SyntaxCircus.Email 0.1.3

SyntaxCircus.Email

An email-sending abstraction: a MailKit-based SMTP implementation with retry, plus Null (dev) and in-memory (test) implementations. Templating and composition are out of scope on purpose — too product-specific to generalize; this only covers the send primitive and provider switch.

No support guaranteed. Published as-is and maintained on a best-effort basis. Issues and PRs are welcome, but there's no SLA — fork it or vendor what you need if that's not enough.

Usage

builder.Services.AddSmtpEmailSender(builder.Configuration); // binds "Email:Smtp"
// or, in Development: builder.Services.AddNullEmailSender();
// or, in tests: builder.Services.AddInMemoryEmailSender();

{
  "Email": {
    "Smtp": {
      "Host": "smtp.example.com",
      "Port": 587,
      "Username": "...",
      "Password": "...",
      "DefaultFrom": "noreply@example.com",
      "MaxRetryAttempts": 3
    }
  }
}

public sealed class WelcomeEmailService(IEmailSender emailSender)
{
    public Task SendWelcomeAsync(string to, CancellationToken ct)
        => emailSender.SendAsync(new EmailMessage(to, "Welcome!", "<p>Hi there.</p>"), ct);
}

SmtpEmailSender retries transient send failures with exponential backoff (MaxRetryAttempts, default 3). InMemoryEmailSender exposes SentMessages (and Clear()) for assertions in tests — resolve it directly (it's also registered as itself, not just as IEmailSender) when you need to inspect what was "sent".

Multipart (HTML + plain text)

await emailSender.SendAsync(new EmailMessage(
    to, "Welcome!", "<p>Hi there.</p>", PlainTextBody: "Hi there."), ct);

PlainTextBody is only used when IsBodyHtml is true (the default) — the message is sent as multipart/alternative with Body as the HTML view and PlainTextBody as the paired text view. It's ignored when IsBodyHtml is false, since there's no HTML view to pair it with.

Contributing

Issues and pull requests are welcome:

• Keep changes focused, with a clear description of the behavior change.
• Match the existing code style (see .editorconfig).
• Call out any breaking changes to the public API in your PR description.

License

MIT — see LICENSE.txt.