Sessions in Blazor ASP.Net app

Question

Hello, i'm new to Blazor pages.

I cannot find how to use sessions in blazor project.
FOR EXAMPLE, in my file myfile.cshtml.cs i catch the post of a form

Ho do i write the session variables? and then how do i read ?

public void OnPostSubmit(string formUsername, string formPassword, User user)  
{      
     this._user = user;  
     // here i want to load the username and password previously saved in session variables.  
     
}  

Answer 1

Hi @Filippo ,

I cannot find how to use sessions in blazor project.

Whether your application is a Blazor server application or a Blazor WebAssembly application?

If it is a Blazor server application, you can try to use the browser's localStorage and sessionStorage collections, or you can try to use ASP.NET Core Protected Browser Storage, code like this:

@using Microsoft.AspNetCore.Components.Server.ProtectedBrowserStorage  
@inject ProtectedSessionStorage ProtectedSessionStore  

private async Task IncrementCount()  
{  
    currentCount++;  
    await ProtectedSessionStore.SetAsync("count", currentCount);  
}  

Then, to get the value from the Protected Session, use the GetAsync method:

protected override async Task OnInitializedAsync()  
{  
    var result = await ProtectedSessionStore.GetAsync<int>("count");  
    currentCount = result.Success ? result.Value : 0;  
}  

If the application is a Blazor WebAssembly application, you can try to use browser's localStorage and sessionStorage collections.

Besides, you can also store the data into database or use the In-memory state container service. More detail information, refer to the following articles:

ASP.NET Core Blazor Server state management

ASP.NET Core Blazor WebAssembly state management

Update:

To use session in Razor page application, you could refer the following steps and code:

1. Configure session state in the program.cs file:

   builder.Services.AddDistributedMemoryCache();  
   
   builder.Services.AddSession(options =>  
   {  
       options.IdleTimeout = TimeSpan.FromSeconds(10);  //you can change the session expired time.  
       options.Cookie.HttpOnly = true;  
       options.Cookie.IsEssential = true;  
   });  
   

   and set the UseSession middleware.

   app.UseSession();  
   

2. Then in the Razor page, you can refer to the following code to use session:

   public class IndexModel : PageModel  
   {  
       public const string SessionKeyName = "_Name";  
       public const string SessionKeyAge = "_Age";  
   
       private readonly ILogger<IndexModel> _logger;  
   
       public IndexModel(ILogger<IndexModel> logger)  
       {  
           _logger = logger;  
       }  
   
       public void OnGet()  
       {  
           if (string.IsNullOrEmpty(HttpContext.Session.GetString(SessionKeyName)))  
           {  
               HttpContext.Session.SetString(SessionKeyName, "The Doctor");   //set session  
               HttpContext.Session.SetInt32(SessionKeyAge, 73);  
           }  
           var name = HttpContext.Session.GetString(SessionKeyName);   //get session value.   
           var age = HttpContext.Session.GetInt32(SessionKeyAge).ToString();  
   
           _logger.LogInformation("Session Name: {Name}", name);  
           _logger.LogInformation("Session Age: {Age}", age);  
       }  
   }  
   

   [Note]If you want to use session to store object, you need to add the SessionExtensions. More detailed information, see Session and state management in ASP.NET Core

   ---

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Best regards,
Dillion

Answer 2

As blazor server is only one request, session is not needed. Just store the user in a state variable, access the HttpContext, or best solution inject an ApiAuthenticationStateProvider

https://learn.microsoft.com/en-us/aspnet/core/blazor/security/?view=aspnetcore-7.0