ddr-import entity sets important values (e.g. record_created) no None

[gjost]

When updating existing Entities, ddr-import entity is setting important fields to empty values:

• record_created -> None
• files -> []

This is a destructive change! We cannot have this!

[gjost]

Problem relates to how we populate Entity objects, how we tell if they are modified (we don't want to write if they're not modified).

In ddrlocal, the webui.views.entities.new view has a horribly convoluted process, mainly due to the requirement that we get IDs from the ID service and that this happen in a single step:

• Hits ID service and retrieves a new ID.
• Writes file at settings.TEMPLATES_EJSON to entity.path_abs,
• Runs DDR.commands.entitiy_create(),
• Writes data entity.write_json(),
• Runs DDR.commands.entity_update(),
• Redirects to webui.views.entities.edit.

In DDR.batch_import.import_entities() we have the following:

entity = eidentifier.object()
if not entity:
    entity = models.Entity.create(eidentifier.path_abs(), eidentifier)
_populate_object(entity, module, field_names, field_directives, rowd)
if _object_writable(entity, field_names):
    entity.write_json()
    ...

We need to see exactly what models.Entity.create and batch_import._populate_object are doing.

[gjost]

• 2b6a1be CSV import directives handling, so certain fields can be present in (or absent from) the CSV without affecting the object.
• 118ac35 Get existing objects using identifier.object()
• e61967c models.create_object: insert default values unless None
• Modified ddr-repo to add CSV directives.
• Modified ddr-repo to add default values (or None in the case of "id").