Replace Background MQ with Background Jobs

MyApp.ServiceInterface/EmailServices.cs

@@ -1,7 +1,7 @@
 using System.Net.Mail;
 using Microsoft.Extensions.Logging;
 using ServiceStack;
-using MyApp.ServiceModel;
+using ServiceStack.Jobs;
 
 namespace MyApp.ServiceInterface;
 
@@ -45,16 +45,26 @@ public class SmtpConfig
     public string? Bcc { get; set; }
 }
 
-/// <summary>
-/// Uses a configured SMTP client to send emails
-/// </summary>
-public class EmailServices(SmtpConfig config, ILogger<EmailServices> log) 
-    // TODO: Uncomment to enable sending emails with SMTP
-    // : Service
+public class SendEmail
+{
+    public string To { get; set; }
+    public string? ToName { get; set; }
+    public string Subject { get; set; }
+    public string? BodyText { get; set; }
+    public string? BodyHtml { get; set; }
+}
+
+[Worker("smtp")]
+public class SendEmailCommand(ILogger<SendEmailCommand> logger, IBackgroundJobs jobs, SmtpConfig config) 
+    : SyncCommand<SendEmail>
 {
-    public object Any(SendEmail request)
+    private static long count = 0;
+    protected override void Run(SendEmail request)
     {
-        log.LogInformation("Sending email to {Email} with subject {Subject}", request.To, request.Subject);
+        Interlocked.Increment(ref count);
+        var log = Request.CreateJobLogger(jobs, logger);
+        log.LogInformation("Sending {Count} email to {Email} with subject {Subject}", 
+            count, request.To, request.Subject);
 
         using var client = new SmtpClient(config.Host, config.Port);
         client.Credentials = new System.Net.NetworkCredential(config.Username, config.Password);
@@ -80,7 +90,5 @@ public object Any(SendEmail request)
         }
 
         client.Send(msg);
-
-        return new EmptyResponse();
     }
 }

MyApp/Areas/Identity/Pages/Account/IdentityNoOpEmailSender.cs

@@ -0,0 +1,20 @@
+using Microsoft.AspNetCore.Identity;
+using Microsoft.AspNetCore.Identity.UI.Services;
+using MyApp.Data;
+
+namespace MyApp.Areas.Identity.Pages.Account;
+
+// Remove the "else if (EmailSender is IdentityNoOpEmailSender)" block from RegisterConfirmation.razor after updating with a real implementation.
+internal sealed class IdentityNoOpEmailSender : IEmailSender<ApplicationUser>
+{
+    private readonly IEmailSender emailSender = new NoOpEmailSender();
+
+    public Task SendConfirmationLinkAsync(ApplicationUser user, string email, string confirmationLink) =>
+        emailSender.SendEmailAsync(email, "Confirm your email", $"Please confirm your account by <a href='{confirmationLink}'>clicking here</a>.");
+
+    public Task SendPasswordResetLinkAsync(ApplicationUser user, string email, string resetLink) =>
+        emailSender.SendEmailAsync(email, "Reset your password", $"Please reset your password by <a href='{resetLink}'>clicking here</a>.");
+
+    public Task SendPasswordResetCodeAsync(ApplicationUser user, string email, string resetCode) =>
+        emailSender.SendEmailAsync(email, "Reset your password", $"Please reset your password using the following code: {resetCode}");
+}

MyApp/Configure.BackgroundJobs.cs

@@ -0,0 +1,90 @@
+using Microsoft.AspNetCore.Identity;
+using ServiceStack.Jobs;
+using MyApp.Data;
+using MyApp.ServiceInterface;
+
+[assembly: HostingStartup(typeof(MyApp.ConfigureBackgroundJobs))]
+
+namespace MyApp;
+
+public class ConfigureBackgroundJobs : IHostingStartup
+{
+    public void Configure(IWebHostBuilder builder) => builder
+        .ConfigureServices((context,services) => {
+            var smtpConfig = context.Configuration.GetSection(nameof(SmtpConfig))?.Get<SmtpConfig>();
+            if (smtpConfig is not null)
+            {
+                services.AddSingleton(smtpConfig);
+            }
+            // Lazily register SendEmailCommand to allow SmtpConfig to only be required if used 
+            services.AddTransient<SendEmailCommand>(c => new SendEmailCommand(
+                c.GetRequiredService<ILogger<SendEmailCommand>>(),
+                c.GetRequiredService<IBackgroundJobs>(),
+                c.GetRequiredService<SmtpConfig>()));
+            
+            services.AddPlugin(new CommandsFeature());
+            services.AddPlugin(new BackgroundsJobFeature());
+            services.AddHostedService<JobsHostedService>();
+        }).ConfigureAppHost(afterAppHostInit: appHost => {
+            var services = appHost.GetApplicationServices();
+
+            // Log if EmailSender is enabled and SmtpConfig missing
+            var log = services.GetRequiredService<ILogger<ConfigureBackgroundJobs>>();
+            var emailSender = services.GetRequiredService<IEmailSender<ApplicationUser>>();
+            if (emailSender is EmailSender)
+            {
+                var smtpConfig = services.GetService<SmtpConfig>();
+                if (smtpConfig is null)
+                {
+                    log.LogWarning("SMTP is not configured, please configure SMTP to enable sending emails");
+                }
+                else
+                {
+                    log.LogWarning("SMTP is configured with <{FromEmail}> {FromName}", smtpConfig.FromEmail, smtpConfig.FromName);
+                }
+            }
+            
+            var jobs = services.GetRequiredService<IBackgroundJobs>();
+            // Example of registering a Recurring Job to run Every Hour
+            //jobs.RecurringCommand<MyCommand>(Schedule.Hourly);
+        });
+}
+
+public class JobsHostedService(ILogger<JobsHostedService> log, IBackgroundJobs jobs) : BackgroundService
+{
+    protected override async Task ExecuteAsync(CancellationToken stoppingToken)
+    {
+        await jobs.StartAsync(stoppingToken);
+
+        using var timer = new PeriodicTimer(TimeSpan.FromSeconds(3));
+        while (!stoppingToken.IsCancellationRequested && await timer.WaitForNextTickAsync(stoppingToken))
+        {
+            await jobs.TickAsync();
+        }
+    }
+}
+
+/// <summary>
+/// Sends emails by executing SendEmailCommand in a background job where it's serially processed by 'smtp' worker
+/// </summary>
+public class EmailSender(IBackgroundJobs jobs) : IEmailSender<ApplicationUser>
+{
+    public Task SendEmailAsync(string email, string subject, string htmlMessage)
+    {
+        jobs.EnqueueCommand<SendEmailCommand>(new SendEmail {
+            To = email,
+            Subject = subject,
+            BodyHtml = htmlMessage,
+        });
+        return Task.CompletedTask;
+    }
+
+    public Task SendConfirmationLinkAsync(ApplicationUser user, string email, string confirmationLink) =>
+        SendEmailAsync(email, "Confirm your email", $"Please confirm your account by <a href='{confirmationLink}'>clicking here</a>.");
+
+    public Task SendPasswordResetLinkAsync(ApplicationUser user, string email, string resetLink) =>
+        SendEmailAsync(email, "Reset your password", $"Please reset your password by <a href='{resetLink}'>clicking here</a>.");
+
+    public Task SendPasswordResetCodeAsync(ApplicationUser user, string email, string resetCode) =>
+        SendEmailAsync(email, "Reset your password", $"Please reset your password using the following code: {resetCode}");
+}

MyApp/MyApp.csproj

@@ -37,6 +37,7 @@
         <PackageReference Include="ServiceStack" Version="8.*" />
         <PackageReference Include="ServiceStack.Mvc" Version="8.*" />
         <PackageReference Include="ServiceStack.Server" Version="8.*" />
+        <PackageReference Include="ServiceStack.Jobs" Version="8.*" />
         <PackageReference Include="ServiceStack.Extensions" Version="8.*" />
         <PackageReference Include="ServiceStack.OrmLite.Sqlite.Data" Version="8.*" />
     </ItemGroup>

MyApp/Program.cs

@@ -1,5 +1,6 @@
 using Microsoft.AspNetCore.HttpOverrides;
 using Microsoft.AspNetCore.Identity;
+using MyApp.Areas.Identity.Pages.Account;
 using MyApp.ServiceInterface;
 
 var builder = WebApplication.CreateBuilder(args);