1.4 What an order carries

A train takes one input and returns one output, and each junction in it does the same. Every value that moves between junctions gets a type of its own.

Trains/PlaceOrder/PlaceOrderInput.cs:

using Shopfront.Trains.PlaceOrder.Models;
 
namespace Shopfront.Trains.PlaceOrder;
 
public record PlaceOrderInput
{
    public required string CustomerId { get; init; }
    public required List<OrderLine> Lines { get; init; }
}

Trains/PlaceOrder/PlaceOrderOutput.cs:

namespace Shopfront.Trains.PlaceOrder;
 
public record PlaceOrderOutput(Guid OrderId, decimal Total, string TransactionId);

PlaceOrderInput is what the customer sends and PlaceOrderOutput is what they get back. Every other type goes in Models/. An order line is part of the input, so callers build it, and it is public:

Trains/PlaceOrder/Models/OrderLine.cs:

namespace Shopfront.Trains.PlaceOrder.Models;
 
public record OrderLine(string Sku, int Quantity);

The other four are what the junctions hand each other on the way. Nothing outside the train should depend on them, so they are internal, as the junctions below are:

Trains/PlaceOrder/Models/PricedCart.cs:

namespace Shopfront.Trains.PlaceOrder.Models;
 
internal record PricedCart(List<PricedLine> Lines, decimal Total);

Trains/PlaceOrder/Models/PricedLine.cs:

namespace Shopfront.Trains.PlaceOrder.Models;
 
internal record PricedLine(string Sku, int Quantity, decimal UnitPrice);

Trains/PlaceOrder/Models/StockReservation.cs:

namespace Shopfront.Trains.PlaceOrder.Models;
 
internal record StockReservation(Guid Id);

Trains/PlaceOrder/Models/Payment.cs:

namespace Shopfront.Trains.PlaceOrder.Models;
 
internal record Payment(string TransactionId, decimal Amount);

SDK Reference

Junctions | Chain | Run / RunEither | TrainException | AddTrax / AddEffects | UseInMemory | SaveTrainParameters | AddMediator

Next: 1.5 The junctions