PRACTICAL 8: SESSION DATA USAGE

STEPS:
1. Create a new ASP.NET Core Web Application (MVC) project (SessionDemoData).
2. In HomeController.cs add the actions SetSessionData, GetSessionData,
   ClearSingleSession and ClearAllSessionData.
3. In Views > Home add the views: Index.cshtml, GetSessionData.cshtml, SetSessionData.cshtml.
4. In Startup.cs add the session services in ConfigureServices
   (AddDistributedMemoryCache + AddSession).
5. In Startup.cs > Configure add app.UseSession(); (line 56) after app.UseRouting();
6. Run the project and click the links on the Index page.

CODE: (Controllers/HomeController.cs)
using System;
using System.Collections.Generic;
using System.Diagnostics;
using System.Linq;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Mvc;
using Microsoft.Extensions.Logging;
using SessionDemoData.Models;

namespace SessionDemoData.Controllers
{
    public class HomeController : Controller
    {
        private readonly ILogger<HomeController> _logger;

        public HomeController(ILogger<HomeController> logger)
        {
            _logger = logger;
        }

        public IActionResult Index()
        {
            return View();
        }

        public IActionResult Privacy()
        {
            return View();
        }

        [ResponseCache(Duration = 0, Location = ResponseCacheLocation.None, NoStore = true)]
        public IActionResult Error()
        {
            return View(new ErrorViewModel { RequestId = Activity.Current?.Id ?? HttpContext.TraceIdentifier });
        }

        public IActionResult SetSessionData()
        {
            HttpContext.Session.SetString("UserName", "Aditya");
            HttpContext.Session.SetInt32("UserAge", 20);
            return View();
        }

        public IActionResult GetSessionData()
        {
            var userName = HttpContext.Session.GetString("UserName");
            var userAge = HttpContext.Session.GetInt32("UserAge");
            if (!string.IsNullOrEmpty(userName) && userAge.HasValue)
            {
                ViewData["Message"] = $"User:{userName},Age:{userAge.Value}";
            }
            else
            {
                ViewData["Message"] = "No session data found";
            }
            return View();
        }

        public IActionResult ClearSingleSession()
        {
            HttpContext.Session.Remove("UserName");
            return RedirectToAction("GetSessionData");
        }

        public IActionResult ClearAllSessionData()
        {
            HttpContext.Session.Clear();
            return RedirectToAction("GetSessionData");
        }
    }
}

CODE: (Views/Home/Index.cshtml)
@{
    ViewData["Title"] = "Home Page";
}

<h2>Welcome to Session Demo</h2>

<ul>
    <li><a href="@Url.Action("SetSessionData","Home")">Set Session Data</a></li>
    <li><a href="@Url.Action("GetSessionData","Home")">Get Session Data</a></li>
    <li><a href="@Url.Action("ClearSingleSession","Home")">Clear Username</a></li>
    <li><a href="@Url.Action("ClearAllSessionData","Home")">Clear All Session Data</a></li>
</ul>

CODE: (Views/Home/GetSessionData.cshtml)
@{
    ViewData["Title"] = "GetSessionData";
}

<h1>GetSessionData</h1>
<h2>@ViewData["Message"]</h2>

<a asp-action="SetSessionData">Set Session</a>
<a asp-action="ClearSingleSession">Remove UserName</a>
<a asp-action="ClearAllSessionData">Clear All Session</a>

CODE: (Views/Home/SetSessionData.cshtml)
@{
    ViewData["Title"] = "SetSessionData";
}

<h1>SetSessionData</h1>
<p>Session data has been set sucessfully</p>
<a href="@Url.Action("GetSessionData")">View Session Data</a>

CODE: (Startup.cs - whole ConfigureServices and Configure; app.UseSession() is line 56)
public void ConfigureServices(IServiceCollection services)
{
    services.AddDistributedMemoryCache();

    services.AddSession(options =>
    {
        options.IdleTimeout = TimeSpan.FromMinutes(30);
        options.Cookie.HttpOnly = true;
        options.Cookie.IsEssential = true;

    });
    services.AddControllersWithViews();
}

public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
{
    if (env.IsDevelopment())
    {
        app.UseDeveloperExceptionPage();
    }
    else
    {
        app.UseExceptionHandler("/Home/Error");
        // The default HSTS value is 30 days. You may want to change this for production scenarios.
        app.UseHsts();
    }
    app.UseHttpsRedirection();
    app.UseStaticFiles();

    app.UseRouting();

    app.UseSession();
    app.UseAuthorization();

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

OUTPUT:
Set Session Data  -> "Session data has been set sucessfully"
Get Session Data  -> "User:Aditya,Age:20"
Clear Username / Clear All Session Data -> "No session data found"
