From 7b106aada09f2e8de30e4d6bcdfaca135fc9b24d Mon Sep 17 00:00:00 2001
From: PascalSenn <senn.pasc@gmail.com>
Date: Fri, 25 Jan 2019 14:48:33 +0100
Subject: [PATCH] feat(Core): adds scoped data context (#538)

---
 .../Middleware/ScopedContextDataTests.cs      | 46 +++++++++++++++++++
 .../Core/Execution/ExecutionStrategyBase.cs   |  4 +-
 .../Execution/Resolvers/DirectiveContext.cs   |  6 +++
 .../Execution/Resolvers/MiddlewareContext.cs  |  6 +++
 .../Execution/Resolvers/ResolverContext.cs    |  6 +++
 .../Core/Execution/Utilities/ResolverTask.cs  | 12 ++++-
 .../FieldValueCompletionContext.cs            |  4 +-
 src/Core/Types/Resolvers/IResolverContext.cs  |  9 +++-
 8 files changed, 88 insertions(+), 5 deletions(-)
 create mode 100644 src/Core/Core.Tests/Execution/Middleware/ScopedContextDataTests.cs

diff --git a/src/Core/Core.Tests/Execution/Middleware/ScopedContextDataTests.cs b/src/Core/Core.Tests/Execution/Middleware/ScopedContextDataTests.cs
new file mode 100644
index 00000000000..3f8f4e60b62
--- /dev/null
+++ b/src/Core/Core.Tests/Execution/Middleware/ScopedContextDataTests.cs
@@ -0,0 +1,46 @@
+using System.Collections.Generic;
+using System.Threading.Tasks;
+using ChilliCream.Testing;
+using Xunit;
+
+namespace HotChocolate.Execution
+{
+    public class ScopedContextDataTests
+    {
+        [Fact]
+        public async Task ScopedContextDataIsPassedAllongCorrectly()
+        {
+            // arrange
+            bool allDataIsPassedAlong = false;
+
+            ISchema schema = Schema.Create(
+                "type Query { nested: Nested }  type Nested { foo: String }",
+                c => c.Use(next => context =>
+                {
+                if (context.ScopedContextData.ContainsKey("field"))
+                {
+                    allDataIsPassedAlong = true;
+                    context.Result = "123";
+                } 
+                else
+                {
+                    context.ScopedContextData = context.ScopedContextData.Add("field", "abc");
+                    context.Result = new { foo = "123"};
+                }
+                    
+                    return Task.CompletedTask;
+                }));
+
+            IQueryExecutor executor = schema.MakeExecutable(
+                b => b.UseDefaultPipeline()
+                   );
+
+            // act
+            IExecutionResult result = await executor.ExecuteAsync(
+                new QueryRequest("{ nested { foo } }"));
+
+            // assert
+            Assert.True(allDataIsPassedAlong);
+        }
+    }
+}
diff --git a/src/Core/Core/Execution/ExecutionStrategyBase.cs b/src/Core/Core/Execution/ExecutionStrategyBase.cs
index 7b5422edbc2..bf0f38d2e25 100644
--- a/src/Core/Core/Execution/ExecutionStrategyBase.cs
+++ b/src/Core/Core/Execution/ExecutionStrategyBase.cs
@@ -163,7 +163,9 @@ protected IEnumerable<ResolverTask> CreateRootResolverTasks(
                     fieldSelection,
                     Path.New(fieldSelection.ResponseName),
                     source,
-                    result);
+                    result,
+                    ImmutableDictionary<string, object>.Empty
+                    );
             }
         }
 
diff --git a/src/Core/Core/Execution/Resolvers/DirectiveContext.cs b/src/Core/Core/Execution/Resolvers/DirectiveContext.cs
index 7fb22e8ae76..533b21dec5e 100644
--- a/src/Core/Core/Execution/Resolvers/DirectiveContext.cs
+++ b/src/Core/Core/Execution/Resolvers/DirectiveContext.cs
@@ -68,6 +68,12 @@ public object Result
         public IDictionary<string, object> ContextData =>
             _middlewareContext.ContextData;
 
+        public IImmutableDictionary<string, object> ScopedContextData
+        {
+            get => _middlewareContext.ScopedContextData;
+            set => _middlewareContext.ScopedContextData = value;
+        }
+
         public T Argument<T>(NameString name) =>
             _middlewareContext.Argument<T>(name);
 
diff --git a/src/Core/Core/Execution/Resolvers/MiddlewareContext.cs b/src/Core/Core/Execution/Resolvers/MiddlewareContext.cs
index edddba2ac3a..bec4e50f9c2 100644
--- a/src/Core/Core/Execution/Resolvers/MiddlewareContext.cs
+++ b/src/Core/Core/Execution/Resolvers/MiddlewareContext.cs
@@ -69,6 +69,12 @@ public object Result
         public IDictionary<string, object> ContextData =>
             _resolverContext.ContextData;
 
+        public IImmutableDictionary<string, object> ScopedContextData
+        {
+            get => _resolverContext.ScopedContextData;
+            set => _resolverContext.ScopedContextData = value;
+        }
+
         public T Argument<T>(NameString name) =>
             _resolverContext.Argument<T>(name);
 
diff --git a/src/Core/Core/Execution/Resolvers/ResolverContext.cs b/src/Core/Core/Execution/Resolvers/ResolverContext.cs
index 19c5adc2eb8..6e53559579f 100644
--- a/src/Core/Core/Execution/Resolvers/ResolverContext.cs
+++ b/src/Core/Core/Execution/Resolvers/ResolverContext.cs
@@ -71,6 +71,12 @@ public ResolverContext(
         public IDictionary<string, object> ContextData =>
             _executionContext.ContextData;
 
+        public IImmutableDictionary<string, object> ScopedContextData
+        {
+            get => _resolverTask.ScopedContextData;
+            set => _resolverTask.ScopedContextData = value;
+        }
+
         public T Argument<T>(NameString name)
         {
             if (string.IsNullOrEmpty(name))
diff --git a/src/Core/Core/Execution/Utilities/ResolverTask.cs b/src/Core/Core/Execution/Utilities/ResolverTask.cs
index d0cdbd22bad..b1668047935 100644
--- a/src/Core/Core/Execution/Utilities/ResolverTask.cs
+++ b/src/Core/Core/Execution/Utilities/ResolverTask.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading.Tasks;
@@ -18,7 +18,8 @@ public ResolverTask(
             FieldSelection fieldSelection,
             Path path,
             IImmutableStack<object> source,
-            IDictionary<string, object> result)
+            IDictionary<string, object> result,
+            IImmutableDictionary<string, object> scopedContextData)
         {
             _executionContext = executionContext;
             Source = source;
@@ -27,6 +28,7 @@ public ResolverTask(
             FieldType = fieldSelection.Field.Type;
             Path = path;
             _result = result;
+            ScopedContextData = scopedContextData;
 
             ResolverContext = new ResolverContext(
                 executionContext, this,
@@ -53,6 +55,12 @@ public ResolverTask(
         public object ResolverResult { get; set; }
 
         public FieldDelegate FieldDelegate { get; }
+        
+        public IImmutableDictionary<string, object> ScopedContextData
+        {
+            get;
+            set;
+        }
 
         public void IntegrateResult(object value)
         {
diff --git a/src/Core/Core/Execution/ValueCompletion/FieldValueCompletionContext.cs b/src/Core/Core/Execution/ValueCompletion/FieldValueCompletionContext.cs
index a6000124d0d..729ffff4c58 100644
--- a/src/Core/Core/Execution/ValueCompletion/FieldValueCompletionContext.cs
+++ b/src/Core/Core/Execution/ValueCompletion/FieldValueCompletionContext.cs
@@ -173,7 +173,9 @@ public void EnqueueForProcessing(
                 _enqueueResolverTask(new ResolverTask(
                     ExecutionContext, objectType, field,
                     Path.Append(field.ResponseName),
-                    Source.Push(Value), objectResult));
+                    Source.Push(Value), objectResult,
+                    _resolverTask.ScopedContextData)
+                    );
             }
         }
 
diff --git a/src/Core/Types/Resolvers/IResolverContext.cs b/src/Core/Types/Resolvers/IResolverContext.cs
index 7f234d584c8..6849029a4df 100644
--- a/src/Core/Types/Resolvers/IResolverContext.cs
+++ b/src/Core/Types/Resolvers/IResolverContext.cs
@@ -1,4 +1,4 @@
-using System;
+using System;
 using System.Collections.Generic;
 using System.Collections.Immutable;
 using System.Threading;
@@ -61,6 +61,13 @@ public interface IResolverContext
         /// </summary>
         IDictionary<string, object> ContextData { get; }
 
+        /// <summary>
+        /// The scoped context data dictionary can be used by middlewares and
+        /// resolvers to store and retrieve data during execution scoped to the
+        /// hierarchy 
+        /// </summary>
+        IImmutableDictionary<string, object> ScopedContextData { get; set; }
+
         /// <summary>
         /// Notifies when the connection underlying this request is aborted
         /// and thus request operations should be cancelled.