A concrete implementation of the .Net Standard 2.0 System.Net.WebSockets.WebSocket abstract class
A WebSocket library that allows you to make WebSocket connections as a client or to respond to WebSocket requests as a server. You can safely pass around a general purpose WebSocket instance throughout your codebase without tying yourself strongly to this library. This is the same WebSocket abstract class used by .net core 2.0 and it allows for asynchronous Websocket communication for improved performance and scalability.
No dependencies.
As a client, use the WebSocketClientFactory
var factory = new WebSocketClientFactory();
WebSocket webSocket = await factory.ConnectAsync(new Uri("wss://example.com"));As a server, use the WebSocketServerFactory
Stream stream = tcpClient.GetStream();
var factory = new WebSocketServerFactory();
WebSocketHttpContext context = await factory.ReadHttpHeaderFromStreamAsync(stream);
if (context.IsWebSocketRequest)
{
WebSocket webSocket = await factory.AcceptWebSocketAsync(context);
}Client and Server send and receive data the same way.
Receiving Data:
private async Task Receive(WebSocket webSocket)
{
var buffer = new ArraySegment<byte>(new byte[1024]);
while (true)
{
WebSocketReceiveResult result = await webSocket.ReceiveAsync(buffer, CancellationToken.None);
switch (result.MessageType)
{
case WebSocketMessageType.Close:
return;
case WebSocketMessageType.Text:
case WebSocketMessageType.Binary:
string value = Encoding.UTF8.GetString(buffer.Array, 0, result.Count);
Console.WriteLine(value);
break;
}
}
}Receive data in an infinite loop until we receive a close frame from the server.
Sending Data:
private async Task Send(WebSocket webSocket)
{
var array = Encoding.UTF8.GetBytes("Hello World");
var buffer = new ArraySegment<byte>(array);
await webSocket.SendAsync(buffer, WebSocketMessageType.Text, true, CancellationToken.None);
} Simple client Request / Response: The best approach to communicating using a web socket is to send and receive data on different worker threads as shown below.
public async Task Run()
{
var factory = new WebSocketClientFactory();
var uri = new Uri("ws://localhost:27416/chat");
using (WebSocket webSocket = await factory.ConnectAsync(uri))
{
// receive loop
Task readTask = Receive(webSocket);
// send a message
await Send(webSocket);
// initiate the close handshake
await webSocket.CloseAsync(WebSocketCloseStatus.NormalClosure, null, CancellationToken.None);
// wait for server to respond with a close frame
await readTask;
}
}Websocket extensions like compression (per message deflate) is currently work in progress.
Tests are written for xUnit
David Haig
This project is licensed under the MIT License - see the LICENSE.md file for details
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Step by step guide: https://developer.mozilla.org/en-US/docs/Web/API/WebSockets_API/Writing_WebSocket_servers
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The official WebSocket spec: http://tools.ietf.org/html/rfc6455
This library is based on all the amazing feedback I got after writing this article (thanks all): https://www.codeproject.com/articles/1063910/websocket-server-in-csharp
The code in the article above was written before Microsoft made System.Net.WebSockets.WebSocket generally available with .NetStandard 2.0 but the concepts remain the same. Take a look if you are interested in the inner workings of the websocket protocol.
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