I am a newbie in ASP.NET, and currently learning ASP.NET Identity. I know it's built on top of OWIN implementation by Microsoft, and I am also still learning that too. So, I came across the extension method CreatePerOwinContext in the Owin startup code, and I don't see a clear purpose of using it. Is it some kind of dependency injection container? What is the real purpose of the method? In what case it should be applied?
CreatePerOwinContext registers a static callback which your application will use to get back a new instance of a specified type.
This callback will be called once per request and will store the object/objects in OwinContext so that you will be able to use them throughout the application.
Let's say you have defined your own implementation of IdentityDbContext:
public class ApplicationDatabaseContext : IdentityDbContext<MyApplicationUser, MyRole, Guid, MyUserLogin, MyUserRole, MyUserClaim>
{
public ApplicationDatabaseContext() : base("<connection string>")
{
}
public static ApplicationDatabaseContext Create()
{
return new ApplicationDatabaseContext();
}
protected override void OnModelCreating(System.Data.Entity.DbModelBuilder modelBuilder)
{
base.OnModelCreating(modelBuilder);
// Customize your table creation here.
#region USERS - INFOS
modelBuilder.Entity<UserInfo>()
.Property(p => p.FirstName)
.HasColumnType("varchar")
.HasMaxLength(70);
modelBuilder.Entity<UserInfo>()
.Property(p => p.LastName)
.HasColumnType("varchar")
.HasMaxLength(70);
modelBuilder.Entity<UserInfo>()
.Property(p => p.Address)
.HasColumnType("varchar")
.HasMaxLength(100);
modelBuilder.Entity<UserInfo>()
.Property(p => p.City)
.HasColumnType("varchar")
.HasMaxLength(100);
modelBuilder.Entity<UserInfo>()
.ToTable("UsersInfo");
#endregion
}
public DbSet<UserInfo> UsersInfo { get; set; }
}
and your implementation of UserManager:
public class ApplicationUserManager : UserManager<MyApplicationUser, Guid>
{
public ApplicationUserManager(IUserStore<MyApplicationUser, Guid> store) : base(store)
{
}
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
var manager = new ApplicationUserManager(new MyUserStore(context.Get<ApplicationDatabaseContext>()));
manager.UserValidator = new UserValidator<MyApplicationUser, Guid>(manager)
{
AllowOnlyAlphanumericUserNames = false,
RequireUniqueEmail = true
};
manager.PasswordValidator = new PasswordValidator()
{
RequiredLength = 6,
RequireNonLetterOrDigit = false,
// RequireDigit = true,
RequireLowercase = false,
RequireUppercase = false,
};
var dataProtectionProvider = options.DataProtectionProvider;
if (dataProtectionProvider != null)
{
manager.UserTokenProvider = new DataProtectorTokenProvider<MyApplicationUser, Guid>(dataProtectionProvider.Create("PasswordReset"));
}
return (manager);
}
}
In your Owin Startup you will register the callback:
// IAppBuilder app
app.CreatePerOwinContext<ApplicationDatabaseContext>(ApplicationDatabaseContext.Create);
app.CreatePerOwinContext<ApplicationUserManager>(ApplicationUserManager.Create);
which will call the static method:
public static ApplicationDatabaseContext Create()
{
return new ApplicationDatabaseContext();
}
and
public static ApplicationUserManager Create(IdentityFactoryOptions<ApplicationUserManager> options, IOwinContext context)
{
...
}
Now you will be able to access your database context and user manager in a simple straightforward way:
ApplicationDatabaseContext dbContext = context.OwinContext.Get<ApplicationDatabaseContext>();
ApplicationUserManager userManager = context.OwinContext.GetUserManager<ApplicationUserManager>();
In your ApiController (if you're using WebApi):
IAuthenticationManager authenticationManager = HttpContext.Current.GetOwinContext().Authentication;
ApplicationUserManager applicationUserManager = HttpContext.Current.GetOwinContext().GetUserManager<ApplicationUserManager>();