Fix batched results with a single request (#753)

Author: Shane32

src/Transports.AspNetCore/GraphQLHttpMiddleware.cs

@@ -65,7 +65,7 @@ public virtual async Task InvokeAsync(HttpContext context, RequestDelegate next)
 
             // Parse POST body
             GraphQLRequest bodyGQLRequest = null;
-            GraphQLRequest[] bodyGQLBatchRequest = null;
+            IList<GraphQLRequest> bodyGQLBatchRequest = null;
             if (isPost)
             {
                 if (!MediaTypeHeaderValue.TryParse(httpRequest.ContentType, out var mediaTypeHeader))
@@ -77,7 +77,7 @@ public virtual async Task InvokeAsync(HttpContext context, RequestDelegate next)
                 switch (mediaTypeHeader.MediaType)
                 {
                     case MediaType.JSON:
-                        GraphQLRequest[] deserializationResult;
+                        IList<GraphQLRequest> deserializationResult;
                         try
                         {
 #if NET5_0_OR_GREATER
@@ -90,14 +90,14 @@ public virtual async Task InvokeAsync(HttpContext context, RequestDelegate next)
                             if (sourceEncoding != null && sourceEncoding != System.Text.Encoding.UTF8)
                             {
                                 using var tempStream = System.Text.Encoding.CreateTranscodingStream(httpRequest.Body, innerStreamEncoding: sourceEncoding, outerStreamEncoding: System.Text.Encoding.UTF8, leaveOpen: true);
-                                deserializationResult = await _serializer.ReadAsync<GraphQLRequest[]>(tempStream, cancellationToken);
+                                deserializationResult = await _serializer.ReadAsync<IList<GraphQLRequest>>(tempStream, cancellationToken);
                             }
                             else
                             {
-                                deserializationResult = await _serializer.ReadAsync<GraphQLRequest[]>(httpRequest.Body, cancellationToken);
+                                deserializationResult = await _serializer.ReadAsync<IList<GraphQLRequest>>(httpRequest.Body, cancellationToken);
                             }
 #else
-                            deserializationResult = await _serializer.ReadAsync<GraphQLRequest[]>(httpRequest.Body, cancellationToken);
+                            deserializationResult = await _serializer.ReadAsync<IList<GraphQLRequest>>(httpRequest.Body, cancellationToken);
 #endif
                         }
                         catch (Exception ex)
@@ -106,7 +106,8 @@ public virtual async Task InvokeAsync(HttpContext context, RequestDelegate next)
                                 throw;
                             return;
                         }
-                        if (deserializationResult?.Length == 1)
+                        // https://github.com/graphql-dotnet/server/issues/751
+                        if (deserializationResult is GraphQLRequest[] array && array.Length == 1)
                             bodyGQLRequest = deserializationResult[0];
                         else
                             bodyGQLBatchRequest = deserializationResult;
@@ -172,7 +173,7 @@ protected virtual async Task HandleRequestAsync(
             HttpContext context,
             RequestDelegate next,
             IDictionary<string, object> userContext,
-            GraphQLRequest[] bodyGQLBatchRequest,
+            IList<GraphQLRequest> bodyGQLBatchRequest,
             GraphQLRequest gqlRequest,
             IGraphQLExecuter<TSchema> executer,
             CancellationToken cancellationToken)
@@ -191,8 +192,8 @@ protected virtual async Task HandleRequestAsync(
             // Execute multiple graphql requests in one batch
             else
             {
-                var executionResults = new ExecutionResult[bodyGQLBatchRequest.Length];
-                for (int i = 0; i < bodyGQLBatchRequest.Length; ++i)
+                var executionResults = new ExecutionResult[bodyGQLBatchRequest.Count];
+                for (int i = 0; i < bodyGQLBatchRequest.Count; ++i)
                 {
                     var gqlRequestInBatch = bodyGQLBatchRequest[i];
 

tests/ApiApprovalTests/GraphQL.Server.Transports.AspNetCore.approved.txt

@@ -32,7 +32,7 @@ namespace GraphQL.Server.Transports.AspNetCore
         protected virtual System.Threading.Tasks.Task HandleInvalidContentTypeErrorAsync(Microsoft.AspNetCore.Http.HttpContext context) { }
         protected virtual System.Threading.Tasks.Task HandleInvalidHttpMethodErrorAsync(Microsoft.AspNetCore.Http.HttpContext context) { }
         protected virtual System.Threading.Tasks.Task HandleNoQueryErrorAsync(Microsoft.AspNetCore.Http.HttpContext context) { }
-        protected virtual System.Threading.Tasks.Task HandleRequestAsync(Microsoft.AspNetCore.Http.HttpContext context, Microsoft.AspNetCore.Http.RequestDelegate next, System.Collections.Generic.IDictionary<string, object> userContext, GraphQL.Transport.GraphQLRequest[] bodyGQLBatchRequest, GraphQL.Transport.GraphQLRequest gqlRequest, GraphQL.Server.IGraphQLExecuter<TSchema> executer, System.Threading.CancellationToken cancellationToken) { }
+        protected virtual System.Threading.Tasks.Task HandleRequestAsync(Microsoft.AspNetCore.Http.HttpContext context, Microsoft.AspNetCore.Http.RequestDelegate next, System.Collections.Generic.IDictionary<string, object> userContext, System.Collections.Generic.IList<GraphQL.Transport.GraphQLRequest> bodyGQLBatchRequest, GraphQL.Transport.GraphQLRequest gqlRequest, GraphQL.Server.IGraphQLExecuter<TSchema> executer, System.Threading.CancellationToken cancellationToken) { }
         public virtual System.Threading.Tasks.Task InvokeAsync(Microsoft.AspNetCore.Http.HttpContext context, Microsoft.AspNetCore.Http.RequestDelegate next) { }
         protected virtual System.Threading.Tasks.Task RequestExecutedAsync(in GraphQL.Server.Transports.AspNetCore.GraphQLRequestExecutionResult requestExecutionResult) { }
         protected virtual System.Threading.Tasks.Task RequestExecutingAsync(GraphQL.Transport.GraphQLRequest request, int? indexInBatch = default) { }

tests/Samples.Server.Tests/ResponseTests.cs

@@ -64,6 +64,15 @@ public async Task Batched_Query_Should_Return_Multiple_Results()
             response.ShouldBeEquivalentJson(@"[{""data"":{""__schema"":{""queryType"":{""name"":""ChatQuery""}}}},{""data"":{""__schema"":{""queryType"":{""name"":""ChatQuery""}}}},{""data"":{""__schema"":{""queryType"":{""name"":""ChatQuery""}}}}]", ignoreExtensions: true);
         }
 
+        [Fact]
+        public async Task Batched_Query_Should_Return_Single_Result_As_Array()
+        {
+            string response = await SendBatchRequestAsync(
+                new GraphQLRequest { Query = "query one { __schema { queryType { name } } }", OperationName = "one" }
+                );
+            response.ShouldBeEquivalentJson(@"[{""data"":{""__schema"":{""queryType"":{""name"":""ChatQuery""}}}}]", ignoreExtensions: true);
+        }
+
         [Theory]
         [MemberData(nameof(WrongQueryData))]
         public async Task Wrong_Query_Should_Return_Error(HttpMethod httpMethod, HttpContent httpContent,