feat: add CommaDelimitedArrayModelBinder

Jellyfin.Api/ModelBinders/CommaDelimitedArrayModelBinder.cs

@@ -0,0 +1,42 @@
+using System;
+using System.ComponentModel;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+
+namespace Jellyfin.Api.ModelBinders
+{
+    /// <summary>
+    /// Comma delimited array model binder.
+    /// Returns an empty array of specified type if there is no query parameter.
+    /// </summary>
+    public class CommaDelimitedArrayModelBinder : IModelBinder
+    {
+        /// <inheritdoc/>
+        public Task BindModelAsync(ModelBindingContext bindingContext)
+        {
+            var valueProviderResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
+            var input = valueProviderResult.FirstValue;
+            var elementType = bindingContext.ModelType.GetElementType();
+
+            if (input != null)
+            {
+                var converter = TypeDescriptor.GetConverter(elementType);
+                var values = Array.ConvertAll(
+                    input.Split(new[] { "," }, StringSplitOptions.RemoveEmptyEntries),
+                    x => { return converter.ConvertFromString(x != null ? x.Trim() : x); });
+
+                var typedValues = Array.CreateInstance(elementType, values.Length);
+                values.CopyTo(typedValues, 0);
+
+                bindingContext.Result = ModelBindingResult.Success(typedValues);
+            }
+            else
+            {
+                var emptyResult = Array.CreateInstance(elementType, 0);
+                bindingContext.Result = ModelBindingResult.Success(emptyResult);
+            }
+
+            return Task.CompletedTask;
+        }
+    }
+}