Has anyone tried building an ASP.NET Session State Provider for Amazon SimpleDB?

Question

If not, are there any fundamental limitations of the service that prevent one from being built?

Answer 1

There's a C# library for working with SDB.

If you want to roll your own, the API, WSDL and other documentation can be found at http://aws.amazon.com/simpledb/#resources.

It's a pretty straight forward API that rides over HTTP. The hardest part is writing the signing code. There's plenty of implementations in other languages.

As for using it for session state, there's a huge speed difference between using SimpleDB from EC2 and anywhere else on the internet. If you're hosting your app on EC2, it'll be fine, otherwise, it'll be brutally slow.

Answer 2

In response to Garys answer. "If you're hosting your app on EC2, it'll be fine"

Even if you're hosting your application on EC2 you should not really use SimpleDB to store session state. It provides an "eventually consistent" guarantee, so if you PUT something there is no guarantee that you will see the item on your next GET.

see: http://docs.amazonwebservices.com/AmazonSimpleDB/2007-11-07/DeveloperGuide/index.html?EventualConsistencySummary.html

This is fine when you want to use simpledb to do indexing on data that does not need to be immediately up to date and can be reconciled later, but in the case of session state, you'd likely want something with ACID guarantees (like SQL Server) as you want to know that once you have committed something you will get it back on the next read.

This obviously depends on your requirements, but most people use session state to store shopping cart items or similar. Your site visitors will soon get upset if things appear to go missing from thier cart, then re-add them and then discover they have added the same item twice when they come to pay.

Answer 3

You could base it off this MySQL provider:

http://harry-kimpel.spaces.live.com/Blog/cns!CAA619CB4C4D1B6C!342.entry