Better formatting of caps as json

src/Jackett.Common/Helpers/LowerCaseNamingStrategy.cs

@@ -0,0 +1,9 @@
+using Newtonsoft.Json.Serialization;
+
+namespace Jackett.Common.Helpers
+{
+    public class LowerCaseNamingStrategy : NamingStrategy
+    {
+        protected override string ResolvePropertyName(string name) => name.ToLowerInvariant();
+    }
+}

src/Jackett.Common/Helpers/XmlToJsonWriter.cs

@@ -0,0 +1,29 @@
+using System.IO;
+using Newtonsoft.Json;
+
+namespace Jackett.Common.Helpers
+{
+    /// <summary>
+    /// JsonTextWriter to convert XML to JSON.
+    /// Makes sure that XML attributes do not have the '@' or '#' prefix in the JSON output.
+    /// https://stackoverflow.com/a/43485727
+    /// </summary>
+    public class XmlToJsonWriter : JsonTextWriter
+    {
+        public XmlToJsonWriter(TextWriter textWriter) : base(textWriter)
+        {
+        }
+
+        public override void WritePropertyName(string name)
+        {
+            if (name.StartsWith("@") || name.StartsWith("#"))
+            {
+                base.WritePropertyName(name.Substring(1));
+            }
+            else
+            {
+                base.WritePropertyName(name);
+            }
+        }
+    }
+}

src/Jackett.Common/Models/TorznabCapabilities.cs

@@ -1,7 +1,11 @@
 using System;
 using System.Collections.Generic;
+using System.IO;
 using System.Linq;
+using System.Text;
 using System.Xml.Linq;
+using Jackett.Common.Helpers;
+using Newtonsoft.Json;
 
 namespace Jackett.Common.Models
 {
@@ -352,6 +356,19 @@ namespace Jackett.Common.Models
         public string ToXml() =>
             GetXDocument().Declaration + Environment.NewLine + GetXDocument();
 
+        public string ToJson(JsonSerializerSettings serializerSettings = null)
+        {
+            var stringBuilder = new StringBuilder();
+            var serializer = JsonSerializer.Create(serializerSettings);
+
+            using var stringWriter = new StringWriter(stringBuilder);
+            using var jsonWriter = new XmlToJsonWriter(stringWriter);
+
+            serializer.Serialize(jsonWriter, GetXDocument().Root);
+
+            return stringBuilder.ToString();
+        }
+
         public static TorznabCapabilities Concat(TorznabCapabilities lhs, TorznabCapabilities rhs)
         {
             lhs.SearchAvailable = lhs.SearchAvailable || rhs.SearchAvailable;

src/Jackett.Server/Controllers/ResultsController.cs

@@ -8,6 +8,7 @@ using System.Threading.Tasks;
 using System.Xml.Linq;
 using Jackett.Common;
 using Jackett.Common.Exceptions;
+using Jackett.Common.Helpers;
 using Jackett.Common.Indexers;
 using Jackett.Common.Indexers.Meta;
 using Jackett.Common.Models;
@@ -20,6 +21,8 @@ using Microsoft.AspNetCore.Mvc;
 using Microsoft.AspNetCore.Mvc.Filters;
 using Microsoft.AspNetCore.Routing;
 using Microsoft.Net.Http.Headers;
+using Newtonsoft.Json;
+using Newtonsoft.Json.Converters;
 using Newtonsoft.Json.Linq;
 using NLog;
 
@@ -176,6 +179,17 @@ namespace Jackett.Server.Controllers
         private readonly IServerService serverService;
         private readonly ICacheService cacheService;
         private readonly Common.Models.Config.ServerConfig serverConfig;
+        private static readonly JsonSerializerSettings _JsonSerializerSettings = new JsonSerializerSettings
+        {
+            Converters = new List<JsonConverter>
+            {
+                new StringEnumConverter
+                {
+                    NamingStrategy = new LowerCaseNamingStrategy()
+                }
+            },
+            NullValueHandling = NullValueHandling.Ignore
+        };
 
         public ResultsController(IIndexerManagerService indexerManagerService, IServerService ss, ICacheService c, Logger logger, Common.Models.Config.ServerConfig sConfig)
         {
@@ -342,7 +356,7 @@ namespace Jackett.Server.Controllers
             if (string.Equals(CurrentQuery.QueryType, "caps", StringComparison.InvariantCultureIgnoreCase))
             {
                 return CurrentQuery.IsJson ?
-                    (IActionResult)Json(CurrentIndexer.TorznabCaps) :
+                    (IActionResult)Json(CurrentIndexer.TorznabCaps.ToJson(_JsonSerializerSettings)) :
                     Content(CurrentIndexer.TorznabCaps.ToXml(), "application/rss+xml", Encoding.UTF8);
             }