public static AppFunc Middleware(AppFunc app)
{
return env =>
{
var request = new OwinRequest(env);
var websocketVersion = request.Get<string>(OwinConstants.WebSocket.Version);
WebSocketAccept webSocketAccept = request.Get<WebSocketAccept>(OwinConstants.WebSocket.Accept);
if (request.CanUpgrade && websocketVersion == null) // If we have opaque support and no WebSocket support yet
{
if (IsWebSocketRequest(env))
{
// TODO: check for correct requested version of WebSocket protocol
IDictionary<string, object> acceptOptions = null;
WebSocketFunc webSocketFunc = null;
// Announce websocket support
env[OwinConstants.WebSocket.Accept] = new WebSocketAccept(
(options, callback) =>
{
acceptOptions = options;
webSocketFunc = callback;
env[OwinConstants.ResponseStatusCode] = 101;
});
return app(env).ContinueWith(t =>
{
OwinResponse response = new OwinResponse(env);
if (response.StatusCode == 101
&& webSocketFunc != null)
{
SetWebSocketResponseHeaders(env, acceptOptions);
request.UpgradeDelegate(acceptOptions, opaqueEnv =>
{
WebSocketLayer webSocket = new WebSocketLayer(opaqueEnv);
return webSocketFunc(webSocket.Environment)
.ContinueWith(tt => webSocket.CleanupAsync());
});
}
});
}
}
// else
return app(env);
};
}