Should I provide different views on the same REST entity? - rest

Question

I've seen this that suggest I can build different views based on user:
different json views for the same entity
However in asp web api, one uses a Model class, I can't just add new properties willy-nilly.
So, for example I may have uri:
http://host/api/products/id
Returning the model:
public class Product{
public string Code { get; set; }
public string Description { get; set; }
}
But for another purpose I want to add more information, suppose this is expensive because it joins other data to build the model, or formats the data in a very specific way:
http://host/api/productsspecial/id
Returning the model:
public class ProductSpecial{
public string Code { get; set; }
public string Description { get; set; }
public decimal Price { get; set; } //assume expensive to look up
}
So obviously I have a way to do this, two different controllers, returning different views on the data. My question is, is this OK or is there a better way?
Anyway I could do this for example: http://host/api/products/id?includeprice=true and use that to return the alternative model? And is that a good idea?

Answer 1

I would suggest
GET /host/api/products/{id}?fields=code,description,price
You should avoid complicating your resource URL in the manner you describe. Every possible configuration of values would need a new name: "productsReallySpecial", etc.
The problem with ?includePrice=true is you then have a parameter for every variable you might want to make optional. Your documentation can list the default return values and the available return values.