12.4 States, events and context

Shopfront.Core/Machines/Checkout/CheckoutState.cs:

namespace Shopfront.Machines.Checkout;
 
public enum CheckoutState
{
    Cart,
    Address,
    Payment,
    Placing,
    Abandoned,
}

Shopfront.Core/Machines/Checkout/CheckoutTrigger.cs:

namespace Shopfront.Machines.Checkout;
 
public enum CheckoutTrigger
{
    SetLines,
    SetAddress,
    Back,
    ChoosePayment,
    PlaceOrder,
    StartOver,
}

The context holds what the customer chose and nothing the server works out. There are no prices in it: PlaceOrder prices the cart from the catalogue when the order is placed, so a price can never be sent by the browser, and there is no total to fall out of step with it. The payment is the token from chapter 3, a reference only the provider can use. A context is stored as plain JSON and served to its owner, so a card number has no place in it.

Shopfront.Core/Machines/Checkout/Models/CartLine.cs:

namespace Shopfront.Machines.Checkout.Models;
 
public sealed record CartLine
{
    public string Sku { get; init; } = "";
    public int Quantity { get; init; }
}

Shopfront.Core/Machines/Checkout/CheckoutContext.cs:

using Shopfront.Machines.Checkout.Models;
 
namespace Shopfront.Machines.Checkout;
 
public sealed record CheckoutContext
{
    public List<CartLine>? Lines { get; init; }
    public string? Address { get; init; }
    public string? PaymentToken { get; init; }
}

Each event's input is a record of its own.

Shopfront.Core/Machines/Checkout/Models/CheckoutStart.cs:

namespace Shopfront.Machines.Checkout.Models;
 
public sealed record CheckoutStart;

Shopfront.Core/Machines/Checkout/Models/LinesInput.cs:

namespace Shopfront.Machines.Checkout.Models;
 
public sealed record LinesInput
{
    public List<CartLine> Lines { get; init; } = [];
}

Shopfront.Core/Machines/Checkout/Models/AddressInput.cs:

namespace Shopfront.Machines.Checkout.Models;
 
public sealed record AddressInput
{
    public string Address { get; init; } = "";
}

Shopfront.Core/Machines/Checkout/Models/PaymentInput.cs:

namespace Shopfront.Machines.Checkout.Models;
 
public sealed record PaymentInput
{
    public string PaymentToken { get; init; } = "";
}

SDK Reference

Machine | Rules | AddStateMachines | Machines over GraphQL | UsePersistedOperations | trax CLI

Next: 12.5 The machine