python-dependency-injector/examples/injections.py

84 lines
1.9 KiB
Python

"""
Concept example of objects injections.
"""
from objects import Catalog, Singleton, NewInstance, InitArg, Attribute, inject
import sqlite3
# Some example class.
class ObjectA(object):
def __init__(self, db):
self.db = db
# Catalog of objects providers.
class AppCatalog(Catalog):
"""
Objects catalog.
"""
database = Singleton(sqlite3.Connection,
InitArg('database', ':memory:'),
Attribute('row_factory', sqlite3.Row))
""" :type: (objects.Provider) -> sqlite3.Connection """
object_a = NewInstance(ObjectA,
InitArg('db', database))
""" :type: (objects.Provider) -> ObjectA """
# Class attributes injections.
@inject(Attribute('a', AppCatalog.object_a))
@inject(Attribute('database', AppCatalog.database))
class Consumer(object):
"""
Some consumer class with database dependency via attribute.
"""
a = None
""" :type: (objects.Provider) -> ObjectA """
database = None
""" :type: (objects.Provider) -> sqlite3.Connection """
def tests(self):
a1, a2 = self.a(), self.a()
assert a1 is not a2
assert a1.db is a2.db is self.database()
consumer = Consumer()
consumer.tests()
# Class __init__ injections.
@inject(InitArg('a1', AppCatalog.object_a))
@inject(InitArg('a2', AppCatalog.object_a))
@inject(InitArg('database', AppCatalog.database))
class ConsumerWithInitArg(object):
"""
Some consumer class with database dependency via init arg.
"""
def __init__(self, a1, a2, database):
"""
Initializer.
:param a1: ObjectA
:param a2: ObjectA
:param database: sqlite3.Connection
"""
self.a1 = a1
self.a2 = a2
self.database = database
def tests(self):
assert self.a1 is not self.a2
assert self.a1.db is self.a2.db is self.database
consumer = ConsumerWithInitArg()
consumer.tests()