def _cascade_soft_delete(inst_or_qs, using, keep_parents=False):
"""
Return collector instance that has marked ArchiveMixin instances for
archive (i.e. update) instead of actual delete.
Arguments:
inst_or_qs (models.Model or models.QuerySet): the instance(s) that
are to be deleted.
using (db connection/router): the db to delete from.
keep_parents (bool): defaults to False. Determine if cascade is true.
Returns:
models.deletion.Collector: this is a standard Collector instance but
the ArchiveMixin instances are in the fields for update list.
"""
if not isinstance(inst_or_qs, models.QuerySet):
instances = [inst_or_qs]
else:
instances = inst_or_qs
# The collector will iteratively crawl the relationships and
# create a list of models and instances that are connected to
# this instance.
collector = NestedObjects(using=using)
collector.collect(instances, keep_parents=keep_parents)
if collector.protected:
raise models.ProtectedError("Delete protected", collector.protected)
collector.sort()
return collector
def duplicate(obj, value=None, field=None, duplicate_order=None):
"""
Duplicate all related objects of obj setting
field to value. If one of the duplicate
objects has an FK to another duplicate object
update that as well. Return the duplicate copy
of obj.
duplicate_order is a list of models which specify how
the duplicate objects are saved. For complex objects
this can matter. Check to save if objects are being
saved correctly and if not just pass in related objects
in the order that they should be saved.
"""
collector = NestedObjects(using=DEFAULT_DB_ALIAS)
collector.collect([obj])
collector.sort()
related_models = list(collector.data.keys())
data_snapshot = {}
for key in list(collector.data.keys()):
data_snapshot.update({
key:
dict(
list(
zip([item.pk for item in collector.data[key]],
[item for item in collector.data[key]])))
})
root_obj = None
if duplicate_order is None:
duplicate_order = reversed(related_models)
for model in duplicate_order:
# Find all FKs on model that point to a related_model.
fks = []
for f in model._meta.fields:
if isinstance(f, ForeignKey) and f.rel.to in related_models:
fks.append(f)
# Replace each `sub_obj` with a duplicate.
if model not in collector.data:
continue
sub_objects = collector.data[model]
for obj in sub_objects:
for fk in fks:
fk_value = getattr(obj, "%s_id" % fk.name)
# If this FK has been duplicated then point to the duplicate.
fk_rel_to = data_snapshot[fk.rel.to]
if fk_value in fk_rel_to:
dupe_obj = fk_rel_to[fk_value]
setattr(obj, fk.name, dupe_obj)
# Duplicate the object and save it.
obj.id = None
if field is not None:
setattr(obj, field, value)
obj.save()
if root_obj is None:
root_obj = obj
return root_obj
