Configure single sign-on with Azure Active Directory in Power Virtual Agents

Article
01/11/2023
8 minutes to read

Note

There is additional information available for people using Power Virtual Agents (preview).

Power Virtual Agents supports single sign-on (SSO), which means chatbots can sign the user in if they're in to the page where the bot is deployed.

For example, the bot is hosted on the corporate intranet or in an app that the user is already signed in to.

There are four main steps to configuring SSO for Power Virtual Agents:

Create an app registration in Azure AD for your custom canvas.
Define a custom scope for your bot.
Configure authentication in Power Virtual Agents to enable SSO.
Configure your custom canvas HTML code to enable SSO.

Important

SSO is currently not supported when a bot has been either:

Published to a SharePoint website.
Published to a Power Apps portal.

Prerequisites

Learn more about what you can do with Power Virtual Agents.
Enable end-user authentication with Azure Active Directory.
- SSO is only supported for Azure Active Directory (Azure AD) V2. Other account types such as Microsoft Account or other OAuth accounts are not supported.
Add an authentication topic to your bot.
Use a custom canvas.

Supported channels

The following table details the channels that currently support SSO. You can suggest support for additional channels at the Power Virtual Agents ideas forum.

Channel	Supported
Azure Bot Service channels	Not supported
Custom Website	Supported
Demo Website	Not supported
Facebook	Not supported
Microsoft Teams¹	Supported
Mobile App	Not supported
Omnichannel for Customer Service²	Supported

¹ If you also have the Teams channel enabled, you need to follow the configuration instructions on the Configure SSO for Teams channel documentation. Failing to configure the Teams SSO settings as instructed on that page will cause your users to always fail authentication when using the Teams channel.

² Only the live chat channel is supported. For more information, see Configure hand-off to Dynamics 365 Customer Service.

Technical overview

The following illustration shows how a user is signed in without seeing a login prompt (SSO) in Power Virtual Agents:

Illustration of SSO authentication flow.

The bot user enters a phrase that triggers a sign-in topic. The sign-in topic is designed to sign the user in and use the user's authenticated token (AuthToken variable).
Power Virtual Agents sends a login prompt to allow the user to sign in with their configured identity provider.
The bot's custom canvas intercepts the sign-in prompt and requests an on-behalf-of (OBO) token from Azure AD. The canvas sends the token to the bot.
On receipt of the OBO token, the bot exchanges the OBO token for an "access token" and fills in the AuthToken variable using the access token's value. The IsLoggedIn variable is also set at this time.

Create an app registration in Azure AD for your custom canvas

To enable SSO, you'll need two separate app registrations:

One for your bot to enable user authentication with Azure AD.
One for your custom canvas to enable SSO.

Important

You can't reuse the same app registration for both your bot's user authentication and your custom canvas.

Create an app registration for the bot's canvas

Sign in to the Azure portal.
Go to App registrations, either by selecting the icon or searching in the top search bar.
Select New registration.
Enter a name for the registration. It can be helpful to use the name of the bot whose canvas you're registering and include "canvas" to help separate it from the app registration for authentication.

For example, if your bot is called "Contoso sales help", you might name the app registration as "ContosoSalesCanvas" or something similar.
Select the account type under Supported account types. We recommend you select Accounts in any organizational directory (Any Azure AD directory - Multitenant) and personal Microsoft accounts (for example Skype, Xbox).
Leave the Redirect URI section blank for now, as you'll enter that information in the next steps. Select Register.
After the registration is completed, it will open to the Overview page. Go to Manifest. Confirm that accessTokenAcceptedVersion is set to 2. If it isn't, change it to 2 and then select Save.

Add the redirect URL

With the registration open, go to Authentication and then select Add a platform.
On the configure platforms blade, select Web.
Under Redirect URIs, add the full URL to the page where your chat canvas is hosted. Under the Implicit grant section, select the Id Tokens and Access Tokens checkboxes.
Select Configure to confirm your changes.
Go to API Permissions. Select Grant admin consent for <your tenant name> and then Yes.

Important

To avoid users from having to consent to each application, a Global Administrator, Application Administrator, or a Cloud Application Administrator must grant tenant-wide consent to your app registrations.

Define a custom scope for your bot

Define a custom scope by exposing an API for the canvas app registration within the authentication app registration. Scopes allow you to determine user and admin roles and access rights.

This step creates a trust relationship between the authentication app registration for authentication and the app registration for your custom canvas.

Open the app registration that you created when you configured authentication.
Go to API Permissions and ensure that the correct permissions are added for your bot. Select Grant admin consent for <your tenant name> and then Yes.

Important

To avoid users from having to consent to each application, a Global Administrator, Application Administrator, or a Cloud Application Administrator must grant tenant-wide consent to your app registrations.
Go to Expose an API and select Add a scope.
Enter a name for the scope, along with the display information that should be shown to users when they come to the SSO screen. Select Add scope.
Select Add a client application.
Enter the Application (client) ID from the Overview page for the canvas app registration into the Client ID field. Select the checkbox for the listed scope that you created.
Select Add application.

Configure authentication in Power Virtual Agents to enable SSO

The Token Exchange URL in the Power Virtual Agents authentication configuration page is used to exchange the OBO token for the requested access token through the bot framework.

Power Virtual Agents calls into Azure AD to perform the actual exchange.

Sign in to Power Virtual Agents.
Confirm you've selected the bot for which you want to enable authentication by selecting the bot icon on the top menu and choosing the correct bot.
In the navigation menu, under Settings, select Security. Then select the Authentication card.
Enter the full scope URI from the Expose an API blade for the bot's authentication app registration in the Token exchange URL field. The URI will be in the format of api://1234-4567/scope.name.
Select Save and then publish the bot content.

Configure your custom canvas HTML code to enable SSO

Update the custom canvas page where the bot is located to intercept the login card request and exchange the OBO token.

Configure the Microsoft Authentication Library (MSAL) by adding the following code into a <script> tag in your <head> section.

Update clientId with the Application (client) ID for the canvas app registration. Replace <Directory ID> with the Directory (tenant) ID. You get these IDs from the Overview page for the canvas app registration.

App registration overview highlighting the Application and Directory IDs.

<head>
 <script>
   var clientApplication;
     (function () {
       var msalConfig = {
           auth: {
             clientId: '<Client ID [CanvasClientId]>',
             authority: 'https://login.microsoftonline.com/<Directory ID>'
           },
           cache: {
             cacheLocation: 'localStorage',
             storeAuthStateInCookie: false
           }
       };
       if (!clientApplication) {
         clientApplication = new Msal.UserAgentApplication(msalConfig);
       }
     } ());
 </script>
</head>

Insert the following <script> in the <body> section. This script calls a method to retrieve the resourceUrl and exchange your current token for a token requested by the OAuth prompt.

<script>
function getOAuthCardResourceUri(activity) {
  if (activity &&
       activity.attachments &&
       activity.attachments[0] &&
       activity.attachments[0].contentType === 'application/vnd.microsoft.card.oauth' &&
       activity.attachments[0].content.tokenExchangeResource) {
         // asking for token exchange with AAD
         return activity.attachments[0].content.tokenExchangeResource.uri;
   }
}

function exchangeTokenAsync(resourceUri) {
  let user = clientApplication.getAccount();
   if (user) {
     let requestObj = {
       scopes: [resourceUri]
     };
     return clientApplication.acquireTokenSilent(requestObj)
       .then(function (tokenResponse) {
         return tokenResponse.accessToken;
         })
         .catch(function (error) {
           console.log(error);
         });
         }
         else {
         return Promise.resolve(null);
   }
}
</script>

Insert the following <script> in the <body> section. Within the main method, this code adds a conditional to your store, with your bot's unique identifier. It also generates a unique ID as your userId variable.

Update <BOT ID> with your bot's ID. You can see your bot's ID by going to the Channels tab for the bot you're using, and selecting Mobile app on the Power Virtual Agents portal.

Bot ID shown on the Mobile app channel configuration page.

<script>
    (async function main() {

        // Add your BOT ID below 
        var BOT_ID = "<BOT ID>";
        var theURL = "https://powerva.microsoft.com/api/botmanagement/v1/directline/directlinetoken?botId=" + BOT_ID;

        const {
            token
        } = await fetchJSON(theURL);
        const directLine = window.WebChat.createDirectLine({
            token
        });
        var userID = clientApplication.account?.accountIdentifier != null ?
            ("Your-customized-prefix-max-20-characters" + clientApplication.account.accountIdentifier).substr(0, 64) :
            (Math.random().toString() + Date.now().toString()).substr(0, 64); // Make sure this will not exceed 64 characters 
        const store = WebChat.createStore({}, ({
            dispatch
        }) => next => action => {
            const {
                type
            } = action;
            if (action.type === 'DIRECT_LINE/CONNECT_FULFILLED') {
                dispatch({
                    type: 'WEB_CHAT/SEND_EVENT',
                    payload: {
                        name: 'startConversation',
                        type: 'event',
                        value: {
                            text: "hello"
                        }
                    }
                });
                return next(action);
            }
            if (action.type === 'DIRECT_LINE/INCOMING_ACTIVITY') {
                const activity = action.payload.activity;
                let resourceUri;
                if (activity.from && activity.from.role === 'bot' &&
                    (resourceUri = getOAuthCardResourceUri(activity))) {
                    exchangeTokenAsync(resourceUri).then(function(token) {
                        if (token) {
                            directLine.postActivity({
                                type: 'invoke',
                                name: 'signin/tokenExchange',
                                value: {
                                    id: activity.attachments[0].content.tokenExchangeResource.id,
                                    connectionName: activity.attachments[0].content.connectionName,
                                    token,
                                },
                                "from": {
                                    id: userID,
                                    name: clientApplication.account.name,
                                    role: "user"
                                }
                            }).subscribe(
                                id => {
                                    if (id === 'retry') {
                                        // bot was not able to handle the invoke, so display the oauthCard
                                        return next(action);
                                    }
                                    // else: tokenexchange successful and we do not display the oauthCard
                                },
                                error => {
                                    // an error occurred to display the oauthCard
                                    return next(action);
                                }
                            );
                            return;
                        } else
                            return next(action);
                    });
                } else
                    return next(action);
            } else
                return next(action);
        });

        const styleOptions = {

            // Add styleOptions to customize Web Chat canvas
            hideUploadButton: true
        };

        window.WebChat.renderWebChat({
                directLine: directLine,
                store,
                userID: userID,
                styleOptions
            },
            document.getElementById('webchat')
        );
    })().catch(err => console.error("An error occurred: " + err));
</script>

Full sample code

For reference, you can find the full sample code, with the MSAL and store conditional scripts already included at our GitHub repo.