在将 newtonsoft 添加到项目时，从 .NET core 2.2 迁移到 3.1 api 结果中间件中断

Question

所以我们有一个中间件，它获取我们 API 响应的响应主体并将其包装在“数据”属性下的 ApiResult 类中。

    namespace Web.Api.ApiResult
{
    public class ApiResultMiddleware
    {
        private readonly RequestDelegate next;

        public ApiResultMiddleware(RequestDelegate next)
        {
            this.next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            var originalBody = context.Response.Body;
            var responseBody = string.Empty;
            try
            {
                CsWebException exception = null;

                using (var stream = new MemoryStream())
                {
                    context.Response.Body = stream;

                    try
                    {
                        await next.Invoke(context);
                    }
                    catch (CsWebException e)
                    {
                        exception = e;
                    }

                    stream.Position = 0;
                    responseBody = new StreamReader(stream).ReadToEnd();
                }

                object result = null;

                if (exception != null)
                {
                    result = new ApiResultResponse(null)
                    {
                        ErrorCode = exception.ErrorCode,
                        ErrorData = exception.ErrorData,
                    };
                    context.Response.StatusCode = (int)ApiResultHttpStatusCodeConverter.ConvertToHttpStatusCode(exception.ErrorCode);
                }
                else
                {
                    var data = JsonConvert.DeserializeObject(responseBody);
                    result = new ApiResultResponse(data);
                }

                var buffer = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(
                    result,
                    new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
                if (context.Response.StatusCode != StatusCodes.Status204NoContent)
                {
                    using (var output = new MemoryStream(buffer))
                    {
                        var test = JsonConvert.DeserializeObject<ApiResultResponse>(new StreamReader(output).ReadToEnd());
                        await output.CopyToAsync(originalBody);
                    }
                }
            }
            catch (JsonReaderException)
            {
                var result = new ApiResultResponse(responseBody);
                var buffer = Encoding.UTF8.GetBytes(JsonConvert.SerializeObject(
                    result,
                    new JsonSerializerSettings { ContractResolver = new CamelCasePropertyNamesContractResolver() }));
                using (var output = new MemoryStream(buffer))
                {
                    await output.CopyToAsync(originalBody);
                }
            }
            finally
            {
                context.Response.Body = originalBody;
            }
        }
    }

    public static class ApiResultMiddlewareExtensions
    {
        public static IApplicationBuilder UseApiResultMiddleware(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<ApiResultMiddleware>();
        }
    }
}

它在 .NET core 2.2 中运行良好，甚至在迁移到 3.1 并使用 Sytem.Text.Json 中的构建之后，但因为我们在补丁端点中需要 newtonsoft。通过添加它

services.AddControllers().AddNewtonsoftJson();

返回的 JSON 在中间某处被剪切。我在编写它之前添加了测试变量并反序列化了 JSON，它看起来很好，但是在我们的前端解析 i 时它不是。

一个例子是写入正文的 jsonbeeing 如下所示：

"{\"errorCode\":0,\"errorData\":null,\"data\":{\"previousWorkingDayWorkOrders\":[],\"nextWorkingDayWorkOrders\":[],\"todaysWorkOrders\":[],\"nonInvoicedWorkOrders\":[{\"workOrderId\":1232753.0,\"employeeNumber\":5000000037.0,\"employeeName\":\"VERKADM, VERKADM\",\"vehicleRegistrationNumber\":\"PXG948\",\"dealerOrderNumber\":null,\"bookingNumber\":null,\"preplannedDate\":null,\"workOrderStatus\":7,\"shortageIndicator\":true,\"customerWaiting\":false,\"vehicleDescriptionShort\":\"Volvo V40 Cross Country\",\"vehicleModelYear\":2018,\"colorDescription\":\"Blå\",\"fuelDescription\":\"Diesel\",\"email\":null,\"customer\":{\"customerNumber\":null,\"name\":\"Volvo Bil I Göteborg AB\",\"telephone\":null,\"email\":null,\"customerType\":1},\"mainPayerCustomerType\":1,\"notes\":null,\"vehicleIdentificationNumber\":\"YV1MZ79L0J2139968\"}],\"webWorkOrders\":[]}}"

当在邮递员中收到相同的响应时，它无法解析为 json，因为它被切断了，在计划文本中它看起来像：

{"errorCode":0,"errorData":null,"data":{"previousWorkingDayWorkOrders":[],"nextWorkingDayWorkOrders":[],"todaysWorkOrders":[{"workOrderId":1229253.0,"employeeNumber":5000000037.0,"employeeName":"VERKADM, VERKADM","vehicleRegistrationNumber":"PXG948","dealerOrderNumber":null,"bookingNumber":"349","preplannedDate":"2020-02-06T07:00:00","workOrderStatus":5,"shortageIndicator":true,"customerWaiting":false,"vehicleDescriptionShort":"Volvo V40 Cross Country","vehicleModelYear":2018,"colorDescription":"Blå","fuelDescription":"Diesel","email":null,"customer":{"customerNumber":null,"name":"Volvo Bil I Göteborg AB","telephone":null,"email":null,"customerType":1},"mainPayerCustomerType":1,"notes":null,"vehicleIdentificationNumber":"YV1MZ79L0J2139968"}],"nonInvoicedWorkOrders":[{"workOrderId":1232753.0,"employeeNumber":5000000037.0,"employeeName":"VERKADM, VERKADM","vehicleRegistrationNumber":"PXG948","dealerOrderNumber":null,"bookingNumber":null,"preplannedDate":null,"workOrderStatus":7,"shortageIndicator":true,"customerWaiting":false,"vehicleDescriptionShort":"Volvo V40 Cross Country","vehicleModelYear":2018,"colorDescription":"Blå","fuelDescription":"Diesel","email":null,"customer":{"customerNumber":null,"name":"Volvo Bil I Göteborg AB","telephone":null,"email":null,"customerType":1},"mainPayerCustomerType":1,"notes":null,"vehicleIdentificationNumber":"Y

知道为什么这不起作用吗？

编辑：我还应该指出，通过删除中间件 app.UseApiResultMiddleware(); 一切正常，但我们仍然想包装我们的回复

编辑 2。感谢 dbc 的回复，我设法解决了这个问题。通过将响应内容的长度设置为缓冲区的长度，它可以完美地工作。

context.Response.ContentLength = buffer.Length;

让我感到困惑的是，在没有使用 System.Text.Json 设置长度以及我们使用 .Net core 2.2 时，这一事实仍然有效

Answer 1

其他可能，你没有跟随the migration guide 到.NET Core 3.0。

使用Microsoft.AspNetCore.Mvc.NewtonsoftJson 包而不是Newtonsoft.Json 包。

Answer 2

你用

添加了 NewtonsoftJson

services.AddControllers().AddNewtonsoftJson();

但我不确定中间件是否能够访问它（之前从未尝试过这种服务注册方法）。

您是否尝试使用旧的添加它？

services.AddMvc().AddNewtonsoftJson();

Answer 3

我遇到了同样的问题。但是在中间件服务中添加以下行后我已经成功了。

 string plainBodyText = await new StreamReader(context.response.Body).ReadToEndAsync();    
context.Response.ContentLength = plainBodyText.Length;