Format with another type or relation by FK

[knopa]

I have two question regarding EntityFramework for .net core 6 version

1. Is it possible to set format for Changes Old, New Value like in EntityFramework-Plus

.Format<OrderItem>(x => x.Price, x => x.ToString("$#.00"));
As example for enum types which stored as int but you want to show them as string.
2. Is possible to grab more info for related object into to changes
Like I have
User -> UserProfile
UserProfile -> MentorId -> User
User -> UserGroup
If I have changed MentorId - be able to Format value to use Mentor.Name or fetch it

[knopa]

I gues with first found a solution but I think itsn't not useful - I think better to do more flexible current format

_auditContext.EntitySettings = new()
                {
                    {
                        typeof(UserProfile), 
                        new EfEntitySettings()
                        {
                            FormatProperties = new Dictionary<string, Func<object, object>>()
                            {
                                {nameof(UserProfile.UserType), val => ((UserType)val).ToString()}
                            }
                        }
                    }
                };

[thepirat000]

For the format, there is a Format method on the fluent API:

https://github.com/thepirat000/Audit.NET/blob/master/src/Audit.EntityFramework/README.md#settings-high-level-interceptor

Audit.EntityFramework.Configuration.Setup()
    .ForContext<MyContext>(config => config
        .ForEntity<OrderItem>(_ => _
            .Format(x => x.Price, x => x.ToString("$#.00"))));

[knopa]

Well it doesn't work as expected because it use same Type as prop not object one

Format<TProp>(Expression<Func<TEntity, TProp>> property, Func<TProp, TProp> format);

Something like that will helps I think

public IContextEntitySetting<TEntity> Format<TProp>(Expression<Func<TEntity, TProp>> property, Func<TProp, object> format)
{
    var name = GetMemberName(property);
    FormatProperties[name] = entity => format.Invoke((TProp)entity);
    return this;
}

[knopa]

I have created PR with that change if you don't mind #527

[thepirat000]

Oh, you're right

Of course I don't mind, thanks a lot!

Will include the changes on the next release

[knopa]

What is ETA for that?

Any suggestion on second question?

[thepirat000]

Maybe today.

Could you elaborate a little bit more on your second question? I think I don't fully understand

[knopa]

You are amazing.

As for second question:
I need a convinient way
how to use fields from FK entity even if need to load it explicitly.
as example
I have model

public class User {
    public string Name { get; set; }
    public int TeacherId { get; set; } // FK to User
    public User Teacher { get; set; }
}

I need something like that or very close to it

Format(x => x.TeacherId, t => t.Teacher.Name, (x, context) => context.Users.FirstOrDefault(u => u.Id == x.TecherId).Name)

Clients be able to see not usual TeacherId from 25 to 234 as their names

[thepirat000]

Which data provider are you using to store the audit events?

[knopa]

Audit.EntityFramework

[thepirat000]

Are you storing the audits on tables in the same database you are auditing?
Could you share your data provider configuration?
Audit.Core.Configuration.Setup().UseEntityFramework(...)

It sounds like the AuditEntityAction is the place to do the override of the property.

For example, assuming a lot of things like you have an entity to store the audits called UserAudit, you could do:

Audit.Core.Configuration.Setup()
    .UseEntityFramework(_ => _
        .AuditTypeMapper(t => typeof(UserAudit))
        .AuditEntityAction<UserAudit>((ev, entry, audit) =>
        {
            audit.Id = 0;  // Just to be sure the automatic mapping User->UserAudit should not map User.Id to UserAudit.Id
            if (entry.GetEntry().Entity is User user)
            {
                var ctx = (MyContext)ev.GetEntityFrameworkEvent().GetDbContext();
                audit.TeacherName = ctx.Teachers.First(t => t.Id == user.TeacherId).TeacherName;
            }
        }));

[knopa]

It looks like that

Audit.Core.Configuration
            .AddCustomAction(ActionType.OnScopeCreated, scope =>
            {
                var id = Guid.NewGuid();
                scope.SetCustomField("AuditScopeId", id);
            });

Audit.Core.Configuration.Setup()
    .UseEntityFramework(_ =>_
        .AuditTypeMapper(_ => typeof(AuditLog))
        .AuditEntityAction<AuditLog>(Handle)
        .IgnoreMatchedProperties());


private static void Handle(AuditEvent ev, EventEntry entry, AuditLog target)
    {
        if (ev.CustomFields.TryGetValue("AuditScopeId", out object value))
        {
            target.TransactionId = (Guid)value;
        }

        AuditConfig config = new();
        if (ev.CustomFields.TryGetValue(nameof(AuditConfig), out object configValue))
        {
            config = (AuditConfig)configValue;
        }

        target.Event = config.Event;
        target.RootEntityId = config.RootEntityId;
        target.RootEntityType = config.RootEntityType;
        target.PerformedById = config.ResponsibleId;

        target.EntityType = entry.EntityType.Name;
        target.AuditDate = DateTime.UtcNow;
        target.ActionType = entry.Action;
        target.EntityId = entry.PrimaryKey.First().Value.ToString();

        target.Changes = new();
        if ((target.ActionType == "Insert"
         || target.ActionType == "Delete")
            && entry.ColumnValues != null)
        {
            target.Changes.AddRange(entry.ColumnValues.Select(c => new PropertyChange()
            {
                Name = c.Key,
                New = c.Value
            }));
        }

        if (entry.Changes != null)
        {
            target.Changes.AddRange(entry.Changes.Select(c => new PropertyChange()
            {
                Name = c.ColumnName,
                New = c.NewValue,
                Old = c.OriginalValue
            }));
        }
    }

[thepirat000]

If you really need to do it with a method like Format(), which replaces the values on Changes and ColumnValues collection, then I think it could be possible to provide another overload for Override() that takes a func of EntityEntry.

So you could do:

  .ForEntity<User>(cfg => cfg
    .Override(u => u.UserName, 
      entry => ((MyContext)entry.Context).Teachers.First(t => t.Id == ((User)entry.Entity).TeacherId).TeacherName

To replace the value of "UserName" column with the Teacher Name (not a very nice example, sorry)

The sad part is that you'll probably need to do some casting.

Do you think something like that will work for you?

[knopa]

Looks not bad. You be able to grab value from entry relation or from context if it not included

[thepirat000]

This was implemented in version 19.4.0, please upgrade your references and re-test.

• Relaxed Format() method to allow returning any type.
• New overload for Override() method taking an EntityEntry

[knopa]

Great