion);
            Debug.WriteLine(myCustomObject.p);
            
            //A shortcut would ofcourse be
            // var customObject = binaryArgs.AsCombinedMessage().Extract<CustomData>();
        }
    }
}

/*This will ofcourse output something like...

grrr
Thu Nov 28 2013 20:50:40 GMT+0100 (W. Europe Standard Time)

*/