Added support for GUILD_SYNC

src/Discord.Net/API/DiscordAPIClient.cs

@@ -409,6 +409,10 @@ namespace Discord.API
             };
             await SendGatewayAsync(GatewayOpCode.VoiceStateUpdate, payload, options: options).ConfigureAwait(false);
         }
+        public async Task SendGuildSyncAsync(IEnumerable<ulong> guildIds, RequestOptions options = null)
+        {
+            await SendGatewayAsync(GatewayOpCode.GuildSync, guildIds, options: options).ConfigureAwait(false);
+        }
 
         //Channels
         public async Task<Channel> GetChannelAsync(ulong channelId, RequestOptions options = null)

src/Discord.Net/API/Gateway/GatewayOpCode.cs

@@ -18,13 +18,15 @@
         Resume = 6,
         /// <summary> C←S - Used to notify a client that they must reconnect to another gateway. </summary>
         Reconnect = 7,
-        /// <summary> C→S - Used to request all members that were withheld by large_threshold </summary>
+        /// <summary> C→S - Used to request members that were withheld by large_threshold </summary>
         RequestGuildMembers = 8,
         /// <summary> C←S - Used to notify the client that their session has expired and cannot be resumed. </summary>
         InvalidSession = 9,
         /// <summary> C←S - Used to provide information to the client immediately on connection. </summary>
         Hello = 10,
         /// <summary> C←S - Used to reply to a client's heartbeat. </summary>
-        HeartbeatAck = 11
+        HeartbeatAck = 11,
+        /// <summary> C→S - Used to request presence updates from particular guilds. </summary>
+        GuildSync = 12
     }
 }

src/Discord.Net/API/Gateway/GuildSyncEvent.cs

@@ -0,0 +1,17 @@
+using Newtonsoft.Json;
+
+namespace Discord.API.Gateway
+{
+    public class GuildSyncEvent
+    {
+        [JsonProperty("id")]
+        public ulong Id { get; set; }
+        [JsonProperty("large")]
+        public bool Large { get; set; }
+
+        [JsonProperty("presences")]
+        public Presence[] Presences { get; set; }
+        [JsonProperty("members")]
+        public GuildMember[] Members { get; set; }
+    }
+}

src/Discord.Net/DiscordSocketClient.cs

@@ -29,6 +29,8 @@ namespace Discord
         private int _lastSeq;
         private ImmutableDictionary<string, VoiceRegion> _voiceRegions;
         private TaskCompletionSource<bool> _connectTask;
+        private ConcurrentHashSet<ulong> _syncedGuilds;
+        private SemaphoreSlim _syncedGuildsLock;
         private CancellationTokenSource _cancelToken;
         private Task _heartbeatTask, _guildDownloadTask, _reconnectTask;
         private long _heartbeatTime;
@@ -102,6 +104,8 @@ namespace Discord
 
             _voiceRegions = ImmutableDictionary.Create<string, VoiceRegion>();
             _largeGuilds = new ConcurrentQueue<ulong>();
+            _syncedGuilds = new ConcurrentHashSet<ulong>();
+            _syncedGuildsLock = new SemaphoreSlim(1, 1);
         }
 
         protected override async Task OnLoginAsync()
@@ -295,7 +299,7 @@ namespace Discord
         {
             return Task.FromResult<IReadOnlyCollection<IUserGuild>>(Guilds);
         }
-        internal CachedGuild AddGuild(API.Gateway.ExtendedGuild model, DataStore dataStore)
+        internal CachedGuild AddGuild(ExtendedGuild model, DataStore dataStore)
         {
             var guild = new CachedGuild(this, model, dataStore);
             dataStore.AddGuild(guild);
@@ -305,6 +309,7 @@ namespace Discord
         }
         internal CachedGuild RemoveGuild(ulong id)
         {
+            _syncedGuilds.TryRemove(id);
             var guild = DataStore.RemoveGuild(id);
             foreach (var channel in guild.Channels)
                 guild.RemoveChannel(channel.Id);
@@ -366,15 +371,44 @@ namespace Discord
         public Task DownloadAllUsersAsync() 
             => DownloadUsersAsync(DataStore.Guilds.Where(x => !x.HasAllMembers));
         /// <summary> Downloads the users list for the provided guilds, if they don't have a complete list. </summary>
-        public async Task DownloadUsersAsync(IEnumerable<IGuild> guilds)
+        public Task DownloadUsersAsync(IEnumerable<IGuild> guilds)
+            => DownloadUsersAsync(guilds.Select(x => x as CachedGuild).Where(x => x != null));
+        public Task DownloadUsersAsync(params IGuild[] guilds)
+            => DownloadUsersAsync(guilds.Select(x => x as CachedGuild).Where(x => x != null));
+        private async Task DownloadUsersAsync(IEnumerable<CachedGuild> guilds)
         {
-            const short batchSize = 50;
+            var cachedGuilds = guilds.ToArray();
-            var cachedGuilds = guilds.Select(x => x as CachedGuild).ToArray();
+            if (cachedGuilds.Length == 0) return;
-            if (cachedGuilds.Length == 0)
+
-                return;
+            //Sync guilds
-            else if (cachedGuilds.Length == 1)
+            if (ApiClient.AuthTokenType == TokenType.User)
             {
-                await cachedGuilds[0].DownloadUsersAsync().ConfigureAwait(false);
+                await _syncedGuildsLock.WaitAsync().ConfigureAwait(false);
+                try
+                {
+                    foreach (var guild in cachedGuilds)
+                        _syncedGuilds.TryAdd(guild.Id);
+                    await ApiClient.SendGuildSyncAsync(_syncedGuilds).ConfigureAwait(false);
+                    await Task.WhenAll(cachedGuilds.Select(x => x.SyncPromise));
+
+                    //Reduce the list only to those with members left to download
+                    cachedGuilds = cachedGuilds.Where(x => !x.HasAllMembers).ToArray();
+                    if (cachedGuilds.Length == 0) return;
+                }
+                finally
+                {
+                    _syncedGuildsLock.Release();
+                }
+            }
+
+            //Download offline members
+            const short batchSize = 50;
+
+            if (cachedGuilds.Length == 1)
+            {
+                if (!cachedGuilds[0].HasAllMembers)
+                    await ApiClient.SendRequestMembersAsync(new ulong[] { cachedGuilds[0].Id }).ConfigureAwait(false);
+                await cachedGuilds[0].DownloaderPromise.ConfigureAwait(false);
                 return;
             }
 
@@ -502,6 +536,15 @@ namespace Discord
                                     _currentUser = currentUser;
                                     _unavailableGuilds = unavailableGuilds;
                                     _lastGuildAvailableTime = Environment.TickCount;
+                                    await _syncedGuildsLock.WaitAsync().ConfigureAwait(false);
+                                    try
+                                    {
+                                        _syncedGuilds = new ConcurrentHashSet<ulong>();
+                                    }
+                                    finally
+                                    {
+                                        _syncedGuildsLock.Release();
+                                    }
                                     DataStore = dataStore;
 
                                     _guildDownloadTask = WaitForGuildsAsync(_cancelToken.Token);
@@ -513,9 +556,11 @@ namespace Discord
                                 }
                                 break;
                             case "RESUMED":
-                                await _gatewayLogger.DebugAsync("Received Dispatch (RESUMED)").ConfigureAwait(false);
+                                {
+                                    await _gatewayLogger.DebugAsync("Received Dispatch (RESUMED)").ConfigureAwait(false);
 
-                                await _gatewayLogger.InfoAsync("Resume").ConfigureAwait(false);
+                                    await _gatewayLogger.InfoAsync("Resumed previous session").ConfigureAwait(false);
+                                }
                                 return;
 
                             //Guilds
@@ -579,9 +624,9 @@ namespace Discord
                                     }
                                 }
                                 break;
-                            case "GUILD_EMOJI_UPDATE": //TODO: Add
+                            case "GUILD_EMOJIS_UPDATE": //TODO: Add
                                 {
-                                    await _gatewayLogger.DebugAsync("Received Dispatch (GUILD_EMOJI_UPDATE)").ConfigureAwait(false);
+                                    await _gatewayLogger.DebugAsync("Received Dispatch (GUILD_EMOJIS_UPDATE)").ConfigureAwait(false);
 
                                     var data = (payload as JToken).ToObject<API.Gateway.GuildEmojiUpdateEvent>(_serializer);
                                     var guild = DataStore.GetGuild(data.GuildId);
@@ -593,13 +638,33 @@ namespace Discord
                                     }
                                     else
                                     {
-                                        await _gatewayLogger.WarningAsync("GUILD_EMOJI_UPDATE referenced an unknown guild.").ConfigureAwait(false);
+                                        await _gatewayLogger.WarningAsync("GUILD_EMOJIS_UPDATE referenced an unknown guild.").ConfigureAwait(false);
                                         return;
                                     }
                                 }
                                 return;
                             case "GUILD_INTEGRATIONS_UPDATE":
-                                await _gatewayLogger.DebugAsync("Ignored Dispatch (GUILD_INTEGRATIONS_UPDATE)").ConfigureAwait(false);
+                                {
+                                    await _gatewayLogger.DebugAsync("Ignored Dispatch (GUILD_INTEGRATIONS_UPDATE)").ConfigureAwait(false);
+                                }
+                                return;
+                            case "GUILD_SYNC":
+                                {
+                                    await _gatewayLogger.DebugAsync("Received Dispatch (GUILD_SYNC)").ConfigureAwait(false);
+                                    var data = (payload as JToken).ToObject<GuildSyncEvent>(_serializer);
+                                    var guild = DataStore.GetGuild(data.Id);
+                                    if (guild != null)
+                                    {
+                                        var before = guild.Clone();
+                                        guild.Update(data, UpdateSource.WebSocket, DataStore);
+                                        await _guildUpdatedEvent.InvokeAsync(before, guild).ConfigureAwait(false);
+                                    }
+                                    else
+                                    {
+                                        await _gatewayLogger.WarningAsync("GUILD_SYNC referenced an unknown guild.").ConfigureAwait(false);
+                                        return;
+                                    }
+                                }
                                 return;
                             case "GUILD_DELETE":
                                 {

src/Discord.Net/Entities/WebSocket/CachedGuild.cs

@@ -10,6 +10,7 @@ using System.Threading.Tasks;
 using ChannelModel = Discord.API.Channel;
 using EmojiUpdateModel = Discord.API.Gateway.GuildEmojiUpdateEvent;
 using ExtendedModel = Discord.API.Gateway.ExtendedGuild;
+using GuildSyncModel = Discord.API.Gateway.GuildSyncEvent;
 using MemberModel = Discord.API.GuildMember;
 using Model = Discord.API.Guild;
 using PresenceModel = Discord.API.Presence;
@@ -18,10 +19,16 @@ using VoiceStateModel = Discord.API.VoiceState;
 
 namespace Discord
 {
+    internal enum MemberDownloadState
+    {
+        Incomplete,
+        Synced,
+        Complete
+    }
     internal class CachedGuild : Guild, ICachedEntity<ulong>, IGuild, IUserGuild
     {
         private readonly SemaphoreSlim _audioLock;
-        private TaskCompletionSource<bool> _downloaderPromise;
+        private TaskCompletionSource<bool> _syncPromise, _downloaderPromise;
         private ConcurrentHashSet<ulong> _channels;
         private ConcurrentDictionary<ulong, CachedGuildUser> _members;
         private ConcurrentDictionary<ulong, VoiceState> _voiceStates;
@@ -29,9 +36,11 @@ namespace Discord
         public bool Available { get; private set; }
         public int MemberCount { get; private set; }
         public int DownloadedMemberCount { get; private set; }
-        public  AudioClient AudioClient { get; private set; }
+        public AudioClient AudioClient { get; private set; }
+        public MemberDownloadState MemberDownloadState { get; private set; }
 
         public bool HasAllMembers => _downloaderPromise.Task.IsCompleted;
+        public Task SyncPromise => _syncPromise.Task;
         public Task DownloaderPromise => _downloaderPromise.Task;
 
         public new DiscordSocketClient Discord => base.Discord as DiscordSocketClient;
@@ -51,6 +60,7 @@ namespace Discord
         public CachedGuild(DiscordSocketClient discord, ExtendedModel model, DataStore dataStore) : base(discord, model)
         {
             _audioLock = new SemaphoreSlim(1, 1);
+            _syncPromise = new TaskCompletionSource<bool>();
             _downloaderPromise = new TaskCompletionSource<bool>();
             Update(model, UpdateSource.Creation, dataStore);
         }
@@ -91,9 +101,12 @@ namespace Discord
                 DownloadedMemberCount = 0;
                 for (int i = 0; i < model.Members.Length; i++)
                     AddUser(model.Members[i], dataStore, members);
-                _downloaderPromise = new TaskCompletionSource<bool>();
+                if (Discord.ApiClient.AuthTokenType != TokenType.User)
-                if (!model.Large)
+                {
-                    _downloaderPromise.SetResult(true);
+                    _syncPromise.TrySetResult(true);
+                    if (!model.Large)
+                        _downloaderPromise.TrySetResult(true);
+                }
 
                 for (int i = 0; i < model.Presences.Length; i++)
                     AddOrUpdateUser(model.Presences[i], dataStore, members);
@@ -107,6 +120,24 @@ namespace Discord
             }
             _voiceStates = voiceStates;
         }
+        public void Update(GuildSyncModel model, UpdateSource source, DataStore dataStore)
+        {
+            if (source == UpdateSource.Rest && IsAttached) return;
+
+            var members = new ConcurrentDictionary<ulong, CachedGuildUser>(1, (int)(model.Presences.Length * 1.05));
+            {
+                DownloadedMemberCount = 0;
+                for (int i = 0; i < model.Members.Length; i++)
+                    AddUser(model.Members[i], dataStore, members);
+                _syncPromise.TrySetResult(true);
+                if (!model.Large)
+                    _downloaderPromise.TrySetResult(true);
+
+                for (int i = 0; i < model.Presences.Length; i++)
+                    AddOrUpdateUser(model.Presences[i], dataStore, members);
+            }
+            _members = members;
+        }
 
         public void Update(EmojiUpdateModel model, UpdateSource source)
         {
@@ -208,9 +239,7 @@ namespace Discord
         }
         public override async Task DownloadUsersAsync()
         {
-            if (!HasAllMembers)
+            await Discord.DownloadUsersAsync(new [] { this });
-                await Discord.ApiClient.SendRequestMembersAsync(new ulong[] { Id }).ConfigureAwait(false);
-            await _downloaderPromise.Task.ConfigureAwait(false);
         }
         public void CompleteDownloadMembers()
         {