Interception point that gets the returned data after serialization

[gdoron]

Hi,

(With some obfuscation because of IP)
All our mapped to EF database entities are deriving from BaseClass:

public class BaseEntity {
  public string RequiredPermission { get; set; }
}

We are trying to validate that no matter what, the data returned from the database does not include rows the current user doesn't have permission to, (even if the developer used set.IgnoreQueryFilter()

We would like having another interception point, with the reference to the data returned from the database after serialization, instead of having to materialize the DbDataReader twice.

[ajcvickers]

with the reference to the data returned from the database after serialization

Can you be more specific about what you mean by this?

[gdoron]

@ajcvickers Consider this code:

await dbContext.Set<Person>().Where(x=> x.Name.Contains("foo").ToListAsync()

We would want to have an interceptor that gets the List<Person>? as the object? Results property of a new interception point of DbCommandInterceptor.

Does it make sense?

[ajcvickers]

@gdoron Yes, but this isn't something that EF can do directly, since enumeration of the query results and the completion of this isn't triggered by EF Core, and EF Core doesn't know what has been done with the results. There is quite a long discussion about this on #23535, and in EF7 we introduced DataReaderClosing that is triggered used when the result set has been consumed. See: https://learn.microsoft.com/en-us/ef/core/what-is-new/ef-core-7.0/whatsnew#new-and-improved-interceptors-and-events

[gdoron]

@ajcvickers I'm afraid I did not understand how to use the DataReaderClosing method for our use case.
How can we get the List<T> that was read from that DataReader?

[ajcvickers]

@gdoron EF doesn't ever create a List<T>. EF reads values from the DbDataReader and inserts them directly into your entity instances without going through any intermediary data structure. The application then determines what to do with each instance streamed back. At that point the application may create a List<T> if it chooses. If you're looking for some kind of data structure that goes between the DbDataReader and the materialized entities, then that doesn't exist.