python-dependency-injector/examples/providers/dependency.py
2017-12-21 22:54:44 +02:00

74 lines
2.4 KiB
Python

"""`Dependency` providers example."""
import sqlite3
import contextlib
import dependency_injector.providers as providers
class UsersService(object):
"""Example class UsersService.
UsersService has dependency on DBAPI 2.0 database connection.
"""
def __init__(self, database):
"""Initializer.
:param database: Database connection.
:type database: sqlite3.dbapi2.Connection
"""
self.database = database
self.database.row_factory = sqlite3.dbapi2.Row
def init_database(self):
"""Initialize database, if it has not been initialized yet."""
with contextlib.closing(self.database.cursor()) as cursor:
cursor.execute("""
CREATE TABLE IF NOT EXISTS users(
id INTEGER PRIMARY KEY AUTOINCREMENT,
name VARCHAR(32)
)
""")
def create(self, name):
"""Create user with provided name and return his id."""
with contextlib.closing(self.database.cursor()) as cursor:
cursor.execute('INSERT INTO users(name) VALUES (?)', (name,))
return cursor.lastrowid
def get_by_id(self, id):
"""Return user info by user id."""
with contextlib.closing(self.database.cursor()) as cursor:
cursor.execute('SELECT id, name FROM users WHERE id=?', (id,))
return cursor.fetchone()
# Database and UsersService providers:
database = providers.Dependency(instance_of=sqlite3.dbapi2.Connection)
users_service_factory = providers.Factory(UsersService,
database=database)
# Out of library's scope.
#
# Setting database provider:
database.provided_by(providers.Singleton(sqlite3.dbapi2.Connection,
database=':memory:',
timeout=30,
detect_types=True,
isolation_level='EXCLUSIVE'))
# Creating UsersService instance:
users_service = users_service_factory()
# Initializing UsersService database:
users_service.init_database()
# Creating test user and retrieving full information about him:
test_user_id = users_service.create(name='test_user')
test_user = users_service.get_by_id(test_user_id)
# Making some asserts:
assert test_user['id'] == 1
assert test_user['name'] == 'test_user'