Access Microsoft Graph from a secured app as the app

# Install the module.
# Install-Module Microsoft.Graph -Scope CurrentUser

# The tenant ID
$TenantId = "aaaabbbb-0000-cccc-1111-dddd2222eeee"

# The name of your web app, which has a managed identity.
$webAppName = "SecureWebApp-20201106120003" 
$resourceGroupName = "SecureWebApp-20201106120003ResourceGroup"

# The name of the app role that the managed identity should be assigned to.
$appRoleName = "User.Read.All"

# Get the web app's managed identity's object ID.
Connect-AzAccount -Environment AzureChinaCloud -Tenant $TenantId
$managedIdentityObjectId = (Get-AzWebApp -ResourceGroupName $resourceGroupName -Name $webAppName).identity.principalid

Connect-MgGraph -Environment China -ClientId 'YOUR_CLIENT_ID' -TenantId $TenantId -Scopes 'Application.Read.All','AppRoleAssignment.ReadWrite.All'

# Get Microsoft Graph app's service principal and app role.
$serverApplicationName = "Microsoft Graph"
$serverServicePrincipal = (Get-MgServicePrincipal -Filter "DisplayName eq '$serverApplicationName'")
$serverServicePrincipalObjectId = $serverServicePrincipal.Id

$appRoleId = ($serverServicePrincipal.AppRoles | Where-Object {$_.Value -eq $appRoleName }).Id

# Assign the managed identity access to the app role.
New-MgServicePrincipalAppRoleAssignment `
    -ServicePrincipalId $managedIdentityObjectId `
    -PrincipalId $managedIdentityObjectId `
    -ResourceId $serverServicePrincipalObjectId `
    -AppRoleId $appRoleId

az login

webAppName="SecureWebApp-20201106120003"

spId=$(az resource list -n $webAppName --query [*].identity.principalId --out tsv)

graphResourceId=$(az ad sp list --display-name "Microsoft Graph" --query [0].id --out tsv)

appRoleId=$(az ad sp list --display-name "Microsoft Graph" --query "[0].appRoles[?value=='User.Read.All' && contains(allowedMemberTypes, 'Application')].id" --output tsv)

uri=https://microsoftgraph.chinacloudapi.cn/v1.0/servicePrincipals/$spId/appRoleAssignments

body="{'principalId':'$spId','resourceId':'$graphResourceId','appRoleId':'$appRoleId'}"

az rest --method post --uri $uri --body $body --headers "Content-Type=application/json"

The ChainedTokenCredential, ManagedIdentityCredential, and EnvironmentCredential classes are used to get a token credential for your code to authorize requests to Microsoft Graph. Create an instance of the ChainedTokenCredential class, which uses the managed identity in the App Service environment or the development environment variables to fetch tokens and attach them to the service client. The following code example gets the authenticated token credential and uses it to create a service client object, which gets the users in the group.

To see this code as part of a sample application, see the sample on GitHub.

Install the Microsoft.Identity.Web.GraphServiceClient client library package

Install the Microsoft.Graph and Microsoft.Identity.Web.GraphServiceClient NuGet packages in your project by using the .NET command-line interface (CLI) or the Package Manager Console in Visual Studio.

.NET CLI

Open a command line, and switch to the directory that contains your project file.

Run the install commands.

dotnet add package Microsoft.Identity.Web.GraphServiceClient
dotnet add package Microsoft.Graph

Package Manager Console

Open the project/solution in Visual Studio, and open the console by using the Tools > NuGet Package Manager > Package Manager Console command.

Run the install commands.

Install-Package Microsoft.Identity.Web.GraphServiceClient
Install-Package Microsoft.Graph

Example

using System;
using System.Collections.Generic;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Mvc.RazorPages;
using Microsoft.Extensions.Logging;
using Microsoft.Graph;
using Azure.Identity;

...

public IList<MSGraphUser> Users { get; set; }

public async Task OnGetAsync()
{
    // Create the Graph service client with a ChainedTokenCredential which gets an access
    // token using the available Managed Identity or environment variables if running
    // in development.
    var credential = new ChainedTokenCredential(
        new ManagedIdentityCredential(),
        new EnvironmentCredential());

    string[] scopes = new[] { "https://microsoftgraph.chinacloudapi.cn/.default" };

    var graphServiceClient = new GraphServiceClient(
        credential, scopes);

    List<MSGraphUser> msGraphUsers = new List<MSGraphUser>();
    try
    {
        //var users = await graphServiceClient.Users.Request().GetAsync();
        var users = await graphServiceClient.Users.GetAsync();
        foreach (var u in users.Value)
        {
            MSGraphUser user = new MSGraphUser();
            user.userPrincipalName = u.UserPrincipalName;
            user.displayName = u.DisplayName;
            user.mail = u.Mail;
            user.jobTitle = u.JobTitle;

            msGraphUsers.Add(user);
        }
    }
    catch (Exception ex)
    {
        string msg = ex.Message;
    }

    Users = msGraphUsers;
}

The DefaultAzureCredential class from @azure/identity package is used to get a token credential for your code to authorize requests to Azure Storage. Create an instance of the DefaultAzureCredential class, which uses the managed identity to fetch tokens and attach them to the service client. The following code example gets the authenticated token credential and uses it to create a service client object, which gets the users in the group.

Example

const graphHelper = require('../utils/graphHelper');
const { DefaultAzureCredential } = require("@azure/identity");

exports.getUsersPage = async(req, res, next) => {

    const defaultAzureCredential = new DefaultAzureCredential();
    
    try {
        const tokenResponse = await defaultAzureCredential.getToken("https://microsoftgraph.chinacloudapi.cn/.default");

        const graphClient = graphHelper.getAuthenticatedClient(tokenResponse.token);

        const users = await graphClient
            .api('/users')
            .get();

        res.render('users', { user: req.session.user, users: users });   
    } catch (error) {
        next(error);
    }
}

To query Microsoft Graph, the sample uses the Microsoft Graph JavaScript SDK.

getAuthenticatedClient = (accessToken) => {
    // Initialize Graph client
    const client = graph.Client.init({
        // Use the provided access token to authenticate requests
        authProvider: (done) => {
            done(null, accessToken);
        }
    });

    return client;
}