Calling a web api using an application identity

Laatst bijgewerkt: 30-6-2017
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In contrast to the WebApp-WebAPI-OpenIDConnect-DotNet sample, this sample shows how to build an MVC web application that uses Azure AD for sign-in using OpenID Connect, and then calls a web API under the application's identity (instead of the user's identity) using tokens obtained via OAuth 2.0. This sample uses the OpenID Connect ASP.Net OWIN middleware and ADAL .Net.

This sample is an example of the trusted sub-system model, where the web API trusts the web application to have authenticated the user, and receives no direct evidence from Azure AD that the user was authenticated. If you want to build a web app that calls a web API using a delegated user identity, please check out the sample named WebApp-WebAPI-OpenIDConnect-DotNet.

For more information about how the protocols work in this scenario and other scenarios, see Authentication Scenarios for Azure AD.

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

How To Run This Sample

To run this sample you will need: - Visual Studio 2013 - An Internet connection - 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, so if you signed in to the Azure portal with a Microsoft 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

From your shell or command line:

git clone https://github.com/Azure-Samples/active-directory-dotnet-webapp-webapi-oauth2-appidentity.git

Step 2: Register the sample with your Azure Active Directory tenant

There are two projects in this sample. Each needs to be separately registered in your Azure AD tenant.

Register the TodoListService web API

  1. Sign in to the Azure portal.
  2. On the top bar, click on your account and under the Directory list, choose the Active Directory tenant where you wish to register your application.
  3. Click on More Services in the left hand nav, and choose Azure Active Directory.
  4. Click on App registrations and choose Add.
  5. Enter a friendly name for the application, for example 'TodoListService' and select 'Web Application and/or Web API' as the Application Type. For the sign-on URL, enter the base URL for the sample, which is by default https://localhost:44321. Click on Create to create the application.
  6. While still in the Azure portal, choose your application, click on Settings and choose Properties.
  7. Find the Application ID value and copy it to the clipboard.
  8. For the App ID URI, enter https://<your_tenant_name>/TodoListService, replacing <your_tenant_name> with the name of your Azure AD tenant.

Register the TodoListWebApp web app

  1. Sign in to the Azure portal.
  2. On the top bar, click on your account and under the Directory list, choose the Active Directory tenant where you wish to register your application.
  3. Click on More Services in the left hand nav, and choose Azure Active Directory.
  4. Click on App registrations and choose Add.
  5. Enter a friendly name for the application, for example 'TodoListWebApp-AppIdentity' and select 'Web Application and/or Web API' as the Application Type. For the sign-on URL, enter the base URL for the sample, which is by default https://localhost:44322. Click on Create to create the application.
  6. While still in the Azure portal, choose your application, click on Settings and choose Properties.
  7. Find the Application ID value and copy it to the clipboard.
  8. From the Settings menu, choose Keys and add a key - select a key duration of either 1 year or 2 years. When you save this page, the key value will be displayed, copy and save the value in a safe location - you will need this key later to configure the project in Visual Studio - this key value will not be displayed again, nor retrievable by any other means, so please record it as soon as it is visible from the Azure Portal.
  9. Configure Permissions for your application - in the Settings menu, choose the 'Required permissions' section, click on Add, then Select an API, and type 'TodoListService' in the textbox. Then, click on Select Permissions and select 'Access TodoListService'.

Step 3: Configure the sample to use your Azure AD tenant

Configure the TodoListService project

  1. Open the solution in Visual Studio 2013.
  2. Open the web.config file.
  3. Find the app key ida:Tenant and replace the value with your AAD tenant name.
  4. Find the app key ida:Audience and replace the value with the App ID URI you registered earlier, for example https://<your_tenant_name>/TodoListService.
  5. Find the app key ida:ClientId and replace the value with the Client ID for the TodoListService from the Azure portal.

Configure the TodoListWebApp project

  1. Open the solution in Visual Studio 2013.
  2. Open the web.config file.
  3. Find the app key ida:Tenant and replace the value with your AAD tenant name.
  4. Find the app key ida:ClientId and replace the value with the Application ID for the TodoListWebApp-AppIdentity from the Azure portal.
  5. Find the app key ida:AppKey and replace the value with the key for the TodoListWebApp-AppIdentity from the Azure portal.
  6. If you changed the base URL of the TodoListWebApp sample, find the app key ida:PostLogoutRedirectUri and replace the value with the new base URL of the sample.
  7. Find the app key todo:TodoListBaseAdress ane make sure it has the correct value for the address of the TodoListService project.
  8. Find the app key todo:TodoListResourceId and replace the value with the App ID URI registered for the TodoListService, for example https://<your_tenant_name>/TodoListService.

Configure the TodoListWebApp as a trusted caller to the TodoListService

  1. Go back to the TodoListService project and open the web.config file.
  2. Find the app key todo:TrustedCallerClientId and replace the value with the Application ID of the TodoListWebApp. This is used to tell the service to trust the web app.

Step 4: Trust the IIS Express SSL certificate

Since the web API is SSL protected, the client of the API (the web app) will refuse the SSL connection to the web API unless it trusts the API's SSL certificate. Use the following steps in Windows Powershell to trust the IIS Express SSL certificate. You only need to do this once. If you fail to do this step, calls to the TodoListService will always throw an unhandled exception where the inner exception message is:

"The underlying connection was closed: Could not establish trust relationship for the SSL/TLS secure channel."

To configure your computer to trust the IIS Express SSL certificate, begin by opening a Windows Powershell command window as Administrator.

Query your personal certificate store to find the thumbprint of the certificate for CN=localhost:

PS C:\windows\system32> dir Cert:\LocalMachine\My


    Directory: Microsoft.PowerShell.Security\Certificate::LocalMachine\My


Thumbprint                                Subject
----------                                -------
C24798908DA71693C1053F42A462327543B38042  CN=localhost

Next, add the certificate to the Trusted Root store:

PS C:\windows\system32> $cert = (get-item cert:\LocalMachine\My\C24798908DA71693C1053F42A462327543B38042)
PS C:\windows\system32> $store = (get-item cert:\Localmachine\Root)
PS C:\windows\system32> $store.Open("ReadWrite")
PS C:\windows\system32> $store.Add($cert)
PS C:\windows\system32> $store.Close()

You can verify the certificate is in the Trusted Root store by running this command:

PS C:\windows\system32> dir Cert:\LocalMachine\Root

Step 5: Run the sample

Clean the solution, rebuild the solution, and run it. You might want to go into the solution properties and set both projects as startup projects, with the service project starting first.

Explore the sample by signing in, clicking the To Do List link, adding items to the To Do list, signing out, and starting again.

How To Deploy This Sample to Azure

Coming soon.

About The Code

Coming soon.

How To Recreate This Sample

First, in Visual Studio 2013 create an empty solution to host the projects. Then, follow these steps to create each project.

Creating the TodoListService Project

  1. In the solution, create a new ASP.Net MVC web API project called TodoListService and while creating the project, click the Change Authentication button, select Organizational Accounts, Cloud - Single Organization, enter the name of your Azure AD tenant, and set the Access Level to Single Sign On. You will be prompted to sign-in to your Azure AD tenant. NOTE: You must sign-in with a user that is in the tenant; you cannot, during this step, sign-in with a Microsoft account.
  2. In the Models folder add a new class called TodoItem.cs. Copy the implementation of TodoItem from this sample into the class.
  3. Add a new, empty, Web API 2 controller called TodoListController.
  4. Copy the implementation of the TodoListController from this sample into the controller. Don't forget to add the [Authorize] attribute to the class.
  5. In TodoListController resolving missing references by adding using statements for System.Collections.Concurrent, TodoListService.Models, System.Security.Claims.
  6. In web.config, in <appSettings>, create a key todo:TrustedCallerClientId and set the value accordingly.

Creating the TodoListWebApp Project

  1. In the solution, create a new ASP.Net MVC web application called TodoListWebApp with Authentication set to No Authentication.
  2. Set SSL Enabled to be True. Note the SSL URL.
  3. In the project properties, Web properties, set the Project Url to be the SSL URL.
  4. Add the following ASP.Net OWIN middleware NuGets: Microsoft.IdentityModel.Protocol.Extensions, System.IdentityModel.Tokens.Jwt, Microsoft.Owin.Security.OpenIdConnect, Microsoft.Owin.Security.Cookies, Microsoft.Owin.Host.SystemWeb.
  5. Add the Active Directory Authentication Library NuGet (Microsoft.IdentityModel.Clients.ActiveDirectory).
  6. In the App_Start folder, create a class Startup.Auth.cs. You will need to remove .App_Start from the namespace name. Replace the code for the Startup class with the code from the same file of the sample app. Be sure to take the whole class definition! The definition changes from public class Startup to public partial class Startup.
  7. Right-click on the project, select Add, select "OWIN Startup class", and name the class "Startup". If "OWIN Startup Class" doesn't appear in the menu, instead select "Class", and in the search box enter "OWIN". "OWIN Startup class" will appear as a selection; select it, and name the class Startup.cs.
  8. In Startup.cs, replace the code for the Startup class with the code from the same file of the sample app. Again, note the definition changes from public class Startup to public partial class Startup.
  9. In the Views --> Shared folder, create a new partial view _LoginPartial.cshtml. Replace the contents of the file with the contents of the file of same name from the sample.
  10. In the Views --> Shared folder, replace the contents of _Layout.cshtml with the contents of the file of same name from the sample. Effectively, all this will do is add a single line, @Html.Partial("_LoginPartial"), that lights up the previously added _LoginPartial view.
  11. Create a new empty controller called AccountController. Replace the implementation with the contents of the file of same name from the sample.
  12. If you want the user to be required to sign-in before they can see any page of the app, then in the HomeController, decorate the HomeController class with the [Authorize] attribute. If you leave this out, the user will be able to see the home page of the app without having to sign-in first, and can click the sign-in link on that page to get signed in.
  13. In the Models folder add a new class called TodoItem.cs. Copy the implementation of TodoItem from this sample into the class.
  14. Add a new empty MVC5 controller TodoListController to the project. Copy the implementation of the controller from the sample. Remember to include the [Authorize] attribute on the class definition.
  15. In Views --> TodoList create a new view, Index.cshtml, and copy the implementation from this sample.
  16. In the shared _Layout view, add the Action Links for Profile and To Do List that are in the sample.
  17. In web.config, in <appSettings>, create keys for ida:ClientId, ida:AppKey, ida:AADInstance, ida:Tenant, and ida:PostLogoutRedirectUri, and set the values accordingly. For the public Azure AD, the value of ida:AADInstance is https://login.microsoftonline.com/{0}.
  18. In web.config in <appSettings>, create keys for todo:TodoListResourceId and todo:TodoListBaseAddress and set the values accordinly.

Finally, in the properties of the solution itself, set both projects as startup projects.