Sharepoint user validating
If you rely on the license token to determine user identityof your trial add-in, you might want to provide a notice to the user asking them to sign in to Office with a Microsoft accountto get the full benefits of your add-in.
Your license checking code should determine if the add-in license token is present, and retrieve it if it is.It's a structure in which you can add code to your add-ins to retrieve and then act on license information.The add-in license framework applies only to add-ins acquired directly from the App Source site or in-product experience, or add-ins from App Source that are made available in an add-in catalog hosted on Share Point.Decide what user experience you want to control or customize based on license information.For example, you might want to: For each experience that you want to customize based on license information, add code for that event that performs a license check.The following sections outline the general pattern for performing add-in license checks.
If you plan on using the licensing framework, you should design your add-in with this in mind.
If the user is not signed in to their Microsoft account, the Office application requesting the add-in home page does not append the license token parameter.
Therefore, you must include code in your add-in that determines whether the license token is present on each HTTP request for the app's home page.
Add-ins made available in other ways—such as from a file system location, or uploaded directly to an add-in catalog hosted on Share Point—cannot use the add-in license framework.
The Office and Share Point add-in license framework includes: The add-in license framework provides a way for you to customize add-in access and behavior based on license information.
Figure 1 shows the add-in license query and validation process for Office Add-ins.