Thanks to everyone who joined me, Scott Hoag, and Dan Usher as we kicked off the new Reston SharePoint User Group today! The group will meet around lunchtime at the Microsoft office in Reston on the first Monday of each month. The group’s meeting time and location should be ideal for the many SharePoint professionals in the Reston area who can’t make it to the various regional SPUGs that traditionally meet in the evenings.

I had the privilege of being the group’s inaugural speaker today, presenting my session “Get Started with Apps for SharePoint 2013!” Much like the session I led last weekend at SPS Virginia Beach, there was great audience participation and interaction. There were a couple of great questions in particular that I wanted to address further here:

If an app requests the Write right at the List scope, is there any way I can install or configure multiple instances of the app to grant it write permissions against two or more lists on a site?

This was an interesting question because the guidance I gave last weekend was that in order to grant the Write right against multiple lists, your app must request permissions at the next highest scope (in the case of this example, that would be the Web scope). However, it is not possible to install multiple instances of an app for SharePoint to the same site. The UI will not show the app in the “Apps you can add” section for that site once an instance of that app is already installed. I even tried forcing my around that by using PowerShell, but was forbidden:

What is the relationship between OAuth and tokens with apps for SharePoint? Is there a token for the user as well as one for the app that factors into authorization decisions?

The OAuth protocol is used to authenticate and authorize apps for SharePoint. Authentication and authorization of users and apps in SharePoint 2013 is a very advanced subject with many potentially complicated scenarios and unique considerations. To learn more about these topics, I strongly encourage you to read the following articles on MSDN:

• Authorization and authentication for apps in SharePoint 2013
• App authorization policy types in SharePoint 2013
• Authentication, authorization, and security in SharePoint 2013

Slides and code from my session

Code for the sample app I demonstrated can be downloaded here.

Thanks again to everyone who was part of today’s Reston SPUG event. I look forward to working with the group much more in the future!