Software magic behind Office 365 Groups document libraries

Software magic behind Office 365 Groups document libraries

The new Office 365 Groups feature includes “Files,” a library intended to hold documents of interest to group members. The implementation of Files has not been without its problems and I received some criticism after publishing an article on the topic because of the way that I referred to OneDrive for Business in the text. This was probably due to some rustiness on my part, so it was time to reacquaint myself with OneDrive for Business and find out more about the implementation.

The technology in OneDrive for Business is based on the old Groove technology that Microsoft acquired when Ray Ozzie joined the company as Chief Software Architect in 2005. I had some knowledge of Groove as Compaq had attempted to use it as a solution to manage file sharing for remote workgroups in the 2000-2002 timeframe. We were attracted to Groove because it offered highly secure communications between client and server.

Unfortunately, like so many technologies, Groove was ahead of its time and the project eventually petered out because the software exerted too heavy a demand on the PCs and networks (dial-up connections mostly) of the time. To their credit, Groove Networks continued to plug away and solved many problems, including the reliable synchronization of delta changes in Office files, but it remained a “pig” in software terms – too big and demanding for the average road warrior.

Given that Groove was all about workgroup sharing, it wasn’t too surprising when Microsoft integrated it into SharePoint where its synchronization capabilities live on as the OneDrive for Business sync client              .

According to Microsoft, OneDrive for Business is designed to let users “update and share (your) files from anywhere and work on Office documents with others at the same time.” All of which sounds exactly like what the Files functionality for Office 365 Groups is attempting to do, albeit in a more all-encompassing manner where files are just part of the overall sharing within Groups, which also supports threaded conversations and shared calendars. But given that the two software components do much the same thing – at least on paper – it’s logical to assume that OneDrive for Business underpins the Files function in Office 365 Groups, especially as “OneDrive” is proudly displayed in the browser tab.

OneDrive for Business uses SharePoint for storage. The items managed by OneDrive for Business are stored in special document libraries in the personal site collection of users. SharePoint also supports document libraries (used for instance in Exchange 2013 site mailboxes), the difference being that the document libraries used by OneDrive for Business are customized for synchronization.

But nothing seems to be simple in the world of SharePoint. Probing under the covers, we discover that the document library created when a new group is set up is placed in a hidden content site collection that is associated with the group (Exchange people might start to tune out at this point).

So a group, which is a mailbox-enabled user object in Active Directory terms, has its own document library that is shared with all members of the group. When a file is uploaded to a Group’s document library, permissions are automatically set so that all group members are able to see the content. Permissions are validated when a user requests to access a file by checking that the user is a member of the group at that point. Anyone can access files in the document library if the group is open for public access.

Well, there’s more. When a user accesses a group document library, the intention is to present users with a unified view of the documents that they can work with. Some documents are personal and some are owned by the group. Software magic comes to the rescue by creating a customized web page to deliver a remote view of all the files in the hidden content site collection that is associated with the group. The web page is presented via OneDrive for Business (which accounts for the name in the browser tab). The page presents some user-specific functionality (Such as “Site Folders” or “Shared with Me”) alongside the files shared by the group and some additional interface to allow users to interact with other groups.

The URL to the Files for an Office 365 group is something like All of which gives some idea of the kind of work done behind the scenes to present the unified view… It also tells us that the document libraries are not stored in “My Site.”

When they were originally released, group document libraries didn't offer the same degree of sophistication when it comes to document control as found in equivalent libraries in SharePoint team sites. For example, you couldn't check-out and check-in documents. Reflecting the dynamic nature of cloud services, I noticed the appearance of the "edit" and "manage" options in mid-January 2015 (see screen shot) to restore functionality to much the same level as SharePoint. You still can't attach a workflow to a document in a Groups file library, but there's some logic in that. The latest changes make group document libraries a lot more useful than they were before.

The word “complex” might occur to you as you read this description, but I am assured that it makes reasonable sense in SharePoint terms. And as we all know, software can weave its own magic to present data in many different and wonderful ways. It just happens that Microsoft has decided to approach the problem of integrating personal and shared files by creating a unified experience linked to OneDrive for Business.

The hidden site collections used for group document libraries are invisible to SharePoint administrators. However, the storage used is charged against the tenant’s SharePoint Online storage (1 TB). I’ve heard mutterings that Microsoft needs to expose information about the space consumed by groups so that these sites can be managed like other sites, which seems fair. For one thing, it is possible to run into a problem when creating a group that has the same name as an existing site. I understand that a fix for this problem is in progress.

No doubt these are teething problems that will be sorted over the next few months as Microsoft receives feedback from customers who use the new functionality. I’m using Groups for real work myself and like the functionality, even if I am still not quite sure how everything fits together.

To finish, on December 9, Microsoft provided a status for the overall roll-up of Groups across Office 365 and said “Groups were (now) available to 25% of tenants. The remaining 75% will be enabled just after the New Year...” All those on the Office 365 First Release program have now been enabled for Groups and it is clearly a sensible move to let things settle down over the holiday period.

Follow Tony @12Knocksinna

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