Make the JsonConverters for delimited arrays more generic (#13396)

* Make the JsonConverters for delimited arrays more generic

Also adds some tests for serialization (with different types) as we didn't have any before.

* Ignore warnings

1 files changed, 89 insertions, 0 deletions

diff --git a/Jellyfin.Api/ModelBinders/CommaDelimitedCollectionModelBinder.cs b/Jellyfin.Api/ModelBinders/CommaDelimitedCollectionModelBinder.cs
new file mode 100644
index 000000000..25b84cbcc
--- /dev/null
+++ b/Jellyfin.Api/ModelBinders/CommaDelimitedCollectionModelBinder.cs
@@ -0,0 +1,89 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel;
+using System.Threading.Tasks;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using Microsoft.Extensions.Logging;
+
+namespace Jellyfin.Api.ModelBinders;
+
+/// <summary>
+/// Comma delimited collection model binder.
+/// Returns an empty array of specified type if there is no query parameter.
+/// </summary>
+public class CommaDelimitedCollectionModelBinder : IModelBinder
+{
+    private readonly ILogger<CommaDelimitedCollectionModelBinder> _logger;
+
+    /// <summary>
+    /// Initializes a new instance of the <see cref="CommaDelimitedCollectionModelBinder"/> class.
+    /// </summary>
+    /// <param name="logger">Instance of the <see cref="ILogger{CommaDelimitedCollectionModelBinder}"/> interface.</param>
+    public CommaDelimitedCollectionModelBinder(ILogger<CommaDelimitedCollectionModelBinder> logger)
+    {
+        _logger = logger;
+    }
+
+    /// <inheritdoc/>
+    public Task BindModelAsync(ModelBindingContext bindingContext)
+    {
+        var valueProviderResult = bindingContext.ValueProvider.GetValue(bindingContext.ModelName);
+        var elementType = bindingContext.ModelType.GetElementType() ?? bindingContext.ModelType.GenericTypeArguments[0];
+        var converter = TypeDescriptor.GetConverter(elementType);
+
+        if (valueProviderResult.Length > 1)
+        {
+            var typedValues = GetParsedResult(valueProviderResult.Values, elementType, converter);
+            bindingContext.Result = ModelBindingResult.Success(typedValues);
+        }
+        else
+        {
+            var value = valueProviderResult.FirstValue;
+
+            if (value is not null)
+            {
+                var splitValues = value.Split(',', StringSplitOptions.RemoveEmptyEntries);
+                var typedValues = GetParsedResult(splitValues, elementType, converter);
+                bindingContext.Result = ModelBindingResult.Success(typedValues);
+            }
+            else
+            {
+                var emptyResult = Array.CreateInstance(elementType, 0);
+                bindingContext.Result = ModelBindingResult.Success(emptyResult);
+            }
+        }
+
+        return Task.CompletedTask;
+    }
+
+    private Array GetParsedResult(IReadOnlyList<string> values, Type elementType, TypeConverter converter)
+    {
+        var parsedValues = new object?[values.Count];
+        var convertedCount = 0;
+        for (var i = 0; i < values.Count; i++)
+        {
+            try
+            {
+                parsedValues[i] = converter.ConvertFromString(values[i].Trim());
+                convertedCount++;
+            }
+            catch (FormatException e)
+            {
+                _logger.LogDebug(e, "Error converting value.");
+            }
+        }
+
+        var typedValues = Array.CreateInstance(elementType, convertedCount);
+        var typedValueIndex = 0;
+        for (var i = 0; i < parsedValues.Length; i++)
+        {
+            if (parsedValues[i] is not null)
+            {
+                typedValues.SetValue(parsedValues[i], typedValueIndex);
+                typedValueIndex++;
+            }
+        }
+
+        return typedValues;
+    }
+}