Added request retry modes

src/Discord.Net.Core/API/DiscordRestApiClient.cs

@@ -32,26 +32,29 @@ namespace Discord.API
         protected readonly JsonSerializer _serializer;
         protected readonly SemaphoreSlim _stateLock;
         private readonly RestClientProvider _restClientProvider;
-        private readonly string _userAgent;
 
         protected string _authToken;
         protected bool _isDisposed;
         private CancellationTokenSource _loginCancelToken;
         private IRestClient _restClient;
+        private bool _fetchCurrentUser;
+
+        public RetryMode DefaultRetryMode { get; }
+        public string UserAgent { get; }
 
         public LoginState LoginState { get; private set; }
         public TokenType AuthTokenType { get; private set; }
         public User CurrentUser { get; private set; }
         public RequestQueue RequestQueue { get; private set; }
-        internal bool FetchCurrentUser { get; set; }
 
-        public DiscordRestApiClient(RestClientProvider restClientProvider, string userAgent, JsonSerializer serializer = null, RequestQueue requestQueue = null)
+        public DiscordRestApiClient(RestClientProvider restClientProvider, string userAgent, RetryMode defaultRetryMode = RetryMode.AlwaysRetry, 
+            JsonSerializer serializer = null, RequestQueue requestQueue = null, bool fetchCurrentUser = true)
         {
             _restClientProvider = restClientProvider;
-            _userAgent = userAgent;
+            UserAgent = userAgent;
             _serializer = serializer ?? new JsonSerializer { DateFormatString = "yyyy-MM-ddTHH:mm:ssZ", ContractResolver = new DiscordContractResolver() };
             RequestQueue = requestQueue;
-            FetchCurrentUser = true;
+            _fetchCurrentUser = fetchCurrentUser;
 
             _stateLock = new SemaphoreSlim(1, 1);
 
@@ -61,7 +64,7 @@ namespace Discord.API
         {
             _restClient = _restClientProvider(baseUrl);
             _restClient.SetHeader("accept", "*/*");
-            _restClient.SetHeader("user-agent", _userAgent);
+            _restClient.SetHeader("user-agent", UserAgent);
             _restClient.SetHeader("authorization", GetPrefixedToken(AuthTokenType, _authToken));
         }
         internal static string GetPrefixedToken(TokenType tokenType, string token)
@@ -120,8 +123,8 @@ namespace Discord.API
                 _authToken = token;
                 _restClient.SetHeader("authorization", GetPrefixedToken(AuthTokenType, _authToken));
 
-                if (FetchCurrentUser)
-                    CurrentUser = await GetMyUserAsync(new RequestOptions { IgnoreState = true }).ConfigureAwait(false);
+                if (_fetchCurrentUser)
+                    CurrentUser = await GetMyUserAsync(new RequestOptions { IgnoreState = true, RetryMode = RetryMode.AlwaysRetry }).ConfigureAwait(false);
 
                 LoginState = LoginState.LoggedIn;
             }
@@ -257,6 +260,8 @@ namespace Discord.API
         {
             if (!request.Options.IgnoreState)
                 CheckState();
+            if (request.Options.RetryMode == null)
+                request.Options.RetryMode = DefaultRetryMode;
 
             var stopwatch = Stopwatch.StartNew();
             var responseStream = await RequestQueue.SendAsync(request).ConfigureAwait(false);

src/Discord.Net.Core/DiscordConfig.cs

@@ -19,6 +19,9 @@ namespace Discord
         public const int MaxMessagesPerBatch = 100;
         public const int MaxUsersPerBatch = 1000;
 
+        /// <summary> Gets or sets how a request should act in the case of an error, by default. </summary>
+        public RetryMode DefaultRetryMode { get; set; } = RetryMode.AlwaysRetry;
+        
         /// <summary> Gets or sets the minimum log level severity that will be sent to the LogMessage event. </summary>
         public LogSeverity LogLevel { get; set; } = LogSeverity.Info;
     }

src/Discord.Net.Core/Entities/Users/IGuildUser.cs

@@ -12,6 +12,7 @@ namespace Discord
         DateTimeOffset? JoinedAt { get; }
         /// <summary> Gets the nickname for this user. </summary>
         string Nickname { get; }
+        /// <summary> Gets the guild-level permissions for this user. </summary>
         GuildPermissions GuildPermissions { get; }
 
         /// <summary> Gets the guild for this user. </summary>

src/Discord.Net.Core/Net/Queue/RequestQueue.cs

@@ -1,6 +1,8 @@
 using System;
 using System.Collections.Concurrent;
+#if DEBUG_LIMITS
 using System.Diagnostics;
+#endif
 using System.IO;
 using System.Linq;
 using System.Threading;
@@ -63,7 +65,11 @@ namespace Discord.Net.Queue
 
         public async Task<Stream> SendAsync(RestRequest request)
         {
-            request.CancelToken = _requestCancelToken;
+            if (request.Options.CancelToken.CanBeCanceled)
+                request.Options.CancelToken = CancellationTokenSource.CreateLinkedTokenSource(_requestCancelToken, request.Options.CancelToken).Token;
+            else
+                request.Options.CancelToken = _requestCancelToken;
+
             var bucket = GetOrCreateBucket(request.Options.BucketId, request);
             return await bucket.SendAsync(request).ConfigureAwait(false);
         }

src/Discord.Net.Core/Net/Queue/RequestQueueBucket.cs

@@ -1,5 +1,4 @@
-using Discord.Net.Rest;
-using Newtonsoft.Json;
+using Newtonsoft.Json;
 using Newtonsoft.Json.Linq;
 using System;
 #if DEBUG_LIMITS
@@ -88,7 +87,10 @@ namespace Discord.Net.Queue
 #if DEBUG_LIMITS
                                 Debug.WriteLine($"[{id}] (!) 502");
 #endif
-                                continue; //Continue
+                                if ((request.Options.RetryMode & RetryMode.Retry502) == 0)
+                                    throw new HttpException(HttpStatusCode.BadGateway, null);
+
+                                continue; //Retry
                             default:
                                 string reason = null;
                                 if (response.Stream != null)
@@ -115,13 +117,28 @@ namespace Discord.Net.Queue
                         return response.Stream;
                     }
                 }
+                catch (TimeoutException)
+                {
 #if DEBUG_LIMITS
-                catch
+                    Debug.WriteLine($"[{id}] Timeout");
+#endif
+                    if ((request.Options.RetryMode & RetryMode.RetryTimeouts) == 0)
+                        throw;
+
+                    await Task.Delay(500);
+                    continue; //Retry
+                }
+                catch (Exception)
                 {
+#if DEBUG_LIMITS
                     Debug.WriteLine($"[{id}] Error");
-                    throw;
-                }
 #endif
+                    if ((request.Options.RetryMode & RetryMode.RetryErrors) == 0)
+                        throw;
+
+                    await Task.Delay(500);
+                    continue; //Retry
+                }
                 finally
                 {
                     UpdateRateLimit(id, request, info, lag, false);
@@ -140,7 +157,7 @@ namespace Discord.Net.Queue
 
             while (true)
             {
-                if (DateTimeOffset.UtcNow > request.TimeoutAt || request.CancelToken.IsCancellationRequested)
+                if (DateTimeOffset.UtcNow > request.TimeoutAt || request.Options.CancelToken.IsCancellationRequested)
                 {
                     if (!isRateLimited)
                         throw new TimeoutException();
@@ -162,6 +179,10 @@ namespace Discord.Net.Queue
                         isRateLimited = true;
                         await _queue.RaiseRateLimitTriggered(Id, null).ConfigureAwait(false);
                     }
+
+                    if ((request.Options.RetryMode & RetryMode.RetryRatelimit) == 0)
+                        throw new RateLimitedException();
+
                     if (resetAt.HasValue)
                     {
                         if (resetAt > timeoutAt)
@@ -171,7 +192,7 @@ namespace Discord.Net.Queue
                         Debug.WriteLine($"[{id}] Sleeping {millis} ms (Pre-emptive)");
 #endif
                         if (millis > 0)
-                            await Task.Delay(millis, request.CancelToken).ConfigureAwait(false);
+                            await Task.Delay(millis, request.Options.CancelToken).ConfigureAwait(false);
                     }
                     else
                     {
@@ -180,7 +201,7 @@ namespace Discord.Net.Queue
 #if DEBUG_LIMITS
                         Debug.WriteLine($"[{id}] Sleeping 500* ms (Pre-emptive)");
 #endif
-                        await Task.Delay(500, request.CancelToken).ConfigureAwait(false);
+                        await Task.Delay(500, request.Options.CancelToken).ConfigureAwait(false);
                     }
                     continue;
                 }

src/Discord.Net.Core/Net/Queue/Requests/JsonRestRequest.cs

@@ -15,7 +15,7 @@ namespace Discord.Net.Queue
 
         public override async Task<RestResponse> SendAsync()
         {
-            return await Client.SendAsync(Method, Endpoint, Json, CancelToken, Options.HeaderOnly).ConfigureAwait(false);
+            return await Client.SendAsync(Method, Endpoint, Json, Options.CancelToken, Options.HeaderOnly).ConfigureAwait(false);
         }
     }
 }

src/Discord.Net.Core/Net/Queue/Requests/MultipartRestRequest.cs

@@ -16,7 +16,7 @@ namespace Discord.Net.Queue
 
         public override async Task<RestResponse> SendAsync()
         {
-            return await Client.SendAsync(Method, Endpoint, MultipartParams, CancelToken, Options.HeaderOnly).ConfigureAwait(false);
+            return await Client.SendAsync(Method, Endpoint, MultipartParams, Options.CancelToken, Options.HeaderOnly).ConfigureAwait(false);
         }
     }
 }

src/Discord.Net.Core/Net/Queue/Requests/RestRequest.cs

@@ -1,7 +1,6 @@
 using Discord.Net.Rest;
 using System;
 using System.IO;
-using System.Threading;
 using System.Threading.Tasks;
 
 namespace Discord.Net.Queue
@@ -14,7 +13,6 @@ namespace Discord.Net.Queue
         public DateTimeOffset? TimeoutAt { get; }
         public TaskCompletionSource<Stream> Promise { get; }
         public RequestOptions Options { get; }
-        public CancellationToken CancelToken { get; internal set; }
 
         public RestRequest(IRestClient client, string method, string endpoint, RequestOptions options)
         {
@@ -24,14 +22,13 @@ namespace Discord.Net.Queue
             Method = method;
             Endpoint = endpoint;
             Options = options;
-            CancelToken = CancellationToken.None;
             TimeoutAt = options.Timeout.HasValue ? DateTimeOffset.UtcNow.AddMilliseconds(options.Timeout.Value) : (DateTimeOffset?)null;
             Promise = new TaskCompletionSource<Stream>();
         }
 
         public virtual async Task<RestResponse> SendAsync()
         {
-            return await Client.SendAsync(Method, Endpoint, CancelToken, Options.HeaderOnly).ConfigureAwait(false);
+            return await Client.SendAsync(Method, Endpoint, Options.CancelToken, Options.HeaderOnly).ConfigureAwait(false);
         }
     }
 }

src/Discord.Net.Core/RequestOptions.cs

@@ -1,11 +1,18 @@
-namespace Discord
+using System.Threading;
+
+namespace Discord
 {
     public class RequestOptions
     {
         public static RequestOptions Default => new RequestOptions();
 
-        /// <summary> The max time, in milliseconds, to wait for this request to complete. If null, a request will not time out. If a rate limit has been triggered for this request's bucket and will not be unpaused in time, this request will fail immediately. </summary>
+        /// <summary> 
+        /// The max time, in milliseconds, to wait for this request to complete. If null, a request will not time out. 
+        /// If a rate limit has been triggered for this request's bucket and will not be unpaused in time, this request will fail immediately. 
+        /// </summary>
         public int? Timeout { get; set; }
+        public CancellationToken CancelToken { get; set; } = CancellationToken.None;
+        public RetryMode? RetryMode { get; set; }
         public bool HeaderOnly { get; internal set; }
 
         internal bool IgnoreState { get; set; }
@@ -13,7 +20,7 @@
         internal bool IsClientBucket { get; set; }
 
         internal static RequestOptions CreateOrClone(RequestOptions options)
-        {
+        {            
             if (options == null)
                 return new RequestOptions();
             else

src/Discord.Net.Core/RetryMode.cs

@@ -0,0 +1,22 @@
+using System;
+
+namespace Discord
+{
+    /// <summary> Specifies how a request should act in the case of an error. </summary>
+    [Flags]
+    public enum RetryMode
+    {
+        /// <summary> If a request fails, an exception is thrown immediately. </summary>
+        AlwaysFail = 0x0,
+        /// <summary> Retry if a request timed out. </summary>
+        RetryTimeouts = 0x1,
+        /// <summary> Retry if a request failed due to a network error. </summary>
+        RetryErrors = 0x2,
+        /// <summary> Retry if a request failed due to a ratelimit. </summary>
+        RetryRatelimit = 0x4,
+        /// <summary> Retry if a request failed due to an HTTP error 502. </summary>
+        Retry502 = 0x8,
+        /// <summary> Continuously retry a request until it times out, its cancel token is triggered, or the server responds with a non-502 error. </summary>
+        AlwaysRetry = RetryTimeouts | RetryErrors | RetryRatelimit | Retry502,
+    }
+}

src/Discord.Net.Rpc/API/DiscordRpcApiClient.cs

@@ -69,15 +69,13 @@ namespace Discord.API
         public ConnectionState ConnectionState { get; private set; }
 
         public DiscordRpcApiClient(string clientId, string userAgent, string origin, RestClientProvider restClientProvider, WebSocketProvider webSocketProvider, 
-                JsonSerializer serializer = null, RequestQueue requestQueue = null)
-            : base(restClientProvider, userAgent, serializer, requestQueue)
+                RetryMode defaultRetryMode = RetryMode.AlwaysRetry, JsonSerializer serializer = null, RequestQueue requestQueue = null)
+            : base(restClientProvider, userAgent, defaultRetryMode, serializer, requestQueue, false)
         {
             _connectionLock = new SemaphoreSlim(1, 1);
             _clientId = clientId;
             _origin = origin;
 
-            FetchCurrentUser = false;
-
             _requestQueue = requestQueue ?? new RequestQueue();
             _requests = new ConcurrentDictionary<Guid, RpcRequest>();
             

src/Discord.Net.WebSocket/API/DiscordSocketApiClient.cs

@@ -32,11 +32,12 @@ namespace Discord.API
 
         public ConnectionState ConnectionState { get; private set; }
 
-        public DiscordSocketApiClient(RestClientProvider restClientProvider, string userAgent, WebSocketProvider webSocketProvider, JsonSerializer serializer = null, RequestQueue requestQueue = null)
-            : base(restClientProvider, userAgent, serializer, requestQueue)
+        public DiscordSocketApiClient(RestClientProvider restClientProvider, string userAgent, WebSocketProvider webSocketProvider,
+            RetryMode defaultRetryMode = RetryMode.AlwaysRetry, JsonSerializer serializer = null, RequestQueue requestQueue = null)
+            : base(restClientProvider, userAgent, defaultRetryMode, serializer, requestQueue, true)
         {            
             _gatewayClient = webSocketProvider();
-            //_gatewayClient.SetHeader("user-agent", DiscordConfig.UserAgent); (Causes issues in .Net 4.6+)
+            //_gatewayClient.SetHeader("user-agent", DiscordConfig.UserAgent); (Causes issues in .NET Framework 4.6+)
             _gatewayClient.BinaryMessage += async (data, index, count) =>
             {
                 using (var compressed = new MemoryStream(data, index + 2, count - 2))

src/Discord.Net.WebSocket/DiscordSocketClient.Events.cs

@@ -221,7 +221,5 @@ namespace Discord.WebSocket
             remove { _recipientRemovedEvent.Remove(value); }
         }
         private readonly AsyncEvent<Func<SocketGroupUser, Task>> _recipientRemovedEvent = new AsyncEvent<Func<SocketGroupUser, Task>>();
-
-        //TODO: Add PresenceUpdated? VoiceStateUpdated?, VoiceConnected, VoiceDisconnected;
     }
 }

src/Discord.Net.WebSocket/DiscordSocketClient.cs

@@ -130,7 +130,7 @@ namespace Discord.WebSocket
         
         protected override async Task OnLoginAsync(TokenType tokenType, string token)
         {
-            var voiceRegions = await ApiClient.GetVoiceRegionsAsync(new RequestOptions { IgnoreState = true}).ConfigureAwait(false);
+            var voiceRegions = await ApiClient.GetVoiceRegionsAsync(new RequestOptions { IgnoreState = true, RetryMode = RetryMode.AlwaysRetry }).ConfigureAwait(false);
             _voiceRegions = voiceRegions.Select(x => RestVoiceRegion.Create(this, x)).ToImmutableDictionary(x => x.Id);
         }
         protected override async Task OnLogoutAsync()