How to filter request based on client in C# (Identity Server 4)

Question

I made this method because the actual project was working with tokens in Header, and for my project I have to read the body (my token is in body). What I did was first checking if the token is under Authorization, if not check the body... But I´ve become the feedback that the best way to solve that is based on my Client, because im the only one reading the token from Body..

private string GetTokenFromHeader()
  {
     string value = _contextAccessor.HttpContext.Request.Headers["Authorization"];
     if (value.IsNull()) //if null, check body. 
        return GoogleGetTokenFromBody(_contextAccessor);
     return value.Substring(IdentityServerAuthenticationDefaults.AuthenticationScheme.Length + 1).Trim();
  }

I have no clue how to filter a request by client name, has someone an idea or suggestion?