如何使用自定义中间件获取响应正文？

Question

问题

如何使用自定义中间件在调用下一个上下文时获取响应正文？

从调试到达 await _next.Invoke(context) 行后；

不从操作结果getusermenu返回json数据

[HttpGet(Contracts.ApiRoutes.Security.GetUserMenus)]
 public IActionResult GetUserMenu(string userId)
        {
            string strUserMenus = _SecurityService.GetUserMenus(userId);
            return Ok(strUserMenus);
        }

我需要从上面的操作结果中获取响应正文

header :
key : Authorization
value : ehhhheeedff .

我的代码我试试看：

public async Task InvokeAsync(HttpContext context, DataContext dataContext)
        {


            // than you logic to validate token              

            if (!validKey)
            {
                context.Response.StatusCode = (int)HttpStatusCode.Forbidden;
                await context.Response.WriteAsync("Invalid Token");
            }
            //if valid than next middleware Invoke
            else
            {
                await _next.Invoke(context);
// i need after that get result on last of thread meaning return data of usermenu

            }
        }
    }
 public static class TokenExtensions
    {
        public static IApplicationBuilder UseTokenAuth(this IApplicationBuilder builder)
        {
              return builder.UseMiddleware<TokenValidateMiddleware>();

        }
    }


          [no return data from access token][1]

https://i.stack.imgur.com/PHUMs.png

if(validtoken)
{
continue display getusermenuaction and show result

}

当令牌有效时，它会在浏览器 googlechrom 上返回如下数据

[
  {
    "form_name": "FrmAddPrograms",
    "title": "Adding Screens",
    "url": "",
    "permissions": {
      "Insert": "True",
      "Edit": "True",
      "Read": "True",
      "Delete": "True",
      "Print": "True",
      "Excel": "False",
      "RecordList": "False"
    }
  },

但在我的应用浏览器返回 无效的令牌

Answer 1

尝试使用以下代码在自定义中间件中获取响应正文：

public class CustomMiddleware
{
    private readonly RequestDelegate next;

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

    public async Task Invoke(HttpContext context)
    {

        if (!validKey)
        {
            context.Response.StatusCode = (int)HttpStatusCode.Forbidden;
            await context.Response.WriteAsync("Invalid Token");
        }
        //if valid than next middleware Invoke
        else
        {
            Stream originalBody = context.Response.Body;

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

                    await next(context);

                    memStream.Position = 0;
                    string responseBody = new StreamReader(memStream).ReadToEnd();//get response body here after next.Invoke()

                    memStream.Position = 0;
                    await memStream.CopyToAsync(originalBody);
                }

            }
            finally
            {
                context.Response.Body = originalBody;
            }
        }          
    }
}