public static class BookStorePermissions
{
    public const string GroupName = "BookStore";

    public static class Books
    {
        public const string Default = GroupName + ".Books";
        public const string Create = Default + ".Create";
        public const string Edit = Default + ".Edit";
        public const string Delete = Default + ".Delete";
    }
}

public class BookStorePermissionDefinitionProvider : PermissionDefinitionProvider
{
    public override void Define(IPermissionDefinitionContext context)
    {
        var bookStoreGroup = context.AddGroup(BookStorePermissions.GroupName, L("Permission:BookStore"));

        var booksPermission = bookStoreGroup.AddPermission(
            BookStorePermissions.Books.Default,
            L("Permission:Books"));

        booksPermission.AddChild(
            BookStorePermissions.Books.Create,
            L("Permission:Books.Create"));

        booksPermission.AddChild(
            BookStorePermissions.Books.Edit,
            L("Permission:Books.Edit"));

        booksPermission.AddChild(
            BookStorePermissions.Books.Delete,
            L("Permission:Books.Delete"));
    }

    private static LocalizableString L(string name)
    {
        return LocalizableString.Create<BookStoreResource>(name);
    }
}

[Authorize(BookStorePermissions.Books.Create)]
public virtual async Task<BookDto> CreateAsync(CreateBookDto input)
{
    // Only users with Books.Create permission can execute
}

public class BookAppService : ApplicationService
{
    public async Task DoSomethingAsync()
    {
        // Check and throw if not granted
        await CheckPolicyAsync(BookStorePermissions.Books.Edit);

        // Or check without throwing
        if (await IsGrantedAsync(BookStorePermissions.Books.Delete))
        {
            // Has permission
        }
    }
}

[AllowAnonymous]
public virtual async Task<BookDto> GetPublicBookAsync(Guid id)
{
    // No authentication required
}

public class BookAppService : ApplicationService
{
    public async Task DoSomethingAsync()
    {
        // CurrentUser is available from base class - no injection needed
        var userId = CurrentUser.Id;
        var userName = CurrentUser.UserName;
        var email = CurrentUser.Email;
        var isAuthenticated = CurrentUser.IsAuthenticated;
        var roles = CurrentUser.Roles;
        var tenantId = CurrentUser.TenantId;
    }
}

// In other services, inject ICurrentUser
public class MyService : ITransientDependency
{
    private readonly ICurrentUser _currentUser;
    public MyService(ICurrentUser currentUser) => _currentUser = currentUser;
}

public async Task UpdateMyBookAsync(Guid bookId, UpdateBookDto input)
{
    var book = await _bookRepository.GetAsync(bookId);

    if (book.CreatorId != CurrentUser.Id)
    {
        throw new AbpAuthorizationException();
    }

    // Update book...
}

bookStoreGroup.AddPermission(
    BookStorePermissions.Books.Default,
    L("Permission:Books"),
    multiTenancySide: MultiTenancySides.Tenant // Only for tenants
);

booksPermission.RequireFeatures("BookStore.PremiumFeature");

public class MyService : ITransientDependency
{
    private readonly IPermissionManager _permissionManager;

    public async Task GrantPermissionToUserAsync(Guid userId, string permissionName)
    {
        await _permissionManager.SetForUserAsync(userId, permissionName, true);
    }

    public async Task GrantPermissionToRoleAsync(string roleName, string permissionName)
    {
        await _permissionManager.SetForRoleAsync(roleName, permissionName, true);
    }
}