How to send a message to Specific Destination through ClientWebSocket in .Net

2021-12-18 07:31 Naveen kumar imported from Stackoverflow

I have a WebSocket server written in Java and I need to create a Client in .Net I am using .Net Library System.Net.WebSockets However the server expects the message to be sent to a specific destination some thing like(/app/message). However through websocket.Send method I can only pass the actual message. (ex in java stompSession.send("/app/destination", "actual Message"))

How Can I send a message to specific destination using ClientWebSocket.

var socket =new ClientWebSocket();
socket.ConnectAsync(new Uri("ws://example"), CancellationToken.None).Wait();
var data = System.Text.Encoding.UTF8.GetBytes("Hi from Client!");
var si = socket.SendAsync(data, WebSocketMessageType.Text,true,CancellationToken.None);
Console.WriteLine("Sent");
var byt = new byte[4096];
var response = new ArraySegment<byte>(byt);
var res =  socket.ReceiveAsync(response, CancellationToken.None);
var responseText = System.Text.Encoding.UTF8.GetString(response);
Console.WriteLine(responseText);

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```
Above code I have written in login method, my question is how to track whether connection is already open for particular user? if credential is different then new connection should be establish and suppose I have more then 1 million users then can I manage this much connection?

Rent a new buffer only when I run out of space, not on every read

In the receive loop I'm renting for every read, what I need is to rent a new buffer when I run out of space. How do I do that?

The idea: rent => fill => then grow if needed and replace the buffer

private async Task ReceiveLoopAsync(WebSocket webSocket, CancellationToken cancellationToken)
{
    try
    {
        var offset = 0;

        while (true)
        {
            // Rent buffer per message
            var buffer = ArrayPool<byte>.Shared.Rent(1024);

            // Memory<byte> overload instead of the ArraySegment one, so we get a ValueTask instead
            var result = await webSocket.ReceiveAsync(buffer.AsMemory()[offset..], cancellationToken).ConfigureAwait(false);

            if (result.MessageType == WebSocketMessageType.Close)
            {
                break;
            }

            if (result.EndOfMessage)
            {
                await _incomingMessageQueue.Writer.WriteAsync(buffer, cancellationToken).ConfigureAwait(false);
                offset = 0;
            }
            else
            {
                offset += result.Count;

                // Read buffer size is too small for the message. Doubling...
                if (offset >= buffer.Length - 1)
                {
                    // Create the new array
                    var newArray = ArrayPool<byte>.Shared.Rent(buffer.Length * 2);

                    // Copy the old array to the new array
                    Array.Copy(buffer, newArray, offset);
                    //buffer.AsSpan().CopyTo(newArray);

                    // Return the old array
                    ArrayPool<byte>.Shared.Return(buffer);

                    buffer = newArray;
                }
            }
        }
    }
    catch (OperationCanceledException)
    {
        // normal upon task/token cancellation, disregard
    }
    catch (Exception)
    {
        // something else happened
    }
    finally
    {
        _outgoingMessageQueue.Writer.TryComplete();
    }
}

ReceiveAsync's CancellationToken paramtere is doing timeout even if the web socket client is still connected
How do I make ClientWebSocket.ReceiveAsync timeout in 5 seconds only if the web socket client is not connected? The current behavior is that it timeouts no matter what conditions are met, i.e. whether the web socket client is connected or not, which is not the behavior I expect.
```
var timeOut = new CancellationTokenSource(5000).Token;
var receiveResult = await _clientWebSocket.ReceiveAsync(buffer.Memory, timeOut).ConfigureAwait(false);
```
Best way to mock System.Net.WebSockets ClientWebSocket class to unit test (nunit)

I have used ClientWebSocket class for webSocket communication. What is the best way of mocking the class?

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