mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-11-22 17:47:02 +03:00
72 lines
2.0 KiB
Python
72 lines
2.0 KiB
Python
"""Concept example of `Dependency Injector`."""
|
|
|
|
from dependency_injector.catalog import AbstractCatalog
|
|
|
|
from dependency_injector.providers import Factory
|
|
from dependency_injector.providers import Singleton
|
|
|
|
from dependency_injector.injections import KwArg
|
|
from dependency_injector.injections import Attribute
|
|
from dependency_injector.injections import inject
|
|
|
|
import sqlite3
|
|
|
|
|
|
class ObjectA(object):
|
|
|
|
"""Example class ObjectA, that has dependency on database."""
|
|
|
|
def __init__(self, db):
|
|
"""Initializer."""
|
|
self.db = db
|
|
|
|
|
|
class ObjectB(object):
|
|
|
|
"""Example class ObjectB, that has dependencies on ObjectA and database."""
|
|
|
|
def __init__(self, a, db):
|
|
"""Initializer."""
|
|
self.a = a
|
|
self.db = db
|
|
|
|
|
|
class Catalog(AbstractCatalog):
|
|
|
|
"""Catalog of dependency_injector providers."""
|
|
|
|
database = Singleton(sqlite3.Connection,
|
|
KwArg('database', ':memory:'),
|
|
Attribute('row_factory', sqlite3.Row))
|
|
""":type: (dependency_injector.Provider) -> sqlite3.Connection"""
|
|
|
|
object_a_factory = Factory(ObjectA,
|
|
KwArg('db', database))
|
|
""":type: (dependency_injector.Provider) -> ObjectA"""
|
|
|
|
object_b_factory = Factory(ObjectB,
|
|
KwArg('a', object_a_factory),
|
|
KwArg('db', database))
|
|
""":type: (dependency_injector.Provider) -> ObjectB"""
|
|
|
|
|
|
# Catalog static provides.
|
|
a1, a2 = Catalog.object_a_factory(), Catalog.object_a_factory()
|
|
b1, b2 = Catalog.object_b_factory(), Catalog.object_b_factory()
|
|
|
|
assert a1 is not a2
|
|
assert b1 is not b2
|
|
assert a1.db is a2.db is b1.db is b2.db is Catalog.database()
|
|
|
|
|
|
# Example of inline injections.
|
|
@inject(KwArg('a', Catalog.object_a_factory))
|
|
@inject(KwArg('b', Catalog.object_b_factory))
|
|
@inject(KwArg('database', Catalog.database))
|
|
def example(a, b, database):
|
|
"""Example callback."""
|
|
assert a.db is b.db is database is Catalog.database()
|
|
|
|
|
|
example()
|