diff options
Diffstat (limited to 'Emby.Server.Implementations/SyncPlay/SyncPlayController.cs')
| -rw-r--r-- | Emby.Server.Implementations/SyncPlay/SyncPlayController.cs | 516 |
1 files changed, 516 insertions, 0 deletions
diff --git a/Emby.Server.Implementations/SyncPlay/SyncPlayController.cs b/Emby.Server.Implementations/SyncPlay/SyncPlayController.cs new file mode 100644 index 000000000..80b977731 --- /dev/null +++ b/Emby.Server.Implementations/SyncPlay/SyncPlayController.cs @@ -0,0 +1,516 @@ +using System; +using System.Collections.Generic; +using System.Globalization; +using System.Linq; +using System.Threading; +using System.Threading.Tasks; +using MediaBrowser.Controller.Session; +using MediaBrowser.Controller.SyncPlay; +using MediaBrowser.Model.Session; +using MediaBrowser.Model.SyncPlay; + +namespace Emby.Server.Implementations.SyncPlay +{ + /// <summary> + /// Class SyncPlayController. + /// </summary> + /// <remarks> + /// Class is not thread-safe, external locking is required when accessing methods. + /// </remarks> + public class SyncPlayController : ISyncPlayController + { + /// <summary> + /// Used to filter the sessions of a group. + /// </summary> + private enum BroadcastType + { + /// <summary> + /// All sessions will receive the message. + /// </summary> + AllGroup = 0, + + /// <summary> + /// Only the specified session will receive the message. + /// </summary> + CurrentSession = 1, + + /// <summary> + /// All sessions, except the current one, will receive the message. + /// </summary> + AllExceptCurrentSession = 2, + + /// <summary> + /// Only sessions that are not buffering will receive the message. + /// </summary> + AllReady = 3 + } + + /// <summary> + /// The session manager. + /// </summary> + private readonly ISessionManager _sessionManager; + + /// <summary> + /// The SyncPlay manager. + /// </summary> + private readonly ISyncPlayManager _syncPlayManager; + + /// <summary> + /// The group to manage. + /// </summary> + private readonly GroupInfo _group = new GroupInfo(); + + /// <summary> + /// Initializes a new instance of the <see cref="SyncPlayController" /> class. + /// </summary> + /// <param name="sessionManager">The session manager.</param> + /// <param name="syncPlayManager">The SyncPlay manager.</param> + public SyncPlayController( + ISessionManager sessionManager, + ISyncPlayManager syncPlayManager) + { + _sessionManager = sessionManager; + _syncPlayManager = syncPlayManager; + } + + /// <inheritdoc /> + public Guid GetGroupId() => _group.GroupId; + + /// <inheritdoc /> + public Guid GetPlayingItemId() => _group.PlayingItem.Id; + + /// <inheritdoc /> + public bool IsGroupEmpty() => _group.IsEmpty(); + + /// <summary> + /// Converts DateTime to UTC string. + /// </summary> + /// <param name="date">The date to convert.</param> + /// <value>The UTC string.</value> + private string DateToUTCString(DateTime date) + { + return date.ToUniversalTime().ToString("o", CultureInfo.InvariantCulture); + } + + /// <summary> + /// Filters sessions of this group. + /// </summary> + /// <param name="from">The current session.</param> + /// <param name="type">The filtering type.</param> + /// <value>The array of sessions matching the filter.</value> + private IEnumerable<SessionInfo> FilterSessions(SessionInfo from, BroadcastType type) + { + switch (type) + { + case BroadcastType.CurrentSession: + return new SessionInfo[] { from }; + case BroadcastType.AllGroup: + return _group.Participants.Values + .Select(session => session.Session); + case BroadcastType.AllExceptCurrentSession: + return _group.Participants.Values + .Select(session => session.Session) + .Where(session => !session.Id.Equals(from.Id, StringComparison.Ordinal)); + case BroadcastType.AllReady: + return _group.Participants.Values + .Where(session => !session.IsBuffering) + .Select(session => session.Session); + default: + return Array.Empty<SessionInfo>(); + } + } + + /// <summary> + /// Sends a GroupUpdate message to the interested sessions. + /// </summary> + /// <param name="from">The current session.</param> + /// <param name="type">The filtering type.</param> + /// <param name="message">The message to send.</param> + /// <param name="cancellationToken">The cancellation token.</param> + /// <value>The task.</value> + private Task SendGroupUpdate<T>(SessionInfo from, BroadcastType type, GroupUpdate<T> message, CancellationToken cancellationToken) + { + IEnumerable<Task> GetTasks() + { + foreach (var session in FilterSessions(from, type)) + { + yield return _sessionManager.SendSyncPlayGroupUpdate(session.Id, message, cancellationToken); + } + } + + return Task.WhenAll(GetTasks()); + } + + /// <summary> + /// Sends a playback command to the interested sessions. + /// </summary> + /// <param name="from">The current session.</param> + /// <param name="type">The filtering type.</param> + /// <param name="message">The message to send.</param> + /// <param name="cancellationToken">The cancellation token.</param> + /// <value>The task.</value> + private Task SendCommand(SessionInfo from, BroadcastType type, SendCommand message, CancellationToken cancellationToken) + { + IEnumerable<Task> GetTasks() + { + foreach (var session in FilterSessions(from, type)) + { + yield return _sessionManager.SendSyncPlayCommand(session.Id, message, cancellationToken); + } + } + + return Task.WhenAll(GetTasks()); + } + + /// <summary> + /// Builds a new playback command with some default values. + /// </summary> + /// <param name="type">The command type.</param> + /// <value>The SendCommand.</value> + private SendCommand NewSyncPlayCommand(SendCommandType type) + { + return new SendCommand() + { + GroupId = _group.GroupId.ToString(), + Command = type, + PositionTicks = _group.PositionTicks, + When = DateToUTCString(_group.LastActivity), + EmittedAt = DateToUTCString(DateTime.UtcNow) + }; + } + + /// <summary> + /// Builds a new group update message. + /// </summary> + /// <param name="type">The update type.</param> + /// <param name="data">The data to send.</param> + /// <value>The GroupUpdate.</value> + private GroupUpdate<T> NewSyncPlayGroupUpdate<T>(GroupUpdateType type, T data) + { + return new GroupUpdate<T>() + { + GroupId = _group.GroupId.ToString(), + Type = type, + Data = data + }; + } + + /// <inheritdoc /> + public void CreateGroup(SessionInfo session, CancellationToken cancellationToken) + { + _group.AddSession(session); + _syncPlayManager.AddSessionToGroup(session, this); + + _group.PlayingItem = session.FullNowPlayingItem; + _group.IsPaused = session.PlayState.IsPaused; + _group.PositionTicks = session.PlayState.PositionTicks ?? 0; + _group.LastActivity = DateTime.UtcNow; + + var updateSession = NewSyncPlayGroupUpdate(GroupUpdateType.GroupJoined, DateToUTCString(DateTime.UtcNow)); + SendGroupUpdate(session, BroadcastType.CurrentSession, updateSession, cancellationToken); + } + + /// <inheritdoc /> + public void SessionJoin(SessionInfo session, JoinGroupRequest request, CancellationToken cancellationToken) + { + if (session.NowPlayingItem?.Id == _group.PlayingItem.Id) + { + _group.AddSession(session); + _syncPlayManager.AddSessionToGroup(session, this); + + var updateSession = NewSyncPlayGroupUpdate(GroupUpdateType.GroupJoined, DateToUTCString(DateTime.UtcNow)); + SendGroupUpdate(session, BroadcastType.CurrentSession, updateSession, cancellationToken); + + var updateOthers = NewSyncPlayGroupUpdate(GroupUpdateType.UserJoined, session.UserName); + SendGroupUpdate(session, BroadcastType.AllExceptCurrentSession, updateOthers, cancellationToken); + + // Syncing will happen client-side + if (!_group.IsPaused) + { + var playCommand = NewSyncPlayCommand(SendCommandType.Play); + SendCommand(session, BroadcastType.CurrentSession, playCommand, cancellationToken); + } + else + { + var pauseCommand = NewSyncPlayCommand(SendCommandType.Pause); + SendCommand(session, BroadcastType.CurrentSession, pauseCommand, cancellationToken); + } + } + else + { + var playRequest = new PlayRequest + { + ItemIds = new Guid[] { _group.PlayingItem.Id }, + StartPositionTicks = _group.PositionTicks + }; + var update = NewSyncPlayGroupUpdate(GroupUpdateType.PrepareSession, playRequest); + SendGroupUpdate(session, BroadcastType.CurrentSession, update, cancellationToken); + } + } + + /// <inheritdoc /> + public void SessionLeave(SessionInfo session, CancellationToken cancellationToken) + { + _group.RemoveSession(session); + _syncPlayManager.RemoveSessionFromGroup(session, this); + + var updateSession = NewSyncPlayGroupUpdate(GroupUpdateType.GroupLeft, _group.PositionTicks); + SendGroupUpdate(session, BroadcastType.CurrentSession, updateSession, cancellationToken); + + var updateOthers = NewSyncPlayGroupUpdate(GroupUpdateType.UserLeft, session.UserName); + SendGroupUpdate(session, BroadcastType.AllExceptCurrentSession, updateOthers, cancellationToken); + } + + /// <inheritdoc /> + public void HandleRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken) + { + // The server's job is to maintain a consistent state for clients to reference + // and notify clients of state changes. The actual syncing of media playback + // happens client side. Clients are aware of the server's time and use it to sync. + switch (request.Type) + { + case PlaybackRequestType.Play: + HandlePlayRequest(session, request, cancellationToken); + break; + case PlaybackRequestType.Pause: + HandlePauseRequest(session, request, cancellationToken); + break; + case PlaybackRequestType.Seek: + HandleSeekRequest(session, request, cancellationToken); + break; + case PlaybackRequestType.Buffer: + HandleBufferingRequest(session, request, cancellationToken); + break; + case PlaybackRequestType.Ready: + HandleBufferingDoneRequest(session, request, cancellationToken); + break; + case PlaybackRequestType.Ping: + HandlePingUpdateRequest(session, request); + break; + } + } + + /// <summary> + /// Handles a play action requested by a session. + /// </summary> + /// <param name="session">The session.</param> + /// <param name="request">The play action.</param> + /// <param name="cancellationToken">The cancellation token.</param> + private void HandlePlayRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken) + { + if (_group.IsPaused) + { + // Pick a suitable time that accounts for latency + var delay = _group.GetHighestPing() * 2; + delay = delay < _group.DefaultPing ? _group.DefaultPing : delay; + + // Unpause group and set starting point in future + // Clients will start playback at LastActivity (datetime) from PositionTicks (playback position) + // The added delay does not guarantee, of course, that the command will be received in time + // Playback synchronization will mainly happen client side + _group.IsPaused = false; + _group.LastActivity = DateTime.UtcNow.AddMilliseconds( + delay); + + var command = NewSyncPlayCommand(SendCommandType.Play); + SendCommand(session, BroadcastType.AllGroup, command, cancellationToken); + } + else + { + // Client got lost, sending current state + var command = NewSyncPlayCommand(SendCommandType.Play); + SendCommand(session, BroadcastType.CurrentSession, command, cancellationToken); + } + } + + /// <summary> + /// Handles a pause action requested by a session. + /// </summary> + /// <param name="session">The session.</param> + /// <param name="request">The pause action.</param> + /// <param name="cancellationToken">The cancellation token.</param> + private void HandlePauseRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken) + { + if (!_group.IsPaused) + { + // Pause group and compute the media playback position + _group.IsPaused = true; + var currentTime = DateTime.UtcNow; + var elapsedTime = currentTime - _group.LastActivity; + _group.LastActivity = currentTime; + + // Seek only if playback actually started + // Pause request may be issued during the delay added to account for latency + _group.PositionTicks += elapsedTime.Ticks > 0 ? elapsedTime.Ticks : 0; + + var command = NewSyncPlayCommand(SendCommandType.Pause); + SendCommand(session, BroadcastType.AllGroup, command, cancellationToken); + } + else + { + // Client got lost, sending current state + var command = NewSyncPlayCommand(SendCommandType.Pause); + SendCommand(session, BroadcastType.CurrentSession, command, cancellationToken); + } + } + + /// <summary> + /// Handles a seek action requested by a session. + /// </summary> + /// <param name="session">The session.</param> + /// <param name="request">The seek action.</param> + /// <param name="cancellationToken">The cancellation token.</param> + private void HandleSeekRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken) + { + // Sanitize PositionTicks + var ticks = SanitizePositionTicks(request.PositionTicks); + + // Pause and seek + _group.IsPaused = true; + _group.PositionTicks = ticks; + _group.LastActivity = DateTime.UtcNow; + + var command = NewSyncPlayCommand(SendCommandType.Seek); + SendCommand(session, BroadcastType.AllGroup, command, cancellationToken); + } + + /// <summary> + /// Handles a buffering action requested by a session. + /// </summary> + /// <param name="session">The session.</param> + /// <param name="request">The buffering action.</param> + /// <param name="cancellationToken">The cancellation token.</param> + private void HandleBufferingRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken) + { + if (!_group.IsPaused) + { + // Pause group and compute the media playback position + _group.IsPaused = true; + var currentTime = DateTime.UtcNow; + var elapsedTime = currentTime - _group.LastActivity; + _group.LastActivity = currentTime; + _group.PositionTicks += elapsedTime.Ticks > 0 ? elapsedTime.Ticks : 0; + + _group.SetBuffering(session, true); + + // Send pause command to all non-buffering sessions + var command = NewSyncPlayCommand(SendCommandType.Pause); + SendCommand(session, BroadcastType.AllReady, command, cancellationToken); + + var updateOthers = NewSyncPlayGroupUpdate(GroupUpdateType.GroupWait, session.UserName); + SendGroupUpdate(session, BroadcastType.AllExceptCurrentSession, updateOthers, cancellationToken); + } + else + { + // Client got lost, sending current state + var command = NewSyncPlayCommand(SendCommandType.Pause); + SendCommand(session, BroadcastType.CurrentSession, command, cancellationToken); + } + } + + /// <summary> + /// Handles a buffering-done action requested by a session. + /// </summary> + /// <param name="session">The session.</param> + /// <param name="request">The buffering-done action.</param> + /// <param name="cancellationToken">The cancellation token.</param> + private void HandleBufferingDoneRequest(SessionInfo session, PlaybackRequest request, CancellationToken cancellationToken) + { + if (_group.IsPaused) + { + _group.SetBuffering(session, false); + + var requestTicks = SanitizePositionTicks(request.PositionTicks); + + var when = request.When ?? DateTime.UtcNow; + var currentTime = DateTime.UtcNow; + var elapsedTime = currentTime - when; + var clientPosition = TimeSpan.FromTicks(requestTicks) + elapsedTime; + var delay = _group.PositionTicks - clientPosition.Ticks; + + if (_group.IsBuffering()) + { + // Others are still buffering, tell this client to pause when ready + var command = NewSyncPlayCommand(SendCommandType.Pause); + var pauseAtTime = currentTime.AddMilliseconds(delay); + command.When = DateToUTCString(pauseAtTime); + SendCommand(session, BroadcastType.CurrentSession, command, cancellationToken); + } + else + { + // Let other clients resume as soon as the buffering client catches up + _group.IsPaused = false; + + if (delay > _group.GetHighestPing() * 2) + { + // Client that was buffering is recovering, notifying others to resume + _group.LastActivity = currentTime.AddMilliseconds( + delay); + var command = NewSyncPlayCommand(SendCommandType.Play); + SendCommand(session, BroadcastType.AllExceptCurrentSession, command, cancellationToken); + } + else + { + // Client, that was buffering, resumed playback but did not update others in time + delay = _group.GetHighestPing() * 2; + delay = delay < _group.DefaultPing ? _group.DefaultPing : delay; + + _group.LastActivity = currentTime.AddMilliseconds( + delay); + + var command = NewSyncPlayCommand(SendCommandType.Play); + SendCommand(session, BroadcastType.AllGroup, command, cancellationToken); + } + } + } + else + { + // Group was not waiting, make sure client has latest state + var command = NewSyncPlayCommand(SendCommandType.Play); + SendCommand(session, BroadcastType.CurrentSession, command, cancellationToken); + } + } + + /// <summary> + /// Sanitizes the PositionTicks, considers the current playing item when available. + /// </summary> + /// <param name="positionTicks">The PositionTicks.</param> + /// <value>The sanitized PositionTicks.</value> + private long SanitizePositionTicks(long? positionTicks) + { + var ticks = positionTicks ?? 0; + ticks = ticks >= 0 ? ticks : 0; + if (_group.PlayingItem != null) + { + var runTimeTicks = _group.PlayingItem.RunTimeTicks ?? 0; + ticks = ticks > runTimeTicks ? runTimeTicks : ticks; + } + + return ticks; + } + + /// <summary> + /// Updates ping of a session. + /// </summary> + /// <param name="session">The session.</param> + /// <param name="request">The update.</param> + private void HandlePingUpdateRequest(SessionInfo session, PlaybackRequest request) + { + // Collected pings are used to account for network latency when unpausing playback + _group.UpdatePing(session, request.Ping ?? _group.DefaultPing); + } + + /// <inheritdoc /> + public GroupInfoView GetInfo() + { + return new GroupInfoView() + { + GroupId = GetGroupId().ToString(), + PlayingItemName = _group.PlayingItem.Name, + PlayingItemId = _group.PlayingItem.Id.ToString(), + PositionTicks = _group.PositionTicks, + Participants = _group.Participants.Values.Select(session => session.Session.UserName).Distinct().ToList() + }; + } + } +} |