Unable to use session in ASP.Net vNext Project

Question

I have an ASP.Net vNext project that uses Session. But I am getting this error while trying to get/set values in the session.

An exception of type 'System.InvalidOperationException' occurred in Microsoft.AspNet.Http.Core.dll but was not handled in user code

Additional information: Session has not been configured for this application or request.

Here's my controller method:

    [AllowAnonymous]
    [HttpGet("/admin")]
    public IActionResult Index()
    {
        if (Context.Session.GetString("UserName") == null) // error thrown here
        {
            return RedirectToAction("Login");
        }

        return View();
    }

I have added the KVM package "Microsoft.AspNet.Session": "1.0.0-beta3" in my project.json file as well and have configured my application to use session via my Startup.cs like so:

public void ConfigureServices(IServiceCollection services)
{
    // code removed for brevity
    services.AddCachingServices();
    services.AddSessionServices();
}

public void Configure(IApplicationBuilder app)
    {
        app.UseMvc();
        app.UseInMemorySession(configure: s => s.IdleTimeout = TimeSpan.FromMinutes(30));
    }

I have looked at the vNext documentation on Github but it does not provide much information about ASP.Net sessions. What am I doing wrong?

Answer 1

So I figured this out. The fix was quite simple actually. Since ASP.Net adds the middlewares sequentially into the request pipeline, all I needed to do was use the session middleware before using MVC. More info here: https://stackoverflow.com/a/29569746/832546

Fixed code:

public void Configure(IApplicationBuilder app)
{
    app.UseInMemorySession(configure: s => s.IdleTimeout = TimeSpan.FromMinutes(30));
    app.UseMvc();
}

Answer 2

Thanks to @acrhistof the link helped.

So if you are using RC1: add this these dependencies in project.json:

 "Microsoft.AspNet.Session": "1.0.0-rc1-final",
 "Microsoft.Extensions.Caching.Memory": "1.0.0",

in Startup.cs file:

    public void ConfigureServices(IServiceCollection services)
    {
        services.AddCaching();
        services.AddSession();
        services.AddMvc();
    }

and

public void Configure(IApplicationBuilder app, IHostingEnvironment env, ILoggerFactory loggerFactory)
    {
     app.UseSession(); //outside of dev  if (env.IsDevelopment())
     ....
     }

Answer 3

It seems like things changed once again and the well-known ASP.NET session has to be configured differently in the rc1. (no UseInMemorySession() or other AppBuilder methods are related to Session, now it is added as a service).

In general Session has to be installed, configured, and then used. All these steps are quite new and somewhat unusual. Moreover, it depends on Cache:

Session is built on top of IDistributedCache, so you must configure this as well, otherwise you will receive an error.

The quotation above is from ASP.NET 5 docs. All you need to do is described here: https://docs.asp.net/en/latest/fundamentals/app-state.html#installing-and-configuring-session.