How to get response body using custom middle ware? - asp.net-core-2.0

Question

problem
How to get response body on invoke next context using custom middle ware ??
After reach to line of await _next.Invoke(context) from debug;
not return json data from action result getusermenu
[HttpGet(Contracts.ApiRoutes.Security.GetUserMenus)]
public IActionResult GetUserMenu(string userId)
{
string strUserMenus = _SecurityService.GetUserMenus(userId);
return Ok(strUserMenus);
}
I need to get response body from action result above
header :
key : Authorization
value : ehhhheeedff .
my code i try it :
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
}
when valid token it return data like below on browser googlechrom
[
{
"form_name": "FrmAddPrograms",
"title": "Adding Screens",
"url": "",
"permissions": {
"Insert": "True",
"Edit": "True",
"Read": "True",
"Delete": "True",
"Print": "True",
"Excel": "False",
"RecordList": "False"
}
},
but on my app browser return
not valid token

Answer 1

Try to get response body in custom middleware using below code:
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;
}
}
}
}