Check Glass Mapper V3 types at runtime

Question

Using Glass Mapper V3, is it possible to check whether a Sitecore item supports a specific Glass Mapper class/interface?

Given these classes

[SitecoreType]
public partial interface IPage : IGlassBase
{
  // ... some properties here ...
}

[SitecoreType]
public partial interface IRateableItem : IGlassBase
{
  // ... some properties here ...
}

I would like to do something like this

var context = SitecoreContext();
var item = context.GetCurrentItem<IRateableItem>();
if (item != null)
  // it's an item that is composed of the Rateable Item template

Unfortunately, if I do that, I do get an item of the type IRateableItem returned, regardless of whether the current item is composed of that template or not.

Answer 1

Dan

Another solution would be to create a custom task that runs in the ObjectConstruction pipeline.

Something like this:

public class LimitByTemplateTask : IObjectConstructionTask
{
    private static readonly Type _templateCheck = typeof (ITemplateCheck);

    public void Execute(ObjectConstructionArgs args)
    {
        if (args.Result != null)
            return;

        if ( _templateCheck.IsAssignableFrom(args.AbstractTypeCreationContext.RequestedType))
        {
            var scContext = args.AbstractTypeCreationContext as SitecoreTypeCreationContext;
            var config = args.Configuration as SitecoreTypeConfiguration;

            var template = scContext.SitecoreService.Database.GetTemplate(scContext.Item.TemplateID);

            //check to see if any base template matched the template for the requested type
            if (template.BaseTemplates.All(x => x.ID != config.TemplateId) && scContext.Item.TemplateID != config.TemplateId)
            {
                args.AbortPipeline();
            }
        }
    }
}


public interface ITemplateCheck{}

You would then change you IRateableItem inteface to have the template ID it needs to match and inherit from ITemplateCheck:

[SitecoreType(TemplateId = "CF9B175D-872E-439A-B358-37A01155EEB1")]
public interface IRateableItem: ITemplateCheck, IGlassBase{}

Finally you will need to register the new task with the Castle IOC container in GlassMapperScCustom:

    public static void CastleConfig(IWindsorContainer container){
        var config = new Config();

        container.Register(
            Component.For<IObjectConstructionTask>().ImplementedBy<LimitByTemplateTask>(),
            );
        container.Install(new SitecoreInstaller(config));
    }

I haven't had a chance to test this so let me know if there are any problems.