Replace shared email commands with MediatR notifications (#280)

web/backend/Features/Features.Emails/Notifications/ConfirmationEmailResendRequestedNotificationHandler.cs

@@ -0,0 +1,44 @@
+using Features.Auth.Notifications;
+using Features.Emails.Services;
+using MediatR;
+using Microsoft.Extensions.Logging;
+
+namespace Features.Emails.Notifications;
+
+/// <summary>
+///     Handles <see cref="ConfirmationEmailResendRequestedNotification" />, the cross-slice notification
+///     published by Features.Users when a user requests a fresh confirmation link, by sending the resend
+///     confirmation email.
+/// </summary>
+public class ConfirmationEmailResendRequestedNotificationHandler(
+    IEmailDispatcher emailDispatcher,
+    ILogger<ConfirmationEmailResendRequestedNotificationHandler> logger
+) : INotificationHandler<ConfirmationEmailResendRequestedNotification>
+{
+    /// <remarks>
+    ///     Delivery failures are logged and swallowed rather than rethrown, so that a broken mail server
+    ///     never fails the resend request that already succeeded.
+    /// </remarks>
+    public async Task Handle(
+        ConfirmationEmailResendRequestedNotification notification,
+        CancellationToken cancellationToken
+    )
+    {
+        try
+        {
+            await emailDispatcher.SendResendConfirmationEmailAsync(
+                notification.FirstName,
+                notification.Email,
+                notification.ConfirmationToken
+            );
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(
+                ex,
+                "Failed to send resend confirmation email to user {UserId}",
+                notification.UserId
+            );
+        }
+    }
+}

web/backend/Features/Features.Emails/Notifications/UserRegisteredNotificationHandler.cs

@@ -0,0 +1,40 @@
+using Features.Auth.Notifications;
+using Features.Emails.Services;
+using MediatR;
+using Microsoft.Extensions.Logging;
+
+namespace Features.Emails.Notifications;
+
+/// <summary>
+///     Handles <see cref="UserRegisteredNotification" />, the cross-slice notification published by
+///     Features.Users after a new user registers, by sending the registration confirmation email.
+/// </summary>
+public class UserRegisteredNotificationHandler(
+    IEmailDispatcher emailDispatcher,
+    ILogger<UserRegisteredNotificationHandler> logger
+) : INotificationHandler<UserRegisteredNotification>
+{
+    /// <remarks>
+    ///     Delivery failures are logged and swallowed rather than rethrown, so that a broken mail server
+    ///     never fails the registration that already succeeded.
+    /// </remarks>
+    public async Task Handle(UserRegisteredNotification notification, CancellationToken cancellationToken)
+    {
+        try
+        {
+            await emailDispatcher.SendRegistrationEmailAsync(
+                notification.FirstName,
+                notification.Email,
+                notification.ConfirmationToken
+            );
+        }
+        catch (Exception ex)
+        {
+            logger.LogError(
+                ex,
+                "Failed to send registration confirmation email to user {UserId}",
+                notification.UserId
+            );
+        }
+    }
+}