Logitar · Utar94 · Dec 28, 2024 · Dec 28, 2024
diff --git a/CHANGELOG.md b/CHANGELOG.md
@@ -7,7 +7,9 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ## [Unreleased]
 
-Nothing yet.
+### Fixed
+
+- Event handlers are now idempotent.
 
 ## [3.0.4] - 2024-12-27
 
@@ -67,7 +69,8 @@ Nothing yet.
 - Relational storage (PostgreSQL and Microsoft SQL Server) for Identity entities.
 - Unit and Integration tests.
 
-[unreleased]: https://github.com/Logitar/Identity/compare/v3.0.4...HEAD
+[unreleased]: https://github.com/Logitar/Identity/compare/v3.0.5...HEAD
+[3.0.5]: https://github.com/Logitar/Identity/compare/v3.0.4...v3.0.5
 [3.0.4]: https://github.com/Logitar/Identity/compare/v3.0.3...v3.0.4
 [3.0.3]: https://github.com/Logitar/Identity/compare/v3.0.2...v3.0.3
 [3.0.2]: https://github.com/Logitar/Identity/compare/v3.0.1...v3.0.2

diff --git a/lib/Logitar.Identity.EntityFrameworkCore.Relational/Entities/UserEntity.cs b/lib/Logitar.Identity.EntityFrameworkCore.Relational/Entities/UserEntity.cs
@@ -198,6 +198,8 @@ public void Enable(UserEnabled @event)
 
   public void RemoveCustomIdentifier(UserIdentifierRemoved @event)
   {
+    Update(@event);
+
     UserIdentifierEntity? identifier = Identifiers.SingleOrDefault(x => x.Key == @event.Key.Value);
     if (identifier != null)
     {
@@ -241,6 +243,8 @@ public void SetAddress(UserAddressChanged @event)
 
   public void SetCustomIdentifier(UserIdentifierChanged @event)
   {
+    Update(@event);
+
     UserIdentifierEntity? identifier = Identifiers.SingleOrDefault(x => x.Key == @event.Key.Value);
     if (identifier == null)
     {

diff --git a/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/ApiKeyEvents.cs b/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/ApiKeyEvents.cs
@@ -14,28 +14,39 @@ public sealed class ApiKeyEvents : INotificationHandler<ApiKeyAuthenticated>,
 {
   private readonly IdentityContext _context;
   private readonly ICustomAttributeService _customAttributes;
+  private readonly IMediator _mediator;
 
-  public ApiKeyEvents(IdentityContext context, ICustomAttributeService customAttributes)
+  public ApiKeyEvents(IdentityContext context, ICustomAttributeService customAttributes, IMediator mediator)
   {
     _context = context;
     _customAttributes = customAttributes;
+    _mediator = mediator;
   }
 
   public async Task Handle(ApiKeyAuthenticated @event, CancellationToken cancellationToken)
   {
-    ApiKeyEntity apiKey = await _context.ApiKeys
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The API key entity 'StreamId={@event.StreamId}' could not be found.");
+    ApiKeyEntity? apiKey = await _context.ApiKeys
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
 
-    apiKey.Authenticate(@event);
+    if (apiKey == null || apiKey.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, apiKey), cancellationToken);
+    }
+    else
+    {
+      apiKey.Authenticate(@event);
 
-    await _context.SaveChangesAsync(cancellationToken);
+      await _context.SaveChangesAsync(cancellationToken);
+
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 
   public async Task Handle(ApiKeyCreated @event, CancellationToken cancellationToken)
   {
     ApiKeyEntity? apiKey = await _context.ApiKeys.AsNoTracking()
       .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
     if (apiKey == null)
     {
       apiKey = new(@event);
@@ -44,61 +55,98 @@ public async Task Handle(ApiKeyCreated @event, CancellationToken cancellationTok
 
       await SaveActorAsync(apiKey, cancellationToken);
       await _context.SaveChangesAsync(cancellationToken);
+
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
+    else
+    {
+      await _mediator.Publish(new EventNotHandled(@event, apiKey), cancellationToken);
     }
   }
 
   public async Task Handle(ApiKeyDeleted @event, CancellationToken cancellationToken)
   {
     ApiKeyEntity? apiKey = await _context.ApiKeys
       .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
-    if (apiKey != null)
+
+    if (apiKey == null)
+    {
+      await _mediator.Publish(new EventNotHandled(@event, apiKey), cancellationToken);
+    }
+    else
     {
       _context.ApiKeys.Remove(apiKey);
 
       await DeleteActorAsync(apiKey, cancellationToken);
       await _customAttributes.RemoveAsync(EntityType.ApiKey, apiKey.ApiKeyId, cancellationToken);
       await _context.SaveChangesAsync(cancellationToken);
+
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
     }
   }
 
   public async Task Handle(ApiKeyRoleAdded @event, CancellationToken cancellationToken)
   {
-    ApiKeyEntity apiKey = await _context.ApiKeys
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The API key entity 'StreamId={@event.StreamId}' could not be found.");
+    ApiKeyEntity? apiKey = await _context.ApiKeys
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
+    if (apiKey == null || apiKey.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, apiKey), cancellationToken);
+    }
+    else
+    {
+      RoleEntity role = await _context.Roles
+        .SingleOrDefaultAsync(x => x.StreamId == @event.RoleId.Value, cancellationToken)
+        ?? throw new InvalidOperationException($"The role entity 'StreamId={@event.RoleId}' could not be found.");
 
-    RoleEntity role = await _context.Roles
-      .SingleOrDefaultAsync(x => x.StreamId == @event.RoleId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The role entity 'StreamId={@event.RoleId}' could not be found.");
+      apiKey.AddRole(role, @event);
 
-    apiKey.AddRole(role, @event);
+      await _context.SaveChangesAsync(cancellationToken);
 
-    await _context.SaveChangesAsync(cancellationToken);
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 
   public async Task Handle(ApiKeyRoleRemoved @event, CancellationToken cancellationToken)
   {
-    ApiKeyEntity apiKey = await _context.ApiKeys
+    ApiKeyEntity? apiKey = await _context.ApiKeys
       .Include(x => x.Roles)
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The API key entity 'StreamId={@event.StreamId}' could not be found.");
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
 
-    apiKey.RemoveRole(@event);
+    if (apiKey == null || apiKey.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, apiKey), cancellationToken);
+    }
+    else
+    {
+      apiKey.RemoveRole(@event);
+
+      await _context.SaveChangesAsync(cancellationToken);
 
-    await _context.SaveChangesAsync(cancellationToken);
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 
   public async Task Handle(ApiKeyUpdated @event, CancellationToken cancellationToken)
   {
-    ApiKeyEntity apiKey = await _context.ApiKeys
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The API key entity 'StreamId={@event.StreamId}' could not be found.");
+    ApiKeyEntity? apiKey = await _context.ApiKeys
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
+    if (apiKey == null || apiKey.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, apiKey), cancellationToken);
+    }
+    else
+    {
+      apiKey.Update(@event);
 
-    apiKey.Update(@event);
+      await SaveActorAsync(apiKey, cancellationToken);
+      await _customAttributes.UpdateAsync(EntityType.ApiKey, apiKey.ApiKeyId, @event.CustomAttributes, cancellationToken);
+      await _context.SaveChangesAsync(cancellationToken);
 
-    await SaveActorAsync(apiKey, cancellationToken);
-    await _customAttributes.UpdateAsync(EntityType.ApiKey, apiKey.ApiKeyId, @event.CustomAttributes, cancellationToken);
-    await _context.SaveChangesAsync(cancellationToken);
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 
   private async Task DeleteActorAsync(ApiKeyEntity apiKey, CancellationToken cancellationToken)

diff --git a/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/EventHandled.cs b/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/EventHandled.cs
@@ -0,0 +1,6 @@
+using Logitar.EventSourcing;
+using MediatR;
+
+namespace Logitar.Identity.EntityFrameworkCore.Relational.Handlers;
+
+public record EventHandled(DomainEvent Event) : INotification;
diff --git a/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/EventNotHandled.cs b/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/EventNotHandled.cs
@@ -0,0 +1,26 @@
+using Logitar.EventSourcing;
+using Logitar.Identity.EntityFrameworkCore.Relational.Entities;
+using MediatR;
+
+namespace Logitar.Identity.EntityFrameworkCore.Relational.Handlers;
+
+public record EventNotHandled : INotification
+{
+  public long ExpectedVersion { get; }
+  public long ActualVersion { get; }
+
+  public EventNotHandled(long expectedVersion, long actualVersion)
+  {
+    ArgumentOutOfRangeException.ThrowIfNegative(expectedVersion);
+    ArgumentOutOfRangeException.ThrowIfNegative(actualVersion);
+
+    ExpectedVersion = expectedVersion;
+    ActualVersion = actualVersion;
+  }
+
+  public EventNotHandled(DomainEvent @event, AggregateEntity? aggregate)
+  {
+    ExpectedVersion = @event.Version - 1;
+    ActualVersion = aggregate?.Version ?? 0;
+  }
+}
diff --git a/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/OneTimePasswordEvents.cs b/lib/Logitar.Identity.EntityFrameworkCore.Relational/Handlers/OneTimePasswordEvents.cs
@@ -13,71 +13,111 @@ public sealed class OneTimePasswordEvents : INotificationHandler<OneTimePassword
 {
   private readonly IdentityContext _context;
   private readonly ICustomAttributeService _customAttributes;
+  private readonly IMediator _mediator;
 
-  public OneTimePasswordEvents(IdentityContext context, ICustomAttributeService customAttributes)
+  public OneTimePasswordEvents(IdentityContext context, ICustomAttributeService customAttributes, IMediator mediator)
   {
     _context = context;
     _customAttributes = customAttributes;
+    _mediator = mediator;
   }
 
   public async Task Handle(OneTimePasswordCreated @event, CancellationToken cancellationToken)
   {
     OneTimePasswordEntity? oneTimePassword = await _context.OneTimePasswords.AsNoTracking()
       .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
     if (oneTimePassword == null)
     {
       oneTimePassword = new(@event);
 
       _context.OneTimePasswords.Add(oneTimePassword);
 
       await _context.SaveChangesAsync(cancellationToken);
+
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
+    else
+    {
+      await _mediator.Publish(new EventNotHandled(@event, oneTimePassword), cancellationToken);
     }
   }
 
   public async Task Handle(OneTimePasswordDeleted @event, CancellationToken cancellationToken)
   {
     OneTimePasswordEntity? oneTimePassword = await _context.OneTimePasswords
       .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
-    if (oneTimePassword != null)
+
+    if (oneTimePassword == null)
+    {
+      await _mediator.Publish(new EventNotHandled(@event, oneTimePassword), cancellationToken);
+    }
+    else
     {
       _context.OneTimePasswords.Remove(oneTimePassword);
 
       await _customAttributes.RemoveAsync(EntityType.OneTimePassword, oneTimePassword.OneTimePasswordId, cancellationToken);
       await _context.SaveChangesAsync(cancellationToken);
+
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
     }
   }
 
   public async Task Handle(OneTimePasswordUpdated @event, CancellationToken cancellationToken)
   {
-    OneTimePasswordEntity oneTimePassword = await _context.OneTimePasswords
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The One-Time Password (OTP) entity 'StreamId={@event.StreamId}' could not be found.");
+    OneTimePasswordEntity? oneTimePassword = await _context.OneTimePasswords
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
+    if (oneTimePassword == null || oneTimePassword.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, oneTimePassword), cancellationToken);
+    }
+    else
+    {
+      oneTimePassword.Update(@event);
 
-    oneTimePassword.Update(@event);
+      await _customAttributes.UpdateAsync(EntityType.OneTimePassword, oneTimePassword.OneTimePasswordId, @event.CustomAttributes, cancellationToken);
+      await _context.SaveChangesAsync(cancellationToken);
 
-    await _customAttributes.UpdateAsync(EntityType.OneTimePassword, oneTimePassword.OneTimePasswordId, @event.CustomAttributes, cancellationToken);
-    await _context.SaveChangesAsync(cancellationToken);
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 
   public async Task Handle(OneTimePasswordValidationFailed @event, CancellationToken cancellationToken)
   {
-    OneTimePasswordEntity oneTimePassword = await _context.OneTimePasswords
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The One-Time Password (OTP) entity 'StreamId={@event.StreamId}' could not be found.");
+    OneTimePasswordEntity? oneTimePassword = await _context.OneTimePasswords
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
+    if (oneTimePassword == null || oneTimePassword.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, oneTimePassword), cancellationToken);
+    }
+    else
+    {
+      oneTimePassword.Fail(@event);
 
-    oneTimePassword.Fail(@event);
+      await _context.SaveChangesAsync(cancellationToken);
 
-    await _context.SaveChangesAsync(cancellationToken);
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 
   public async Task Handle(OneTimePasswordValidationSucceeded @event, CancellationToken cancellationToken)
   {
-    OneTimePasswordEntity oneTimePassword = await _context.OneTimePasswords
-      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken)
-      ?? throw new InvalidOperationException($"The One-Time Password (OTP) entity 'StreamId={@event.StreamId}' could not be found.");
+    OneTimePasswordEntity? oneTimePassword = await _context.OneTimePasswords
+      .SingleOrDefaultAsync(x => x.StreamId == @event.StreamId.Value, cancellationToken);
+
+    if (oneTimePassword == null || oneTimePassword.Version != (@event.Version - 1))
+    {
+      await _mediator.Publish(new EventNotHandled(@event, oneTimePassword), cancellationToken);
+    }
+    else
+    {
+      oneTimePassword.Succeed(@event);
 
-    oneTimePassword.Succeed(@event);
+      await _context.SaveChangesAsync(cancellationToken);
 
-    await _context.SaveChangesAsync(cancellationToken);
+      await _mediator.Publish(new EventHandled(@event), cancellationToken);
+    }
   }
 }