The getAccessToken API in Office.js enables users who are signed into Office to get access to an AAD-protected add-in and to Microsoft Graph without needing to sign-in again. This sample is built on ASP.NET and Microsoft Identity Library (MSAL) .NET.

There are two versions of the sample in this repo, one of which has its own README file:

• In the Begin folder is the starting point for the SSO walkthrough at at Create an ASP.NET Office Add-in that uses single sign-on. Please follow the instructions in the article.
• In the Complete folder is the completed sample you would have if you completed the walkthrough. To use this version, follow the instructions in the article Create an ASP.NET Office Add-in that uses single sign-on, but substitute "Complete" for "Begin" in those instructions and skip the sections Code the client-side and Code the server-side.

Integrating data from online service providers increases the value and adoption of your add-ins. This code sample shows you how to connect your add-in to Microsoft Graph. Use this code sample to:

• See how to use the Single Sign-on (SSO) API
• Connect to Microsoft Graph from an Office Add-in.
• Build an Add-in using ASP.NET MVC, MSAL 3.x.x for .NET, and Office.js.
• Use the MSAL.NET Library to implement the OAuth 2.0 authorization framework in an add-in.
• Use the OneDrive REST APIs from Microsoft Graph.
• See how an add-in can fall back to an interactive sign-in in scenarios where SSO is not supported.
• Show a dialog using the Office UI namespace in scenarios where SSO is not supported.
• Use add-in commands in an add-in.

• Excel on Windows (subscription)
• PowerPoint on Windows (subscription)
• Word on Windows (subscription)

To run this code sample, the following are required.

• Visual Studio 2019 or later.
• Office Developer Tools
• An Microsoft 365 account which you can get by joining the Microsoft 365 developer program that includes a free 1 year subscription to Microsoft 365. During the preview phase, the SSO requires a Microsoft 365 (which includes the subscription version of Office). You should use the latest monthly version and build from the Insiders channel. You need to be an Office Insider to get this version. For more information, see Be an Office Insider.

  Note: When a build graduates to the production semi-annual channel, support for preview features, including SSO, is turned off for that build.

• At least a few files and folders stored on OneDrive for Business in your Microsoft 365 subscription.
• A Microsoft Azure Tenant. This add-in requires Azure Active Directory (AD). Azure AD provides identity services that applications use for authentication and authorization. A trial subscription can be acquired here: Microsoft Azure.

THIS CODE IS PROVIDED AS IS WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESS OR IMPLIED, INCLUDING ANY IMPLIED WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, OR NON-INFRINGEMENT.

The sample sends a hardcoded query parameter on the URL for the Microsoft Graph REST API. If you modify this code in a production add-in and any part of query parameter comes from user input, be sure that it is sanitized so that it cannot be used in a Response header injection attack.

We'd love to get your feedback about this sample. You can send your feedback to us in the Issues section of this repository. Questions about developing Office Add-ins should be posted to Stack Overflow. Ensure your questions are tagged with [office-js] and [MicrosoftGraph].

• Microsoft Graph documentation
• Office Add-ins documentation

Copyright (c) 2019 Microsoft Corporation. All rights reserved.

This project has adopted the Microsoft Open Source Code of Conduct. For more information, see the Code of Conduct FAQ or contact opencode@microsoft.com with any additional questions or comments.