ASP.NET Core 8.0 - Authorized Access

This article will describe authorization attributes and authorization conventions to restrict access to pages for anonymous users. You should review the earlier articles of the Cookies And Claims Project series. Registered users can download the ASP.NET Core 8.0 - Cookies And Claims Project for free.

If an anonymous user attempts to access a resource protected by authorization, they are redirected to the Log In page. You can implement authorization attributes with the Microsoft .AspNetCore .Authorization Namespace. In its most basic form, applying the [Authorize] attribute to a controller, action, or Razor Page, limits access to that component to authenticated users. See MS - Simple authorization in ASP.NET Core.

Pages > Members > Index.cshtml.cs:

[Authorize]
public class IndexModel : PageModel

If you implement authorization conventions to limit access to a folder, you can use the [AllowAnonymous] attribute to allow anonymous access to a page in that folder.

Pages > Members > IdleLogout.cshtml.cs:

[AllowAnonymous]
public class IdleLogoutModel() : PageModel

The CACP implements authorization conventions at startup to authorize users and allow anonymous users to access individual pages or folders of pages. See MS - Razor Pages authorization conventions in ASP.NET Core.

Program.cs:

builder.Services.AddRazorPages(options =>
    {
        options.Conventions.AuthorizeFolder("/Account/Manage");
        options.Conventions.AuthorizeFolder("/Members");
        options.Conventions.AllowAnonymousToPage("/Members/IdleLogout");
        options.Conventions.AuthorizeFolder("/Admin", AppSettings.AdministratorOnlyPolicy);
    })
    .AddJsonOptions(options => { options.JsonSerializerOptions.PropertyNamingPolicy = null; })
    .AddCookieTempDataProvider(options => { options.Cookie.IsEssential = true; });

The CACP implements AddJsonOptions to set PropertyNamingPolicy = null, which replaces camelCase with PascalCase during serializations. The CACP implements AddCookieTempDataProvider's CookieTempDataProviderOptions to set Cookie.IsEssential = true, which allows TempData before non-essential cookie consent. IsEssential defaults to false. This property is only considered when a user opts into the CookiePolicyMiddleware. If you are using the CookiePolicyMiddleware middleware together with CookieTempDataProvider, then either set this property to true or request user consent for non-essential cookies. See MS - CookieTempDataProviderOptions.Cookie Property.