7.3 The catalogue and the orders become queries

An entity marked [TraxQueryModel] is served as a query with paging, filtering and sorting. Like a train, it must say who may read it, or the host does not start.

The catalogue is public on purpose. Its type has a member a shopper has no use for, the row version from chapter 4, so the query serves an interface that lists what a listing shows.

Data/Models/IProductListing.cs:

namespace Shopfront.Data.Models;
 
// What the catalogue shows anyone who asks.
public interface IProductListing
{
    string Sku { get; }
    string Name { get; }
    decimal Price { get; }
    int Stock { get; }
}

Data/Models/Product.cs:

using System.ComponentModel.DataAnnotations;
using Trax.Effect.Attributes;
 
namespace Shopfront.Data.Models;
 
[TraxAllowAnonymous]
[TraxQueryModel(ExposeAs = typeof(IProductListing))]
public class Product : IProductListing
{
    public required string Sku { get; set; }
    public required string Name { get; set; }
    public decimal Price { get; set; }
    public int Stock { get; set; }
 
    // Postgres's row version. A save that finds the row changed since it was read is refused.
    [Timestamp]
    public uint Version { get; set; }
}

The orders need a signed-in caller, and the query filter from chapter 6 decides which rows that caller gets: the query model reads through the same context, so a customer's query returns their orders and a member of staff's returns all of them. The attribute is a bare [TraxAuthorize], any signed-in caller, because the rows, not the role, are the rule.

Data/Models/Order.cs:

using Trax.Effect.Attributes;
 
namespace Shopfront.Data.Models;
 
[TraxAuthorize]
[TraxQueryModel]
public class Order
{
    public Guid Id { get; set; }
    public required string CustomerId { get; set; }
    public decimal Total { get; set; }
    public required string TransactionId { get; set; }
    public DateTime PlacedAt { get; set; }
    public List<OrderItem> Items { get; set; } = [];
}

An order's items are reached through the order, and anything the schema reaches needs a posture too, even when it is not a query of its own.

Data/Models/OrderItem.cs:

using Trax.Effect.Attributes;
 
namespace Shopfront.Data.Models;
 
[TraxAuthorize]
public class OrderItem
{
    public int Id { get; set; }
    public Guid OrderId { get; set; }
    public required string Sku { get; set; }
    public int Quantity { get; set; }
    public decimal UnitPrice { get; set; }
}

SDK Reference

AddTraxGraphQL | TraxMutation | Query models | Run progress | AddJunctionEvents | dispatch mutations

Next: 7.4 Serve the schema