/// <summary>
/// Discards the prepared audit records. This method should be called
/// when the actual changes could not be saved to the database.
/// </summary>
/// <param name="context">
/// The database context whose changes were recorded.
/// </param>
/// <param name="cancellationToken">
/// A token to monitor for cancellation requests.
/// </param>
/// <returns>A task that represents the asynchronous operation.</returns>
public static async Task DiscardRecordedChangesAsync(this IAuditedContext context, CancellationToken cancellationToken = default)
{
if (!context.CanAudit())
{
return;
}
await Task.WhenAll(context.ChangeRecorders.Select(x => x.DiscardAsync(cancellationToken)));
}
private static void RecordChange(this IAuditedContext context, EntityEntry entity, IAuditedEntity auditedEntity)
{
if (!context.CanAudit())
{
return;
}
switch (entity.State)
{
case EntityState.Added:
foreach (var changeRecorder in context.ChangeRecorders)
{
changeRecorder.RecordAdd(auditedEntity);
}
break;
case EntityState.Deleted:
foreach (var changeRecorder in context.ChangeRecorders)
{
changeRecorder.RecordDelete(auditedEntity);
}
break;
case EntityState.Modified:
foreach (var property in entity.CurrentValues.Properties)
{
var entry = entity.Property(property.Name);
// Note: do not change the line below into `!=`!
// `Equals(object, object)` calls an overridden Equals,
// whereas `object != object` does not.
if (entry.IsModified && !Equals(entry.CurrentValue, entry.OriginalValue))
{
foreach (var changeRecorder in context.ChangeRecorders)
{
changeRecorder.RecordChange(auditedEntity, property.Name, entry.OriginalValue, entry.CurrentValue);
}
}
}
break;
}
}
/// <summary>
/// Records the currently tracked changes in the database context to all
/// change recorders.
/// </summary>
/// <param name="context">
/// The database context that contains the changes.
/// </param>
public static void RecordChanges(this IAuditedContext context)
{
if (context.ChangeTracker.AutoDetectChangesEnabled)
{
context.ChangeTracker.DetectChanges();
}
foreach (var entity in context.ChangeTracker.Entries().Where(e => e.Entity is IAuditedEntity))
{
var auditedEntity = (IAuditedEntity)entity.Entity;
switch (entity.State)
{
case EntityState.Added:
auditedEntity.Created = DateTimeOffset.Now;
auditedEntity.CreatedBy = context.Identity?.Id;
break;
case EntityState.Modified:
auditedEntity.LastModified = DateTimeOffset.Now;
auditedEntity.LastModifiedBy = context.Identity?.Id;
break;
}
context.RecordChange(entity, auditedEntity);
}
if (context.CanAudit())
{
foreach (var changeRecorder in context.ChangeRecorders)
{
if (changeRecorder is IHasParentContext parentContextRecorder)
{
parentContextRecorder.ParentContext = (IAuditContext)context;
}
changeRecorder.OnSavingChanges();
}
}
}
