Task UpgradeToWebSockets(OwinRequest request, OwinResponse response, Func<Task> next)
{
if (!request.CanAccept)
return next();
request.Accept(WebSocketEcho);
return Task.FromResult<object>(null);
}
private AppFunc WebSocketHandler(AppFunc next)
{
return (env) =>
{
var request = new OwinRequest(env);
if (request.Path == "/Echo" && request.CanAccept)
{
request.Accept(async (socket) =>
{
const int maxMessageSize = 1024;
byte[] receiveBuffer = new byte[maxMessageSize];
Console.WriteLine("WebSocket connection established.");
while (true)
{
ArraySegment<byte> buffer = new ArraySegment<byte>(receiveBuffer);
var received = await socket.ReceiveAsync(buffer, CancellationToken.None);
if (received.MessageType == 0x8) // close
{
await socket.CloseAsync(CancellationToken.None);
return;
}
else if (received.MessageType == 0x2) // binary
{
await socket.CloseAsync((int)WebSocketCloseStatus.InvalidMessageType, "Cannot accept binary frame", CancellationToken.None);
}
else
{
int count = received.Count;
while (received.EndOfMessage == false)
{
if (count >= maxMessageSize)
{
throw new NotSupportedException();
}
received = await socket.ReceiveAsync(new ArraySegment<byte>(receiveBuffer, count, maxMessageSize - count), CancellationToken.None);
count += received.Count;
}
var receivedString = Encoding.UTF8.GetString(receiveBuffer, 0, count);
var echoString = receivedString;
ArraySegment<byte> outputBuffer = new ArraySegment<byte>(Encoding.UTF8.GetBytes(echoString));
await socket.SendAsync(outputBuffer, (int)WebSocketMessageType.Text, true, CancellationToken.None);
}
}
});
return TaskHelpers.Completed();
}
else if (request.Path == "/Echo")
{
var response = new OwinResponse(env);
return response.RespondString(HtmlContentEcho, "text/html");
}
else if (request.Path == "/")
{
var response = new OwinResponse(env);
return response.RespondString(HtmlContent, "text/html");
}
else
{
return next(env);
}
};
}
