Implement JobQueue from Korga (resolves #4)

Author: daniel-lerch

src/TravelBlog/Configuration/MailingOptions.cs

@@ -8,8 +8,8 @@ public class MailingOptions
     public bool EnableMailing { get; set; }
     [Required] public string? SenderName { get; set; }
     [Required, EmailAddress] public string? SenderAddress { get; set; }
-    public string? AuthorName { get; set; }
-    [EmailAddress] public string? AuthorAddress { get; set; }
+    [Required] public string? AuthorName { get; set; }
+    [Required, EmailAddress] public string? AuthorAddress { get; set; }
 
     [Required] public string? SmtpUsername { get; set; }
     [Required] public string? SmtpPassword { get; set; }

src/TravelBlog/Controllers/BlogPostController.cs

@@ -8,32 +8,34 @@
 using Microsoft.EntityFrameworkCore;
 using Microsoft.Extensions.Options;
 using Microsoft.Extensions.Primitives;
+using MimeKit;
 using TravelBlog.Configuration;
 using TravelBlog.Database;
 using TravelBlog.Database.Entities;
 using TravelBlog.Extensions;
 using TravelBlog.Models;
 using TravelBlog.Services;
-using TravelBlog.Services.LightJobManager;
 using UAParser;
 
 namespace TravelBlog.Controllers;
 
 [Route("~/post/{id?}/{action=Index}")]
 public class BlogPostController : Controller
 {
-    private readonly IOptions<SiteOptions> options;
+    private readonly IOptions<SiteOptions> siteOptions;
+    private readonly IOptions<MailingOptions> mailingOptions;
     private readonly DatabaseContext database;
-    private readonly JobSchedulerService<MailJob, MailJobContext> scheduler;
+    private readonly EmailDeliveryService deliveryService;
     private readonly AuthenticationService authentication;
     private readonly MarkdownService markdown;
 
-    public BlogPostController(IOptions<SiteOptions> options, DatabaseContext database,
-        JobSchedulerService<MailJob, MailJobContext> scheduler, AuthenticationService authentication, MarkdownService markdown)
+    public BlogPostController(IOptions<SiteOptions> siteOptions, IOptions<MailingOptions> mailingOptions, DatabaseContext database,
+        EmailDeliveryService deliveryService, AuthenticationService authentication, MarkdownService markdown)
     {
-        this.options = options;
+        this.siteOptions = siteOptions;
+        this.mailingOptions = mailingOptions;
         this.database = database;
-        this.scheduler = scheduler;
+        this.deliveryService = deliveryService;
         this.authentication = authentication;
         this.markdown = markdown;
     }
@@ -202,17 +204,25 @@ public async Task<IActionResult> Publish(int id, string title, string? content,
     private async Task NotifySubscribers(BlogPost post)
     {
         List<Subscriber> subscribers = await database.Subscribers
-            .Where(s => s.ConfirmationTime != default && s.DeletionTime == default).ToListAsync();
+            .Where(s => s.MailAddress != null && s.ConfirmationTime != default && s.DeletionTime == default).ToListAsync();
 
-        await scheduler.Enqueue(subscribers.Select(s =>
+        await deliveryService.Enqueue(subscribers.Select(subscriber =>
         {
-            string postUrl = Url.ContentLink($"~/post/{post.Id}/auth?token={s.Token}");
-            string unsubscribeUrl = Url.ContentLink("~/unsubscribe?token=" + s.Token);
-            string message = $"Hey {s.GivenName},\r\n" +
-                $"es wurde etwas neues auf {options.Value.BlogName} gepostet:\r\n" +
+            string postUrl = Url.ContentLink($"~/post/{post.Id}/auth?token={subscriber.Token}");
+            string unsubscribeUrl = Url.ContentLink("~/unsubscribe?token=" + subscriber.Token);
+            string message = $"Hey {subscriber.GivenName},\r\n" +
+                $"es wurde etwas neues auf {siteOptions.Value.BlogName} gepostet:\r\n" +
                 $"{postUrl}\r\n\r\n" +
                 $"Du kannst dich von diesem Blog jederzeit hier abmelden: {unsubscribeUrl}";
-            return new MailJob(id: default, s.Id, subject: "Neuer Post", message);
-        }));
+
+            MimeMessage mimeMessage = new();
+            mimeMessage.From.Add(new MailboxAddress(mailingOptions.Value.SenderName, mailingOptions.Value.SenderAddress));
+            mimeMessage.To.Add(new MailboxAddress(subscriber.GetName(), subscriber.MailAddress));
+            mimeMessage.ReplyTo.Add(new MailboxAddress(mailingOptions.Value.AuthorName, mailingOptions.Value.AuthorAddress));
+            mimeMessage.Subject = "Neuer Post";
+            mimeMessage.Body = new TextPart("plain") { Text = message };
+
+            return (subscriber.MailAddress!, mimeMessage);
+        }), post.Id);
     }
 }

src/TravelBlog/Database/DatabaseContext.cs

@@ -13,7 +13,8 @@ public class DatabaseContext : DbContext
     public DbSet<Subscriber> Subscribers => Set<Subscriber>();
     public DbSet<BlogPost> BlogPosts => Set<BlogPost>();
     public DbSet<PostRead> PostReads => Set<PostRead>();
-    public DbSet<MailJob> MailJobs => Set<MailJob>();
+    public DbSet<OutboxEmail> OutboxEmails => Set<OutboxEmail>();
+    public DbSet<SentEmail> SentEmails => Set<SentEmail>();
 
     public DatabaseContext(IOptions<DatabaseOptions> options)
     {
@@ -47,8 +48,14 @@ protected override void OnModelCreating(ModelBuilder modelBuilder)
         postRead.HasOne(r => r.Post).WithMany(p => p!.Reads).HasForeignKey(r => r.PostId);
         postRead.HasOne(r => r.Subscriber).WithMany(s => s!.Reads).HasForeignKey(r => r.SubscriberId);
 
-        var mailJob = modelBuilder.Entity<MailJob>();
-        mailJob.HasKey(t => t.Id);
-        mailJob.HasOne(t => t.Subscriber).WithMany().HasForeignKey(t => t.SubscriberId);
+        var outboxEmail = modelBuilder.Entity<OutboxEmail>();
+        outboxEmail.HasKey(e => e.Id);
+        outboxEmail.HasOne(e => e.BlogPost).WithMany().HasForeignKey(e => e.BlogPostId);
+
+        var sentEmail = modelBuilder.Entity<SentEmail>();
+        sentEmail.HasKey(e => e.Id);
+        sentEmail.HasOne(e => e.BlogPost).WithMany().HasForeignKey(e => e.BlogPostId);
+        sentEmail.HasIndex(e => e.DeliveryTime);
+        sentEmail.Property(e => e.Id).ValueGeneratedNever();
     }
 }

src/TravelBlog/Database/Entities/MailJob.cs

@@ -0,0 +1,12 @@
+namespace TravelBlog.Database.Entities;
+
+public class OutboxEmail
+{
+    public int Id { get; set; }
+
+    public int? BlogPostId { get; set; }
+    public BlogPost? BlogPost { get; set; }
+
+    public required string EmailAddress { get; set; }
+    public required byte[] Content { get; set; }
+}

src/TravelBlog/Database/Entities/OutboxEmail.cs

@@ -0,0 +1,16 @@
+using System;
+
+namespace TravelBlog.Database.Entities;
+
+public class SentEmail
+{
+    public int Id { get; set; }
+
+    public int? BlogPostId { get; set; }
+    public BlogPost? BlogPost { get; set; }
+
+    public required string EmailAddress { get; set; }
+    public required int ContentSize { get; set; }
+    public string? ErrorMessage { get; set; }
+    public required DateTime DeliveryTime { get; set; }
+}

src/TravelBlog/Database/Entities/SentEmail.cs

@@ -0,0 +1,27 @@
+using Nito.AsyncEx;
+using System.Threading.Tasks;
+using System.Threading;
+using System;
+
+namespace TravelBlog.Extensions;
+
+public static class AsyncExtensions
+{
+    // Inspired by https://github.com/StephenCleary/AsyncEx/issues/212#issuecomment-653765593
+    public static async Task<bool> WaitAsync(this AsyncAutoResetEvent mEvent, TimeSpan timeout, CancellationToken token = default)
+    {
+        using var timeOut = new CancellationTokenSource(timeout);
+        using var combined = CancellationTokenSource.CreateLinkedTokenSource(timeOut.Token, token);
+
+        try
+        {
+            await mEvent.WaitAsync(combined.Token).ConfigureAwait(false);
+            return true;
+        }
+        // Don't catch the OperationCanceledException from external Token
+        catch (OperationCanceledException) when (!token.IsCancellationRequested) 
+        {
+            return false; //Here the OperationCanceledException was raised by Timeout
+        }
+    }
+}

src/TravelBlog/Extensions/AsyncExtensions.cs

@@ -0,0 +1,8 @@
+// This file is used by Code Analysis to maintain SuppressMessage
+// attributes that are applied to this project.
+// Project-level suppressions either have no target or are given
+// a specific target and scoped to a namespace, type, member, etc.
+
+using System.Diagnostics.CodeAnalysis;
+
+[assembly: SuppressMessage("Style", "IDE0290:Use primary constructor", Justification = "Primary constructors do not support readonly values in .NET 8.0")]