Session has not been configured for this application or request error

Question

I am very new to asp.net I recently I came across this exception:

System.InvalidOperationException

The details of the exception says:

Session has not been configured for this application or request.

Here is the code snippet where it happens:

[HttpPost]         public object Post([FromBody]loginCredentials value)         {             if (value.username.Equals("Admin")                 &&                 value.password.Equals("admin"))             {                 HttpContext.Session.Set("userLogin", System.Text.UTF8Encoding.UTF8.GetBytes(value.username)); //This the line that throws the exception.                 return new                 {                     account = new                     {                         email = value.username                     }                 };             }             throw new UnauthorizedAccessException("invalid credentials");         } 

I have no idea why it's happening or what does this error actually mean. Can someone please explain what might be causing this?

Answer 1

In your Startup.cs you might need to call

app.UseSession before app.UseMvc

app.UseSession();    app.UseMvc();  

For this to work, you will also need to make sure the Microsoft.AspNetCore.Session nuget package is installed.

Update

You dont not need to use app.UseMvc(); in .NET Core 3.0 or higher

Answer 2

Following code worked out for me:

Configure Services :

    public void ConfigureServices(IServiceCollection services)     {           //In-Memory           services.AddDistributedMemoryCache();           services.AddSession(options => {           options.IdleTimeout = TimeSpan.FromMinutes(1);           });                         // Add framework services.           services.AddMvc();      } 

Configure the HTTP Request Pipeline:

public void Configure(IApplicationBuilder app, IHostingEnvironment env,                        ILoggerFactory loggerFactory) {     loggerFactory.AddConsole(Configuration.GetSection("Logging"));     loggerFactory.AddDebug();     if (env.IsDevelopment())     {        app.UseDeveloperExceptionPage();        app.UseBrowserLink();     }     else     {        app.UseExceptionHandler("/Home/Error");     }     app.UseStaticFiles();     app.UseSession();     app.UseMvc(routes =>     {         routes.MapRoute(            name: "default",            template: "{controller=Home}/{action=Index}/{id?}");      });  }