New: Use ASP.NET Core instead of Nancy

(cherry picked from commit 58ddbcd77e17ef95ecfad4b746084ee9326116f3)

src/Prowlarr.Api.V1/FileSystem/FileSystemController.cs

@@ -0,0 +1,41 @@
+using System;
+using System.IO;
+using System.Linq;
+using Microsoft.AspNetCore.Mvc;
+using NzbDrone.Common.Disk;
+using Prowlarr.Http;
+
+namespace Prowlarr.Api.V1.FileSystem
+{
+    [V1ApiController]
+    public class FileSystemController : Controller
+    {
+        private readonly IFileSystemLookupService _fileSystemLookupService;
+        private readonly IDiskProvider _diskProvider;
+
+        public FileSystemController(IFileSystemLookupService fileSystemLookupService,
+                                IDiskProvider diskProvider)
+        {
+            _fileSystemLookupService = fileSystemLookupService;
+            _diskProvider = diskProvider;
+        }
+
+        [HttpGet]
+        public IActionResult GetContents(string path, bool includeFiles = false, bool allowFoldersWithoutTrailingSlashes = false)
+        {
+            return Ok(_fileSystemLookupService.LookupContents(path, includeFiles, allowFoldersWithoutTrailingSlashes));
+        }
+
+        [HttpGet("type")]
+        public object GetEntityType(string path)
+        {
+            if (_diskProvider.FileExists(path))
+            {
+                return new { type = "file" };
+            }
+
+            //Return folder even if it doesn't exist on disk to avoid leaking anything from the UI about the underlying system
+            return new { type = "folder" };
+        }
+    }
+}