Processing an emaillist async in MVC4 - multithreading

Question

I'm trying to make my MVC4-website check to see if people should be alerted with an email because they haven't done something.
I'm having a hard time figuring out how to approach this. I checked if the shared hosting platform would allow me to activate some sort of cronjob, but this is not available.
So now my idea is to perform this check on each page-request, which already seems suboptimal (because of the overhead). But I thought that with using an async it would not be in the way of people just visiting the site.
I first tried to do this in the Application_BeginRequest method in Global.asax, but then it gets called multiple times per page-request, so that didn't work.
Next I found that I can make a Global Filter which executes on OnResultExecuted, which would seemed promising, but still it's no go.
The problem I get there is that I'm using MVCMailer to send the mails, and when I execute it I get the error: {"Value cannot be null.\r\nParameter name: httpContext"}
This probably means that mailer needs the context.
The code I now have in my global filter is the following:
public override void OnResultExecuted(ResultExecutedContext filterContext)
{
base.OnResultExecuted(filterContext);
HandleEmptyProfileAlerts();
}
private void HandleEmptyProfileAlerts()
{
new Thread(() =>
{
bool active = false;
new UserMailer().AlertFirst("bla#bla.com").Send();
DB db = new DB();
DateTime CutoffDate = DateTime.Now.AddDays(-5);
var ProfilesToAlert = db.UserProfiles.Where(x => x.CreatedOn < CutoffDate && !x.ProfileActive && x.AlertsSent.Where(y => y.AlertType == "First").Count() == 0).ToList();
foreach (UserProfile up in ProfilesToAlert)
{
if (active)
{
new UserMailer().AlertFirst(up.UserName).Send();
up.AlertsSent.Add(new UserAlert { AlertType = "First", DateSent = DateTime.Now, UserProfileID = up.UserId });
}
else
System.Diagnostics.Debug.WriteLine(up.UserName);
}
db.SaveChanges();
}).Start();
}
So my question is, am I going about this the right way, and if so, how can I make sure that MVCMailer gets the right context?

Answer 1

The usual way to do this kind of thing is to have a single background thread that periodically does the checks you're interested in.
You would start the thread from Application_Start(). It's common to use a database to queue and store work items, although it can also be done in memory if it's better for your app.