Generic Approach to Access WCF Data Services

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WCF Data Services allow to publish your data very fast and easily. If you use Visual Studio to create the client which consumes the services, you just have to click "add service reference" and the classes you need to work with the service are generated (you will find a sample for WCF Data Service in my previous post). But what if you have a bunch of services which all follow the same convention and you want to access them in a generic way? This is also as simple as accessing the service with the generated stub. As a sample service, we use one which returns all the startup date and time of the service (uses EF CT4 which can be downloaded here).

public class ServerInfo
{
    public int ID { get; set; }
    public DateTime Startup { get; set; }
}

public class ServerContext : DbContext
{
    public DbSet ServerInfos { get; set; }
}

[ServiceBehavior(IncludeExceptionDetailInFaults = true)]
public class ServerInfoService : DataService<ServerContext> 
{
    public static void InitializeService(DataServiceConfiguration config)
    {
        ServerContext conn = new ServerContext();
        conn.ServerInfos.Add(new ServerInfo() { Startup = DateTime.Now });
        conn.SaveChanges();

        config.SetEntitySetAccessRule("*", EntitySetRights.All);
    }
}

All you need to access the service is the URL (of the service and the data). So you can use the base classes to call the service. But you still need a data container. WCF Data Services supports custom class binding, which means if a class contains the properties with the same name as the source class, the data will be mapped to these properties. You also have the possibility to configure that missing properties in the destination class will be ignored.

public class ServerInfo
{
    public DateTime Startup { get; set; }
}

static void Main(string[] args)
{
    var serveruri = new Uri("http://localhost:7640/ServerInfoService.svc");
    var datauri = new Uri("/ServerInfos", UriKind.Relative);

    var context = new DataServiceContext(serveruri);
    context.IgnoreMissingProperties = true;

    var infos = context.Execute<ServerInfo>(datauri);

    foreach (var values in infos)
    {
        Console.WriteLine(values.Startup);
    }

    Console.ReadLine(); 
}

The DataServiceContext replaces your custom context class. To load the collection of ServerInfo objects, which normally would be accessed over a generated property, the generic method execute will be called. The data will be mapped automatically to the new class. When the property "IgnoreMissingProperties" is set to true, the mapping will also cause no failure if a property is missing!