python-dependency-injector/examples/providers/factory_delegation.py

50 lines
1.2 KiB
Python

"""`Factory` providers delegation example."""
from dependency_injector.providers import Factory
from dependency_injector.injections import KwArg
class User(object):
"""Example class User."""
def __init__(self, photos_factory):
"""Initializer.
:param photos_factory: (dependency_injector.providers.Factory) -> Photo
"""
self.photos_factory = photos_factory
self._main_photo = None
super(User, self).__init__()
@property
def main_photo(self):
"""Return user's main photo."""
if not self._main_photo:
self._main_photo = self.photos_factory()
return self._main_photo
class Photo(object):
"""Example class Photo."""
# User and Photo factories:
photos_factory = Factory(Photo)
users_factory = Factory(User,
KwArg('photos_factory', photos_factory.delegate()))
# Creating several User objects:
user1 = users_factory()
user2 = users_factory()
# Making some asserts:
assert isinstance(user1, User)
assert isinstance(user1.main_photo, Photo)
assert isinstance(user2, User)
assert isinstance(user2.main_photo, Photo)
assert user1 is not user2
assert user1.main_photo is not user2.main_photo