Live transformation question

[Niclas Emdelius]

Hi,

I use Raven to store orders. In the order document I want all the original product details for tracking purposes.

The product objects are basically a proxy for an external object. When I read back orders I want them in a simple View object rather in their original form.

The test code below works, but it it feels it could be made in a simpler way?

In the index' TransformResult the Order is converted into an anonymous type, when I already have a type for OrderViewModel. And why do I need a index at all? 

Anyone that could give me a few hints?

Thanks

----

public class Order

{

public Guid Guid;

public IEnumerable<OrderRow> OrderRows { get; set; }

}

public class OrderViewModel

{

public Guid Guid;

public IEnumerable<OrderRowViewModel> OrderRows { get; set; }

}

public class OrderRow

{

public IProduct Product;

}

public class OrderRowViewModel

{

public ProductViewModel Product;

}

public interface IProduct

{

string DisplayName { get; }

}

public class VeryComplicatedProductInstance : IProduct

{

public string DisplayName { get { return "Product Name"; } }

}

public class ProductViewModel 

{

public string DisplayName { get; set; }

}

[TestClass]

public class UnitTest1

{

[TestMethod]

public void TestMethod1()

{

var documentStore = new DocumentStore { Url = "http://localhost:99", DefaultDatabase = "test" };

documentStore.Initialize();

IndexCreation.CreateIndexes(typeof(Order_ById).Assembly, documentStore);     

var orderId = Guid.NewGuid();

var order = new Order

{

Guid = orderId,

OrderRows = new[]

{

new OrderRow {Product = new VeryComplicatedProductInstance()}

}

};

using (var session = documentStore.OpenSession())

{

session.Store(order, order.Guid.ToString());

session.SaveChanges();

}

OrderViewModel loadedOrder;

using (var session = documentStore.OpenSession())

{

loadedOrder = session.Query<Order, Order_ById>()

.Where(o => o.Guid == orderId)

.OfType<OrderViewModel>()

.FirstOrDefault();

}

Assert.IsNotNull(loadedOrder);

Assert.IsNotInstanceOfType(loadedOrder.OrderRows.First().Product, typeof(VeryComplicatedProductInstance));

Assert.IsInstanceOfType(loadedOrder.OrderRows.First().Product, typeof(ProductViewModel));

Assert.AreEqual("Product Name", loadedOrder.OrderRows.First().Product.DisplayName);

}

}

public class Order_ById: AbstractIndexCreationTask<Order>

{

public Order_ById()

{

Map = orders => from order in orders

                 select new { order.Guid, order.OrderRows};

TransformResults = (database, results) => from order in results

 select new

 {

 order.Guid,

 OrderRows = order.OrderRows.Select(or=>new 

 {

 Product = new {

 DisplayName = or.Product.DisplayName

 }

 })  

 };

}

}

[Oren Eini (Ayende Rahien)]

If you need just the display name, why are you storing the full thing?

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[Niclas Emdelius]

Hi,

This is just an example. I need lots of other fields as well and that is why I'm asking if there is another way to do it. 

As I've done now I have to make sure the index' TransformResult matches the field names in ProductViewModel, and it won't give me a compile time error if they don't.

As it is orders I'm storing I also need to store as much info as possible in the event of post mortem debug analysis, such as how the product's prices was calculated and stuff like that.

/Niclas

[Oren Eini (Ayende Rahien)]

You are mixing a lot of different concerns here.

Point in Time reference is one thing: http://ayende.com/blog/156353/entities-associations-point-in-time-vs-current-associations

Then you want to pull data from other documents, which is Immediate Reference.

[Niclas Emdelius]

No, I think you misunderstand me. I don't want to pull data from other documents, just a single document which contains all data I need, (and more).

What I'd like to do is use one type for creating a document, and then load the document into another type (simpler) with the same field names.

Thanks

[Oren Eini (Ayende Rahien)]

Load the document in your client app, then transfrom it in your code

[Niclas Emdelius]

How do I load a document without deserializing into a type?

[Oren Eini (Ayende Rahien)]

No, load it into the doc type, then transform it.

Alternatively: http://ayende.com/blog/161346/robs-sprint-result-transformers

[Niclas Emdelius]

How do I load it into the "doc type"? 

Very interesting re result transformers!

[Oren Eini (Ayende Rahien)]

session.Load<YourType>(docId);

[Niclas Emdelius]

The problem is that I can't deserialize into the original product type. 

session.Load<OrderViewModel>(orderId) doesn't work (invalid cast exception)

Is it possible to retrieve the document in a untyped format (dictionaries?) and handle the deserialization myself?

Anyway, I think I'll solve it with result transformers. 

Thanks!

[Mauro Servienti]

Have you tried, just guessing, something like:

 

session.Load<RavenJObject>( yourId );

[Niclas Emdelius]

Yes it works! Thanks!

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