Display Home page based on a condition-CodePudding

I have a ASP.Net MVC application which returns a page called Customer as home page. But I need show an app not available page when the user tries to access the application on a holiday(holiday list is stored in a table)instead of the Customer page. In the startup I have like below

app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllerRoute(
                    name: "default",
                    pattern: "{controller=Customers}/{action=Index}/{id?}");
            });

Now I created a new page called AppNotAvialable.cshmtl and trying to return to this page if today is stored as a holiday in the HolidayWeeks table

 public async Task<IActionResult> Index(string sortOrder, string searchString,
                                               int? pageNumber, string currentFilter)
        {

            var timeUtc = DateTime.UtcNow;
            var easternZone = TimeZoneInfo.FindSystemTimeZoneById("Eastern Standard Time");
            var todayDt = TimeZoneInfo.ConvertTimeFromUtc(timeUtc, easternZone);

            var holidaycheck = (from hc in _context.HolidayWeeks
                               where hc.HolidateDate.Date == todayDt.Date
                                select hc).Count();

            if (holidaycheck != 0)
            {
                return View("/Views/Customers/AppNotAvailable.cshtml");
            }

            else
            {
               // Show customer page

My concern is everytime the users tried to access the homepage the query is made to the database to check if today is holiday or not. So I wanted to check if there is any better way of checking, should I be storing the data in the session/cache so everytime they access the homepage the query is not made. Can anyone please suggests me how can I do it

CodePudding user response：

Add the MemoryCache service to the service collection (This service caches the data on the server):

services.AddMemoryCache();

Then can be injected by DI using the interface IMemoryCache.

//Check if there is a cached holiday vm
if (!memoryCache.TryGetValue("HolidayModelVM", out HolidayModelVM HM))//"HolidayModelVM" is the cache key for the vm
{
    //Not present in the cache, we create a new one using the database

    HM = new HolidayModelVM
    {
        //Fetch the actual entity that contains the holiday dates
    }

    //Cache the VM
    _ = memoryCache.Set<HolidayModelVM>("HolidayModelVM", HM, new MemoryCacheEntryOptions
    {
        AbsoluteExpirationRelativeToNow = TimeSpan.FromHours(4),//Expiration time, when expired, the database will be used to fetch and cache a new version of the data.
        SlidingExpiration = TimeSpan.FromHours(2)
    });
}

//Do your holiday check using the HolidayModelVM
if (HM.TodayIsHoliday())
{
    return View("/Views/Customers/AppNotAvailable.cshtml");
}
else {
    // Show customer page 
}

When updating the holiday data clear the VM from the cache in order for the new data to be fetched next time someone visits the page:

memoryCache.Remove("HolidayModelVM");

CodePudding user response：

If your holiday has fixed days, such as Saturdays and Sundays, you can do this. Here is just a demo written without caching, you can refer to it.

Model:

 public static class CacheKeys
    {
        public static string Saturday => "Saturday";
        public static string Sunday => "Sunday";

    }

Controller:

public async Task<IActionResult> Index(string sortOrder, string searchString,
                                               int? pageNumber, string currentFilter)
        {
            
          DayOfWeek wk = DateTime.Today.DayOfWeek;

            if (CacheKeys.Saturday == wk.ToString()|| CacheKeys.Sunday == wk.ToString())
            {
                return View("/Views/Customers/AppNotAvailable.cshtml");
            }
            else
            {
                return View("/Views/Customers/WorkDay.cshtml");
            }

            
        }

Just judge the current day of the week and combine your fixed holiday time.

Of course you can store the data in the session/cache, you can refer to the documentation to add it.

https://docs.microsoft.com/en-us/aspnet/core/performance/caching/memory?view=aspnetcore-6.0