Mitc.Email.Abstractions

Abstractions and default implementation for sending email in MITC applications. Provides a MailService that routes outbound email through a pluggable IMailTransport, with configurable recipient filtering and service modes.

Features

• Service modes — SendAll, SendWithRestrictions, or DenyAllOutbound to control whether email leaves the system.
• Recipient filtering — optional rules that match recipients by exact address or regular expression.
• Attachments — send file attachments, including inline images referenced by content ID.
• Options validation — MailSettingsValidator validates configuration at startup via IValidateOptions<MailSettings>.
• Transport abstraction — implement IMailTransport to plug in any email provider (SMTP, SendGrid, etc.).

Configuration

Add MailSettings to your configuration (e.g. appsettings.json):

{
  "MailSettings": {
    "ServiceMode": "SendWithRestrictions",
    "FromAddress": "no-reply@example.com",
    "RecipientFilterRules": [
      { "AddressType": "Literal", "RecipientAddress": "allowed@example.com" },
      { "AddressType": "RegEx", "RecipientAddress": "@example\\.com$" }
    ]
  }
}

Registration

AddMitcMailSettings binds and validates MailSettings and registers the RecipientEvaluator that MailService depends on:

builder.AddMitcMailSettings();
builder.Services.AddScoped<IMailTransport, MySmtpTransport>(); // your implementation
builder.Services.AddScoped<MailService>();

Usage

await mailService.SendAsync(new SendEmailRequest(
    address: "user@example.com",
    subject: "Welcome",
    body: "<p>Hello!</p>"
));

The body is sent as HTML by default. Pass bodyFormat: BodyFormat.PlainText for a plain-text body:

await mailService.SendAsync(new SendEmailRequest(
    address: "user@example.com",
    subject: "Welcome",
    body: "Hello!",
    bodyFormat: BodyFormat.PlainText
));

Attachments

Pass an EmailAttachment for each file. Supplying a contentId marks the attachment for inline display, letting you reference it from the HTML body via cid::

var pdf = await File.ReadAllBytesAsync("invoice.pdf");
var logo = await File.ReadAllBytesAsync("logo.png");

await mailService.SendAsync(new SendEmailRequest(
    address: "user@example.com",
    subject: "Your invoice",
    body: "<p>See attached.</p><img src=\"cid:logo\">",
    attachments: new[]
    {
        new EmailAttachment(pdf, "application/pdf", "invoice.pdf"),
        new EmailAttachment(logo, "image/png", "logo.png", contentId: "logo"),
    }));