.NET Membership with Repository Pattern

Question

My team is in the process of designing a domain model which will hide various different data sources behind a unified repository abstraction. One of the main drivers for this approach is the very high probability that these data sources will undergo significant change in the near future and we don't want to be re-writing business logic when this happens. One data source will be our membership database which was originally implemented using the default ASP.Net Membership Provider. The membership provider is tied to the System.Web.Security namespace but we have a design guideline requiring that our domain model layer is not dependent upon System.Web (or any other implementation/environment dependency) as it will be consumed in different environments - nor do we want our websites directly communicating with databases.

I am considering what would be a good approach to reconciling the MembershipProvider approach with our abstracted n-tier architecture. My initial feeling is that we could create a "DomainMembershipProvider" which interacts with the domain model and then implement objects in the model which deal with the repository and handle validation/business logic. The repository would then implement data access using our (as-yet undecided) ORM/data access tool.

Are there are any glaring holes in this approach - I haven't worked closely with the MembershipProvider class so may well be missing something. Alternatively, is there an approach that you think will better serve the requirements I described above?

Thanks in advance for your thoughts and advice.

Regards, Zac

Answer 1

It's been 6 months since the question was asked and no one seems to have been able to provide an answer so I thought I'd explain the solution we eventually chose.

Basically, we have decided not to use any implementation of the MembershipProvider - instead we use our own custom Membership Service sitting atop a repository. It was important for us to maintain the existing aspnet_Membership database so our repository has basically duplicated the built-in SQLMembershipProvider functionality (at least, the aspects we need of it) - initially via Linq-to-SQL but now we're transitioning to NHibernate. The plan is to replace the membership database in a year or so when all of our websites are upgraded to use the new model.

It was possible to use a custom membership provider but in the end it became apparent that it was simpler, more consistent, and more maintainable to use a custom implementation. We are still using the built-in forms authentication functionality for verifying that a user is logged in and for redirecting users who try to access secure areas of our site without first being authenticated - but we have overridden the functionality that is tied to the profile provider.

Ultimately, our feelings on this are that while the membership provider is a powerful and easy-to-use tool within ASP.Net, if it doesn't fit with the wider approach used in your application, it is worth considering an alternative approach.