Add torrent caching.

server/RdtClient.Data/Data/TorrentData.cs

@@ -1,6 +1,7 @@
 using System;
 using System.Collections.Generic;
 using System.Linq;
+using System.Threading;
 using System.Threading.Tasks;
 using Microsoft.EntityFrameworkCore;
 using RdtClient.Data.Models.Data;
@@ -21,6 +22,9 @@ namespace RdtClient.Data.Data
 
     public class TorrentData : ITorrentData
     {
+        private static IList<Torrent> _torrentCache;
+        private static readonly SemaphoreSlim _torrentCacheLock = new SemaphoreSlim(1);
+
         private readonly DataContext _dataContext;
 
         public TorrentData(DataContext dataContext)
@@ -30,12 +34,32 @@ namespace RdtClient.Data.Data
 
         public async Task<IList<Torrent>> Get()
         {
-            var results = await _dataContext.Torrents
+            await _torrentCacheLock.WaitAsync();
+
+            try
+            {
+                if (_torrentCache == null)
+                {
+                    _torrentCache = await _dataContext.Torrents
                                                       .AsNoTracking()
                                                       .Include(m => m.Downloads)
                                                       .ToListAsync();
+                }
 
-            return results.OrderByDescending(m => m.Added).ToList();
+                foreach (var torrent in _torrentCache)
+                {
+                    foreach (var download in torrent.Downloads)
+                    {
+                        download.Torrent = null;
+                    }
+                }
+
+                return _torrentCache.OrderByDescending(m => m.Added).ToList();
+            }
+            finally
+            {
+                _torrentCacheLock.Release();
+            }
         }
 
         public async Task<Torrent> GetById(Guid torrentId)
@@ -79,6 +103,10 @@ namespace RdtClient.Data.Data
         }
 
         public async Task<Torrent> Add(String realDebridId, String hash, String category, Boolean autoDelete, String fileOrMagnetContents, Boolean isFile)
+        {
+            await _torrentCacheLock.WaitAsync();
+
+            try
             {
                 var torrent = new Torrent
                 {
@@ -96,10 +124,21 @@ namespace RdtClient.Data.Data
 
                 await _dataContext.SaveChangesAsync();
 
+                _torrentCache = null;
+
                 return torrent;
             }
+            finally
+            {
+                _torrentCacheLock.Release();
+            }
+        }
 
         public async Task UpdateRdData(Torrent torrent)
+        {
+            await _torrentCacheLock.WaitAsync();
+
+            try
             {
                 var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrent.TorrentId);
 
@@ -126,9 +165,20 @@ namespace RdtClient.Data.Data
                 }
 
                 await _dataContext.SaveChangesAsync();
+
+                _torrentCache = null;
+            }
+            finally
+            {
+                _torrentCacheLock.Release();
+            }
         }
         
         public async Task UpdateCategory(Guid torrentId, String category)
+        {
+            await _torrentCacheLock.WaitAsync();
+
+            try
             {
                 var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);
 
@@ -140,18 +190,40 @@ namespace RdtClient.Data.Data
                 dbTorrent.Category = category;
 
                 await _dataContext.SaveChangesAsync();
+
+                _torrentCache = null;
+            }
+            finally
+            {
+                _torrentCacheLock.Release();
+            }
         }
 
         public async Task UpdateComplete(Guid torrentId, DateTimeOffset? datetime)
+        {
+            await _torrentCacheLock.WaitAsync();
+
+            try
             {
                 var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);
 
                 dbTorrent.Completed = datetime;
 
                 await _dataContext.SaveChangesAsync();
+
+                _torrentCache = null;
+            }
+            finally
+            {
+                _torrentCacheLock.Release();
+            }
         }
 
         public async Task Delete(Guid torrentId)
+        {
+            await _torrentCacheLock.WaitAsync();
+
+            try
             {
                 var dbTorrent = await _dataContext.Torrents.FirstOrDefaultAsync(m => m.TorrentId == torrentId);
 
@@ -163,6 +235,13 @@ namespace RdtClient.Data.Data
                 _dataContext.Torrents.Remove(dbTorrent);
 
                 await _dataContext.SaveChangesAsync();
+
+                _torrentCache = null;
+            }
+            finally
+            {
+                _torrentCacheLock.Release();
+            }
         }
     }
 }