Enable email sender to publish an event if smtp is not configured (#10352)

src/Umbraco.Core/Mail/IEmailSender.cs

@@ -10,6 +10,8 @@ namespace Umbraco.Cms.Core.Mail
     {
         Task SendAsync(EmailMessage message);
 
+        Task SendAsync(EmailMessage message, bool enableNotification);
+
         bool CanSendRequiredEmail();
     }
 }

src/Umbraco.Core/Mail/NotImplementedEmailSender.cs

@@ -9,6 +9,10 @@ namespace Umbraco.Cms.Core.Mail
         public Task SendAsync(EmailMessage message)
             => throw new NotImplementedException("To send an Email ensure IEmailSender is implemented with a custom implementation");
 
+        public Task SendAsync(EmailMessage message, bool enableNotification) =>
+            throw new NotImplementedException(
+                "To send an Email ensure IEmailSender is implemented with a custom implementation");
+
         public bool CanSendRequiredEmail()
             => throw new NotImplementedException("To send an Email ensure IEmailSender is implemented with a custom implementation");
     }

src/Umbraco.Core/Notifications/SendEmailNotification.cs

@@ -0,0 +1,11 @@
+using Umbraco.Cms.Core.Models;
+
+namespace Umbraco.Cms.Core.Notifications
+{
+    public class SendEmailNotification : INotification
+    {
+        public SendEmailNotification(EmailMessage message) => Message = message;
+
+        public EmailMessage Message { get; set; }
+    }
+}

src/Umbraco.Infrastructure/EmailSender.cs

@@ -5,8 +5,10 @@ using System.Net.Mail;
 using System.Threading.Tasks;
 using Microsoft.Extensions.Options;
 using Umbraco.Cms.Core.Configuration.Models;
+using Umbraco.Cms.Core.Events;
 using Umbraco.Cms.Core.Mail;
 using Umbraco.Cms.Core.Models;
+using Umbraco.Cms.Core.Notifications;
 using Umbraco.Cms.Infrastructure.Extensions;
 using SmtpClient = MailKit.Net.Smtp.SmtpClient;
 
@@ -18,20 +20,41 @@ namespace Umbraco.Cms.Infrastructure
     public class EmailSender : IEmailSender
     {
         // TODO: This should encapsulate a BackgroundTaskRunner with a queue to send these emails!
-
+        private readonly IEventAggregator _eventAggregator;
         private readonly GlobalSettings _globalSettings;
+        private readonly bool _notificationHandlerRegistered;
 
-        public EmailSender(IOptions<GlobalSettings> globalSettings) => _globalSettings = globalSettings.Value;
+        public EmailSender(IOptions<GlobalSettings> globalSettings, IEventAggregator eventAggregator)
+            : this(globalSettings, eventAggregator, null)
+        {
+
+        }
+
+        public EmailSender(IOptions<GlobalSettings> globalSettings, IEventAggregator eventAggregator, INotificationHandler<SendEmailNotification> handler)
+        {
+            _eventAggregator = eventAggregator;
+            _globalSettings = globalSettings.Value;
+            _notificationHandlerRegistered = handler is not null;
+        }
 
         /// <summary>
         /// Sends the message async
         /// </summary>
         /// <param name="message"></param>
         /// <returns></returns>
-        public async Task SendAsync(EmailMessage message)
+        public async Task SendAsync(EmailMessage message) => await SendAsyncInternal(message, false);
+
+        public async Task SendAsync(EmailMessage message, bool enableNotification) =>
+            await SendAsyncInternal(message, enableNotification);
+
+        private async Task SendAsyncInternal(EmailMessage message, bool enableNotification)
         {
             if (_globalSettings.IsSmtpServerConfigured == false)
             {
+                if (enableNotification)
+                {
+                    await _eventAggregator.PublishAsync(new SendEmailNotification(message));
+                }
                 return;
             }
 
@@ -66,6 +89,6 @@ namespace Umbraco.Cms.Infrastructure
         /// <remarks>
         /// We assume this is possible if either an event handler is registered or an smtp server is configured
         /// </remarks>
-        public bool CanSendRequiredEmail() => _globalSettings.IsSmtpServerConfigured;
+        public bool CanSendRequiredEmail() => _globalSettings.IsSmtpServerConfigured || _notificationHandlerRegistered;
     }
 }

src/Umbraco.Tests.UnitTests/TestHelpers/TestHelper.cs

@@ -20,6 +20,7 @@ using Umbraco.Cms.Core.Composing;
 using Umbraco.Cms.Core.Configuration;
 using Umbraco.Cms.Core.Configuration.Models;
 using Umbraco.Cms.Core.Diagnostics;
+using Umbraco.Cms.Core.Events;
 using Umbraco.Cms.Core.Hosting;
 using Umbraco.Cms.Core.IO;
 using Umbraco.Cms.Core.Logging;
@@ -136,7 +137,7 @@ namespace Umbraco.Cms.Tests.UnitTests.TestHelpers
 
         public static UriUtility UriUtility => s_testHelperInternal.UriUtility;
 
-        public static IEmailSender EmailSender { get; } = new EmailSender(Options.Create(new GlobalSettings()));
+        public static IEmailSender EmailSender { get; } = new EmailSender(Options.Create(new GlobalSettings()), Mock.Of<IEventAggregator>());
 
         /// <summary>
         /// Some test files are copied to the /bin (/bin/debug) on build, this is a utility to return their physical path based on a virtual path name

src/Umbraco.Web.BackOffice/Controllers/UsersController.cs

@@ -552,7 +552,7 @@ namespace Umbraco.Cms.Web.BackOffice.Controllers
 
             var mailMessage = new EmailMessage(fromEmail, to.Email, emailSubject, emailBody, true);
 
-            await _emailSender.SendAsync(mailMessage);
+            await _emailSender.SendAsync(mailMessage, true);
         }
 
         /// <summary>