External Data Resolution

[izabelab-cdcdevelopment]

I am using EF Core in a .NET 8 project to manage database operations. For auditing purposes, I am leveraging the Audit.EntityFramework.Core library (27.2.0) to log changes made to entities. One of requirements is to log human-readable values instead of ids for certain properties. The ids correspond to data residing in an external source.

For example, I have an Order entity which contains a DeliveryMethodId property:

public sealed class Order
{
    public decimal OrderId { get; set; }
    public decimal DeliveryMethodId { get; set; }
    // Other properties...
}

The details for delivery methods are stored in an external system. One can fetch them using a repository:

public sealed record DeliveryMethod
{
    public required decimal DeliveryMethodId { get; init; }
    public string? Name { get; init; }
}

public interface IDeliveryMethodRepository
{
    Task<DeliveryMethod?> GetDeliveryMethodByIdOrDefaultAsync(decimal deliveryMethodId, CancellationToken cancellationToken = default);
    Task<IReadOnlyCollection<DeliveryMethod>> GetDeliveryMethodsAsync(CancellationToken cancellationToken = default);
}

I need to replace the DeliveryMethodId with the corresponding DeliveryMethod's Name. Here is the current configuration of the application's db context:

public sealed class ApplicationDbContext : AuditDbContext
{
    public DbSet<Order> Orders => Set<Order>();
    // Other db sets...

    public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options) : base(options)
    {
        AuditDataProvider = new EntityFrameworkDataProvider(entityFrameworkProviderConfigurator =>
        {
            entityFrameworkProviderConfigurator
                .UseDbContext<ApplicationDbContext>(options)
                .AuditTypeMapper(_ => typeof(EntityLog))
                .AuditEntityAction<EntityLog>((auditEvent, eventEntry, entityLog) =>
                {
                    entityLog.Table = eventEntry.Table;
                    entityLog.EntityId = string.Join(",", eventEntry.PrimaryKey.Values);
                    entityLog.EntityType = eventEntry.EntityType;
                    entityLog.Action = Enum.Parse<DatabaseAction>(eventEntry.Action);

                    foreach (var property in eventEntry.Changes ?? [])
                    {
                        var rowChange = new RowChange
                        {
                            ColumnName = property.ColumnName,
                            OldValue = property.OriginalValue,
                            NewValue = property.NewValue
                        };

                        entityLog.Changes.Add(rowChange);
                    }

                    entityLog.UserId = Thread.CurrentPrincipal?.GetUserId() ?? 0;
                    entityLog.Timestamp = new DateTimeOffset(auditEvent.StartDate);
                })
                .IgnoreMatchedProperties();
        });
    }

I could inject an IDeliveryMethodRepository in the ApplicationDbContext's constructor, fetch the required data in the AuditEntityAction, and set the RowChange's OldValue and NewValue to delivery method names... but I am not sure it is the right approach. Any insights or suggestions would be greatly appreciated!

[thepirat000]

As long as the repository doesn't depend on your DbContext, it should be fine. I would probably extract the Audit Entity action into a dedicated method within the DbContext:

public sealed class ApplicationDbContext : AuditDbContext
{  
  private readonly IDeliveryMethodRepository _deliveryMethodRepository;
  
  public ApplicationDbContext(DbContextOptions<ApplicationDbContext> options, IDeliveryMethodRepository deliveryMethodRepository) : base(options)
  {
      _deliveryMethodRepository = deliveryMethodRepository;
  
      AuditDataProvider = new EntityFrameworkDataProvider(entityFrameworkProviderConfigurator =>
      {
          entityFrameworkProviderConfigurator
              .UseDbContext<ApplicationDbContext>(options)
              .AuditTypeMapper(_ => typeof(EntityLog))
              .AuditEntityAction<EntityLog>(AuditEntityAction)
              .IgnoreMatchedProperties();
      });
  }
  
  private void AuditEntityAction(AuditEvent auditEvent, EventEntry eventEntry, EntityLog entityLog)
  {
      entityLog.Table = eventEntry.Table;
      // use _deliveryMethodRepository ...
  }
}

[izabelab-cdcdevelopment]

Thank you for your prompt response!