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    An unhandled error has occurred.
    <a href="" class="reload">Reload</a>
    <a class="dismiss">🗙</a>
</div>

using System;
using System.Net.Http;
using Microsoft.AspNetCore.Components;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;

namespace BlazorWasmTelegramLogger.Client.Logging
{
    public class ClientLoggerProvider : ILoggerProvider
    {
        private readonly HttpClient _httpClient;
        private readonly WebApiLoggerOptions _options;
        private readonly NavigationManager _navigationManager;

        public ClientLoggerProvider(
                IServiceProvider serviceProvider,
                IOptions<WebApiLoggerOptions> options,
                NavigationManager navigationManager)
        {
            if (serviceProvider is null)
            {
                throw new ArgumentNullException(nameof(serviceProvider));
            }

            if (options is null)
            {
                throw new ArgumentNullException(nameof(options));
            }

            _httpClient = serviceProvider.CreateScope().ServiceProvider.GetRequiredService<HttpClient>();
            _options = options.Value;
            _navigationManager = navigationManager ?? throw new ArgumentNullException(nameof(navigationManager));
        }

        public ILogger CreateLogger(string categoryName)
        {
            return new WebApiLogger(_httpClient, _options, _navigationManager);
        }

        public void Dispose()
        {
        }
    }
}

using System;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Logging;

namespace BlazorWasmTelegramLogger.Client.Logging
{
    public static class ClientLoggerProviderExtensions
    {
        public static ILoggingBuilder AddWebApiLogger(this ILoggingBuilder builder)
        {
            if (builder == null)
            {
                throw new ArgumentNullException(nameof(builder));
            }

            builder.Services.AddSingleton<ILoggerProvider, ClientLoggerProvider>();
            return builder;
        }
    }
}

public ClientLoggerProvider(
                IServiceProvider serviceProvider,
                IOptions<WebApiLoggerOptions> options,
                NavigationManager navigationManager)

public ILogger CreateLogger(string categoryName)
{
   return new WebApiLogger(_httpClient, _options, _navigationManager);
}

using System;
using System.Net.Http;
using System.Net.Http.Json;
using BlazorWasmTelegramLogger.Shared;
using Microsoft.AspNetCore.Components;
using Microsoft.Extensions.Logging;

namespace BlazorWasmTelegramLogger.Client.Logging
{
    public class WebApiLogger : ILogger
    {
        private readonly WebApiLoggerOptions _options;
        private readonly HttpClient _httpClient;
        private readonly NavigationManager _navigationManager;

        public WebApiLogger(HttpClient httpClient, WebApiLoggerOptions options, NavigationManager navigationManager)
        {
            _httpClient = httpClient ?? throw new ArgumentNullException(nameof(httpClient));
            _options = options ?? throw new ArgumentNullException(nameof(options));
            _navigationManager = navigationManager ?? throw new ArgumentNullException(nameof(navigationManager));
        }

        public IDisposable BeginScope<TState>(TState state) => default;

        public bool IsEnabled(LogLevel logLevel) => logLevel >= _options.LogLevel;

        public void Log<TState>(
            LogLevel logLevel,
            EventId eventId,
            TState state,
            Exception exception,
            Func<TState, Exception, string> formatter)
        {
            if (!IsEnabled(logLevel))
            {
                return;
            }

            if (formatter is null)
            {
                throw new ArgumentNullException(nameof(formatter));
            }

            try
            {
                ClientLog log = new()
                {
                    LogLevel = logLevel,
                    EventId = eventId,
                    Message = formatter(state, exception),
                    Exception = exception?.Message,
                    StackTrace = exception?.StackTrace,
                    Url = _navigationManager.Uri
                };
                _httpClient.PostAsJsonAsync(_options.LoggerEndpointUrl, log);
            }
            catch
            {
                // don't throw exceptions from the logger
            }
        }
    }
}

using Microsoft.Extensions.Logging;

namespace BlazorWasmTelegramLogger.Client.Logging
{
    public class WebApiLoggerOptions
    {
        public string LoggerEndpointUrl { set; get; }

        public LogLevel LogLevel { get; set; } = LogLevel.Information;
    }
}

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "WebApiLogger": {
    "LogLevel": "Warning",
    "LoggerEndpointUrl": "/api/logs"
  }
}

namespace BlazorWasmTelegramLogger.Client
{
    public class Program
    {
        public static async Task Main(string[] args)
        {
            var builder = WebAssemblyHostBuilder.CreateDefault(args);
            builder.RootComponents.Add<App>("#app");

            builder.Services.Configure<WebApiLoggerOptions>(options => builder.Configuration.GetSection("WebApiLogger").Bind(options));
            // …
        }
    }
}

using Microsoft.Extensions.Logging;

namespace BlazorWasmTelegramLogger.Shared
{
    public class ClientLog
    {
        public LogLevel LogLevel { get; set; }

        public EventId EventId { get; set; }

        public string Message { get; set; }

        public string Exception { get; set; }

        public string StackTrace { get; set; }

        public string Url { get; set; }
    }
}

namespace BlazorWasmTelegramLogger.Client
{
    public class Program
    {
        public static async Task Main(string[] args)
        {
            var builder = WebAssemblyHostBuilder.CreateDefault(args);
            builder.RootComponents.Add<App>("#app");

            builder.Services.AddScoped(sp => new HttpClient { BaseAddress = new Uri(builder.HostEnvironment.BaseAddress) });

            builder.Services.Configure<WebApiLoggerOptions>(options => builder.Configuration.GetSection("WebApiLogger").Bind(options));
            builder.Services.AddLogging(configure =>
            {
                configure.AddWebApiLogger();
            });

            await builder.Build().RunAsync();
        }
    }
}

public bool IsEnabled(LogLevel logLevel) => logLevel >= _options.LogLevel;

using System;
using System.Text;
using System.Threading.Tasks;
using BlazorWasmTelegramLogger.Shared;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.Options;
using Telegram.Bot;
using Telegram.Bot.Types.Enums;

namespace BlazorWasmTelegramLogger.Server.Services
{
    public class TelegramLoggingBotOptions
    {
        public string AccessToken { get; set; }
        public string ChatId { get; set; }
    }

    public interface ITelegramBotService
    {
        Task SendLogAsync(ClientLog log);
    }

    public class TelegramBotService : ITelegramBotService
    {
        private readonly string _chatId;
        private readonly TelegramBotClient _client;

        public TelegramBotService(IOptions<TelegramLoggingBotOptions> options)
        {
            _chatId = options.Value.ChatId;
            _client = new TelegramBotClient(options.Value.AccessToken);
        }

        public async Task SendLogAsync(ClientLog log)
        {
            var text = formatMessage(log);
            if (string.IsNullOrWhiteSpace(text))
            {
                return;
            }

            await _client.SendTextMessageAsync(_chatId, text, ParseMode.Markdown);
        }

        private static string formatMessage(ClientLog log)
        {
            if (string.IsNullOrWhiteSpace(log.Message))
            {
                return string.Empty;
            }

            var sb = new StringBuilder();
            sb.Append(toEmoji(log.LogLevel))
                .Append(" *")
                .AppendFormat("{0:hh:mm:ss}", DateTime.Now)
                .Append("* ")
                .AppendLine(log.Message);

            if (!string.IsNullOrWhiteSpace(log.Exception))
            {
                sb.AppendLine()
                    .Append('`')
                    .AppendLine(log.Exception)
                    .AppendLine(log.StackTrace)
                    .AppendLine("`")
                    .AppendLine();
            }

            sb.Append("*Url:* ").AppendLine(log.Url);
            return sb.ToString();
        }

        private static string toEmoji(LogLevel level) =>
            level switch
            {
                LogLevel.Trace => "⬜️",
                LogLevel.Debug => "🟦",
                LogLevel.Information => "⬛️️️",
                LogLevel.Warning => "🟧",
                LogLevel.Error => "🟥",
                LogLevel.Critical => "❌",
                LogLevel.None => "🔳",
                _ => throw new ArgumentOutOfRangeException(nameof(level), level, null)
            };
    }
}

<Project Sdk="Microsoft.NET.Sdk.Web">
  <ItemGroup>
    <PackageReference Include="Telegram.Bot" Version="15.7.1" />
  </ItemGroup>
</Project>

    public class TelegramLoggingBotOptions
    {
        public string AccessToken { get; set; }
        public string ChatId { get; set; }
    }

{
  "Logging": {
    "LogLevel": {
      "Default": "Information",
      "Microsoft": "Warning",
      "Microsoft.Hosting.Lifetime": "Information"
    }
  },
  "AllowedHosts": "*",
  "TelegramLoggingBot": {
    "AccessToken": "1826…",
    "ChatId": "-1001…" 
  }
}

namespace BlazorWasmTelegramLogger.Server
{
    public class Startup
    {
        // ...

        public void ConfigureServices(IServiceCollection services)
        {
            services.Configure<TelegramLoggingBotOptions>(options =>
                            Configuration.GetSection("TelegramLoggingBot").Bind(options));
            services.AddSingleton<ITelegramBotService, TelegramBotService>();

            // ...
        }

        // ...
    }
}

    public class TelegramBotService : ITelegramBotService
    {
        private readonly string _chatId;
        private readonly TelegramBotClient _client;

        public TelegramBotService(IOptions<TelegramLoggingBotOptions> options)
        {
            _chatId = options.Value.ChatId;
            _client = new TelegramBotClient(options.Value.AccessToken);
        }

using System;
using System.Threading.Tasks;
using BlazorWasmTelegramLogger.Server.Services;
using BlazorWasmTelegramLogger.Shared;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;

namespace BlazorWasmTelegramLogger.Server.Controllers
{
    [ApiController]
    [Route("api/[controller]")]
    public class LogsController : ControllerBase
    {
        private readonly ILogger<LogsController> _logger;
        private readonly ITelegramBotService _telegramBotService;

        public LogsController(ILogger<LogsController> logger, ITelegramBotService telegramBotService)
        {
            _logger = logger ?? throw new ArgumentNullException(nameof(logger));
            _telegramBotService = telegramBotService;
        }

        [HttpPost]
        public async Task<IActionResult> PostLog(ClientLog log)
        {
            // TODO: Save the client's `log` in the database

            _logger.Log(log.LogLevel, log.EventId, log.Url + Environment.NewLine + log.Message);

            await _telegramBotService.SendLogAsync(log);

            return Ok();
        }
    }
}

@page "/counter"

<h1>Counter</h1>

<p>Current count: @currentCount</p>

<button class="btn btn-primary" @onclick="IncrementCount">Click me</button>

@code {
    private int currentCount = 0;

    private void IncrementCount()
    {
        currentCount++;

        throw new InvalidOperationException("This is an exception message from the client!");
    }
}

public class CirclePreview:IPeiview
    {
        private readonly Graphics graphics;

        public CirclePreview(Graphics graphics)
        {
            this.graphics = graphics;
        }
        public void Draw(ShapeSpecification shapeScepification)
        {
            var startPoints = AreaParser.Parse(shapeScepification.StartPoint, shapeScepification.EndPoint);

            float raduis = Math.Max(startPoints.Width, startPoints.Height);

            if (shapeScepification.IsFill)
                this.graphics.FillEllipse(shapeScepification.BackgroundBrush, startPoints.XPoint, startPoints.YPoint, raduis, raduis);
            else
                this.graphics.DrawEllipse(new Pen(shapeScepification.ForeColor, shapeScepification.Thickness), startPoints.XPoint, startPoints.YPoint, raduis, raduis);
        }
    }

1.  Get/GetAsync(with data retriever)
2.  Get/GetAsync(without data retriever)
3.  Set/SetAsync
4.  Remove/RemoveAsync
5.  ~~Refresh/RefreshAsync (was removed)~~
6.  RemoveByPrefix/RemoveByPrefixAsync
7.  SetAll/SetAllAsync
8.  GetAll/GetAllAsync
9.  GetByPrefix/GetByPrefixAsync
10.  RemoveAll/RemoveAllAsync
11.  GetCount
12.  Flush/FlushAsync
13.  TrySet/TrySetAsync
14.  GetExpiration/GetExpirationAsync

1. In-Memory
2. Memcached
3. Redis(Based on StackExchange.Redis)
4. Redis(Based on csredis)
5. SQLite
6. Hybrid
7. Disk
8. LiteDb

1. BinaryFormatter
2. MessagePack
3. Newtonsoft.Json
4. Protobuf
5. System.Text.Json

• MessagePack
• Newtonsoft.Json
• Protobuf
• System.Text.Json

        public DateTime BirthDate { get; set; }
        public DateTime HireDate { get; set; }
        public DateTime? LeaveDate { get; set; }

از این جدول چه می‌فهمید؟ با یک نگاه می‌توان فهمید که ساختار بالای من باید 24 بایت گرفته باشد؛ برای ساختاری که هم تاریخ و هم زمان (ساعت) را پشتیبانی می‌کند. ولی با نگاه دقیق‌تر به نام پراپرتی‌ها این نکته روشن می‌شود که ما یک گپ Gap (فضای بیهوده) داریم چون زمان تولد، استخدام و ترک سازمان اصلا نیازی به ساعت ندارند و همان تاریخ کافی است. یعنی نوع Date با حجم کلی 9 بایت؛ که در نتیجه 15 بایت صرفه جویی در یک رکورد صورت خواهد گرفت.

پس کد بالا را به شکل زیر تغییر می‌دهم:

          [Column(TypeName = "date")]
        public DateTime BirthDate { get; set; }

        [Column(TypeName = "date")]
        public DateTime HireDate { get; set; }

        [Column(TypeName = "date")]
        public DateTime? LeaveDate { get; set; }

خصوصیت Column از نسخه 4.5دات نت فریم ورک اضافه شده و در فضای نام System.ComponentModel.DataAnnotations.Schema قرار گرفته است.

public abstract class Product
{
  public string Name { get; set; }
  public abstract ProductOrder Order(int quantity);
}

public class Book : Product
{
  public string ISBN { get; set; }
  public override ProductOrder Order(int quantity) =>
new BookOrder { Quantity = quantity, Product = this };
}

public class ProductOrder
{
  public int Quantity { get; set; }
}

public class BookOrder : ProductOrder
{
  public Book Product { get; set; }
}

var book = new Book
{
  Name = "My book",
  ISBN = "11-1-12-22-0"
};
BookOrder orderBook = (BookOrder)book.Order(1);

public class Book : Product
{
  public string ISBN { get; set; }
  public override BookOrder Order(int quantity) =>
      new BookOrder { Quantity = quantity, Product = this };
}

BookOrder orderBook = book.Order(1);

using System.Collections.Generic;
using System.Runtime.CompilerServices;

namespace ConditionalWeakTableSamples
{
    public static class AttachedProperties
    {
        public static ConditionalWeakTable<object,
            Dictionary<string, object>> ObjectCache = new ConditionalWeakTable<object,
                Dictionary<string, object>>();

        public static void SetValue<T>(this T obj, string name, object value) where T : class
        {
            var properties = ObjectCache.GetOrCreateValue(obj);

            if (properties.ContainsKey(name))
                properties[name] = value;
            else
                properties.Add(name, value);
        }

        public static T GetValue<T>(this object obj, string name)
        {
            Dictionary<string, object> properties;
            if (ObjectCache.TryGetValue(obj, out properties) && properties.ContainsKey(name))
                return (T)properties[name];
            return default(T);
        }

        public static object GetValue(this object obj, string name)
        {
            return obj.GetValue<object>(name);
        }
    }
}

    public static class ISecurityPrincipalExtension
    {
        public static bool Disclaimer(this IPrincipal principal)
        {
            return principal.GetValue<bool>("Disclaimer");
        }

        public static void SetDisclaimer(this IPrincipal principal, bool value)
        {
            principal.SetValue("Disclaimer", value);
        }
    }

using System.Runtime.CompilerServices;

namespace ConditionalWeakTableSamples
{
    public static class PropertyExtensions
    {
        private class ExtraPropertyHolder
        {
            public bool IsDirty { get; set; }
        }

        private static readonly ConditionalWeakTable<object, ExtraPropertyHolder> _isDirtyTable
                = new ConditionalWeakTable<object, ExtraPropertyHolder>();

        public static bool IsDirty(this object @this)
        {
            return _isDirtyTable.GetOrCreateValue(@this).IsDirty;
        }

        public static void SetIsDirty(this object @this, bool isDirty)
        {
            _isDirtyTable.GetOrCreateValue(@this).IsDirty = isDirty;
        }
    }
}

public void Closed(DbConnection connection, DbConnectionInterceptionContext interceptionContext)
{
}

using System;
using System.Runtime.CompilerServices;

namespace ConditionalWeakTableSamples
{
    public static class UniqueIdExtensions
    {
        static readonly ConditionalWeakTable<object, string> _idTable = 
                                    new ConditionalWeakTable<object, string>();

        public static string GetUniqueId(this object obj)
        {
            return _idTable.GetValue(obj, o => Guid.NewGuid().ToString());
        }

        public static string GetUniqueId(this object obj, string key)
        {
            return _idTable.GetValue(obj, o => key);
        }
    }
}

namespace DNT.IDP
{
    public class Startup
    {
        public const string TwoFactorAuthenticationScheme = "idsrv.2FA";

        public void ConfigureServices(IServiceCollection services)
        {
            // ...

            services.AddAuthentication()
                .AddCookie(authenticationScheme: TwoFactorAuthenticationScheme)
                .AddGoogle(authenticationScheme: "Google", configureOptions: options =>
                {
                    options.SignInScheme = IdentityServerConstants.ExternalCookieAuthenticationScheme;
                    options.ClientId = Configuration["Authentication:Google:ClientId"];
                    options.ClientSecret = Configuration["Authentication:Google:ClientSecret"];
                });
        }

namespace DNT.IDP.Controllers.Account
{
    [SecurityHeaders]
    [AllowAnonymous]
    public class AccountController : Controller
    {
        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> Login(LoginInputModel model, string button)
        {
    // ... 

            if (ModelState.IsValid)
            {
                if (await _usersService.AreUserCredentialsValidAsync(model.Username, model.Password))
                {
                    var user = await _usersService.GetUserByUsernameAsync(model.Username);
                    
                    var id = new ClaimsIdentity();
                    id.AddClaim(new Claim(JwtClaimTypes.Subject, user.SubjectId));
                    await HttpContext.SignInAsync(scheme: Startup.TwoFactorAuthenticationScheme, principal: new ClaimsPrincipal(id));

                    await _twoFactorAuthenticationService.SendTemporaryCodeAsync(user.SubjectId);

                    var redirectToAdditionalFactorUrl =
                        Url.Action("AdditionalAuthenticationFactor",
                            new
                            {
                                returnUrl = model.ReturnUrl,
                                rememberLogin = model.RememberLogin
                            });                   

                    // request for a local page
                    if (Url.IsLocalUrl(model.ReturnUrl))
                    {
                        return Redirect(redirectToAdditionalFactorUrl);
                    }

                    if (string.IsNullOrEmpty(model.ReturnUrl))
                    {
                        return Redirect("~/");
                    }

                    // user might have clicked on a malicious link - should be logged
                    throw new Exception("invalid return URL");
                }

                await _events.RaiseAsync(new UserLoginFailureEvent(model.Username, "invalid credentials"));
                ModelState.AddModelError("", AccountOptions.InvalidCredentialsErrorMessage);
            }

            // something went wrong, show form with error
            var vm = await BuildLoginViewModelAsync(model);
            return View(vm);
        }

 await HttpContext.SignInAsync(scheme: Startup.TwoFactorAuthenticationScheme, principal: new ClaimsPrincipal(id));

    public interface ITwoFactorAuthenticationService
    {
        Task SendTemporaryCodeAsync(string subjectId);
        Task<bool> IsValidTemporaryCodeAsync(string subjectId, string code);
    }

using System.ComponentModel.DataAnnotations;

namespace DNT.IDP.Controllers.Account
{
    public class AdditionalAuthenticationFactorViewModel
    {
        [Required]
        public string Code { get; set; }

        public string ReturnUrl { get; set; }

        public bool RememberLogin { get; set; }
    }
}

namespace DNT.IDP.Controllers.Account
{
    public class AccountController : Controller
    {
        [HttpGet]
        public IActionResult AdditionalAuthenticationFactor(string returnUrl, bool rememberLogin)
        {
            // create VM
            var vm = new AdditionalAuthenticationFactorViewModel
            {
                RememberLogin = rememberLogin,
                ReturnUrl = returnUrl
            };

            return View(vm);
        }

        [HttpPost]
        [ValidateAntiForgeryToken]
        public async Task<IActionResult> AdditionalAuthenticationFactor(
            AdditionalAuthenticationFactorViewModel model)
        {
            if (!ModelState.IsValid)
            {
                return View(model);
            }

            // read identity from the temporary cookie
            var info = await HttpContext.AuthenticateAsync(Startup.TwoFactorAuthenticationScheme);
            var tempUser = info?.Principal;
            if (tempUser == null)
            {
                throw new Exception("2FA error");
            }

            // ... check code for user
            if (!await _twoFactorAuthenticationService.IsValidTemporaryCodeAsync(tempUser.GetSubjectId(), model.Code))
            {
                ModelState.AddModelError("code", "2FA code is invalid.");
                return View(model);
            }

            // login the user
            AuthenticationProperties props = null;
            if (AccountOptions.AllowRememberLogin && model.RememberLogin)
            {
                props = new AuthenticationProperties
                {
                    IsPersistent = true,
                    ExpiresUtc = DateTimeOffset.UtcNow.Add(AccountOptions.RememberMeLoginDuration)
                };
            }

            // issue authentication cookie for user
            var user = await _usersService.GetUserBySubjectIdAsync(tempUser.GetSubjectId());
            await _events.RaiseAsync(new UserLoginSuccessEvent(user.Username, user.SubjectId, user.Username));
            await HttpContext.SignInAsync(user.SubjectId, user.Username, props);

            // delete temporary cookie used for 2FA
            await HttpContext.SignOutAsync(Startup.TwoFactorAuthenticationScheme);

            if (_interaction.IsValidReturnUrl(model.ReturnUrl) || Url.IsLocalUrl(model.ReturnUrl))
            {
                return Redirect(model.ReturnUrl);
            }

            return Redirect("~/");
        }

@model AdditionalAuthenticationFactorViewModel

<div>
    <div class="page-header">
        <h1>2-Factor Authentication</h1>
    </div>

    @Html.Partial("_ValidationSummary")

    <div class="row">
        <div class="panel panel-default">
            <div class="panel-heading">
                <h3 class="panel-title">Input your 2FA code</h3>
            </div>
            <div class="panel-body">
                <form asp-route="Login">
                    <input type="hidden" asp-for="ReturnUrl" />
                    <input type="hidden" asp-for="RememberLogin" />

                    <fieldset>
                        <div class="form-group">
                            <label asp-for="Code"></label>
                            <input class="form-control" placeholder="Code" asp-for="Code" autofocus>
                        </div>

                        <div class="form-group">
                            <button class="btn btn-primary">Submit code</button>
                        </div>
                    </fieldset>
                </form>

            </div>
        </div>
    </div>
</div>

{
    "dependencies": {
        "Microsoft.Extensions.Caching.SqlServer": "1.1.0"
    },
    "tools": {
        "Microsoft.Extensions.Caching.SqlConfig.Tools": "1.1.0-preview4-final"
    }
}

 dotnet sql-cache create "Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=sql_cache;Integrated Security=True;" "dbo" "AppSqlCache"

CREATE TABLE AppSqlCache (
    Id                         NVARCHAR (449)  COLLATE SQL_Latin1_General_CP1_CS_AS NOT NULL,
    Value                      VARBINARY (MAX) NOT NULL,
    ExpiresAtTime              DATETIMEOFFSET  NOT NULL,
    SlidingExpirationInSeconds BIGINT          NULL,
    AbsoluteExpiration         DATETIMEOFFSET  NULL,
    CONSTRAINT pk_Id PRIMARY KEY (Id)
);

CREATE NONCLUSTERED INDEX Index_ExpiresAtTime
    ON AppSqlCache(ExpiresAtTime);

    public class AppSqlCache
    {
        public string Id { get; set; }
        public byte[] Value { get; set; }
        public DateTimeOffset ExpiresAtTime { get; set; }
        public long? SlidingExpirationInSeconds { get; set; }
        public DateTimeOffset? AbsoluteExpiration { get; set; }
    }

    public class MyDBDataContext : DbContext
    {
        public virtual DbSet<AppSqlCache> AppSqlCache { get; set; }

        protected override void OnModelCreating(ModelBuilder modelBuilder)
        {
            modelBuilder.Entity<AppSqlCache>(entity =>
            {
                entity.ToTable(name: "AppSqlCache", schema: "dbo");
                entity.HasIndex(e => e.ExpiresAtTime).HasName("Index_ExpiresAtTime");
                entity.Property(e => e.Id).HasMaxLength(449);
                entity.Property(e => e.Value).IsRequired();
            });
        }
    }

public void ConfigureServices(IServiceCollection services)
{
    services.AddDistributedSqlServerCache(options =>
    {
        options.ConnectionString = @"Data Source=(localdb)\MSSQLLocalDB;Initial Catalog=sql_cache;Integrated Security=True;";
        options.SchemaName = "dbo";
        options.TableName = "AppSqlCache";
    });

public IActionResult Index()
{
   HttpContext.Session.SetString("User", "VahidN");
   return Json(true);
}

public IActionResult About()
{
   var userContent = HttpContext.Session.GetString("User");
   return Json(userContent);
}

 services.Add(ServiceDescriptor.Singleton<IDistributedCache, SqlServerCache>());

using System;
using System.Text;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Caching.Distributed;
 
namespace Core1RtmEmptyTest.Controllers
{
    public class CacheTestController : Controller
    {
        readonly IDistributedCache _cache;
        public CacheTestController(IDistributedCache cache)
        {
            _cache = cache;
        }
 
        public IActionResult SetCacheData()
        {
            var time = DateTime.Now.ToLocalTime().ToString();
            var cacheOptions = new DistributedCacheEntryOptions
            {
                AbsoluteExpiration = DateTime.Now.AddYears(1)
 
            };
            _cache.Set("Time", Encoding.UTF8.GetBytes(time), cacheOptions);
            return View();
        }
 
        public IActionResult GetCacheData()
        {
            var time = Encoding.UTF8.GetString(_cache.Get("Time"));
            ViewBag.data = time;
            return View();
        }
 
        public bool RemoveCacheData()
        {
            _cache.Remove("Time");
            return true;
        }
    }
}

  Value  VARBINARY (MAX) NOT NULL,

  public byte[] Value { get; set; }

<distributed-cache name="MyCacheItem2" expires-sliding="TimeSpan.FromMinutes(30)">
    <p>From distributed-cache</p>
    @DateTime.Now.ToString()
</distributed-cache>