URL Object Serialization: An Effortless Approach to User Account Confirmation

#region File and License Information
/*
<File>
	<Copyright>Copyright © 2007, Daniel Vaughan. All rights reserved.</Copyright>
	<License see="prj:///Documentation/License.txt"/>
	<Owner Name="Daniel Vaughan" Email="dbvaughan@gmail.com"/>
	<CreationDate>2008-01-18 21:09:17Z</CreationDate>
	<LastSubmissionDate>$Date: $</LastSubmissionDate>
	<Version>$Revision: $</Version>
</File>
*/
#endregion

using System;
using System.Configuration.Provider;
using System.Threading;
using System.Web.Security;

namespace Orpius.Web
{
	class AspNetMembershipUserPurger : ProviderBase, IUserPurger
	{
		static readonly object usersLock = new object();

		public void Purge(double olderThanMinutes)
		{
			if (olderThanMinutes < 0)
			{
				throw new ArgumentException("Value must be greater than 0", "olderThanMinutes");
			}

			if (!Monitor.TryEnter(usersLock))
			{
				return;
			}

			try
			{
				DateTime expireTime = DateTime.Now.AddMinutes(-olderThanMinutes);

				/* TODO: Change to a stored procedure. 
				 * This is very inefficient, 
				 * and is provided only for demonstration purposes. */
				MembershipUserCollection userCollection = Membership.GetAllUsers();
				foreach (MembershipUser user in userCollection)
				{
					if (!user.IsApproved && user.CreationDate < expireTime)
					{
						Membership.DeleteUser(user.UserName);
					}
				}
			}
			finally
			{
				Monitor.Exit(usersLock);
			}
		}
	}
}