ResponseCache: GetVaryByCustomString for .net 5 or .net Core 1.0?

Question

I am trying figure out how to implement GetVaryByCustomString function for asp.net core 1.0.

Have you implemented that kind of functionality for asp.net core 1.0?

Thanks

Answer 1

After I ask this question, using Middleware has suddenly came to my mind and i have implemented a class like below:

public class OutputCacheHeaderMiddleware
    {
        private readonly RequestDelegate _next;

        public OutputCacheHeaderMiddleware(RequestDelegate next)
        {
            _next = next;
        }

        public async Task Invoke(HttpContext context)
        {
            var user = UserHelper.GetUser(context);

            if (user?.UserInfos != null)
            {
                var key = "user_1_a_" + string.Join(",", user.UserInfos.Select(u => u.Id));
                context.Request.Headers.Add("dt-cache-user", key);
            }   


            await _next.Invoke(context);

        }
    }

and then, there is the extension method for it:

public static class OutputCacheHeaderExtensions
    {
        public static IApplicationBuilder UseOutputCacheHeader(this IApplicationBuilder builder)
        {
            return builder.UseMiddleware<OutputCacheHeaderMiddleware>();
        }
    }

and in Startup.cs Configure method, i added app.UseOutputCacheHeader();

public void Configure(IApplicationBuilder app, IHostingEnvironment env)
        {

            app.UseOutputCacheHeader();

            app.UseIISPlatformHandler();
            app.UseStaticFiles();

            app.UseMvc(routes =>
            {
                routes.MapRoute(
                    name: "default",
                    template: "{controller=Home}/{action=Index}/{id?}");
            });
        }

and on Controller:

[ResponseCache(VaryByHeader = "dt-cache-user", Duration = 6000)]
public IActionResult Index()
{
   return View();
}

After all of this, when i debug it, i can see that there is a header "dt-cache-user" with the proper value but ResponseCache isn't working. Everytime I hit F5 to refresh the page it always hit debug point.

What might be the reason that it doesn't work?

Thanks.