Add binding attribute to converter context (#1660)

src/DotNetWorker.Core/Context/Features/DefaultFunctionInputBindingFeature.cs

@@ -75,6 +75,7 @@ public async ValueTask<FunctionInputBindingResult> BindFunctionInputAsync(Functi
                         AddFunctionParameterPropertyIfPresent(properties, param, PropertyBagKeys.ConverterType);
                         AddFunctionParameterPropertyIfPresent(properties, param, PropertyBagKeys.ConverterFallbackBehavior);
                         AddFunctionParameterPropertyIfPresent(properties, param, PropertyBagKeys.BindingAttributeSupportedConverters);
+                        AddFunctionParameterPropertyIfPresent(properties, param, PropertyBagKeys.BindingAttribute);
 
                         var converterContext = _converterContextFactory.Create(param.Type, source, context, properties.Count() != 0
                                              ? properties.ToImmutableDictionary()
@@ -117,7 +118,7 @@ public async ValueTask<FunctionInputBindingResult> BindFunctionInputAsync(Functi
 
         private void AddFunctionParameterPropertyIfPresent(IDictionary<string, object> properties, FunctionParameter param, string key)
         {
-            if (param.Properties.TryGetValue(key, out object val))
+            if (param.Properties.TryGetValue(key, out object? val))
             {
                 properties.Add(key, val);
             }

src/DotNetWorker.Core/Converters/Converter/ConverterContextExtensions.cs

@@ -0,0 +1,44 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the MIT License. See License.txt in the project root for license information.
+
+using System;
+
+namespace Microsoft.Azure.Functions.Worker.Converters
+{
+    /// <summary>
+    /// Provides extension methods to work with an <see cref="ConverterContext"/> instance.
+    /// </summary>
+    public static class ConverterContextExtensions
+    {
+        /// <summary>
+        /// Tries to retrieve the binding attribute from the <see cref="ConverterContext"/>.
+        /// </summary>
+        /// <param name="context">The converter context.</param>
+        /// <param name="bindingAttribute">When this method returns, contains the binding attribute if found; otherwise, <c>null</c>.</param>
+        /// <returns><c>true</c> if the binding attribute is found in the converter context; otherwise, <c>false</c>.</returns>
+        public static bool TryGetBindingAttribute<T>(this ConverterContext context, out object? bindingAttribute) where T : Attribute
+            => context.Properties.TryGetValue(PropertyBagKeys.BindingAttribute, out bindingAttribute);
+
+        /// <summary>
+        /// Tries to retrieve the binding attribute from the <see cref="ConverterContext"/>.
+        /// </summary>
+        /// <param name="context">The converter context.</param>
+        /// <param name="type">Binding attribute type.</param>
+        /// <param name="bindingAttribute">When this method returns, contains the binding attribute if found; otherwise, <c>null</c>.</param>
+        /// <returns><c>true</c> if the binding attribute is found in the converter context; otherwise, <c>false</c>.</returns>
+        public static bool TryGetBindingAttribute(this ConverterContext context, Type type, out object? bindingAttribute)
+        {
+            if (type is null)
+            {
+                throw new ArgumentNullException(nameof(type));
+            }
+
+            if (!typeof(Attribute).IsAssignableFrom(type))
+            {
+                throw new ArgumentException($"The type '{type}' must be an attribute.", nameof(type));
+            }
+
+            return context.Properties.TryGetValue(PropertyBagKeys.BindingAttribute, out bindingAttribute);
+        }
+    }
+}

src/DotNetWorker.Core/Converters/Converter/PropertyBagKeys.cs

@@ -6,6 +6,7 @@ namespace Microsoft.Azure.Functions.Worker.Converters
     internal static class PropertyBagKeys
     {
         internal const string ConverterType = "converterType";
+        internal const string BindingAttribute = "bindingAttribute";
         internal const string ConverterFallbackBehavior = "converterFallbackBehavior";
         internal const string BindingAttributeSupportedConverters = "bindingAttributeSupportedConverters";
     }

src/DotNetWorker.Grpc/Definition/GrpcFunctionDefinition.cs

@@ -107,6 +107,8 @@ public GrpcFunctionDefinition(FunctionLoadRequest loadRequest, IMethodInfoLocato
             var output = new Dictionary<string, object>();
             bool isInputConverterAttributeAdvertised = false;
 
+            output.Add(PropertyBagKeys.BindingAttribute, bindingAttribute);
+
             // ConverterTypesDictionary will be "object" part of the return value - ImmutableDictionary<string, object>
             // The dictionary has key of type IInputConverter and value as List of Types supported by the converter.
             var converterTypesDictionary = new Dictionary<Type, List<Type>>();