Cancellationtoken tuning (#285)

* add virtual method for setting cancellationToken

* add example

Author: sungam3r

samples/Samples.Server/GraphQLHttpMiddlewareWithLogs.cs

@@ -5,11 +5,12 @@
 using Microsoft.Extensions.Logging;
 using Newtonsoft.Json;
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace GraphQL.Samples.Server
 {
-    // Example of a custom GraphQL Middleware which logs errors to Microsoft.Extensions.Logging API
+    // Example of a custom GraphQL Middleware that sends execution result to Microsoft.Extensions.Logging API
     public class GraphQLHttpMiddlewareWithLogs<TSchema> : GraphQLHttpMiddleware<TSchema>
         where TSchema : ISchema
     {
@@ -35,5 +36,12 @@ protected override Task RequestExecutedAsync(in GraphQLRequestExecutionResult re
 
             return base.RequestExecutedAsync(requestExecutionResult);
         }
+
+        protected override CancellationToken GetCancellationToken(HttpContext context)
+        {
+            // custom CancellationToken example 
+            var cts = CancellationTokenSource.CreateLinkedTokenSource(base.GetCancellationToken(context), new CancellationTokenSource(TimeSpan.FromSeconds(5)).Token);
+            return cts.Token;
+        }
     }
 }

src/Transports.AspNetCore/GraphQLHttpMiddleware.cs

@@ -11,6 +11,7 @@
 using System.Collections.Generic;
 using System.IO;
 using System.Net.Http.Headers;
+using System.Threading;
 using System.Threading.Tasks;
 
 namespace GraphQL.Server.Transports.AspNetCore
@@ -99,6 +100,7 @@ public async Task InvokeAsync(HttpContext context)
                 userContext = new Dictionary<string, object>(); // in order to allow resolvers to exchange their state through this object
 
             var executer = context.RequestServices.GetRequiredService<IGraphQLExecuter<TSchema>>();
+            var token = GetCancellationToken(context);
 
             // normal execution with single graphql request
             if (gqlBatchRequest == null)
@@ -109,7 +111,7 @@ public async Task InvokeAsync(HttpContext context)
                     gqlRequest.Query,
                     gqlRequest.GetInputs(),
                     userContext,
-                    context.RequestAborted).ConfigureAwait(false);
+                    token).ConfigureAwait(false);
 
                 await RequestExecutedAsync(new GraphQLRequestExecutionResult(gqlRequest, result, stopwatch.Elapsed));
 
@@ -129,7 +131,7 @@ public async Task InvokeAsync(HttpContext context)
                         request.Query,
                         request.GetInputs(),
                         userContext,
-                        context.RequestAborted).ConfigureAwait(false);
+                        token).ConfigureAwait(false);
 
                     await RequestExecutedAsync(new GraphQLRequestExecutionResult(gqlRequest, result, stopwatch.Elapsed, i));
 
@@ -140,6 +142,8 @@ public async Task InvokeAsync(HttpContext context)
             }
         }
 
+        protected virtual CancellationToken GetCancellationToken(HttpContext context) => context.RequestAborted;
+
         protected virtual Task RequestExecutedAsync(in GraphQLRequestExecutionResult requestExecutionResult)
         {
             // nothing to do in this middleware