Question

I’m hosting my WCF application with IIS. To serve some methods I need a reference to helper object which is heavily initialized. A good scenario is to initialise it once and put in a cache, then all requests just use the object from cache. How can I do caching?

The easyiest way is to use static field of mywebmethod. IIS creates several ServiceHosts to serve requests. And in every servicehost static fields will be different.

I aso tried using System.Web.HttpRuntime.Cache. Again, I have some independent caches.

To clarify, I need to cache not the result of the request, but some intermediate data needed to process request.

So what can be a solution?

Answer 1

Running diferent services in separate AppDomains gives you crash-protection and some other, security-related benefits. If you are sure you need shared statics, consider using self-hosted servies.

I can think of only one way to achieve this using IIS: implement a ServiceHostFactory, that will return custom ServiceHost that will start and stop multiple ServiceHosts under the hood. But it’s waaay too hacky to be a piece of production code )

Update I stumbled upon this today, and this answer looks like a total mess. Different Service host do share one AppDomain if they reside inside the same IIS site, so static fields should be the same for all services.