ASP.NET缓存管理

Question

I have three applications running in three separate app pools. One of the applications is an administrative app that few people have privileged access to. One of the function the administrative app allows is creating downtime notices. So when a user goes into the administrative app and creates a downtime notice the other two apps are supposed to pick up on there being a new notice and display it on the login page.

The problem is that these notices are cached and being that each app is in a separate app pool the administrative app doesn't have any way to clear the downtime notices cache in the other two applications.

I'm trying to figure out a way around this. The only thing I can think of is to insert a record in the DB that denotes the cache needs to be cleared and the other two apps will check the DB when loading the login page. Does anyone have another approach that might work a little cleaner?

*Side note, this is more widespread than just the downtime notices, but I just used this as an example.

EDIT

Restarting the app pools is not feasible as it will most likely kill background threads.

Answer 1

If I understand correctly, you're basically trying to send a message from the administrative app to other apps. Maybe you should consider creating WCF service on these apps that could be called from the administrative application. That is a standard way to communicate between different apps if you don't want to use eg shared medium such a database and it doesn't force you to use polling model.

Answer 2

Another way to look at this is that this is basically an inter-application messaging problem, which has a number of libraries already out there that could help you solve it. RabbitMQ comes to mind for this. It has a C# client all ready to go. MSMQ is another potential technology, and one that already comes with Windows - you just need to install it.

Answer 3

If it's database information you're caching, you might try your luck at setting up and SqlCacheDependency .

Otherwise, I would recommend not using the ASP.NET cache, and either find a 3rd party solution that uses a distributed caching scheme, that way all applications are using one cache, instead of 3 separate ones.

Answer 4

I'm not saying this is the best answer or even the right answer, its just what I did.

I have a series of ecommerce websites on separate servers and data centers that rely on pulling catalog data from a central backoffice website location and then caches them locally. In my first iteration of this I simply used GET requests that the central location could ping the corresponding consuming website to initiate its own cache refresh routine. I used SSL on each of the eCommerce servers as I already had that setup and could then have the backoffice web app send credentials via SSL GET to initiate the refresh securely.

At a later stage, we found it more efficient to use sockets instead on the backoffice where each consuming website would be a client and listen for changes in the data. The backoffice website could then communicate to its corresponding website when a particular account change and then communicate this very specifically. This approach is much more granular and we could update in small bits as needed as opposed to a large chunked update but this was definitely more complicated than our first try.