OneDrive Business for Outlook an Outlook App


As I have mentioned before I really like the app concept introduced with Office 2013. Today I’m going to show my latest creation which is a Mail App for Outlook that lets you access files in your OneDrive and upload new files, manage their permissions and insert links to them in your emails or appointments. This is usefull if you are on a computer where you can’t install the OneDrive deskop app, or if you simple don’t want to send the files as attachments, maybe because they are too big as Exchange online have a file size limitation on attachments of 25 MB.

The App can be found on and in the Office store once Microsoft approves it (I will post a link here).

I created a little demo of the app which you can watch here:

Technical Details

The technical savy persons have probably already guessed how this app works, but for completness let me just give a brief overview.

The app is a MVC5 application that uses the Office 365 API Tools (link to my article on the subject) to access the user’s files in their OneDrive for Business. For this to work, the user have to grant the app permissions to do so. This is handle by an Azure AD Multitenant Application, that the users grants access to read their files. Unfortunately the Azure consent framework, is not allowed to be iframe, hence the rather wonky popup window.

But once the users have given their consent that the app is allowed to access their files in OneDrive the rest is pretty straight forward. It’s a simple filebrowser that allows you to upload files via the Office 365 REST API to the folder you are currently in. Setting permissions to files in OneDrive to external users are currently not supported by the API, so instead we simply open the standard SharePoint dialog, and let the user handle it. Hopefully in the future I will be able to improve this experience and make it more integrated with the mail recipients from Outlook.

Finally I did a little cross browser and mobile testing, as that is required for the app to be published to the Office Store, so if I got all the Safari and mobile quirks ironed out hopefully the app will be published in the store sometimes next week.