Home / My Disclaimer / Who am I? / Search... / Sign in

// Entity Framework

Adjusting the Home Realm Discovery page in ADFS to support Email Addresses

by Steve Syfuhs / July 12, 2011 04:00 PM

Over on the Geneva forums a question was asked:

Does anyone have an example of how to change the HomeRealmDiscovery Page in ADFSv2 to accept an e-mail address in a text field and based upon that (actually the domain suffix) select the correct Claims/Identity Provider?

It's pretty easy to modify the HomeRealmDiscovery page, so I thought I'd give it a go.

Based on the question, two things need to be known: the email address and the home realm URI.  Then we need to translate the email address to a home realm URI and pass it on to ADFS.

This could be done a couple ways.  First it could be done by keeping a list of email addresses and their related home realms, or a list of email domains and their related home realms.  For the sake of this being an example, lets do both.

I've created a simple SQL database with three tables:

image

Each entry in the EmailAddress and Domain table have a pointer to the home realm URI (you can find the schema in the zip file below).

Then I created a new ADFS web project and added a new entity model to it:

image

From there I modified the HomeRealmDiscovery page to do the check:

//------------------------------------------------------------
// Copyright (c) Microsoft Corporation.  All rights reserved.
//------------------------------------------------------------

using System;

using Microsoft.IdentityServer.Web.Configuration;
using Microsoft.IdentityServer.Web.UI;
using AdfsHomeRealm.Data;
using System.Linq;

public partial class HomeRealmDiscovery : Microsoft.IdentityServer.Web.UI.HomeRealmDiscoveryPage
{
    protected void Page_Init(object sender, EventArgs e)
    {
    }

    protected void PassiveSignInButton_Click(object sender, EventArgs e)
    {
        string email = txtEmail.Text;

        if (string.IsNullOrWhiteSpace(email))
        {
            SetError("Please enter an email address");
            return;
        }

        try
        {
            SelectHomeRealm(FindHomeRealmByEmail(email));
        }
        catch (ApplicationException)
        {
            SetError("Cannot find home realm based on email address");
        }
    }

    private string FindHomeRealmByEmail(string email)
    {
        using (AdfsHomeRealmDiscoveryEntities en = new AdfsHomeRealmDiscoveryEntities())
        {
            var emailRealms = from e in en.EmailAddresses where e.EmailAddress1.Equals(email) select e;

            if (emailRealms.Any()) // email address exists
                return emailRealms.First().HomeRealm.HomeRealmUri;

            // email address does not exist
            string domain = ParseDomain(email);

            var domainRealms = from d in en.Domains where d.DomainAddress.Equals(domain) select d;

            if (domainRealms.Any()) // domain exists
                return domainRealms.First().HomeRealm.HomeRealmUri;

            // neither email nor domain exist
            throw new ApplicationException();
        }
    }

    private string ParseDomain(string email)
    {
        if (!email.Contains("@"))
            return email;

        return email.Substring(email.IndexOf("@") + 1);
    }

    private void SetError(string p)
    {
        lblError.Text = p;
    }
}

 

If you compare the original code, there was some changes.  I removed the code that loaded the original home realm drop down list, and removed the code to choose the home realm based on the drop down list's selected value.

You can find my code here: http://www.syfuhs.net/AdfsHomeRealm.zip

Getting the Data to the Phone

by Steve Syfuhs / July 31, 2010 04:00 PM

A few posts back I started talking about what it would take to create a new application for the new Windows Phone 7.  I’m not a fan of learning from trivial applications that don’t touch on the same technologies that I would be using in the real world, so I thought I would build a real application that someone can use.

Since this application uses a well known dataset I kind of get lucky because I already have my database schema, which is in a reasonably well designed way.  My first step is to get it to the Phone, so I will use WCF Data Services and an Entity Model.  I created the model and just imported the necessary tables.  I called this model RaceInfoModel.edmx.  The entities name is RaceInfoEntities  This is ridiculously simple to do.

The following step is to expose the model to the outside world through an XML format in a Data Service.  I created a WCF Data Service and made a few config changes:

using System.Data.Services;
using System.Data.Services.Common;
using System;

namespace RaceInfoDataService
{
    public class RaceInfo : DataService
{ public static void InitializeService(DataServiceConfiguration config) { if (config
== null) throw new ArgumentNullException("config"); config.UseVerboseErrors
= true; config.SetEntitySetAccessRule("*", EntitySetRights.AllRead); //config.SetEntitySetPageSize("*",
25); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;
} } }

This too is reasonably simple.  Since it’s a web service, I can hit it from a web browser and I get a list of available datasets:

image

This isn’t a complete list of available items, just a subset.

At this point I can package everything up and stick it on a web server.  It could technically be ready for production if you were satisfied with not having any Access Control’s on reading the data.  In this case, lets say for arguments sake that I was able to convince the powers that be that everyone should be able to access it.  There isn’t anything confidential in the data, and we provide the data in other services anyway, so all is well.  Actually, that’s kind of how I would prefer it anyway.  Give me Data or Give me Death!

Now we create the Phone project.  You need to install the latest build of the dev tools, and you can get that here http://developer.windowsphone.com/windows-phone-7/.  Install it.  Then create the project.  You should see:

image

The next step is to make the Phone application actually able to use the data.  Here it gets tricky.  Or really, here it gets stupid.  (It better he fixed by RTM or else *shakes fist*)

For some reason, the Visual Studio 2010 Phone 7 project type doesn’t allow you to automatically import services.  You have to generate the service class manually.  It’s not that big a deal since my service won’t be changing all that much, but nevertheless it’s still a pain to regenerate it manually every time a change comes down the pipeline.  To generate the necessary class run this at a command prompt:

cd C:\Windows\Microsoft.NET\Framework\v4.0.30319
DataSvcutil.exe
     /uri:http://localhost:60141/RaceInfo.svc/
     /DataServiceCollection
     /Version:2.0
     /out:"PATH.TO.PROJECT\RaceInfoService.cs"

(Formatted to fit my site layout)

Include that file in the project and compile.

UPDATE: My bad, I had already installed the reference, so this won’t compile for most people.  The Windows Phone 7 runtime doesn’t have the System.Data namespace available that we need.  Therefore we need to install them…  They are still in development, so here is the CTP build http://www.microsoft.com/downloads/details.aspx?displaylang=en&FamilyID=b251b247-70ca-4887-bab6-dccdec192f8d.

You should now have a compile-able project with service references that looks something like:

image

We have just connected our phone application to our database!  All told, it took me 10 minutes to do this.  Next up we start playing with the data.

Data as a Service and the Applications that consume it

by Steve Syfuhs / July 30, 2010 04:00 PM

Over the past few months I have seen quite a few really cool technologies released or announced, and I believe they have a very real potential in many markets.  A lot of companies that exist outside the realm of Software Development, rarely have the opportunity to use such technologies.

Take for instance the company I work for: Woodbine Entertainment Group.  We have a few different businesses, but as a whole our market is Horse Racing.  Our business is not software development.  We don’t always get the chance to play with or use some of the new technologies released to the market.  I thought this would be a perfect opportunity to see what it will take to develop a new product using only new technologies.

Our core customer pretty much wants Race information.  We have proof of this by the mere fact that on our two websites, HorsePlayer Interactive and our main site, we have dedicated applications for viewing Races.  So lets build a third race browser.  Since we already have a way of viewing races from your computer, lets build it on the new Windows Phone 7.

The Phone – The application

This seems fairly straightforward.  We will essentially be building a Silverlight application.  Let’s take a look at what we need to do (in no particular order):

  1. Design the interface – Microsoft has loads of guidance on following with the Metro design.  In future posts I will talk about possible designs.
  2. Build the interface – XAML and C#.  Gotta love it.
  3. Build the Business Logic that drives the views – I would prefer to stay away from this, suffice to say I’m not entirely sure how proprietary this information is
  4. Build the Data Layer – Ah, the fun part.  How do you get the data from our internal servers onto the phone?  Easy, OData!

The Data

We have a massive database of all the Races on all the tracks that you can wager on through our systems.  The data updates every few seconds relative to changes from the tracks for things like cancellations or runner odds.  How do we push this data to the outside world for the phone to consume?  We create a WCF Data Service:

  1. Create an Entities Model of the Database
  2. Create Data Service
  3. Add Entity reference to Data Service (See code below)
 
    public class RaceBrowserData : DataService
{ public static void InitializeService(DataServiceConfiguration config) { if (config
== null) throw new ArgumentNullException("config"); config.UseVerboseErrors
= true; config.SetEntitySetAccessRule("*", EntitySetRights.AllRead); //config.SetEntitySetPageSize("*",
25); config.DataServiceBehavior.MaxProtocolVersion = DataServiceProtocolVersion.V2;
} } 

That’s actually all there is to it for the data.

The Authentication

The what?  Chances are the business will want to limit application access to only those who have accounts with us.  Especially so if we did something like add in the ability to place a wager on that race.  There are lots of ways to lock this down, but the simplest approach in this instance is to use a Secure Token Service.  I say this because we already have a user store and STS, and duplication of effort is wasted effort.  We create a STS Relying Party (The application that connects to the STS):

  1. Go to STS and get Federation Metadata.  It’s an XML document that tells relying parties what you can do with it.  In this case, we want to authenticate and get available Roles.  This is referred to as a Claim.  The role returned is a claim as defined by the STS.  Somewhat inaccurately, we would do this:
    1. App: Hello! I want these Claims for this user: “User Roles”.  I am now going to redirect to you.
    2. STS: I see you want these claims, very well.  Give me your username and password.
    3. STS: Okay, the user passed.  Here are the claims requested.  I am going to POST them back to you.
    4. App: Okay, back to our own processes.
  2. Once we have the Metadata, we add the STS as a reference to the Application, and call a web service to pass the credentials.
  3. If the credentials are accepted, we get returned the claims we want, which in this case would be available roles.
  4. If the user has the role to view races, we go into the Race view.  (All users would have this role, but adding Roles is a good thing if we needed to distinguish between wagering and non-wagering accounts)

One thing I didn’t mention is how we lock down the Data Service.  That’s a bit more tricky, and more suited for another post on the actual Data Layer itself.

So far we have laid the ground work for the development of a Race Browser application for the Windows Phone 7 using the Entity Framework and WCF Data Services, as well as discussed the use of the Windows Identity Foundation for authentication against an STS.

With any luck (and permission), more to follow.

// About

Steve is a renaissance kid when it comes to technology. He spends his time in the security stack.