Require properly typed ActionResult<T> (#8382)

Jellyfin.Api/BaseJellyfinApiController.cs

@@ -1,4 +1,6 @@
+using System.Collections.Generic;
 using System.Net.Mime;
+using Jellyfin.Api.Results;
 using Jellyfin.Extensions.Json;
 using Microsoft.AspNetCore.Mvc;
 
@@ -15,5 +17,40 @@ namespace Jellyfin.Api
         JsonDefaults.PascalCaseMediaType)]
     public class BaseJellyfinApiController : ControllerBase
     {
+        /// <summary>
+        /// Create a new <see cref="OkResult{T}"/>.
+        /// </summary>
+        /// <param name="value">The value to return.</param>
+        /// <typeparam name="T">The type to return.</typeparam>
+        /// <returns>The <see cref="ActionResult{T}"/>.</returns>
+        protected ActionResult<IEnumerable<T>> Ok<T>(List<T> value)
+            => new OkResult<IEnumerable<T>>(value);
+
+        /// <summary>
+        /// Create a new <see cref="OkResult{T}"/>.
+        /// </summary>
+        /// <param name="value">The value to return.</param>
+        /// <typeparam name="T">The type to return.</typeparam>
+        /// <returns>The <see cref="ActionResult{T}"/>.</returns>
+        protected ActionResult<IEnumerable<T>> Ok<T>(IReadOnlyList<T> value)
+            => new OkResult<IEnumerable<T>>(value);
+
+        /// <summary>
+        /// Create a new <see cref="OkResult{T}"/>.
+        /// </summary>
+        /// <param name="value">The value to return.</param>
+        /// <typeparam name="T">The type to return.</typeparam>
+        /// <returns>The <see cref="ActionResult{T}"/>.</returns>
+        protected ActionResult<IEnumerable<T>> Ok<T>(IEnumerable<T>? value)
+            => new OkResult<IEnumerable<T>?>(value);
+
+        /// <summary>
+        /// Create a new <see cref="OkResult{T}"/>.
+        /// </summary>
+        /// <param name="value">The value to return.</param>
+        /// <typeparam name="T">The type to return.</typeparam>
+        /// <returns>The <see cref="ActionResult{T}"/>.</returns>
+        protected ActionResult<T> Ok<T>(T value)
+            => new OkResult<T>(value);
     }
 }