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Invoking an API protected by Azure AD from a text-only device

Senast uppdaterad: 2018-08-24
Redigera på GitHub

About this sample

Overview

This sample demonstrates how to leverage ADAL .NET from apps that do not have the capability of offering an interactive authentication experience. It enables this app to:

  • authenticate a user
  • and call to a web API (in this case, the Microsoft Graph)

The sample uses the OAuth2 device profile flow similar to the one described here. The app is built entirely on .NET Core, hence it can be ran as-is on Windows (including Nano Server), OSX, and Linux machines.

To emulate a device not capable of showing UX, the sample is packaged as a console application. The application signs users in with Azure Active Directory (Azure AD), using the Active Directory Authentication Library (ADAL) to obtain a JWT access token through the OAuth 2.0 protocol. The access token is sent to Azure AD's Microsoft Graph API to obtain information about other users in their organization.

Looking for previous versions of this code sample? Check out the tags on the releases GitHub page.

If you would like to get started immediately, skip this section and jump to How To Run The Sample.

Scenario

This sample solution is a command-line utility that can be used for looking up basic information for users in Azure AD tenants. The project targets .NET Core: it has been tested on Windows, OSX, and Ubuntu Linux.

The application obtains tokens through a two steps process especially designed for devices and operating systems that cannot display any UX. Examples of such applications are applications running on iOT, or Command-Line tools (CLI). The idea is that:

  1. whenever a user authentication is required, the command-line app provides a code and asks the user to use another device (such as an internet-connected smartphone) to navigate to http://aka.ms/devicelogin, where the user will be prompted to enter the code. That done, the web page will lead the user through a normal authentication experience, including consent prompts and multi factor authentication if necessary.

  1. Upon successful authentication, the command-line app will receive the required tokens through a back channel and will use it to perform the web API calls it needs.

About the code

The code for handling the token acquisition process is simple, as it boils down to:

  • one call for obtaining the code to display to the user (via AcquireDeviceCodeAsync)
  • and one call to poll the service to retrieve the tokens when available (via AcquireTokenByDeviceCodeAsync).

You can find both calls in the sample in the static method GetTokenViaCode, from the app root class Program in program.cs.

static async Task<AuthenticationResult> GetTokenViaCode(AuthenticationContext ctx)
{
    AuthenticationResult result = null;
    try
    {
        DeviceCodeResult codeResult = await ctx.AcquireDeviceCodeAsync(resource, clientId);
        Console.WriteLine("You need to sign in.");
        Console.WriteLine("Message: " + codeResult.Message + "\n");
        result = await ctx.AcquireTokenByDeviceCodeAsync(codeResult);
    }
    catch (Exception exc)
    {
        Console.WriteLine("Something went wrong.");
        Console.WriteLine("Message: " + exc.Message + "\n");
    }
    return result;
}

How to run this sample

To run this sample, you'll need:

  • Visual Studio 2017 or just the .NET Core SDK
  • An Internet connection
  • A Windows machine (necessary if you want to run the app on Windows)
  • An OS X machine (necessary if you want to run the app on OSX)
  • A Linux machine (necessary if you want to run the app on OSX)
  • An Azure Active Directory (Azure AD) tenant. For more information on how to get an Azure AD tenant, please see How to get an Azure AD tenant
  • A user account in your Azure AD tenant. This sample will not work with a Microsoft account. If you signed in to the Azure portal with a Microsoft account (previously named live account) and have never created a user account in your directory before, you need to do that now.

Step 1: Clone or download this repository

git clone https://github.com/Azure-Samples/active-directory-dotnet-deviceprofile.git

or download and exact the repository .zip file.

Given that the name of the sample is pretty long, and so are the name of the referenced NuGet pacakges, you might want to clone it in a folder close to the root of your hard drive, to avoid file size limitations on Windows.

Step 2: Setup .NET core

The .NET core documentation pages provide step by step instructions for installing .NET Core (the .NET Execution Environment) for your platform of choice.

Step 3: Run the sample

If you prefer to use Visual Studio

Open the solution in Visual Studio, restore the NuGet packages, select the project, and start it in the debugger.

(otherwise) on any platform

Open a terminal and navigate to the project folder (DirSearcherClient). Restore the packages with the following command:

    dotnet restore

Launch the app by entering the following command:

    dotnet run

Operating the sample

As soon as you start the sample, you will be presented with the following prompt.

> Enter command (search | clear | printcache | exit | help) >

To see the device code authentication experience in action, enter a command for searching a user in one of your tenants. In my case, I want to search a user with alias mario in my tenant developertenant.onmicrosoft.com. Hence, the command I'll enter will be:

> search mario developertenant.onmicrosoft.com

The app will respond with the following prompt.

> You need to sign in.
> Message: To sign in, use a web browser to open the page https://aka.ms/devicelogin. Enter the code B7D3SVXHV to authenticate. If you're signing in as an Azure AD application, use the --username and --password parameters.

Then:

  1. Open a browser on any device. For instance, the browser can be on the computer on which you are running the sample, or even your smartphone. Then navigate, as instructed, to https://aka.ms/devicelogin
  2. Once there, type in the code provided by the app (in this sample, I am typing B7D3SVXHV) and hit enter. The web page will proceed to prompt you for authentication: please authenticate as a user (native or guest) in the tenant that you specified in the search command. Note that, thanks to the fact that you are using an external browser or a different, browser capable device, you can authenticate without restrictions: for example, if your tenant requires you to authenticate using MFA, you are able to do so. That experience would not have been possible if you had to drive the authentication operations exclusively in the console.
  3. Once you successfully authenticate, go back to the console app. You'll see that the app has now access to the token it needs to query the Microsoft Graph API. In my case, a mario does exist in my tenant: hence I'll receive the following result.
> Users found.
> displayName: Mario Rossi
> givenName: Mario
> surname: Rossi
> userPrincipalName: mario@developertenant.onmicrosoft.com
> telephoneNumbe: Not Listed.
> Enter command (search | clear | printcache | exit | help) >
>

As a next step, you can search for other users. If you search for users in the same tenant, you'll be able to perform the query without extra prompts. If you indicate a new tenant, you will be prompted again. Note that, if your authenticated user is provisioned in the new tenant and your sample app already received consent in that tenant, you'll be able to get tokens for the new tenant without extra prompts as well.

Optional: configure the sample as an app in your directory tenant

The instructions so far leveraged the Azure AD entry for the app in a Microsoft test tenant: given that the app is multitenant, anybody can run the sample against that app entry. To register your project in your own Azure AD tenant, you can:

  • either use PowerShell scripts that:

    • automatically create for you the Azure AD applications and related objects (passwords, permissions, dependencies)
    • modify the Visual Studio projects' configuration files.
  • or follow the steps in the paragraphs below

If you want to use this automation, read the instructions in App Creation Scripts

Below you'll find instructions to manually provision the sample in your own tenant, so that you can exercise complete control on the app settings and behavior.

First step: choose the Azure AD tenant where you want to create your applications

As a first step you'll need to:

  1. Sign in to the Azure portal.
  2. On the top bar, click on your account, and then on Switch Directory.
  3. Once the Directory + subscription pane opens, choose the Active Directory tenant where you wish to register your application, from the Favorites or All Directories list.
  4. Click on All services in the left-hand nav, and choose Azure Active Directory.

In the next steps, you might need the tenant name (or directory name) or the tenant ID (or directory ID). These are presented in the Properties of the Azure Active Directory window respectively as Name and Directory ID

Register the client app (active-directory-dotnet-deviceprofile)

  1. In the Azure Active Directory pane, click on App registrations and choose New application registration.
  2. Enter a friendly name for the application, for example 'active-directory-dotnet-deviceprofile' and select 'Native' as the Application Type.
  3. For the Redirect URI, enter https://<your_tenant_name>/active-directory-dotnet-deviceprofile, replacing <your_tenant_name> with the name of your Azure AD tenant.
  4. Click Create to create the application.
  5. In the succeeding page, Find the Application ID value and record it for later. You'll need it to configure the Visual Studio configuration file for this project.
  6. Then click on Settings, and choose Properties.
  7. Configure Permissions for your application. To that extent, in the Settings menu, choose the 'Required permissions' section and then, click on Add, then Select an API, and type Microsoft Graph in the textbox. Then, click on Select Permissions and select User.ReadBasic.All.

Configure the sample to use your Azure AD tenant

In the steps below, ClientID is the same as Application ID or AppId.

Open the solution in Visual Studio to configure the projects

Configure the client project

  1. Open the DirSearcherClient\Program.cs file
  2. Find the line where clientId is set and replace the existing value with the application ID (clientId) of the active-directory-dotnet-deviceprofile application copied from the Azure portal.

Community Help and Support

Use Stack Overflow to get support from the community. Ask your questions on Stack Overflow first and browse existing issues to see if someone has asked your question before. Make sure that your questions or comments are tagged with [adal dotnet].

If you find a bug in the sample, please raise the issue on GitHub Issues.

To provide a recommendation, visit the following User Voice page.

Contributing

If you'd like to contribute to this sample, see CONTRIBUTING.MD.

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.

More information

For more information, see ADAL.NET's conceptual documentation:

Provide links to the flows from the conceptual documentation for instance: - Device profile for devices without web browsers - Customizing Token cache serialization (was not done in this sample)