Emails should not be sent synchronously (#6555)

Author: xavierdecoster

src/NuGetGallery.Core/Infrastructure/mail/AsynchronousEmailMessageService.cs

@@ -0,0 +1,116 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using System.Threading.Tasks;
+using NuGet.Services.Messaging;
+
+namespace NuGetGallery.Infrastructure.Mail
+{
+    public class AsynchronousEmailMessageService : IMessageService
+    {
+        private readonly IMessageServiceConfiguration _configuration;
+        private readonly IEmailMessageEnqueuer _emailMessageEnqueuer;
+
+        public AsynchronousEmailMessageService(
+            IMessageServiceConfiguration configuration,
+            IEmailMessageEnqueuer emailMessageEnqueuer)
+        {
+            _configuration = configuration ?? throw new ArgumentNullException(nameof(configuration));
+            _emailMessageEnqueuer = emailMessageEnqueuer ?? throw new ArgumentNullException(nameof(emailMessageEnqueuer));
+        }
+
+        public Task SendMessageAsync(
+            IEmailBuilder emailBuilder,
+            bool copySender = false,
+            bool discloseSenderAddress = false)
+        {
+            if (emailBuilder == null)
+            {
+                throw new ArgumentNullException(nameof(emailBuilder));
+            }
+
+            var message = CreateMessage(
+                emailBuilder,
+                copySender,
+                discloseSenderAddress);
+
+            return EnqueueMessageAsync(message);
+        }
+
+        private static EmailMessageData CreateMessage(
+            IEmailBuilder emailBuilder,
+            bool copySender = false,
+            bool discloseSenderAddress = false)
+        {
+            var recipients = emailBuilder.GetRecipients();
+
+            if (recipients == EmailRecipients.None)
+            {
+                // Optimization: no need to construct message body when no recipients.
+                return null;
+            }
+
+            if (emailBuilder.Sender == null)
+            {
+                throw new ArgumentException(
+                    $"No sender defined for message of type '{emailBuilder.GetType()}'.",
+                    nameof(emailBuilder.Sender));
+            }
+
+            return new EmailMessageData(
+                emailBuilder.GetSubject(),
+                emailBuilder.GetBody(EmailFormat.PlainText),
+                emailBuilder.GetBody(EmailFormat.Html),
+                emailBuilder.Sender.Address,
+                to: recipients.To.Select(e => e.Address).ToList(),
+                cc: GenerateCC(
+                    emailBuilder.Sender.Address,
+                    recipients.CC.Select(e => e.Address).ToList(),
+                    copySender,
+                    discloseSenderAddress),
+                bcc: recipients.Bcc.Select(e => e.Address).ToList(),
+                replyTo: recipients.ReplyTo.Select(e => e.Address).ToList(),
+                messageTrackingId: Guid.NewGuid());
+        }
+
+        private static IReadOnlyList<string> GenerateCC(
+            string fromAddress,
+            IReadOnlyList<string> cc, bool copySender,
+            bool discloseSenderAddress)
+        {
+            var ccList = new List<string>();
+            if (cc != null)
+            {
+                ccList.AddRange(cc);
+            }
+
+            if (copySender && discloseSenderAddress && !ccList.Contains(fromAddress))
+            {
+                ccList.Add(fromAddress);
+            }
+
+            return ccList;
+        }
+
+        private Task EnqueueMessageAsync(EmailMessageData message)
+        {
+            if (message == null || !message.To.Any())
+            {
+                return Task.CompletedTask;
+            }
+
+            if (string.IsNullOrEmpty(message.HtmlBody)
+                && string.IsNullOrEmpty(message.PlainTextBody))
+            {
+                throw new ArgumentException(
+                    "No message body defined. Both plain-text and html bodies are empty.",
+                    nameof(message));
+            }
+
+            return _emailMessageEnqueuer.SendEmailMessageAsync(message);
+        }
+    }
+}

src/NuGetGallery.Core/Infrastructure/mail/EmailBuilder.cs

@@ -22,6 +22,8 @@ public string GetBody(EmailFormat format)
                     return GetPlainTextBody();
                 case EmailFormat.Markdown:
                     return GetMarkdownBody();
+                case EmailFormat.Html:
+                    return GetHtmlBody();
                 default:
                     throw new ArgumentOutOfRangeException(nameof(format));
             }
@@ -33,6 +35,7 @@ public string GetBody(EmailFormat format)
 
         protected abstract string GetPlainTextBody();
         protected abstract string GetMarkdownBody();
+        protected abstract string GetHtmlBody();
 
         /// <summary>
         /// Markdown sees the underscore as italics indicator, so underscores are stripped in the message.

src/NuGetGallery.Core/Infrastructure/mail/EmailFormat.cs

@@ -18,6 +18,11 @@ public enum EmailFormat
         /// Indicates that <see cref="EmailBuilder"/> will create email messages using Markdown formatting,
         /// which will be rendered as HTML by email clients.
         /// </summary>
-        Markdown
+        Markdown,
+
+        /// <summary>
+        /// Indicates that <see cref="EmailBuilder"/> will create email messages using HTML formatting.
+        /// </summary>
+        Html
     }
 }

src/NuGetGallery.Core/Infrastructure/mail/EmailMessageFooter.cs

@@ -0,0 +1,62 @@
+// Copyright (c) .NET Foundation. All rights reserved.
+// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
+
+using System;
+
+namespace NuGetGallery.Infrastructure.Mail
+{
+    /// <summary>
+    /// Utility class to construct common email message footers.
+    /// </summary>
+    public static class EmailMessageFooter
+    {
+        public static string ForPackageOwnerNotifications(EmailFormat format, string galleryOwnerDisplayName, string emailSettingsUrl)
+        {
+            return ForReason(
+                format,
+                galleryOwnerDisplayName,
+                emailSettingsUrl,
+                "To stop receiving emails as an owner of this package");
+        }
+
+        public static string ForContactOwnerNotifications(EmailFormat format, string galleryOwnerDisplayName, string emailSettingsUrl)
+        {
+            return ForReason(
+                format, 
+                galleryOwnerDisplayName, 
+                emailSettingsUrl, 
+                "To stop receiving contact emails as an owner of this package");
+        }
+               
+        private static string ForReason(EmailFormat format, string galleryOwnerDisplayName, string emailSettingsUrl, string reason)
+        {
+            switch (format)
+            {
+                case EmailFormat.PlainText:
+                    // Hyperlinks within an HTML emphasis tag are not supported by the Plain Text renderer in Markdig.
+                    return $@"
+
+-----------------------------------------------
+    {reason}, sign in to the {galleryOwnerDisplayName} and
+    change your email notification settings ({emailSettingsUrl}).";
+                case EmailFormat.Html:
+                    // Hyperlinks within an HTML emphasis tag are not supported by the HTML renderer in Markdig.
+                    return $@"<hr />
+<em style=""font-size: 0.8em;"">
+    {reason}, sign in to the {galleryOwnerDisplayName} and
+    <a href=""{emailSettingsUrl}"">change your email notification settings</a>.
+</em>";
+                case EmailFormat.Markdown:
+                    return $@"
+
+-----------------------------------------------
+<em style=""font-size: 0.8em;"">
+    {reason}, sign in to the {galleryOwnerDisplayName} and
+    [change your email notification settings]({emailSettingsUrl}).
+</em>";
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(format));
+            }
+        }
+    }
+}

src/NuGetGallery.Core/Infrastructure/mail/MarkdownEmailBuilder.cs

@@ -15,6 +15,11 @@ protected override string GetPlainTextBody()
         {
             var markdown = GetMarkdownBody();
 
+            return ToPlainText(markdown);
+        }
+
+        protected string ToPlainText(string markdown)
+        {
             var writer = new StringWriter();
             var pipeline = new MarkdownPipelineBuilder().Build();
 
@@ -29,5 +34,10 @@ protected override string GetPlainTextBody()
 
             return writer.ToString();
         }
+
+        protected override string GetHtmlBody()
+        {
+            return Markdown.ToHtml(GetMarkdownBody());
+        }
     }
 }

src/NuGetGallery.Core/Infrastructure/mail/Messages/PackageAddedMessage.cs

@@ -5,6 +5,7 @@
 using System.Collections.Generic;
 using System.Linq;
 using System.Net.Mail;
+using Markdig;
 
 namespace NuGetGallery.Infrastructure.Mail.Messages
 {
@@ -58,38 +59,57 @@ public override string GetSubject()
 
         protected override string GetMarkdownBody()
         {
-            var warningMessagesPlaceholder = string.Empty;
-            if (_hasWarnings)
+            return GetBodyInternal(EmailFormat.Markdown);
+        }
+
+        protected override string GetPlainTextBody()
+        {
+            return GetBodyInternal(EmailFormat.PlainText);
+        }
+
+        protected override string GetHtmlBody()
+        {
+            return GetBodyInternal(EmailFormat.Html);
+        }
+
+        private string GetBodyInternal(EmailFormat format)
+        {
+            var warningMessages = GetWarningMessages();
+
+            var markdown = $@"The package [{Package.PackageRegistration.Id} {Package.Version}]({_packageUrl}) was recently published on {_configuration.GalleryOwner.DisplayName} by {Package.User.Username}. If this was not intended, please [contact support]({_packageSupportUrl}).";
+
+            if (!string.IsNullOrEmpty(warningMessages))
             {
-                warningMessagesPlaceholder = Environment.NewLine + string.Join(Environment.NewLine, _warningMessages);
+                markdown += warningMessages;
             }
 
-            return $@"The package [{Package.PackageRegistration.Id} {Package.Version}]({_packageUrl}) was recently published on {_configuration.GalleryOwner.DisplayName} by {Package.User.Username}. If this was not intended, please [contact support]({_packageSupportUrl}).
-{warningMessagesPlaceholder}
+            string body;
+            switch (format)
+            {
+                case EmailFormat.PlainText:
+                    body = ToPlainText(markdown);
+                    break;
+                case EmailFormat.Markdown:
+                    body = markdown;
+                    break;
+                case EmailFormat.Html:
+                    body = Markdown.ToHtml(markdown);
+                    break;
+                default:
+                    throw new ArgumentOutOfRangeException(nameof(format));
+            }
 
------------------------------------------------
-<em style=""font-size: 0.8em;"">
-    To stop receiving emails as an owner of this package, sign in to the {_configuration.GalleryOwner.DisplayName} and
-    [change your email notification settings]({_emailSettingsUrl}).
-</em>";
+            return body + EmailMessageFooter.ForPackageOwnerNotifications(format, _configuration.GalleryOwner.DisplayName, _emailSettingsUrl);
         }
 
-        protected override string GetPlainTextBody()
+        private string GetWarningMessages()
         {
-            // The HTML emphasis tag is not supported by the Plain Text renderer in Markdig.
-            // Manually overriding this one.
             var warningMessagesPlaceholder = string.Empty;
             if (_hasWarnings)
             {
-                warningMessagesPlaceholder = Environment.NewLine + string.Join(Environment.NewLine, _warningMessages);
+                warningMessagesPlaceholder = Environment.NewLine + Environment.NewLine + string.Join(Environment.NewLine, _warningMessages);
             }
-
-            return $@"The package {Package.PackageRegistration.Id} {Package.Version} ({_packageUrl}) was recently published on {_configuration.GalleryOwner.DisplayName} by {Package.User.Username}. If this was not intended, please contact support ({_packageSupportUrl}).
-{warningMessagesPlaceholder}
-
------------------------------------------------
-    To stop receiving emails as an owner of this package, sign in to the {_configuration.GalleryOwner.DisplayName} and
-    change your email notification settings ({_emailSettingsUrl}).";
+            return warningMessagesPlaceholder;
         }
     }
 }