AttachmentsDemo Sample Outlook Add-in

The sample implements an Outlook add-in that adds buttons to the Outlook ribbon. It allows the user to save all attachments to their OneDrive. The sample illustrates the following concepts:

Adding add-in command buttons to the Outlook ribbon when reading mail, including a UI-less button and a button that opens a task pane
Implementing a WebAPI to retrieve attachments via a callback token and the Outlook REST API
Using the SSO access token to call the Microsoft Graph API without prompting the user
If the SSO token is not available, authenticating to the user's OneDrive using the OAuth2 implicit flow via the office-js-helpers library.
Using the Microsoft Graph API to create files in OneDrive.

Configuring the Sample

Before you run the sample, you'll need to do a few things to make it work properly.

You need an Office 365 tenant or Outlook.com account. While mail apps will work with on-premise installations of Exchange, the Microsoft Graph API requires Office 365 or Outlook.com.
You need to register the sample application in the Microsoft Application Registration Portal in order to obtain an app ID for accessing the Microsoft Graph API.
1. Browse to the Microsoft Application Registration Portal. If you're not asked to sign in, click the Go to app list button and sign in with either your Microsoft account (Outlook.com), or your work or school account (Office 365). Once you're signed in, click the Add an app button. Enter AttachmentsDemo for the name and click Create application.
2. Locate the Application Secrets section, and click Generate New Password. A dialog box will appear with the generated password. Copy this value before dismissing the dialog and save it.
3. Locate the Platforms section, and click Add Platform. Choose Web, then enter https://localhost:44349/MessageRead.html under Redirect URIs.
  
  Note: The port number in the redirect URI (44349) may be different on your development machine. You can find the correct port number for your machine by selecting the AttachmentDemoWeb project in Solution Explorer, then looking at the SSL URL setting under Development Server in the properties window.
4. Click Add Platform. Choose Web API. Configure this section as follows:
  - Under Application ID URI, change the default value by inserting your host and port number before the GUID listed there. For example, if the default value is api://05adb30e-50fa-4ae2-9cec-eab2cd6095b0, and your app is running on localhost:44349, the value is api://localhost:44349/05adb30e-50fa-4ae2-9cec-eab2cd6095b0.
  - Under Pre-authorized applications, enter d3590ed6-52b3-4102-aeff-aad2292ab01c for the Application ID. Click the Scope dropdown and select the only entry there. This preauthorizes Office to access the app.
5. Locate the Microsoft Graph Permissions section in the app registration. Next to Delegated Permissions, click Add. Select Files.ReadWrite, Mail.Read, offline_access, openid, and profile. Click OK.

Click Save to complete the registration. Copy the Application Id and save it in the same place with the app password you saved earlier. We'll need those values soon.

Here's what the details of your app registration should look like when you are done.

Edit authconfig.js and replace the YOUR APP ID HERE value with the application ID you generated as part of the app registration process.

Edit AttachmentDemo.xml and replace the YOUR APP ID HERE value with the application ID you generated as part of the app registration process.

Note: Make sure that the port number in the Resource element matches the port used by your project. It should also match the port you used when registering the application.

Edit Web.config and replace the YOUR APP ID HERE value in with the application ID and YOUR APP PASSWORD HERE with the application password you generated as part of the app registration process.

Provide user consent to the app

In this step we will provide user consent to the permissions we just configured on the app. This step is only necessary because we will be sideloading the add-in for development and testing. Normally a production add-in will be listed in the Office Store, and users will be prompted to give consent during the installation process through the store.

You have two choices for providing consent. You can use an administrator account and consent once for all users in your Office 365 organization, or you can use any account to consent for just that user.

Provide admin consent for all users

If you have access to a tenant administrator account, this method will allow you to provide consent for all users in your organization, which can be convenient if you have multiple developers that need to develop and test your add-in.

Browse to https://login.microsoftonline.com/common/adminconsent?client_id={application_ID}&state=12345, where {application_ID} is the application ID shown in your app registration.
Sign in with your administrator account.
Review the permissions and click Accept.

The browser will attempt to redirect back to your app, which may not be running. You might see a "this site cannot be reached" error after clicking Accept. This is OK, the consent was still recorded.

Provide consent for a single user

If you don't have access to a tenant administrator account, or you just want to limit consent to a few users, this method will allow you to provide consent for a single user.

Browse to https://login.microsoftonline.com/common/oauth2/authorize?client_id={application_ID}&state=12345&response_type=code, where {application_ID} is the application ID shown in your app registration.
Sign in with your account.
Review the permissions and click Accept.

Running the Sample

Note: Visual Studio may show a warning or error about the WebApplicationInfo element being invalid. The error may not show up until you try to build the solution. As of this writing, Visual Studio has not updated their schema files to include the WebApplicationInfo element. To work around this problem, you can use the updated schema file in this repository: MailAppVersionOverridesV1_1.xsd.

On your development machine, locate the existing MailAppVersionOverridesV1_1.xsd. This should be located in your Visual Studio installation directory under ./Xml/Schemas/{lcid}. For example, on a typical installation of VS 2017 32-bit on an English (US) system, the full path would be C:\Program Files (x86)\Microsoft Visual Studio\2017\Enterprise\Xml\Schemas\1033.

Rename the existing file to MailAppVersionOverridesV1_1.old.

Move the version of the file from this repository into the folder.

You can run the sample right from Visual Studio. Select the AttachmentDemo project in Solution Explorer, then choose the Start Action value you want (under Add-in in the properties window). You can choose any installed browser to launch Outlook on the web, or you can choose Office Desktop Client to launch Outlook. If you choose Office Desktop Client, be sure to configure Outlook to connect to the Office 365 or Outlook.com user you want to install the add-in for.

Note: The SSO token feature is in preview in Outlook 2016 for Windows only at this time.

Press F5 to build and debug the project. You should be prompted for a user account and password. Be sure to use a user in your Office 365 tenant, or an Outlook.com account. The add-in will be installed for that user, and either Outlook on the web or Outlook will open. Select any message, and you should see the add-in buttons on the Outlook ribbon.

Add-in in Outlook on desktop

** Add-in in Outlook on the web**