Fixed: (Newznab API) Response with StatusCode 429 when limits are reached

src/NzbDrone.Common/Http/TooManyRequestsException.cs

@@ -11,15 +11,13 @@ namespace NzbDrone.Common.Http
         {
             if (response.Headers.ContainsKey("Retry-After"))
             {
-                var retryAfter = response.Headers["Retry-After"].ToString();
+                var retryAfter = response.Headers["Retry-After"];
-                int seconds;
-                DateTime date;
 
-                if (int.TryParse(retryAfter, out seconds))
+                if (int.TryParse(retryAfter, out var seconds))
                 {
                     RetryAfter = TimeSpan.FromSeconds(seconds);
                 }
-                else if (DateTime.TryParse(retryAfter, out date))
+                else if (DateTime.TryParse(retryAfter, out var date))
                 {
                     RetryAfter = date.ToUniversalTime() - DateTime.UtcNow;
                 }

src/NzbDrone.Core/Download/DownloadService.cs

@@ -92,8 +92,7 @@ namespace NzbDrone.Core.Download
             }
             catch (ReleaseDownloadException ex)
             {
-                var http429 = ex.InnerException as TooManyRequestsException;
+                if (ex.InnerException is TooManyRequestsException http429)
-                if (http429 != null)
                 {
                     _indexerStatusService.RecordFailure(release.IndexerId, http429.RetryAfter);
                 }
@@ -141,8 +140,7 @@ namespace NzbDrone.Core.Download
             }
             catch (ReleaseDownloadException ex)
             {
-                var http429 = ex.InnerException as TooManyRequestsException;
+                if (ex.InnerException is TooManyRequestsException http429)
-                if (http429 != null)
                 {
                     _indexerStatusService.RecordFailure(indexerId, http429.RetryAfter);
                 }

src/NzbDrone.Core/History/HistoryRepository.cs

@@ -19,6 +19,7 @@ namespace NzbDrone.Core.History
         List<History> Since(DateTime date, HistoryEventType? eventType);
         void Cleanup(int days);
         int CountSince(int indexerId, DateTime date, List<HistoryEventType> eventTypes);
+        History FindFirstForIndexerSince(int indexerId, DateTime date, List<HistoryEventType> eventTypes, int limit);
     }
 
     public class HistoryRepository : BasicRepository<History>, IHistoryRepository
@@ -115,5 +116,24 @@ namespace NzbDrone.Core.History
                 return conn.ExecuteScalar<int>(sql.RawSql, sql.Parameters);
             }
         }
+
+        public History FindFirstForIndexerSince(int indexerId, DateTime date, List<HistoryEventType> eventTypes, int limit)
+        {
+            var intEvents = eventTypes.Select(t => (int)t).ToList();
+
+            var builder = Builder()
+                .Where<History>(x => x.IndexerId == indexerId)
+                .Where<History>(x => x.Date >= date)
+                .Where<History>(x => intEvents.Contains((int)x.EventType));
+
+            var query = Query(builder);
+
+            if (limit > 0)
+            {
+                query = query.OrderByDescending(h => h.Date).Take(limit).ToList();
+            }
+
+            return query.MinBy(h => h.Date);
+        }
     }
 }

src/NzbDrone.Core/History/HistoryService.cs

@@ -27,6 +27,7 @@ namespace NzbDrone.Core.History
         List<History> Between(DateTime start, DateTime end);
         List<History> Since(DateTime date, HistoryEventType? eventType);
         int CountSince(int indexerId, DateTime date, List<HistoryEventType> eventTypes);
+        History FindFirstForIndexerSince(int indexerId, DateTime date, List<HistoryEventType> eventTypes, int limit);
     }
 
     public class HistoryService : IHistoryService,
@@ -232,5 +233,10 @@ namespace NzbDrone.Core.History
         {
             return _historyRepository.CountSince(indexerId, date, eventTypes);
         }
+
+        public History FindFirstForIndexerSince(int indexerId, DateTime date, List<HistoryEventType> eventTypes, int limit)
+        {
+            return _historyRepository.FindFirstForIndexerSince(indexerId, date, eventTypes, limit);
+        }
     }
 }

src/NzbDrone.Core/Indexers/IndexerLimitService.cs

@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using NLog;
-using NzbDrone.Common.Extensions;
 using NzbDrone.Core.History;
 
 namespace NzbDrone.Core.Indexers
@@ -10,6 +9,8 @@ namespace NzbDrone.Core.Indexers
     {
         bool AtDownloadLimit(IndexerDefinition indexer);
         bool AtQueryLimit(IndexerDefinition indexer);
+        int CalculateRetryAfterDownloadLimit(IndexerDefinition indexer);
+        int CalculateRetryAfterQueryLimit(IndexerDefinition indexer);
     }
 
     public class IndexerLimitService : IIndexerLimitService
@@ -31,9 +32,9 @@ namespace NzbDrone.Core.Indexers
                 var grabCount = _historyService.CountSince(indexer.Id, DateTime.Now.AddHours(-24), new List<HistoryEventType> { HistoryEventType.ReleaseGrabbed });
                 var grabLimit = ((IIndexerSettings)indexer.Settings).BaseSettings.GrabLimit;
 
-                if (grabCount > grabLimit)
+                if (grabCount >= grabLimit)
                 {
-                    _logger.Info("Indexer {0} has exceeded maximum grab limit for last 24 hours", indexer.Name);
+                    _logger.Info("Indexer {0} has performed {1} of possible {2} grabs in last 24 hours, exceeding the maximum grab limit", indexer.Name, grabCount, grabLimit);
 
                     return true;
                 }
@@ -51,9 +52,9 @@ namespace NzbDrone.Core.Indexers
                 var queryCount = _historyService.CountSince(indexer.Id, DateTime.Now.AddHours(-24), new List<HistoryEventType> { HistoryEventType.IndexerQuery, HistoryEventType.IndexerRss });
                 var queryLimit = ((IIndexerSettings)indexer.Settings).BaseSettings.QueryLimit;
 
-                if (queryCount > queryLimit)
+                if (queryCount >= queryLimit)
                 {
-                    _logger.Info("Indexer {0} has exceeded maximum query limit for last 24 hours", indexer.Name);
+                    _logger.Info("Indexer {0} has performed {1} of possible {2} queries in last 24 hours, exceeding the maximum query limit", indexer.Name, queryCount, queryLimit);
 
                     return true;
                 }
@@ -63,5 +64,39 @@ namespace NzbDrone.Core.Indexers
 
             return false;
         }
+
+        public int CalculateRetryAfterDownloadLimit(IndexerDefinition indexer)
+        {
+            if (indexer.Id > 0 && ((IIndexerSettings)indexer.Settings).BaseSettings.GrabLimit.HasValue)
+            {
+                var grabLimit = ((IIndexerSettings)indexer.Settings).BaseSettings.GrabLimit.GetValueOrDefault();
+
+                var firstHistorySince = _historyService.FindFirstForIndexerSince(indexer.Id, DateTime.Now.AddHours(-24), new List<HistoryEventType> { HistoryEventType.ReleaseGrabbed }, grabLimit);
+
+                if (firstHistorySince != null)
+                {
+                    return Convert.ToInt32(firstHistorySince.Date.ToLocalTime().AddHours(24).Subtract(DateTime.Now).TotalSeconds);
+                }
+            }
+
+            return 0;
+        }
+
+        public int CalculateRetryAfterQueryLimit(IndexerDefinition indexer)
+        {
+            if (indexer.Id > 0 && ((IIndexerSettings)indexer.Settings).BaseSettings.QueryLimit.HasValue)
+            {
+                var queryLimit = ((IIndexerSettings)indexer.Settings).BaseSettings.QueryLimit.GetValueOrDefault();
+
+                var firstHistorySince = _historyService.FindFirstForIndexerSince(indexer.Id, DateTime.Now.AddHours(-24), new List<HistoryEventType> { HistoryEventType.IndexerQuery, HistoryEventType.IndexerRss }, queryLimit);
+
+                if (firstHistorySince != null)
+                {
+                    return Convert.ToInt32(firstHistorySince.Date.ToLocalTime().AddHours(24).Subtract(DateTime.Now).TotalSeconds);
+                }
+            }
+
+            return 0;
+        }
     }
 }

src/Prowlarr.Api.V1/Indexers/NewznabController.cs

@@ -1,21 +1,25 @@
 using System;
 using System.Collections.Generic;
+using System.Linq;
 using System.Net;
+using System.Net.Http.Headers;
 using System.Text;
 using System.Threading.Tasks;
 using System.Xml.Linq;
 using Microsoft.AspNetCore.Cors;
+using Microsoft.AspNetCore.Http;
 using Microsoft.AspNetCore.Mvc;
 using NzbDrone.Common.Extensions;
 using NzbDrone.Common.Http;
 using NzbDrone.Core.Download;
-using NzbDrone.Core.History;
+using NzbDrone.Core.Exceptions;
 using NzbDrone.Core.Indexers;
 using NzbDrone.Core.IndexerSearch;
-using NzbDrone.Core.Parser;
 using NzbDrone.Core.Parser.Model;
+using NzbDrone.Core.ThingiProvider.Status;
 using Prowlarr.Http.Extensions;
 using Prowlarr.Http.REST;
+using BadRequestException = NzbDrone.Core.Exceptions.BadRequestException;
 
 namespace NzbDrone.Api.V1.Indexers
 {
@@ -27,18 +31,21 @@ namespace NzbDrone.Api.V1.Indexers
         private IIndexerFactory _indexerFactory { get; set; }
         private ISearchForNzb _nzbSearchService { get; set; }
         private IIndexerLimitService _indexerLimitService { get; set; }
+        private IIndexerStatusService _indexerStatusService;
         private IDownloadMappingService _downloadMappingService { get; set; }
         private IDownloadService _downloadService { get; set; }
 
         public NewznabController(IndexerFactory indexerFactory,
             ISearchForNzb nzbSearchService,
             IIndexerLimitService indexerLimitService,
+            IIndexerStatusService indexerStatusService,
             IDownloadMappingService downloadMappingService,
             IDownloadService downloadService)
         {
             _indexerFactory = indexerFactory;
             _nzbSearchService = nzbSearchService;
             _indexerLimitService = indexerLimitService;
+            _indexerStatusService = indexerStatusService;
             _downloadMappingService = downloadMappingService;
             _downloadService = downloadService;
         }
@@ -54,7 +61,7 @@ namespace NzbDrone.Api.V1.Indexers
 
             if (requestType.IsNullOrWhiteSpace())
             {
-                return Content(CreateErrorXML(200, "Missing parameter (t)"), "application/rss+xml");
+                return CreateResponse(CreateErrorXML(200, "Missing parameter (t)"), statusCode: StatusCodes.Status400BadRequest);
             }
 
             request.imdbid = request.imdbid?.TrimStart('t') ?? null;
@@ -63,7 +70,7 @@ namespace NzbDrone.Api.V1.Indexers
             {
                 if (!int.TryParse(request.imdbid, out var imdb) || imdb == 0)
                 {
-                    return Content(CreateErrorXML(201, "Incorrect parameter (imdbid)"), "application/rss+xml");
+                    return CreateResponse(CreateErrorXML(201, "Incorrect parameter (imdbid)"), statusCode: StatusCodes.Status400BadRequest);
                 }
             }
 
@@ -97,25 +104,27 @@ namespace NzbDrone.Api.V1.Indexers
                             caps.Categories.AddCategoryMapping(1, cat);
                         }
 
-                        return Content(caps.ToXml(), "application/rss+xml");
+                        return CreateResponse(caps.ToXml());
                     case "search":
                     case "tvsearch":
                     case "music":
                     case "book":
                     case "movie":
-                        var results = new NewznabResults();
+                        var results = new NewznabResults
-                        results.Releases = new List<ReleaseInfo>
                         {
-                            new ReleaseInfo
+                            Releases = new List<ReleaseInfo>
                             {
-                                Title = "Test Release",
+                                new ()
-                                Guid = "https://prowlarr.com",
+                                {
-                                DownloadUrl = "https://prowlarr.com",
+                                    Title = "Test Release",
-                                PublishDate = DateTime.Now
+                                    Guid = "https://prowlarr.com",
+                                    DownloadUrl = "https://prowlarr.com",
+                                    PublishDate = DateTime.Now
+                                }
                             }
                         };
 
-                        return Content(results.ToXml(DownloadProtocol.Usenet), "application/rss+xml");
+                        return CreateResponse(results.ToXml(DownloadProtocol.Usenet));
                 }
             }
 
@@ -126,19 +135,37 @@ namespace NzbDrone.Api.V1.Indexers
                 throw new NotFoundException("Indexer Not Found");
             }
 
+            if (!indexerDef.Enable)
+            {
+                return CreateResponse(CreateErrorXML(410, "Indexer is disabled"), statusCode: StatusCodes.Status410Gone);
+            }
+
             var indexer = _indexerFactory.GetInstance(indexerDef);
 
+            var blockedIndexerStatus = GetBlockedIndexerStatus(indexer);
+
+            if (blockedIndexerStatus?.DisabledTill != null)
+            {
+                var retryAfterDisabledTill = Convert.ToInt32(blockedIndexerStatus.DisabledTill.Value.ToLocalTime().Subtract(DateTime.Now).TotalSeconds);
+                AddRetryAfterHeader(retryAfterDisabledTill);
+
+                return CreateResponse(CreateErrorXML(429, $"Indexer is disabled till {blockedIndexerStatus.DisabledTill.Value.ToLocalTime()} due to recent failures."), statusCode: StatusCodes.Status429TooManyRequests);
+            }
+
             //TODO Optimize this so it's not called here and in NzbSearchService (for manual search)
             if (_indexerLimitService.AtQueryLimit(indexerDef))
             {
-                return Content(CreateErrorXML(429, $"Request limit reached ({((IIndexerSettings)indexer.Definition.Settings).BaseSettings.QueryLimit})"), "application/rss+xml");
+                var retryAfterQueryLimit = _indexerLimitService.CalculateRetryAfterQueryLimit(indexerDef);
+                AddRetryAfterHeader(retryAfterQueryLimit);
+
+                return CreateResponse(CreateErrorXML(429, $"User configurable Indexer Query Limit of {((IIndexerSettings)indexer.Definition.Settings).BaseSettings.QueryLimit} reached."), statusCode: StatusCodes.Status429TooManyRequests);
             }
 
             switch (requestType)
             {
                 case "caps":
                     var caps = indexer.GetCapabilities();
-                    return Content(caps.ToXml(), "application/rss+xml");
+                    return CreateResponse(caps.ToXml());
                 case "search":
                 case "tvsearch":
                 case "music":
@@ -156,9 +183,9 @@ namespace NzbDrone.Api.V1.Indexers
                         }
                     }
 
-                    return Content(results.ToXml(indexer.Protocol), "application/rss+xml");
+                    return CreateResponse(results.ToXml(indexer.Protocol));
                 default:
-                    return Content(CreateErrorXML(202, $"No such function ({requestType})"), "application/rss+xml");
+                    return CreateResponse(CreateErrorXML(202, $"No such function ({requestType})"), statusCode: StatusCodes.Status400BadRequest);
             }
         }
 
@@ -167,11 +194,35 @@ namespace NzbDrone.Api.V1.Indexers
         public async Task<object> GetDownload(int id, string link, string file)
         {
             var indexerDef = _indexerFactory.Get(id);
+
+            if (indexerDef == null)
+            {
+                throw new NotFoundException("Indexer Not Found");
+            }
+
+            if (!indexerDef.Enable)
+            {
+                return CreateResponse(CreateErrorXML(410, "Indexer is disabled"), statusCode: StatusCodes.Status410Gone);
+            }
+
             var indexer = _indexerFactory.GetInstance(indexerDef);
 
+            var blockedIndexerStatus = GetBlockedIndexerStatus(indexer);
+
+            if (blockedIndexerStatus?.DisabledTill != null)
+            {
+                var retryAfterDisabledTill = Convert.ToInt32(blockedIndexerStatus.DisabledTill.Value.ToLocalTime().Subtract(DateTime.Now).TotalSeconds);
+                AddRetryAfterHeader(retryAfterDisabledTill);
+
+                return CreateResponse(CreateErrorXML(429, $"Indexer is disabled till {blockedIndexerStatus.DisabledTill.Value.ToLocalTime()} due to recent failures."), statusCode: StatusCodes.Status429TooManyRequests);
+            }
+
             if (_indexerLimitService.AtDownloadLimit(indexerDef))
             {
-                return Content(CreateErrorXML(429, $"Grab limit reached ({((IIndexerSettings)indexer.Definition.Settings).BaseSettings.GrabLimit})"), "application/rss+xml");
+                var retryAfterDownloadLimit = _indexerLimitService.CalculateRetryAfterDownloadLimit(indexerDef);
+                AddRetryAfterHeader(retryAfterDownloadLimit);
+
+                return CreateResponse(CreateErrorXML(429, $"User configurable Indexer Grab Limit of {((IIndexerSettings)indexer.Definition.Settings).BaseSettings.GrabLimit} reached."), statusCode: StatusCodes.Status429TooManyRequests);
             }
 
             if (link.IsNullOrWhiteSpace() || file.IsNullOrWhiteSpace())
@@ -181,11 +232,6 @@ namespace NzbDrone.Api.V1.Indexers
 
             file = WebUtility.UrlDecode(file);
 
-            if (indexerDef == null)
-            {
-                throw new NotFoundException("Indexer Not Found");
-            }
-
             var source = UserAgentParser.ParseSource(Request.Headers["User-Agent"]);
             var host = Request.GetHostName();
 
@@ -198,8 +244,27 @@ namespace NzbDrone.Api.V1.Indexers
                 return RedirectPermanent(unprotectedlLink);
             }
 
-            var downloadBytes = Array.Empty<byte>();
+            byte[] downloadBytes;
-            downloadBytes = await _downloadService.DownloadReport(unprotectedlLink, id, source, host, file);
+
+            try
+            {
+                downloadBytes = await _downloadService.DownloadReport(unprotectedlLink, id, source, host, file);
+            }
+            catch (ReleaseUnavailableException ex)
+            {
+                return CreateResponse(CreateErrorXML(410, ex.Message), statusCode: StatusCodes.Status410Gone);
+            }
+            catch (ReleaseDownloadException ex) when (ex.InnerException is TooManyRequestsException http429)
+            {
+                var http429RetryAfter = Convert.ToInt32(http429.RetryAfter.TotalSeconds);
+                AddRetryAfterHeader(http429RetryAfter);
+
+                return CreateResponse(CreateErrorXML(429, ex.Message), statusCode: StatusCodes.Status429TooManyRequests);
+            }
+            catch (Exception ex)
+            {
+                return CreateResponse(CreateErrorXML(500, ex.Message), statusCode: StatusCodes.Status500InternalServerError);
+            }
 
             // handle magnet URLs
             if (downloadBytes.Length >= 7
@@ -232,5 +297,32 @@ namespace NzbDrone.Api.V1.Indexers
 
             return xdoc.Declaration + Environment.NewLine + xdoc;
         }
+
+        private ContentResult CreateResponse(string content, string contentType = "application/rss+xml", int statusCode = StatusCodes.Status200OK)
+        {
+            var mediaTypeHeaderValue = MediaTypeHeaderValue.Parse(contentType);
+
+            return new ContentResult
+            {
+                StatusCode = statusCode,
+                Content = content,
+                ContentType = mediaTypeHeaderValue.ToString()
+            };
+        }
+
+        private ProviderStatusBase GetBlockedIndexerStatus(IIndexer indexer)
+        {
+            var blockedIndexers = _indexerStatusService.GetBlockedProviders().ToDictionary(v => v.ProviderId, v => v);
+
+            return blockedIndexers.TryGetValue(indexer.Definition.Id, out var blockedIndexerStatus) ? blockedIndexerStatus : null;
+        }
+
+        private void AddRetryAfterHeader(int retryAfterSeconds)
+        {
+            if (!HttpContext.Response.Headers.ContainsKey("Retry-After") && retryAfterSeconds > 0)
+            {
+                HttpContext.Response.Headers.Add("Retry-After", $"{retryAfterSeconds}");
+            }
+        }
     }
 }