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77 lines
1.9 KiB
ReStructuredText
77 lines
1.9 KiB
ReStructuredText
Providers delegation
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--------------------
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Example:
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.. code-block:: python
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"""Providers delegation example."""
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from objects.providers import Factory
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from objects.providers import Singleton
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from objects.providers import Delegate
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from objects.injections import KwArg
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class User(object):
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"""Example class User."""
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def __init__(self, id, name):
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"""Initializer.
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:param id: int
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:param name: str
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:return:
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"""
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self.id = id
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self.name = name
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class UserService(object):
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"""Example class UserService.
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UserService has dependency on users factory.
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"""
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def __init__(self, users_factory):
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"""Initializer.
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:param users_factory: (objects.providers.Factory) -> User
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:return:
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"""
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self.users_factory = users_factory
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def get_by_id(self, id):
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"""Return user info by user id."""
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return self.users_factory(id=id, name=self._get_name_from_db(id))
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def _get_name_from_db(self, id):
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"""Return user's name from database by his id.
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Main purpose of this method is just to show the fact of retrieving
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some user's data from database, so, actually, it simulates work
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with database just by merging constant string with provided user's id.
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"""
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return ''.join(('user', str(id)))
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# Users factory and UserService provider:
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users_factory = Factory(User)
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users_service = Singleton(UserService,
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KwArg('users_factory', Delegate(users_factory)))
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# Creating several User objects:
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user1 = users_service().get_by_id(1)
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user2 = users_service().get_by_id(2)
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# Making some asserts:
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assert user1.id == 1
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assert user1.name == 'user1'
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assert user2.id == 2
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assert user2.name == 'user2'
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