GallJ93 GallJ93 - 12 days ago 6
ASP.NET (C#) Question

MVC UserManager Login Case Insensitive Username

I'm trying to fix a bug in my application at the moment where the user email used for login is case sensitive when it should be case insensitive.

I am using the following code to do this in MVC:

public ActionResult Login(LoginViewModel model, string returnUrl)
{
if (ModelState.IsValid)
{
var user = _userManager.Find(model.UserName, model.Password);

if (user != null)
{
SignIn(user, model.RememberMe);
return RedirectToAction("List", "Survey");
}

ModelState.AddModelError("LoginFailure", "Invalid username or password.");
}

return View(model);
}


_userManager
is a
UserManager
, an override of the standard AspNet Identity
UserManager
. It seems as though this is using case sensitive comparisons.

I have looked into a number of ways of fixing this problem, including the obvious one of lower- or upper-casing all of the usernames as they are entered and changing the database to match, but I would rather fix this problem without having to edit the database if possible. I have already tried using lambda expressions but these do not seem to work for the Find method unfortunately.

My username column in the database has its collation as
SQL_Latin1_General_CP1_CI_AS
which I believe makes it case-insensitive for comparisons.

I have looked around for some time now and cannot find anybody complaining of exactly the same problem apart from the person in this link.

I would be very grateful for any help with this problem that does not involve DB manipulations, or even confirmation if that is the only way possible. Thank you.

Answer

Thanks to Sam Farajpour Ghamari's comments, I was able to find the override for the UserStore's findUserByName method and change this code:

public User GetByUsername(string username)
{
    return GetAll().FirstOrDefault(u => u.UserName == username);
}

to this:

public User GetByUsername(string username)
{
    return GetAll().FirstOrDefault(u => u.UserName.ToLower() == username.ToLower());
}

And it worked. Thanks for the help.