C# Owin中间件中的覆盖响应体

我正在使用一个Owin中间件类。其目的是在检测到401、403或405 HTTP状态代码时覆盖响应主体，并用JSON对象替换主体。这是我目前的方法：

public override async Task Invoke(IOwinContext context)
        {
            await Next.Invoke(context);

            if (context.Response.StatusCode == 401 || context.Response.StatusCode == 403 || context.Response.StatusCode == 405)
            {

                var owinResponse = context.Response;
                var owinResponseStream = owinResponse.Body;
                var responseBuffer = new MemoryStream();
                owinResponse.Body = responseBuffer;

                string message;

                switch (context.Response.StatusCode)
                {
                    case 401:
                        message = "unauthorized request";
                        break;
                    case 403:
                        message = "forbidden request";
                        break;
                    default:
                        message = "request not allowed";
                        break;
                }
                var newResponse = new ResponseMessage<string>
                {
                    IsError = true,
                    StatusCode = (HttpStatusCode) Enum.Parse(typeof(HttpStatusCode), context.Response.StatusCode.ToString()),
                    Data = null,
                    Message = message
                };

                var customResponseBody = new StringContent(JsonConvert.SerializeObject(newResponse));
                var customResponseStream = await customResponseBody.ReadAsStreamAsync();
                await customResponseStream.CopyToAsync(owinResponseStream);
                owinResponse.ContentType = "application/json";
                owinResponse.ContentLength = customResponseStream.Length;
                owinResponse.StatusCode = 200;
                owinResponse.Body = owinResponseStream;
            }

        }

而不是：

{"IsError":true,"StatusCode":401,"Data":null,"Message":"unauthorized request"}

我确信这与我给回复机构写信的方式有关，但到目前为止还没有解决这个问题

如有任何建议，将不胜感激

---

谢谢

当您第一次将响应主体设置为内存流时，光标（当前位置）将移动到它的末尾<代码>owinResponse.Body=响应缓冲区 ，因此，我们得到了

{“message”：“此请求的授权已被拒绝”。}

存储，光标指向末尾

同样，在方法的末尾，编写新的响应

owinResponse.Body=owinResponseStream其中包含消息<代码>{“iError”：true，“StatusCode”：401，“Data”：null，“message”：“unauthorized request”}

由于当前位置指向流的末尾，因此它将追加

---

尝试删除第一组正文

owinResponse.body=responseBuffer因为您不需要原始响应消息。
因为您在
之后编写下面的代码，等待下一步。调用（上下文）

这是错误的

下一个代码可以根据您的需要工作：

public override async Task Invoke(IOwinContext context)
        {
            var owinResponse = context.Response;
            var owinResponseStream = owinResponse.Body;
            var responseBuffer = new MemoryStream();
            owinResponse.Body = responseBuffer;

            await Next.Invoke(context);

            if (context.Response.StatusCode == 401 || context.Response.StatusCode == 403 || context.Response.StatusCode == 405)
            {

                string message;

                switch (context.Response.StatusCode)
                {
                    case 401:
                        message = "unauthorized request";
                        break;
                    case 403:
                        message = "forbidden request";
                        break;
                    default:
                        message = "request not allowed";
                        break;
                }
                var newResponse = new ResponseMessage<string>
                {
                    IsError = true,
                    StatusCode = (HttpStatusCode) Enum.Parse(typeof(HttpStatusCode), context.Response.StatusCode.ToString()),
                    Data = null,
                    Message = message
                };

                var customResponseBody = new StringContent(JsonConvert.SerializeObject(newResponse));
                var customResponseStream = await customResponseBody.ReadAsStreamAsync();
                await customResponseStream.CopyToAsync(owinResponseStream);
                owinResponse.ContentType = "application/json";
                owinResponse.ContentLength = customResponseStream.Length;
                owinResponse.StatusCode = 200;
                owinResponse.Body = owinResponseStream;
            }

        }

公共重写异步任务调用（IOwinContext上下文）
{
var owinResponse=context.Response；
var owinResponseStream=owinResponse.Body；
var responseBuffer=newmemoryStream（）；
owinResponse.Body=响应缓冲区；
等待下一步。调用（上下文）；
if（context.Response.StatusCode==401 | | context.Response.StatusCode==403 | | context.Response.StatusCode==405）
{
字符串消息；
开关（context.Response.StatusCode）
{
案例401：
message=“未经授权的请求”；
打破
案例403：
message=“禁止请求”；
打破
违约：
message=“不允许请求”；
打破
}
var newResponse=新响应消息
{
IsError=true，
StatusCode=（HttpStatusCode）Enum.Parse（typeof（HttpStatusCode），context.Response.StatusCode.ToString（），
数据=空，
消息=消息
};
var customResponseBody=newstringcontent（JsonConvert.SerializeObject（newResponse））；
var customResponseStream=等待customResponseBody.ReadAsStreamAsync（）；
等待customResponseStream.CopyToAsync（owinResponseStream）；
owinResponse.ContentType=“应用程序/json”；
owinResponse.ContentLength=customResponseStream.Length；
owinResponse.StatusCode=200；
owinResponse.Body=owinResponseStream；
}
}

await Next.Invoke(context);

            if (context.Response.StatusCode == 401 || context.Response.StatusCode == 403 || context.Response.StatusCode == 405)
            {

                var owinResponse = context.Response;
                var owinResponseStream = owinResponse.Body;
                var responseBuffer = new MemoryStream();
                owinResponse.Body = responseBuffer;

public override async Task Invoke(IOwinContext context)
        {
            var owinResponse = context.Response;
            var owinResponseStream = owinResponse.Body;
            var responseBuffer = new MemoryStream();
            owinResponse.Body = responseBuffer;

            await Next.Invoke(context);

            if (context.Response.StatusCode == 401 || context.Response.StatusCode == 403 || context.Response.StatusCode == 405)
            {

                string message;

                switch (context.Response.StatusCode)
                {
                    case 401:
                        message = "unauthorized request";
                        break;
                    case 403:
                        message = "forbidden request";
                        break;
                    default:
                        message = "request not allowed";
                        break;
                }
                var newResponse = new ResponseMessage<string>
                {
                    IsError = true,
                    StatusCode = (HttpStatusCode) Enum.Parse(typeof(HttpStatusCode), context.Response.StatusCode.ToString()),
                    Data = null,
                    Message = message
                };

                var customResponseBody = new StringContent(JsonConvert.SerializeObject(newResponse));
                var customResponseStream = await customResponseBody.ReadAsStreamAsync();
                await customResponseStream.CopyToAsync(owinResponseStream);
                owinResponse.ContentType = "application/json";
                owinResponse.ContentLength = customResponseStream.Length;
                owinResponse.StatusCode = 200;
                owinResponse.Body = owinResponseStream;
            }

        }