How To: Transform Incoming Claims

Articolo
03/30/2017

Applies To

Microsoft® Windows® Identity Foundation (WIF)
ASP.NET® Web Forms

Summary

This How-To provides detailed step-by-step procedures for creating a simple claims-aware ASP.NET Web Forms application and transforming incoming claims. It also provides instructions for how to test the application to verify that transformed claims are presented when the application is run.

Objectives
Overview
Summary of Steps
Step 1 – Create a Simple ASP.NET Web Forms Application
Step 2 – Implement Claims Transformation Using a Custom ClaimsAuthenticationManager
Step 3 – Test Your Solution

Objectives

Configure an ASP.NET Web Forms application for claims-based authentication
Transform incoming claims by adding an Administrator role claim
Test the ASP.NET Web Forms application to see if it is working properly

Overview

WIF exposes a class named ClaimsAuthenticationManager that enables users to modify claims before they are presented to a relying party (RP) application. The ClaimsAuthenticationManager is useful for separation of concerns between authentication and the underlying application code. The example below demonstrates how to add a role to the claims in the incoming ClaimsPrincipal that may be required by the RP.

Summary of Steps

Step 1 – Create a Simple ASP.NET Web Forms Application
Step 2 – Implement Claims Transformation Using a Custom ClaimsAuthenticationManager
Step 3 – Test Your Solution

Step 1 – Create a Simple ASP.NET Web Forms Application

In this step, you will create a new ASP.NET Web Forms application.

To create a simple ASP.NET application

Start Visual Studio in elevated mode as administrator.
In Visual Studio, click File, click New, and then click Project.
In the New Project window, click ASP.NET Web Forms Application.
In Name, enter TestApp and press OK.
Right-click the TestApp project under Solution Explorer, then select Identity and Access.
The Identity and Access window appears. Under Providers, select Test your application with the Local Development STS, then click Apply.

In the Default.aspx file, replace the existing markup with the following, then save the file:

<%@ Page Title="Home Page" Language="C#" MasterPageFile="~/Site.Master" AutoEventWireup="true"
    CodeBehind="Default.aspx.cs" Inherits="TestApp._Default" %>

<asp:Content runat="server" ID="BodyContent" ContentPlaceHolderID="MainContent">
      <h3>Your Claims</h3>
    <p>
        <asp:GridView ID="ClaimsGridView" runat="server" CellPadding="3">
            <AlternatingRowStyle BackColor="White" />
            <HeaderStyle BackColor="#7AC0DA" ForeColor="White" />
        </asp:GridView>
    </p>
</asp:Content>

Open the code-behind file named Default.aspx.cs. Replace the existing code with the following, then save the file:

using System;
using System.Web.UI;
using System.Security.Claims;

namespace TestApp
{
    public partial class _Default : Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            ClaimsPrincipal claimsPrincipal = Page.User as ClaimsPrincipal;
            this.ClaimsGridView.DataSource = claimsPrincipal.Claims;
            this.ClaimsGridView.DataBind();
        }
    }
}

Step 2 – Implement Claims Transformation Using a Custom ClaimsAuthenticationManager

In this step you will override default functionality in the ClaimsAuthenticationManager class to add an Administrator role to the incoming Principal.

To implement claims transformation using a custom ClaimsAuthenticationManager

In Visual Studio, right-click the on the solution, click Add, and then click New Project.
In the Add New Project window, select Class Library from the Visual C# templates list, enter ClaimsTransformation, and then press OK. The new project will be created in your solution folder.
Right-click on References under the ClaimsTransformation project, and then click Add Reference.
In the Reference Manager window, select System.IdentityModel, and then click OK.
Open Class1.cs, or if it doesn’t exist, right-click ClaimsTransformation, click Add, then click Class…

Add the following using directives to the code file:

using System.Security.Claims;
using System.Security.Principal;

Add the following class and method in the code file.

Warning

The following code is for demonstration purposes only; make sure that you verify your intended permissions in production code.

public class ClaimsTransformationModule : ClaimsAuthenticationManager
{
    public override ClaimsPrincipal Authenticate(string resourceName, ClaimsPrincipal incomingPrincipal)
    {
        if (incomingPrincipal != null && incomingPrincipal.Identity.IsAuthenticated == true)
        {
           ((ClaimsIdentity)incomingPrincipal.Identity).AddClaim(new Claim(ClaimTypes.Role, "Admin"));
        }

        return incomingPrincipal;
    }
}

Save the file and build the ClaimsTransformation project.
In your TestApp ASP.NET project, right-click on References, and then click Add Reference.
In the Reference Manager window, select Solution from the left menu, select ClaimsTransformation from the populated options, and then click OK.
In the root Web.config file, navigate to the <system.identityModel> entry. Within the <identityConfiguration> elements, add the following line and save the file:
```
<claimsAuthenticationManager type="ClaimsTransformation.ClaimsTransformationModule, ClaimsTransformation" />
```

Step 3 – Test Your Solution

In this step you will test your ASP.NET Web Forms application, and verify that claims are presented when a user signs in with Forms authentication.

To test your ASP.NET Web Forms application for claims using Forms authentication

Press F5 to build and run the application. You should be presented with Default.aspx.
On the Default.aspx page, you should see a table beneath the Your Claims heading that includes the Issuer, OriginalIssuer, Type, Value, and ValueType claims information about your account. The last row should be presented in the following way:

LOCAL AUTHORITY LOCAL AUTHORITY https://schemas.microsoft.com/ws/2008/06/identity/claims/role Admin https://www.w3.org/2001/XMLSchema#string

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