We want to synchronize the data in our application with the data of an external service. (Such as accountancy software. This synchronization should be executed every night and when the customer wants to.
I am aware that long running threads don’t belong in web applications and this synchronization should be executed within an external windows service. But the downside of this method is, that is becomes harder to deploy / maintain, since the application can be installed on the customer’s webserver too.
Is it possible to completely integrate this synchronization with just the use of a class library project withing my solution, which will start up at the Application_Start event?
Since your application is hosted on IIS, it’s maintained by the application pool process. If you create additional module for your task, it will be running within context of the same process. You have to be sure this process is still working in the middle of the night, when application is not used, in order to perform the synchronization you want. You can use Quartz.NET to schedule your sync task.
But still, I think much better idea is to perform the synchronization from windows service. Service should communicate with the application for example by using database, where it logs its current activity. It gives you the possibility to monitor of the service state from the web by connecting to such database. I know service forces some additional administration effort, but it will be much more reliable and secure. You can also add service starting possibility from your web application (if pool process user has access rights to windows service) to overcome (or at least minimize) administration effort connecting with restarting your service after some failure.
I’ve written such functionality, so just to give you an overall look of what I mean by web monitoring of such external service, check the screen below. It can be written with the ajax support to achieve more responsiveness (pooling mechanism), which will be convenient for the end user.