Custom user licensing

Question

Hello
I develop a product for SharePoint (2010-2013) which propose a new kind of document library. I want to sell it with a license per user. I don't want to rely on the SP2013 online licensing feature.
I develop custom administration pages to register licence keys (specific to my product). Licence keys are stored in SPPersistedObject of the SPFarm. Each licence key gives a number of authorized users; for example you can buy a licence for 100
users. I want that a licence is dedicated to a farm. I developed administration pages to manage these keys.
No my goal is to control the number of users authorized to use my product. Only authorized users can use my special document library.
That's where I need some advices to achieve this: how to manage and store the authorized user list ? Here are some options I thought about :
- a list of SPUser ids in a SPPersistedObject of the farm. Pros: easy to count the number of authorized users. Cons: this object can be heavy (if you have thousands of users) and managing the authorized users in an administration page would be painful.
- a list of SPGroup ids in a SPPersistedObject of the farm. Pros: lightweight and easy to manage. Cons: how to control the number of authenticated users ? If the number of users in registered SPGroup exceeds the license user count, what can I do? Reject
access to my component for all users ?
This is not a post about a specific technical problem, but any idea or advice of experienced people would be great.
J.

Answer 1

Hi,
Per my knowledge, the role of SharePoint in licensing is that of a broker: once it retrieves a license token from the Office Store, it allows license managers to add or remove users to a given license (up to the number purchased).
However, it does not enforce the license. Your app must add code to enforce licensing. 
To add code to license the apps contains three steps:
import a test license, add code to your app that retrieves and validates the license, and then make decisions based on the outcome. 
For more information, you can have a look at the following articles.
http://blogs.msdn.com/b/officeapps/archive/2012/11/09/licensing-your-apps-for-sharepoint.aspx
http://code.msdn.microsoft.com/officeapps/SharePoint-2013-Import-f5f680a6/sourcecode?fileId=85458&pathId=1993203300
Thanks & Regards,
Jason
Jason Guo
TechNet Community Support