Fixed StateAttribute support in resolver compilers.

src/Core/Abstractions/StateAttribute.cs

@@ -20,5 +20,9 @@ public StateAttribute(string key)
         }
 
         public string Key { get; }
+
+        public bool IsScoped { get; set; }
+
+        public bool DefaultIfNotExists { get; set; }
     }
 }

src/Core/Types.Tests/Resolvers/ResolverPropertyGeneratorTests.cs

@@ -1,18 +1,14 @@
-using System;
+using System.Collections.Immutable;
 using System.Collections.Generic;
+using System;
 using System.Linq;
-using System.Linq.Expressions;
 using System.Reflection;
-using System.Text;
 using System.Threading;
 using System.Threading.Tasks;
 using HotChocolate.Language;
-using HotChocolate.Resolvers.CodeGeneration;
-using HotChocolate.Resolvers.Expressions.Parameters;
 using HotChocolate.Subscriptions;
 using HotChocolate.Types;
 using Moq;
-using Snapshooter.Xunit;
 using Xunit;
 
 namespace HotChocolate.Resolvers.Expressions
@@ -738,6 +734,155 @@ public async Task Compile_Arguments_Service()
             Assert.True(result);
         }
 
+        [Fact]
+        public async Task Compile_Arguments_ContextData()
+        {
+            // arrange
+            Type type = typeof(Resolvers);
+            MemberInfo resolverMember =
+                type.GetMethod("ResolveWithContextData");
+            var resolverDescriptor = new ResolverDescriptor(
+                type,
+                new FieldMember("A", "b", resolverMember));
+            var contextData = new Dictionary<string, object>
+            {
+                { "foo", "bar"}
+            };
+
+            // act
+            var compiler = new ResolverCompiler();
+            FieldResolver resolver = compiler.Compile(resolverDescriptor);
+
+            // assert
+            var context = new Mock<IResolverContext>();
+            context.Setup(t => t.Parent<Resolvers>()).Returns(new Resolvers());
+            context.Setup(t => t.ContextData).Returns(contextData);
+            string result = (string)await resolver.Resolver(context.Object);
+            Assert.Equal("bar", result);
+        }
+
+        [Fact]
+        public async Task Compile_Arguments_ContextData_DefaultValue()
+        {
+            // arrange
+            Type type = typeof(Resolvers);
+            MemberInfo resolverMember =
+                type.GetMethod("ResolveWithContextDataDefault");
+            var resolverDescriptor = new ResolverDescriptor(
+                type,
+                new FieldMember("A", "b", resolverMember));
+            var contextData = new Dictionary<string, object>();
+
+            // act
+            var compiler = new ResolverCompiler();
+            FieldResolver resolver = compiler.Compile(resolverDescriptor);
+
+            // assert
+            var context = new Mock<IResolverContext>();
+            context.Setup(t => t.Parent<Resolvers>()).Returns(new Resolvers());
+            context.Setup(t => t.ContextData).Returns(contextData);
+            object result = await resolver.Resolver(context.Object);
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public void Compile_Arguments_ContextData_NotExists()
+        {
+            // arrange
+            Type type = typeof(Resolvers);
+            MemberInfo resolverMember =
+                type.GetMethod("ResolveWithContextData");
+            var resolverDescriptor = new ResolverDescriptor(
+                type,
+                new FieldMember("A", "b", resolverMember));
+            var contextData = new Dictionary<string, object>();
+
+            // act
+            var compiler = new ResolverCompiler();
+            FieldResolver resolver = compiler.Compile(resolverDescriptor);
+
+            // assert
+            var context = new Mock<IResolverContext>();
+            context.Setup(t => t.Parent<Resolvers>()).Returns(new Resolvers());
+            context.Setup(t => t.ContextData).Returns(contextData);
+            Action action = () => resolver.Resolver(context.Object);
+            Assert.Throws<ArgumentException>(action);
+        }
+
+        [Fact]
+        public async Task Compile_Arguments_ScopedContextData()
+        {
+            // arrange
+            Type type = typeof(Resolvers);
+            MemberInfo resolverMember =
+                type.GetMethod("ResolveWithScopedContextData");
+            var resolverDescriptor = new ResolverDescriptor(
+                type,
+                new FieldMember("A", "b", resolverMember));
+            var contextData = ImmutableDictionary<string, object>.Empty
+                .SetItem("foo", "bar");
+
+            // act
+            var compiler = new ResolverCompiler();
+            FieldResolver resolver = compiler.Compile(resolverDescriptor);
+
+            // assert
+            var context = new Mock<IResolverContext>();
+            context.Setup(t => t.Parent<Resolvers>()).Returns(new Resolvers());
+            context.Setup(t => t.ScopedContextData).Returns(contextData);
+            string result = (string)await resolver.Resolver(context.Object);
+            Assert.Equal("bar", result);
+        }
+
+        [Fact]
+        public async Task Compile_Arguments_ScopedContextData_DefaultValue()
+        {
+            // arrange
+            Type type = typeof(Resolvers);
+            MemberInfo resolverMember =
+                type.GetMethod("ResolveWithScopedContextDataDefault");
+            var resolverDescriptor = new ResolverDescriptor(
+                type,
+                new FieldMember("A", "b", resolverMember));
+            var contextData = ImmutableDictionary<string, object>.Empty;
+
+            // act
+            var compiler = new ResolverCompiler();
+            FieldResolver resolver = compiler.Compile(resolverDescriptor);
+
+            // assert
+            var context = new Mock<IResolverContext>();
+            context.Setup(t => t.Parent<Resolvers>()).Returns(new Resolvers());
+            context.Setup(t => t.ScopedContextData).Returns(contextData);
+            object result = await resolver.Resolver(context.Object);
+            Assert.Null(result);
+        }
+
+        [Fact]
+        public void Compile_Arguments_ScopedContextData_NotExists()
+        {
+            // arrange
+            Type type = typeof(Resolvers);
+            MemberInfo resolverMember =
+                type.GetMethod("ResolveWithScopedContextData");
+            var resolverDescriptor = new ResolverDescriptor(
+                type,
+                new FieldMember("A", "b", resolverMember));
+            var contextData = ImmutableDictionary<string, object>.Empty;
+
+            // act
+            var compiler = new ResolverCompiler();
+            FieldResolver resolver = compiler.Compile(resolverDescriptor);
+
+            // assert
+            var context = new Mock<IResolverContext>();
+            context.Setup(t => t.Parent<Resolvers>()).Returns(new Resolvers());
+            context.Setup(t => t.ScopedContextData).Returns(contextData);
+            Action action = () => resolver.Resolver(context.Object);
+            Assert.Throws<ArgumentException>(action);
+        }
+
+
         public class Resolvers
         {
             public Task<object> ObjectTaskResolver() =>
@@ -806,6 +951,19 @@ public bool ResolverWithSchema(
             public bool ResolverWithService(
                 [Service]MyService service) =>
                 service != null;
+
+            public string ResolveWithContextData(
+                [State("foo")]string s) => s;
+
+            public string ResolveWithContextDataDefault(
+                [State("foo", DefaultIfNotExists = true)]string s) => s;
+
+            public string ResolveWithScopedContextData(
+                [State("foo", IsScoped = true)]string s) => s;
+
+            public string ResolveWithScopedContextDataDefault(
+                [State("foo", IsScoped = true, DefaultIfNotExists = true)]
+                string s) => s;
         }
 
         public class Entity { }

src/Core/Types/Resolvers/Expressions/Arguments/GetCustomContextCompiler.cs

@@ -0,0 +1,64 @@
+using System;
+using System.Linq.Expressions;
+using System.Reflection;
+
+namespace HotChocolate.Resolvers.Expressions.Parameters
+{
+    internal sealed class GetCustomContextCompiler<T>
+        : ResolverParameterCompilerBase<T>
+        where T : IResolverContext
+    {
+        private static readonly MethodInfo _resolveContextData =
+            typeof(ExpressionHelper).GetMethod("ResolveContextData");
+        private static readonly MethodInfo _resolveScopedContextData =
+            typeof(ExpressionHelper).GetMethod("ResolveScopedContextData");
+
+        private readonly PropertyInfo _contextData;
+        private readonly PropertyInfo _scopedContextData;
+
+        public GetCustomContextCompiler()
+        {
+            _contextData = typeof(IHasContextData)
+                .GetTypeInfo().GetDeclaredProperty(
+                    nameof(IResolverContext.ContextData));
+            _scopedContextData = ContextTypeInfo.GetDeclaredProperty(
+                nameof(IResolverContext.ScopedContextData));
+        }
+
+        public override bool CanHandle(
+            ParameterInfo parameter,
+            Type sourceType) =>
+            parameter.IsDefined(typeof(StateAttribute));
+
+        public override Expression Compile(
+            Expression context,
+            ParameterInfo parameter,
+            Type sourceType)
+        {
+            StateAttribute attribute =
+                parameter.GetCustomAttribute<StateAttribute>();
+
+            ConstantExpression key =
+                Expression.Constant(attribute.Key);
+
+            ConstantExpression defaultIfNotExists =
+                Expression.Constant(attribute.DefaultIfNotExists);
+
+            MemberExpression contextData = attribute.IsScoped
+                ? Expression.Property(context, _scopedContextData)
+                : Expression.Property(context, _contextData);
+
+            MethodInfo resolveContextData = attribute.IsScoped
+                ? _resolveScopedContextData.MakeGenericMethod(
+                    parameter.ParameterType)
+                : _resolveContextData.MakeGenericMethod(
+                    parameter.ParameterType);
+
+            return Expression.Call(
+                resolveContextData,
+                contextData,
+                key,
+                defaultIfNotExists);
+        }
+    }
+}

src/Core/Types/Resolvers/Expressions/Arguments/ParameterCompilerFactory.cs

@@ -4,7 +4,7 @@ namespace HotChocolate.Resolvers.Expressions.Parameters
 {
     internal static class ParameterCompilerFactory
     {
-        public static IEnumerable<IResolverParameterCompiler> CreateForResolverContext()
+        public static IEnumerable<IResolverParameterCompiler> Create()
         {
             return CreateFor<IResolverContext>();
         }
@@ -14,6 +14,7 @@ private static IEnumerable<IResolverParameterCompiler> CreateFor<T>()
         {
             yield return new GetCancellationTokenCompiler<T>();
             yield return new GetContextCompiler<T, IResolverContext>();
+            yield return new GetCustomContextCompiler<T>();
             yield return new GetDataLoaderCompiler<T>();
             yield return new GetEventMessageCompiler<T>();
             yield return new GetFieldSelectionCompiler<T>();

src/Core/Types/Resolvers/Expressions/ResolverCompiler.cs

@@ -25,7 +25,7 @@ internal sealed class ResolverCompiler
         private readonly MethodInfo _taskResult;
 
         public ResolverCompiler()
-            : this(ParameterCompilerFactory.CreateForResolverContext())
+            : this(ParameterCompilerFactory.Create())
         {
         }
 
@@ -185,5 +185,59 @@ public static Task<object> WrapResultHelper<T>(T result)
         {
             return Task.FromResult<object>(result);
         }
+
+        public static TContextData ResolveContextData<TContextData>(
+            IDictionary<string, object> contextData,
+            string key,
+            bool defaultIfNotExists)
+        {
+            if (contextData.TryGetValue(key, out object value))
+            {
+                if (value is null)
+                {
+                    return default;
+                }
+
+                if (value is TContextData v)
+                {
+                    return v;
+                }
+            }
+            else if (defaultIfNotExists)
+            {
+                return default;
+            }
+
+            // TODO : resources
+            throw new ArgumentException(
+                "The specified context key does not exist.");
+        }
+
+        public static TContextData ResolveScopedContextData<TContextData>(
+            IReadOnlyDictionary<string, object> contextData,
+            string key,
+            bool defaultIfNotExists)
+        {
+            if (contextData.TryGetValue(key, out object value))
+            {
+                if (value is null)
+                {
+                    return default;
+                }
+
+                if (value is TContextData v)
+                {
+                    return v;
+                }
+            }
+            else if (defaultIfNotExists)
+            {
+                return default;
+            }
+
+            // TODO : resources
+            throw new ArgumentException(
+                "The specified context key does not exist.");
+        }
     }
 }