How to use Session variables in ASP.NET 5

Using session in your ASP.NET 5 apps are a little tricky at first. Since ASP.NET 5 has been redesigned to be so modular/configurable, you need to explicitly enable sessions in your app.

Step 1

Project.json file is the central place where we define all the configuration options for the project. The dependecies section in this file defines what other libraries/api’s are being used in this project. You can think about each items in the dependecies section as project references in projects from pre-ASP.NET 5 days.

To enable session, we need to include two items, Microsoft.AspNet.Session and Microsoft.Extensions.Caching.Memory. The great thing about editing project.js is the intellisense support from visual studio.

Everytime you make a change to the file, Visual studio (dnu, behind the scene i guess) will restore the packages/dependecies definded in this file. (more like a nuget restore from packages.config)

Step 2

Now we need to update the Startup.cs classe’s ConfigureServices method where we will call AddCaching and AddSession methods.

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

    // Added these 2 lines
    services.AddCaching();
    services.AddSession(s => s.IdleTimeout = TimeSpan.FromMinutes(30));

    services.AddMvc();
}

You can see that i set the session timeout as 30 minutes.

Also we need to update the Configure method to call the UseSession method on the IApplicationBuilder instance

public void Configure(IApplicationBuilder app, IHostingEnvironment env, 
                                                  ILoggerFactory loggerFactory)
{
   // Your other existing code also goes here.
   app.UseSession();
   
   app.UseMvc(routes =>
   {
 	routes.MapRoute(
			name: "default",
			template: "{controller=Home}/{action=Index}/{id?}");
   });
}

That is all. You should be good to use session variables in your ASP.NET 5 applications.

To set session,

 HttpContext.Session.SetInt32("SomeCounter",1)

To get session,

 var val = HttpContext.Session.GetInt32("SomeCounter");

Anyone using session in their app MUST READ this excellent blog post.