MetroYam–WPF desktop edition

Part 2 of a series on developing .NET clients for Yammer.

The first client that I've attempted is the WPF version. This version of MetroYam uses the MahApps.Metro library to enable a Metro interface.

Once the UI framework is in place it's time to register with Yammer for an API key. You need this to access their REST API. Initially this just allows you to access the Developer Yammer group, but it may be possible to apply to Yammer to make it useable by any Yammer user.

Using the OAuth1 integration test from the RestSharp source code repository as a guide, I created a class with the following method prototype accessing a feed of messages (keys changed to protect the innocent!)

public List<MessageViewModel> Request()
{
    var client = new RestClient();

    client.BaseUrl = "https://www.yammer.com/";
    string consumerKey = "0121212121212";
    string consumerSecret = "abcdefgkskdlasllkjsfien3234sdfsdf";

    client.Authenticator = OAuth1Authenticator.ForRequestToken( consumerKey, consumerSecret );
    var request = new RestRequest( "oauth/request\_token", Method.POST );

    var response = client.Execute( request );

    var qs = HttpUtility.ParseQueryString( response.Content );
    var oauth\_token = qs\[ "oauth\_token" \];
    var oauth\_token\_secret = qs\[ "oauth\_token\_secret" \];

    request = new RestRequest( "oauth/authorize" );
    request.AddParameter( "oauth\_token", oauth\_token );
    var url = client.BuildUri( request ).ToString();
    Process.Start( url );

    var verifier = "01234"; // <-- Breakpoint here (set verifier in debugger)

    request = new RestRequest( "oauth/access\_token", Method.POST );
    client.Authenticator = OAuth1Authenticator.ForAccessToken(
    consumerKey, consumerSecret, oauth\_token, oauth\_token\_secret, verifier
    );
    response = client.Execute( request );

    qs = HttpUtility.ParseQueryString( response.Content );
    oauth\_token = qs\[ "oauth\_token" \];
    oauth\_token\_secret = qs\[ "oauth\_token\_secret" \];

    Debug.WriteLine("oauth\_token {0}", oauth\_token);
    Debug.WriteLine( "oauth\_token\_secret {0}", oauth\_token\_secret );

    request = new RestRequest( "api/v1/messages.json", Method.GET );
    client.Authenticator = OAuth1Authenticator.ForProtectedResource(
    consumerKey, consumerSecret, oauth\_token, oauth\_token\_secret
    );

    // 2011/03/28 20:39:12 +0000
    request.DateFormat = "yyyy/MM/dd HH:mm:ss zzzzz";

    RestResponse<MessageList> responseList = client.Execute<MessageList>( request );

    var users = new Dictionary<int, User>();
    foreach ( Reference reference in responseList.Data.References )
    {
        if ( reference.Type == "user" )
            users.Add( reference.Id, new User() { Fullname = reference.FullName, Photo = reference.mugshot\_url});
    }

    var messages = new List<MessageViewModel>();

    foreach ( var message in responseList.Data.messages )
    {
        var vm = new MessageViewModel();
        vm.Body = message.Body.Plain;
        vm.Created = message.created\_at.LocalDateTime;
        User user = users\[ message.sender\_id \];
        vm.Sender = user.Fullname;
        if ( user.Photo != null )
            vm.PhotoUrl = user.Photo;
        else
            vm.PhotoUrl = new Uri( "https://c64.assets-yammer.com/images/no\_photo\_small.gif" );

        messages.Add(vm);
    }

    return messages;

}

The Models (Message, User etc) and ViewModel (MessageViewModel) are declared in the 'portable' class library. This library is shared between the WPF, Windows Phone and Metro-style WinRT applications.

This particular method causes a web browser to load part-way through to obtain a user authentication code. Normally an application would cache the oauth_token and oauth_token_secret values returned by the "oauth/access_token" call so the user wouldn't need to re-authenticate the app each time.

The relevant XAML to render this is pretty straightforward (not that I'm a XAML expert like Nigel!)

<ListView Grid.Column="1" Grid.Row="1" Margin="20,0,0,0" x:Name="Messages"
            HorizontalContentAlignment="Stretch"
            ScrollViewer.HorizontalScrollBarVisibility="Disabled">
    <ListView.ItemTemplate>
        <DataTemplate>

            <Border Padding="0,0,0,10">
                <DockPanel ScrollViewer.HorizontalScrollBarVisibility="Disabled" >
                    <Image Width="48" Height="48" Source="{Binding PhotoUrl, IsAsync=True}" DockPanel.Dock="Left" VerticalAlignment="Top" />
                    <TextBlock Text="{Binding Path=Sender}" DockPanel.Dock="Top" FontWeight="Bold" />
                    <TextBlock Text="{Binding Path=Created}" DockPanel.Dock="Top" />
                    <TextBlock Text="{Binding Path=Body}" DockPanel.Dock="Bottom" TextWrapping="WrapWithOverflow" />

                </DockPanel>
            </Border>
        </DataTemplate>
    </ListView.ItemTemplate>
</ListView>

And to confirm that this does actually render something, here's a screenshot of work in progress:

I like how the <Image/> element can take an Internet URL so that it just loads the photos automatically.

My plan is that the client will default to the 'company' list in the first column, but let you add additional columns to follow other groups that you are a member of.

MetroYam–a .NET Yammer client (or three)

I first came across Yammer via Rob Farley when I was working at LobsterPot Solutions. Imagine Twitter and Facebook morphed together, but just for a single organisation instead of publishing your thoughts for all the world (or your friends) to see. Yammer knows what information to show you because it's based around your email address – so for example everyone who has a @gardiner.net.au email address would be able to collaborate on Yammer together, without worrying that their posts would be seen by non @gardiner.net.au users.

It's quite a useful platform for sharing resources and information amongst colleagues, and a useful adjunct to other communication methods (face to face, phone, email, IM). The basic offering is free, but if you want to have more administrative control you pay for the privilege.

Access is via their website, but they also provide a number of platform-specific clients too. Unfortunately the Windows client isn't the greatest. I've had problems where it wouldn't auto-update, and the current version doesn't seem to have working notifications. It also uses Adobe AIR, which is just one more think to keep patched. It's enough to make you want to write a decent client and maybe learn a few things along the way – queue 'MetroYam' – my name for a Yammer client built on .NET.

My plans are to build a number of clients:

• a WPF-based Windows desktop application
• a Metro-style app for Windows 8 (WinRT)
• a Windows Phone app

It will be interesting to see how much code I can share and reuse between the 3 different platforms.

The inspiration for the user interface I plan to build is MetroTwit (my Twitter client of choice) – a great example of the Metro design that Microsoft are building into Windows 8.

It won't be a carbon-copy but they've got some good ideas worth emulating.

Resources

Yammer API

Lucky for me, Yammer have a REST API that they provide for things just like this. It uses OAuth for authentication and JSON.

Caliburn Micro

I plan to use Caliburn Micro for all three clients. I've used CM before, for my 'Aussie Toilets' Windows Phone app, so this will be a chance to explore it's support for WPF and WinRT.

RestSharp

For the WPF and Windows Phone clients, I'm going to make use of the RestSharp library to access the Yammer API as it provides support for JSON as well as OAuth. RestSharp doesn't support support WinRT, so I'll need to take a different approach there.

Visual Studio 2010 + 2012 beta

And finally it's happened! You can open solutions and projects in 2012 not be restricted from still using them in 2010. I'll need to use VS 2012 to build the WinRT projects, but I'll also need to still use VS2010 to build the phone app (as the 2012 beta doesn't come with Windows Phone support yet).

Updating Castle Windsor from v2.5 to 3.0

Late last year the Castle Windsor project released a major update to some of their components - from version 2.5 to 3.0. There are some breaking changes (most of which are documented in the BreakingChanges.txt files for Core and Windsor), so I thought I’d highlight a few issues that may be more common.

ILogger

The logging abstraction interface has been simplified, with a number of the overloaded methods removed. Whereas before you might have called ILogger.Debug("A message {0}", arg1), you now would use ILogger.DebugFormat() instead.

Component Registration

In 2.5 you could use the .Unless() method to add a condition (usually to skip registration if component already exists). This method has been replaced with the equivalent OnlyNewServices() method.

IHandler

This used to have a 'Service' property. Now refer to the IHandler.ComponentModel property which has a Services collection property.

Facilities

Previously, the IWindsorContainer.AddFacility() method required a string 'key' parameter. This is has been removed.

IHandler.AddCustomDependencyValue

This method has been removed, but you can now use the new Depends() method instead during registration. eg.

Component.For() .ImplementedBy() .DependsOn( Dependency.OnValue("parameterName", "CustomValue") );

IKernel.RemoveComponent

This method has been removed. There is now no way to remove a component.

Compatibility

NServiceBus 2.x

NServiceBus 3 is compatible with Castle 3.0, but if you're still using NServiceBus 2 and don't want to upgrade, you'll need to update your WindsorObjectBuilder class. Have a look at the source code in NServiceBus 3 and adapt it to your implementation - https://github.com/NServiceBus/NServiceBus/blob/master/src/impl/ObjectBuilder/ObjectBuilder.CastleWindsor/WindsorObjectBuilder.cs

NHibernate

As of NHibernate 3.2, there is no longer a requirement to have a Castle-compatible bytecode provider. The old NHibernateIntegration facility is not compatible with Castle 3.0 or NHibernate 3.2. There is an alternate facility- 'Castle NHibernate' that leverages FluentNHibernate for configuration. This has been patched to work with Castle 3.0 but not NHibernate 3.2 (partly because FluentNHibernate hasn't been updated for 3.2). It also depends on Castle.Transactions, which ironically whilst at version 3.0 isn't actually compatible with Castle 3.0 either. So for the meantime if you want to use NHibernate with Castle 3.0 you're going to have to get your hands dirty and update those dependant projects yourself. I've done some of this on forks of these projects, and will update this post to the source repositories when they are available.