Email Sending Issue #10065

2 Answer(s)

• 

  0

  AI-Bot created yesterday

  Support Team ABP Agent

  1. Solution

  • Goal: Let each tenant choose which email sender implementation (e.g., MailKit vs. another provider) is used when IEmailSender is called.

  Approach A — Per-tenant setting + selector that resolves the right sender at runtime:

  1. Define a per-tenant setting that stores the selected provider name:

  public static class EmailProviderSettingNames
  {
      public const string Prefix = "MyApp.Emailing";
      public const string SelectedProvider = Prefix + ".SelectedProvider"; // Values: "MailKit", "Custom"
  }
  

  Register it (e.g., in your DomainShared module):

  public class MyAppSettingDefinitionProvider : SettingDefinitionProvider
  {
      public override void Define(ISettingDefinitionContext context)
      {
          context.Add(
              new SettingDefinition(
                  EmailProviderSettingNames.SelectedProvider,
                  "MailKit", // default
                  isVisibleToClients: false
              )
          );
      }
  }
  

  2. Implement your email senders (concrete classes). For example, reuse ABP MailKit sender and your custom one:

  • MailKit sender is provided by Volo.Abp.MailKit (IEmailSender impl).
  • Your second sender (example):

  public class CustomEmailSender : IEmailSender
  {
      public Task SendAsync(string to, string subject, string body, bool isBodyHtml = true) => /*...*/;
      public Task SendAsync(string from, string to, string subject, string body, bool isBodyHtml = true) => /*...*/;
      public Task SendAsync(MailMessage mail, bool normalize = true) => /*...*/;
      public Task QueueAsync(string to, string subject, string body, bool isBodyHtml = true) => /*...*/;
  }
  

  3. Register both senders as named/typed services, but do NOT wire either directly to IEmailSender:

  context.Services.AddTransient<CustomEmailSender>();
  // MailKit sender is added by AbpMailKitModule. Make sure to add the module dependency.
  

  4. Create a router that implements IEmailSender and delegates to the correct concrete sender per tenant:

  public class TenantAwareEmailSender : IEmailSender
  {
      private readonly ICurrentTenant _currentTenant;
      private readonly ISettingProvider _settingProvider;
      private readonly IServiceProvider _serviceProvider;
  
      public TenantAwareEmailSender(
          ICurrentTenant currentTenant,
          ISettingProvider settingProvider,
          IServiceProvider serviceProvider)
      {
          _currentTenant = currentTenant;
          _settingProvider = settingProvider;
          _serviceProvider = serviceProvider;
      }
  
      private async Task<IEmailSender> ResolveActualSenderAsync()
      {
          // read per-tenant selection (falls back to host/default if not set)
          var selected = await _settingProvider.GetOrNullAsync(EmailProviderSettingNames.SelectedProvider)
                         ?? "MailKit";
  
          // resolve the concrete implementation
          return selected switch
          {
              "Custom" => _serviceProvider.GetRequiredService<CustomEmailSender>(),
              _ => _serviceProvider.GetRequiredService<IEmailSender>() // MailKit already registered, but beware recursion
          };
      }
  
      // to avoid recursion, inject MailKit concrete type instead of IEmailSender in ResolveActualSenderAsync:
  }
  

  To avoid recursion when defaulting to MailKit, register MailKit’s internal implementation separately and resolve that:

  • Replace MailKit’s default registration with your own wiring:

  // After AbpMailKitModule is added, capture its concrete sender type:
  context.Services.AddTransient<MailKitBasedEmailSender, MailKitBasedEmailSender>(); // replace with actual type if needed
  // Then override IEmailSender with your router:
  context.Services.Replace(ServiceDescriptor.Transient<IEmailSender, TenantAwareEmailSender>());
  

  If the concrete MailKit type is internal, register the original IEmailSender as a named service before replacing:

  // Save the existing IEmailSender factory under a key
  var original = context.Services.First(sd => sd.ServiceType == typeof(IEmailSender));
  context.Services.Add(new ServiceDescriptor(typeof(IEmailSender), original.ImplementationFactory ?? original.ImplementationType!, original.Lifetime));
  // Register a key-based accessor:
  context.Services.AddTransient<Func<IEmailSender>>((sp) => () => (IEmailSender)ActivatorUtilities.CreateInstance(sp, original.ImplementationType!));
  // Then replace IEmailSender with your router
  context.Services.Replace(ServiceDescriptor.Transient<IEmailSender, TenantAwareEmailSender>());
  

  And update ResolveActualSenderAsync to use the saved factory for the “MailKit” path to avoid self-resolution.

  5. Expose the setting in UI for tenants:

  • Use ABP Setting Management to allow tenants to set MyApp.Emailing.SelectedProvider (e.g., a dropdown “MailKit” / “Custom”).
  • Ensure the tenant has access: ABP now controls tenant visibility of Email settings via SaaS features/permissions. In SaaS page, enable the related feature for the tenant to manage emailing settings when needed.

  Approach B — Feature toggle approach (ABP Features):

  • Define two mutually exclusive features (Email:UseMailKit, Email:UseCustom) as tenant-level features, and in the router use IFeatureChecker to pick the sender. This is similar to the setting approach but leverages feature management and SaaS UI out of the box.

  Minimal working router example using settings and explicit DI to avoid recursion:

  public class TenantAwareEmailSender : IEmailSender
  {
      private readonly ISettingProvider _settings;
      private readonly CustomEmailSender _custom;
      private readonly MailKitEmailSender _mailKit; // concrete MailKit sender from Volo.Abp.MailKit
  
      public TenantAwareEmailSender(
          ISettingProvider settings,
          CustomEmailSender custom,
          MailKitEmailSender mailKit)
      {
          _settings = settings;
          _custom = custom;
          _mailKit = mailKit;
      }
  
      private async Task<IEmailSender> GetSenderAsync()
      {
          var selected = await _settings.GetOrNullAsync(EmailProviderSettingNames.SelectedProvider) ?? "MailKit";
          return selected == "Custom" ? _custom : _mailKit;
      }
  
      public async Task SendAsync(string to, string subject, string body, bool isBodyHtml = true)
          => await (await GetSenderAsync()).SendAsync(to, subject, body, isBodyHtml);
  
      public async Task SendAsync(string from, string to, string subject, string body, bool isBodyHtml = true)
          => await (await GetSenderAsync()).SendAsync(from, to, subject, body, isBodyHtml);
  
      public async Task SendAsync(MailMessage mail, bool normalize = true)
          => await (await GetSenderAsync()).SendAsync(mail, normalize);
  
      public async Task QueueAsync(string to, string subject, string body, bool isBodyHtml = true)
          => await (await GetSenderAsync()).QueueAsync(to, subject, body, isBodyHtml);
  }
  

  Then register:

  [DependsOn(typeof(AbpMailKitModule))]
  public class MyAppModule : AbpModule
  {
      public override void ConfigureServices(ServiceConfigurationContext context)
      {
          context.Services.AddTransient<CustomEmailSender>();
          context.Services.AddTransient<MailKitEmailSender>(); // from Volo.Abp.MailKit
          context.Services.Replace(ServiceDescriptor.Transient<IEmailSender, TenantAwareEmailSender>());
      }
  }
  

  Notes:

  • Per-tenant configuration is supported by ABP’s Setting Management; settings are resolved in the context of the current tenant automatically.
  • If you manage email settings via the built-in Setting Management UI, give tenants the capability on the SaaS features screen (commercial) as needed.
  • If you prefer a single abstraction, keep IEmailSender as the router and wire concrete senders explicitly to avoid circular DI.

  2. Sources

  • https://abp.io/docs/latest/framework/infrastructure/emailing
  • https://abp.io/support/questions/260
  • https://abp.io/support/questions/7579

  ---

  This response was generated by AI. If it didn’t solve your problem, feel free to post a new answer — our support team will jump in to help you soon.

  Save Cancel
• 

  0

  maliming created 6 hours ago

  Support Team Fullstack Developer

  hi

  You can add a hybrid implementation of IEmailSender.

  Inject the MailKitSmtpEmailSender and SmtpEmailSender into your hybrid class.

  Check the current tenant ID to determine which one to use for sending the email.

  Thanks.

  Save Cancel