Add Header ValueProvider

src/HybridModelBinding/DefaultHybridModelBinder.cs

@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Mvc.Formatters;
+using HybridModelBinding.ModelBinding;
+using Microsoft.AspNetCore.Mvc.Formatters;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Binders;
 using System.Collections.Generic;
@@ -23,7 +24,8 @@ public DefaultHybridModelBinder(
                 .AddModelBinder(Body, new BodyModelBinder(formatters, readerFactory))
                 .AddValueProviderFactory(Form, new FormValueProviderFactory())
                 .AddValueProviderFactory(Route, new RouteValueProviderFactory())
-                .AddValueProviderFactory(QueryString, new QueryStringValueProviderFactory());
+                .AddValueProviderFactory(QueryString, new QueryStringValueProviderFactory())
+                .AddValueProviderFactory(Header, new HeaderValueProviderFactory());
         }
     }
 }

src/HybridModelBinding/DefaultPassthroughHybridModelBinder.cs

@@ -1,4 +1,5 @@
-using Microsoft.AspNetCore.Mvc.Formatters;
+using HybridModelBinding.ModelBinding;
+using Microsoft.AspNetCore.Mvc.Formatters;
 using Microsoft.AspNetCore.Mvc.ModelBinding;
 using Microsoft.AspNetCore.Mvc.ModelBinding.Binders;
 using System.Collections.Generic;
@@ -23,7 +24,8 @@ public DefaultPassthroughHybridModelBinder(
                 .AddModelBinder(Body, new BodyModelBinder(formatters, readerFactory))
                 .AddValueProviderFactory(Form, new FormValueProviderFactory())
                 .AddValueProviderFactory(Route, new RouteValueProviderFactory())
-                .AddValueProviderFactory(QueryString, new QueryStringValueProviderFactory());
+                .AddValueProviderFactory(QueryString, new QueryStringValueProviderFactory())
+                .AddValueProviderFactory(Header, new HeaderValueProviderFactory());
         }
     }
 }

src/HybridModelBinding/HybridModelBinding.csproj

@@ -12,7 +12,7 @@
         <GenerateAssemblyCompanyAttribute>false</GenerateAssemblyCompanyAttribute>
         <GenerateAssemblyProductAttribute>false</GenerateAssemblyProductAttribute>
         <GeneratePackageOnBuild>true</GeneratePackageOnBuild>
-        <Version>0.12.0</Version>
+        <Version>0.13.0</Version>
     </PropertyGroup>
     <ItemGroup>
         <PackageReference Include="Microsoft.AspNetCore.Mvc.Abstractions" Version="2.1.1" />

src/HybridModelBinding/ModelBinding/HeaderValueProvider.cs

@@ -0,0 +1,82 @@
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc.Internal;
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using System;
+using System.Collections.Generic;
+using System.Globalization;
+
+namespace HybridModelBinding.ModelBinding
+{
+    /// <summary>
+    /// Modified from https://github.com/aspnet/Mvc/blob/8d66f104f7f2ca42ee8b21f75b0e2b3e1abe2e00/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/QueryStringValueProvider.cs.
+    /// </summary>
+    public class HeaderValueProvider : BindingSourceValueProvider, IEnumerableValueProvider
+    {
+        public HeaderValueProvider(
+            BindingSource bindingSource,
+            IHeaderDictionary values,
+            CultureInfo culture)
+            : base(bindingSource)
+        {
+            if (bindingSource == null)
+            {
+                throw new ArgumentNullException(nameof(bindingSource));
+            }
+
+            this.values = values ?? throw new ArgumentNullException(nameof(values));
+            Culture = culture;
+        }
+
+        public CultureInfo Culture { get; private set; }
+
+        private readonly IHeaderDictionary values;
+        private PrefixContainer prefixContainer;
+
+        protected PrefixContainer PrefixContainer
+        {
+            get
+            {
+                if (prefixContainer == null)
+                {
+                    prefixContainer = new PrefixContainer(values.Keys);
+                }
+
+                return prefixContainer;
+            }
+        }
+
+        public override bool ContainsPrefix(string prefix)
+        {
+            return PrefixContainer.ContainsPrefix(prefix);
+        }
+
+        public virtual IDictionary<string, string> GetKeysFromPrefix(string prefix)
+        {
+            if (prefix == null)
+            {
+                throw new ArgumentNullException(nameof(prefix));
+            }
+
+            return PrefixContainer.GetKeysFromPrefix(prefix);
+        }
+
+        public override ValueProviderResult GetValue(string key)
+        {
+            if (key == null)
+            {
+                throw new ArgumentNullException(nameof(key));
+            }
+
+            var values = this.values[key];
+
+            if (values.Count == 0)
+            {
+                return ValueProviderResult.None;
+            }
+            else
+            {
+                return new ValueProviderResult(values, Culture);
+            }
+        }
+    }
+}

src/HybridModelBinding/ModelBinding/HeaderValueProviderFactory.cs

@@ -0,0 +1,49 @@
+using Microsoft.AspNetCore.Mvc.ModelBinding;
+using System;
+using System.Globalization;
+using System.Threading.Tasks;
+
+namespace HybridModelBinding.ModelBinding
+{
+    public class HeaderValueProviderFactory : IValueProviderFactory
+    {
+        /// <summary>
+        /// We need to re-create a Header BindingSource since the default ASP.NET MVC version
+        /// is greedy and that won't work as a ValueProvider.
+        /// 
+        /// Ref. https://github.com/aspnet/Mvc/blob/8d66f104f7f2ca42ee8b21f75b0e2b3e1abe2e00/src/Microsoft.AspNetCore.Mvc.Abstractions/ModelBinding/BindingSource.cs
+        /// Ref. https://github.com/aspnet/Mvc/blob/8d66f104f7f2ca42ee8b21f75b0e2b3e1abe2e00/src/Microsoft.AspNetCore.Mvc.Core/ModelBinding/BindingSourceValueProvider.cs#L41
+        /// ArgumentException: The provided binding source 'Header' is a greedy data source. 'BindingSourceValueProvider' does not support greedy data sources.        /// Parameter name: bindingSource
+        /// </summary>
+        private BindingSource Header = new BindingSource(
+            BindingSource.Header.Id,
+            BindingSource.Header.DisplayName,
+            isGreedy: false,
+            isFromRequest: BindingSource.Header.IsFromRequest);
+
+        public Task CreateValueProviderAsync(ValueProviderFactoryContext context)
+        {
+            if (context == null)
+            {
+                throw new ArgumentNullException(nameof(context));
+            }
+
+            var headers = context.ActionContext.HttpContext.Request.Headers;
+            if (headers != null && headers.Count > 0)
+            {
+                var valueProvider = new HeaderValueProvider(
+                    Header,
+                    headers,
+                    CultureInfo.InvariantCulture);
+
+                context.ValueProviders.Add(valueProvider);
+            }
+
+#if NET451
+            return Task.FromResult(0);
+#else
+            return Task.CompletedTask;
+#endif
+        }
+    }
+}

src/HybridModelBinding/Source.cs

@@ -4,6 +4,7 @@ public static class Source
     {
         public const string Body = nameof(Body);
         public const string Form = nameof(Form);
+        public const string Header = nameof(Header);
         public const string QueryString = nameof(QueryString);
         public const string Route = nameof(Route);
     }