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I have an ASP.NET web app providing access to a database on the server. What I need is a way to run code in the background on a given schedule that auto-updates the server database from another source.

I know how to do this in a windows app by adding a timer, linking up a function to the timer tick event and starting the timer. I do not know how to do this in a web app.

Is there a start-up event for a web app or somewhere where I can start this background process regardless of whatever any users are doing on the site?

Mike Webb
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6 Answers6

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You should not do this in an ASP.NET website - this is a major no-no. You are correct in thinking to use a timer on a background .exe. You should look into creating either a Windows Task (a console .exe executed by the server task timer), or a Windows Service. I would suggest the Windows Service as that is standard practice.

Steve Stokes
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  • Good idea, but what if the user doesn't have access to the computer hosting the site, as @aquinas has already pointed out? – walther Jul 02 '12 at 20:27
  • @walther -- to solve this would be somewhat easy once thought about. Since the user can create a website / webservice, he should create a page (.aspx) or a webservice (.aspx / .svc) that handles a request from a server that he does have access to. A windows service or task can reference that page or service and send the request to 'do the work' that is needed in the database. I would suggest a webservice. – Steve Stokes Jul 03 '12 at 13:20
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If you have access to the computer hosting your site I would write a little app that was run from the Task Scheduler.

The web server is not meant to handle long-running background tasks. It's the wrong tool.

If you dont have access to the hosting computer then I would suggest building some kind of interface whereby another computer rebuilt the database and uploaded it. I'm using the terms "interface" and "upload" in the loosest, broadest sense - apply your own definition.

Sam Axe
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I was searching for a solution myself couple of months ago, and even though I haven't found enough time to try it so far, I guess I can share the link with you. Maybe you'll find it helpful.

If yes, please, let me know here.

http://quartznet.sourceforge.net/

How to use Quartz.net with ASP.NET

Community
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walther
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you can use Windows Service or use Timer Control (In the Ajax Category)

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Or

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Aghilas Yakoub
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As other answers have stated, doing this full function - updating a database and scheduling it as an ASP.NET app is using the wrong tool for the job.

ASP.NET can be used to update a database - that's perfectly valid. Where it breaks down is in the timer. ASP.NET apps aren't meant to be long-running, which is necessary for the timer to work.

If you can do it, I'd strongly suggest using the approach others have suggested - a Windows Service or a Scheduled Task.

However, if you have no access to the actual server, other than to post ASP.NET code - you can't install a service and you can't set up a Windows app to run on a scheduled basis, here's an out-of-the box idea.

Set up a web service or ASPX page that does the update, and then call that page from a scheduled task on a machine you DO control.

So if this was at http://www.someserver.net/updatedb.aspx, there's no reason you can't set a scheduled task on your own PC to call that URL.

I'd consider this a last-ditch solution to be used only if you can't do one of the other options.

David
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    Let's get even *more* outside the box: Use the asp.net cache with a callback function. You don't have to store anything important in this cache, you're just using it for the timing functionality built into asp.net. In your callback function, you call: new WebClient().DownloadString(theUrlOfYourUpdatingPage); Yep. That's right. Have the website call *itself*. That way IIS can never unload your app pool. How's *that* for outside the box? :) – aquinas Jul 02 '12 at 20:44
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The global.asax.cs file has a method that is fired when your application starts: Application_Start. You can hook up your timer method in that event. Just beware, depending on how IIS configured, your app pool may shutdown. For example, if no one hits the site in 20 minutes for example. Just make sure if you HAVE to have this run every X minutes that you have IIS configured to ALWAYS be running and start your app. This is harder than it sounds. In the end, you may want to go with a regular windows scheduled task.

aquinas
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