Switch collection in mongoengine for find query

Question

I've read mongoengine documentation about switching collection to save document. And test this code and it worked successfully:

from mongoengine.context_managers import switch_db

class Group(Document):
    name = StringField()

Group(name="test").save()  # Saves in the default db

with switch_collection(Group, 'group2000') as Group:
    Group(name="hello Group 2000 collection!").save()  # Saves in group2000 collection

But the problem is when I want to find saved document in switch collection switch_collection doesn't work at all.

with switch_collection(Group, 'group2000') as GroupT:
    GroupT.objects.get(name="hello Group 2000 collection!")  # Finds in group2000 collection

Answer 1

As of mongoengine==0.10.0 mongoengine.context_managers.switch_collection(cls, collection_name) used as "with switch_collection(Group, 'group1') as Group:" in the example doesn't work inside functions. It gives unboundlocalerror. A simple get around with existing resources is :

To get:

new_group = Group.switch_collection(Group(),'group1')
from mongoengine.queryset import QuerySet
new_objects = QuerySet(Group,new_group._get_collection())

Use new_objects.all() to get all objects etc.

To save:

group_obj = Group()
group_obj.switch_collection('group2')
group_obj.save()