Support for SMTP OAuth authentication through easier IEmailSenderClient implementation (#17484)

* Implement IEmailSenderClient interface and implementation

In an effort to support oauth 2 and other schemes, we extract a emailsenderclient interface, allowing to replace default smtp client with one that fits the usecase, without having to implement all of Umbracos logic that builds the mimemessage

* fix test

* Documentation

* EmailMessageExtensions public, use EmailMessage in interface and impl.

* move mimemessage into implementation

* revert EmailMessageExtensions back to internal

* use StaticServiceProvider to avoid breaking change

* Fix test after changing constructor

* revert constructor change and add new constructor an obsoletes

* Moved a paranthesis so it will build in release-mode

Author: kasparboelkjeldsen

src/Umbraco.Infrastructure/DependencyInjection/UmbracoBuilder.CoreServices.cs

@@ -46,6 +46,7 @@
 using Umbraco.Cms.Infrastructure.HostedServices;
 using Umbraco.Cms.Infrastructure.Install;
 using Umbraco.Cms.Infrastructure.Mail;
+using Umbraco.Cms.Infrastructure.Mail.Interfaces;
 using Umbraco.Cms.Infrastructure.Manifest;
 using Umbraco.Cms.Infrastructure.Migrations;
 using Umbraco.Cms.Infrastructure.Migrations.Install;
@@ -172,14 +173,18 @@ public static IUmbracoBuilder AddCoreInitialServices(this IUmbracoBuilder builde
 
         builder.Services.AddSingleton<IContentLastChanceFinder, ContentFinderByConfigured404>();
 
+        builder.Services.AddTransient<IEmailSenderClient, BasicSmtpEmailSenderClient>();
+
         // replace
         builder.Services.AddSingleton<IEmailSender, EmailSender>(
             services => new EmailSender(
                 services.GetRequiredService<ILogger<EmailSender>>(),
                 services.GetRequiredService<IOptionsMonitor<GlobalSettings>>(),
                 services.GetRequiredService<IEventAggregator>(),
+                services.GetRequiredService<IEmailSenderClient>(),
                 services.GetService<INotificationHandler<SendEmailNotification>>(),
                 services.GetService<INotificationAsyncHandler<SendEmailNotification>>()));
+
         builder.Services.AddTransient<IUserInviteSender, EmailUserInviteSender>();
         builder.Services.AddTransient<IUserForgotPasswordSender, EmailUserForgotPasswordSender>();
 

src/Umbraco.Infrastructure/Mail/BasicSmtpEmailSenderClient.cs

@@ -0,0 +1,50 @@
+using System.Net.Mail;
+using Microsoft.Extensions.Options;
+using Umbraco.Cms.Core.Configuration.Models;
+using Umbraco.Cms.Core.Models.Email;
+using Umbraco.Cms.Infrastructure.Extensions;
+using Umbraco.Cms.Infrastructure.Mail.Interfaces;
+using SecureSocketOptions = MailKit.Security.SecureSocketOptions;
+using SmtpClient = MailKit.Net.Smtp.SmtpClient;
+
+namespace Umbraco.Cms.Infrastructure.Mail
+{
+    /// <summary>
+    ///    A basic SMTP email sender client using MailKits SMTP client.
+    /// </summary>
+    public class BasicSmtpEmailSenderClient : IEmailSenderClient
+    {
+        private readonly GlobalSettings _globalSettings;
+        public BasicSmtpEmailSenderClient(IOptionsMonitor<GlobalSettings> globalSettings)
+        {
+            _globalSettings = globalSettings.CurrentValue;
+        }
+
+        public async Task SendAsync(EmailMessage message)
+        {
+            using var client = new SmtpClient();
+
+            await client.ConnectAsync(
+                _globalSettings.Smtp!.Host,
+            _globalSettings.Smtp.Port,
+                (SecureSocketOptions)(int)_globalSettings.Smtp.SecureSocketOptions);
+
+            if (!string.IsNullOrWhiteSpace(_globalSettings.Smtp.Username) &&
+            !string.IsNullOrWhiteSpace(_globalSettings.Smtp.Password))
+            {
+                await client.AuthenticateAsync(_globalSettings.Smtp.Username, _globalSettings.Smtp.Password);
+            }
+
+            var mimeMessage = message.ToMimeMessage(_globalSettings.Smtp!.From);
+
+            if (_globalSettings.Smtp.DeliveryMethod == SmtpDeliveryMethod.Network)
+            {
+                await client.SendAsync(mimeMessage);
+            }
+            else
+            {
+                client.Send(mimeMessage);
+            }
+        }
+    }
+}

src/Umbraco.Infrastructure/Mail/EmailSender.cs

@@ -1,20 +1,20 @@
 // Copyright (c) Umbraco.
 // See LICENSE for more details.
 
-using System.Net.Mail;
 using MailKit.Net.Smtp;
+using Microsoft.Extensions.DependencyInjection;
 using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 using MimeKit;
 using MimeKit.IO;
 using Umbraco.Cms.Core.Configuration.Models;
+using Umbraco.Cms.Core.DependencyInjection;
 using Umbraco.Cms.Core.Events;
 using Umbraco.Cms.Core.Mail;
 using Umbraco.Cms.Core.Models.Email;
 using Umbraco.Cms.Core.Notifications;
 using Umbraco.Cms.Infrastructure.Extensions;
-using SecureSocketOptions = MailKit.Security.SecureSocketOptions;
-using SmtpClient = MailKit.Net.Smtp.SmtpClient;
+using Umbraco.Cms.Infrastructure.Mail.Interfaces;
 
 namespace Umbraco.Cms.Infrastructure.Mail;
 
@@ -28,15 +28,18 @@ public class EmailSender : IEmailSender
     private readonly ILogger<EmailSender> _logger;
     private readonly bool _notificationHandlerRegistered;
     private GlobalSettings _globalSettings;
+    private readonly IEmailSenderClient _emailSenderClient;
 
+    [Obsolete("Please use the non-obsolete constructor. Will be removed in V17.")]
     public EmailSender(
         ILogger<EmailSender> logger,
         IOptionsMonitor<GlobalSettings> globalSettings,
         IEventAggregator eventAggregator)
-        : this(logger, globalSettings, eventAggregator, null, null)
+        : this(logger, globalSettings, eventAggregator,null, null)
     {
     }
 
+    [Obsolete("Please use the non-obsolete constructor. Will be removed in V17.")]
     public EmailSender(
         ILogger<EmailSender> logger,
         IOptionsMonitor<GlobalSettings> globalSettings,
@@ -48,6 +51,24 @@ public EmailSender(
         _eventAggregator = eventAggregator;
         _globalSettings = globalSettings.CurrentValue;
         _notificationHandlerRegistered = handler1 is not null || handler2 is not null;
+        _emailSenderClient = StaticServiceProvider.Instance.GetRequiredService<IEmailSenderClient>();
+        globalSettings.OnChange(x => _globalSettings = x);
+    }
+
+    [ActivatorUtilitiesConstructor]
+    public EmailSender(
+        ILogger<EmailSender> logger,
+        IOptionsMonitor<GlobalSettings> globalSettings,
+        IEventAggregator eventAggregator,
+        IEmailSenderClient emailSenderClient,
+        INotificationHandler<SendEmailNotification>? handler1,
+        INotificationAsyncHandler<SendEmailNotification>? handler2)
+    {
+        _logger = logger;
+        _eventAggregator = eventAggregator;
+        _globalSettings = globalSettings.CurrentValue;
+        _notificationHandlerRegistered = handler1 is not null || handler2 is not null;
+        _emailSenderClient = emailSenderClient;
         globalSettings.OnChange(x => _globalSettings = x);
     }
 
@@ -152,29 +173,7 @@ private async Task SendAsyncInternal(EmailMessage message, string emailType, boo
             while (true);
         }
 
-        using var client = new SmtpClient();
-
-        await client.ConnectAsync(
-            _globalSettings.Smtp!.Host,
-            _globalSettings.Smtp.Port,
-            (SecureSocketOptions)(int)_globalSettings.Smtp.SecureSocketOptions);
-
-        if (!string.IsNullOrWhiteSpace(_globalSettings.Smtp.Username) &&
-            !string.IsNullOrWhiteSpace(_globalSettings.Smtp.Password))
-        {
-            await client.AuthenticateAsync(_globalSettings.Smtp.Username, _globalSettings.Smtp.Password);
-        }
-
-        var mailMessage = message.ToMimeMessage(_globalSettings.Smtp.From);
-        if (_globalSettings.Smtp.DeliveryMethod == SmtpDeliveryMethod.Network)
-        {
-            await client.SendAsync(mailMessage);
-        }
-        else
-        {
-            client.Send(mailMessage);
-        }
-
-        await client.DisconnectAsync(true);
+        await _emailSenderClient.SendAsync(message);
     }
+
 }

src/Umbraco.Infrastructure/Mail/Interfaces/IEmailSenderClient.cs

@@ -0,0 +1,17 @@
+using Umbraco.Cms.Core.Models.Email;
+
+namespace Umbraco.Cms.Infrastructure.Mail.Interfaces
+{
+    /// <summary>
+    /// Client for sending an email from a MimeMessage
+    /// </summary>
+    public interface IEmailSenderClient
+    {
+        /// <summary>
+        /// Sends the email message
+        /// </summary>
+        /// <param name="message"></param>
+        /// <returns></returns>
+        public Task SendAsync(EmailMessage message);
+    }
+}

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

@@ -35,6 +35,7 @@
 using Umbraco.Cms.Core.Serialization;
 using Umbraco.Cms.Core.Strings;
 using Umbraco.Cms.Infrastructure.Mail;
+using Umbraco.Cms.Infrastructure.Mail.Interfaces;
 using Umbraco.Cms.Infrastructure.Persistence;
 using Umbraco.Cms.Infrastructure.Persistence.Mappers;
 using Umbraco.Cms.Persistence.SqlServer.Services;
@@ -80,7 +81,7 @@ public static class TestHelper
 
     public static UriUtility UriUtility => s_testHelperInternal.UriUtility;
 
-    public static IEmailSender EmailSender { get; } = new EmailSender(new NullLogger<EmailSender>(), new TestOptionsMonitor<GlobalSettings>(new GlobalSettings()), Mock.Of<IEventAggregator>());
+    public static IEmailSender EmailSender { get; } = new EmailSender(new NullLogger<EmailSender>(), new TestOptionsMonitor<GlobalSettings>(new GlobalSettings()), Mock.Of<IEventAggregator>(), Mock.Of<IEmailSenderClient>(), null,null);
 
     public static ITypeFinder GetTypeFinder() => s_testHelperInternal.GetTypeFinder();