Fixed: Support large calibre libraries

src/NzbDrone.Core/Books/Calibre/CalibreProxy.cs

@@ -245,16 +245,21 @@ namespace NzbDrone.Core.Books.Calibre
         {
             _bookCache.Clear();
 
-            try
+            var ids = GetAllBookIds(settings);
+            var result = new List<string>();
+
+            const int count = 100;
+            var offset = 0;
+
+            while (offset < ids.Count)
             {
                 var builder = GetBuilder($"ajax/books", settings);
-                builder.LogResponseContent = false;
+                builder.AddQueryParam("ids", ids.Skip(offset).Take(count).ConcatToString(","));
 
                 var request = builder.Build();
+                try
+                {
                     var response = _httpClient.Get<Dictionary<int, CalibreBook>>(request);
-
-                var result = new List<string>();
-
                     foreach (var book in response.Resource.Values)
                     {
                         var remotePath = book?.Formats.Values.OrderBy(f => f.LastModified).FirstOrDefault()?.Path;
@@ -268,9 +273,54 @@ namespace NzbDrone.Core.Books.Calibre
 
                         _bookCache.Set(localPath, book, TimeSpan.FromMinutes(5));
                     }
+                }
+                catch (HttpException ex)
+                {
+                    throw new CalibreException("Unable to connect to calibre library: {0}", ex, ex.Message);
+                }
+
+                offset += count;
+            }
 
             return result;
         }
+
+        public List<int> GetAllBookIds(CalibreSettings settings)
+        {
+            // the magic string is 'allbooks' converted to hex
+            var builder = GetBuilder($"/ajax/category/616c6c626f6f6b73", settings);
+            const int count = 100;
+            var offset = 0;
+
+            var ids = new List<int>();
+
+            while (true)
+            {
+                var result = GetPaged<CalibreCategory>(builder, count, offset);
+                if (!result.Resource.BookIds.Any())
+                {
+                    break;
+                }
+
+                offset += count;
+                ids.AddRange(result.Resource.BookIds);
+            }
+
+            return ids;
+        }
+
+        private HttpResponse<T> GetPaged<T>(HttpRequestBuilder builder, int count, int offset)
+            where T : new()
+        {
+            builder.AddQueryParam("num", count, replace: true);
+            builder.AddQueryParam("offset", offset, replace: true);
+
+            var request = builder.Build();
+
+            try
+            {
+                return _httpClient.Get<T>(request);
+            }
             catch (HttpException ex)
             {
                 throw new CalibreException("Unable to connect to calibre library: {0}", ex, ex.Message);

src/NzbDrone.Core/Books/Calibre/Resources/CalibreCategory.cs

@@ -0,0 +1,20 @@
+using System.Collections.Generic;
+using Newtonsoft.Json;
+
+namespace NzbDrone.Core.Books.Calibre
+{
+    public class CalibreCategory
+    {
+        [JsonProperty("total_num")]
+        public int TotalNum { get; set; }
+        [JsonProperty("sort_order")]
+        public string SortOrder { get; set; }
+        public int Offset { get; set; }
+        public int Num { get; set; }
+        public string Sort { get; set; }
+        [JsonProperty("base_url")]
+        public string BaseUrl { get; set; }
+        [JsonProperty("book_ids")]
+        public List<int> BookIds { get; set; }
+    }
+}