Alternative to HttpContext.Cache within a Timer Job

Question

A coworker of mine has created a centralized Logging utility that works throughout our SP projects. It does a good job of queuing up a large number of logs, deals with logging level, etc.

However, it utilizes HttpContext.Cache in order to do some caching. This causes it to break when I attempt to Log from a custom timer job that I've written.

Can anyone think of a good way to fix this so that it'll work in a Timer, without completely tearing apart the architecture and re-writing it? Are there any System.Web.Caching.Cache objects that exist, or can be created, from within the SharePoint timer?

Answer 1

HttpContext.Cache uses HttpRuntime.Cache as the real underlying implementation, and that is not bound to a web context (despite the name implying otherwise). It can be used in any application (class library, WinForms, etc.) without issue - other than it can look a little jarring to pull in System.Web.

Your colleague's utility should be using a cache abstraction (if not, a good opportunity to replace it) so you can use dependency injection to define the specific implementation.

Also important to consider especially in the context of a SharePoint Timer Job - the cache is server-local, so if you're running a multi-server farm and you're not carefully controlling which server these jobs are executed on, it makes the cache essentially useless at best (or worst, introduces some odd bugs). If you need a cache that's distributed across the farm, consider something like AppFabric instead of .NET's native web cache.