EntityFramework code-first - right place for entity "import" function [closed]

Question

I have an EF-driven Repository pattern implementation. Roughly looks like this:

public class DataRepository : IDataRepository
{
  public IDbSet<Contacts> Contacts { get; set; }
}

I would like to implement a Contact import functionality, which has some custom logic for manipulating the entity which is being imported (i.e. it is different from Adding an entity to the repo).

I see two options right now:

1. Implement an extension method on the IDbSet<Contacts> Contacts, which would allow me to do:

   dataRepository.Contacts.Import(contact);

   dataRepository.Save();

2. Implement a static method on the Contact class, which will then allow me to do something like:

   Contact.Import(contact);

   but then I am not sure how I would attach the entity to the context, without breaking my abstraction...

I could also implement an 'Import Service' which wraps this functionality, but it seems very old-school. e.g.:

public class ContactsImportService
{
  public ContactsImportService(IDataRepository dataRepo)
  {
    ...
  }

  public void Import(Contact contact)
  {
    // Manipulate contact here
    this.dataRepo.Add(contact);
    this.dataRepo.Save();
  }
}

Any thoughts?

Answer 1

Implementing an extension method will be a good approach.

However, since you already have a repository layer with IDataRepository & an implementation class DataRepository, the best approach will be to declare a method signature in IDataRepository interface & implement the method in DataRepository class itself.

This will ensure, we are not touching/extending the direct data access objects of entity framework that is IDbSet<Contact>.

Also its always good thing to group the methods working on object sets (aka Add, edit, delete) in a single place like DataRepository (Since you already have this in place).

The import operation as you have specified is specifically for a single entity & I hope its carrying all relevant information for the import within the Contact object itself.