add-email-template

Adds a transactional email template using Fluid (Liquid).

Each email has a 3-file pattern plus a model record.

Steps

1. Create the model record in src/backend/MyProject.Application/Features/Email/Models/EmailTemplateModels.cs:

/// <summary>
/// Model for the order-confirmation template. Exposed as <c>order_number</c> and <c>total</c> in Liquid.
/// </summary>
public record OrderConfirmationModel(string OrderNumber, string Total);

Properties auto-map to snake_case Liquid variables (OrderNumber -> order_number).

2. Create 3 template files in src/backend/MyProject.Infrastructure/Features/Email/Templates/:

• order-confirmation.liquid - HTML body fragment (injected into _base.liquid via {{ body | raw }}):

  <h2 style="margin: 0 0 20px 0; font-size: 22px; font-weight: 700; color: #333333;">Order Confirmed</h2>
  <p style="margin: 0 0 16px 0;">Your order <strong>{{ order_number }}</strong> totaling {{ total }} has been confirmed.</p>

• order-confirmation.subject.liquid - Subject line (plain text, no HTML)
• order-confirmation.text.liquid - Plain text body (optional but recommended)

All marked as EmbeddedResource (verify .csproj has <EmbeddedResource Include="Features\Email\Templates\*.liquid" />).

3. Register the model type in FluidEmailTemplateRenderer.CreateOptions():

options.MemberAccessStrategy.Register<OrderConfirmationModel>();

4. Use in a service:

await templatedEmailSender.SendSafeAsync("order-confirmation",
    new OrderConfirmationModel(order.Number, order.FormattedTotal),
    customer.Email, cancellationToken);

5. Add tests in FluidEmailTemplateRendererTests.cs - test subject rendering, HTML variable injection, and plain text variant.

6. Verify: dotnet test src/backend/MyProject.slnx -c Release

Conventions

• Template names: kebab-case (order-confirmation, not orderConfirmation)
• HTML templates: inline styles (email clients ignore <style> blocks in fragments)
• _base.liquid provides the wrapper (header with {{ app_name }}, card, footer) - fragments provide inner content only
• HTML body: HtmlEncoder.Default (XSS-safe). Subject/plain text: unencoded
• Subject: static text or config-sourced variables only - never raw user input
• {{ app_name }} is automatically available from EmailOptions.FromName