diff options
Diffstat (limited to 'Emby.Server.Implementations/Session/SessionWebSocketListener.cs')
| -rw-r--r-- | Emby.Server.Implementations/Session/SessionWebSocketListener.cs | 156 |
1 files changed, 156 insertions, 0 deletions
diff --git a/Emby.Server.Implementations/Session/SessionWebSocketListener.cs b/Emby.Server.Implementations/Session/SessionWebSocketListener.cs index 930f2d35d..d8e02ef39 100644 --- a/Emby.Server.Implementations/Session/SessionWebSocketListener.cs +++ b/Emby.Server.Implementations/Session/SessionWebSocketListener.cs @@ -1,8 +1,13 @@ using System; +using System.Collections.Concurrent; +using System.Linq; +using System.Net.WebSockets; +using System.Threading; using System.Threading.Tasks; using MediaBrowser.Controller.Net; using MediaBrowser.Controller.Session; using MediaBrowser.Model.Events; +using MediaBrowser.Model.Net; using MediaBrowser.Model.Serialization; using Microsoft.AspNetCore.Http; using Microsoft.Extensions.Logging; @@ -15,6 +20,21 @@ namespace Emby.Server.Implementations.Session public class SessionWebSocketListener : IWebSocketListener, IDisposable { /// <summary> + /// The timeout in seconds after which a WebSocket is considered to be lost. + /// </summary> + public readonly int WebSocketLostTimeout = 60; + + /// <summary> + /// The timer factor; controls the frequency of the timer. + /// </summary> + public readonly double TimerFactor = 0.2; + + /// <summary> + /// The ForceKeepAlive factor; controls when a ForceKeepAlive is sent. + /// </summary> + public readonly double ForceKeepAliveFactor = 0.75; + + /// <summary> /// The _session manager /// </summary> private readonly ISessionManager _sessionManager; @@ -31,6 +51,15 @@ namespace Emby.Server.Implementations.Session private readonly IHttpServer _httpServer; + /// <summary> + /// The KeepAlive timer. + /// </summary> + private Timer _keepAliveTimer; + + /// <summary> + /// The WebSocket watchlist. + /// </summary> + private readonly ConcurrentDictionary<IWebSocketConnection, byte> _webSockets = new ConcurrentDictionary<IWebSocketConnection, byte>(); /// <summary> /// Initializes a new instance of the <see cref="SessionWebSocketListener" /> class. @@ -55,6 +84,7 @@ namespace Emby.Server.Implementations.Session if (session != null) { EnsureController(session, e.Argument); + KeepAliveWebSocket(e.Argument); } else { @@ -82,6 +112,7 @@ namespace Emby.Server.Implementations.Session public void Dispose() { _httpServer.WebSocketConnected -= _serverManager_WebSocketConnected; + StopKeepAliveTimer(); } /// <summary> @@ -99,5 +130,130 @@ namespace Emby.Server.Implementations.Session var controller = (WebSocketController)controllerInfo.Item1; controller.AddWebSocket(connection); } + + /// <summary> + /// Called when a WebSocket is closed. + /// </summary> + /// <param name="sender">The WebSocket.</param> + /// <param name="e">The event arguments.</param> + private void _webSocket_Closed(object sender, EventArgs e) + { + var webSocket = (IWebSocketConnection) sender; + webSocket.Closed -= _webSocket_Closed; + _webSockets.TryRemove(webSocket, out _); + } + + /// <summary> + /// Adds a WebSocket to the KeepAlive watchlist. + /// </summary> + /// <param name="webSocket">The WebSocket to monitor.</param> + private async void KeepAliveWebSocket(IWebSocketConnection webSocket) + { + _webSockets.TryAdd(webSocket, 0); + webSocket.Closed += _webSocket_Closed; + webSocket.LastKeepAliveDate = DateTime.UtcNow; + + // Notify WebSocket about timeout + try + { + await SendForceKeepAlive(webSocket); + } + catch (WebSocketException exception) + { + _logger.LogDebug(exception, "Error sending ForceKeepAlive message to WebSocket."); + } + + StartKeepAliveTimer(); + } + + /// <summary> + /// Starts the KeepAlive timer. + /// </summary> + private void StartKeepAliveTimer() + { + if (_keepAliveTimer == null) + { + _keepAliveTimer = new Timer( + KeepAliveSockets, + null, + TimeSpan.FromSeconds(WebSocketLostTimeout * TimerFactor), + TimeSpan.FromSeconds(WebSocketLostTimeout * TimerFactor) + ); + } + } + + /// <summary> + /// Stops the KeepAlive timer. + /// </summary> + private void StopKeepAliveTimer() + { + if (_keepAliveTimer != null) + { + _keepAliveTimer.Dispose(); + _keepAliveTimer = null; + } + + foreach (var pair in _webSockets) + { + pair.Key.Closed -= _webSocket_Closed; + } + } + + /// <summary> + /// Checks status of KeepAlive of WebSockets. + /// </summary> + /// <param name="state">The state.</param> + private async void KeepAliveSockets(object state) + { + var inactive = _webSockets.Keys.Where(i => + { + var elapsed = (DateTime.UtcNow - i.LastKeepAliveDate).TotalSeconds; + return (elapsed > WebSocketLostTimeout * ForceKeepAliveFactor) && (elapsed < WebSocketLostTimeout); + }); + var lost = _webSockets.Keys.Where(i => (DateTime.UtcNow - i.LastKeepAliveDate).TotalSeconds >= WebSocketLostTimeout); + + if (inactive.Any()) + { + _logger.LogDebug("Sending ForceKeepAlive message to {0} WebSockets.", inactive.Count()); + } + + foreach (var webSocket in inactive) + { + try + { + await SendForceKeepAlive(webSocket); + } + catch (WebSocketException exception) + { + _logger.LogDebug(exception, "Error sending ForceKeepAlive message to WebSocket."); + lost.Append(webSocket); + } + } + + if (lost.Any()) + { + // TODO: handle lost webSockets + _logger.LogDebug("Lost {0} WebSockets.", lost.Count()); + } + + if (!_webSockets.Any()) + { + StopKeepAliveTimer(); + } + } + + /// <summary> + /// Sends a ForceKeepAlive message to a WebSocket. + /// </summary> + /// <param name="webSocket">The WebSocket.</param> + /// <returns>Task.</returns> + private Task SendForceKeepAlive(IWebSocketConnection webSocket) + { + return webSocket.SendAsync(new WebSocketMessage<int> + { + MessageType = "ForceKeepAlive", + Data = WebSocketLostTimeout + }, CancellationToken.None); + } } } |