Polling an access database inside a non-dedicated windows server - asp.net

Question

We have a website that runs on ASP.NET. I would like to run a service that checks the database table every XX hours and do an action ( send mail ) if some conditions are not met.
We cannot use
Windows Service as the hosted server is not a dedicated server. (We just have the control panel)
SQL Service for sending mail as we are using Access 2003 (mdb) as our database. It resides at App_Data
IIS is also not available
Its very critical that we need some kind of polling in the server.
We are kind of stuck now. What are the alternatives we have?

Answer 1

its mentioned here
Easy Background Tasks in ASP.NET
here are some snippets from that link
private static CacheItemRemovedCallback OnCacheRemove = null;
protected void Application_Start(object sender, EventArgs e)
{
AddTask("DoStuff", 60);
}
private void AddTask(string name, int seconds)
{
OnCacheRemove = new CacheItemRemovedCallback(CacheItemRemoved);
HttpRuntime.Cache.Insert(name, seconds, null,
DateTime.Now.AddSeconds(seconds), Cache.NoSlidingExpiration,
CacheItemPriority.NotRemovable, OnCacheRemove);
}
public void CacheItemRemoved(string k, object v, CacheItemRemovedReason r)
{
// do stuff here if it matches our taskname, like WebRequest
// re-add our task so it recurs
AddTask(k, Convert.ToInt32(v));
}
Works well in my testing; badges are awarded every 60 seconds like clockwork for all >users - Jeff Atwood

Answer 2

There's a trick you can use to simulate a windows service using just your ASP.NET web service.
The gist of it goes as follows:
Place an item in your cache with an expiry period that is equal to how often you would like to poll your database.
Add a callback that is fired when the item is removed from the cache. In the callback method, add your polling code to do the thing you want to do (call access database, send mails, etc.)
so: in your global asax, something like this:
private const string DummyCacheItemKey = "pollingCacheKey";
protected void Application_Start(Object sender, EventArgs e)
{
RegisterCacheEntry();
}
private bool RegisterCacheEntry()
{
if( null != HttpContext.Current.Cache[ DummyCacheItemKey ] ) return false;
HttpContext.Current.Cache.Add( DummyCacheItemKey, "Test", null,
DateTime.MaxValue, TimeSpan.FromMinutes(1),
CacheItemPriority.Normal,
new CacheItemRemovedCallback( CacheItemRemovedCallback ) );
return true;
}
public void CacheItemRemovedCallback( string key,
object value, CacheItemRemovedReason reason)
{
Debug.WriteLine("Cache item callback: " + DateTime.Now.ToString() );
// Do the service works
DoWork();
ReregisterCacheItem();
}
Whilst it's not ideal, it fits your constraints.
Full details of the technique can be found here: http://www.codeproject.com/Articles/12117/Simulate-a-Windows-Service-using-ASP-NET-to-run-sc