mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-11-22 09:36:48 +03:00
360 lines
8.5 KiB
Markdown
360 lines
8.5 KiB
Markdown
Objects
|
|
=======
|
|
|
|
Python catalogs of objects providers.
|
|
|
|
|
|
Example of objects catalog definition and usage:
|
|
|
|
```python
|
|
"""
|
|
Concept example of objects catalogs.
|
|
"""
|
|
|
|
from objects import AbstractCatalog
|
|
from objects.providers import Singleton, NewInstance
|
|
from objects.injections import InitArg, Attribute
|
|
|
|
import sqlite3
|
|
|
|
|
|
# Some example classes.
|
|
class ObjectA(object):
|
|
def __init__(self, db):
|
|
self.db = db
|
|
|
|
|
|
class ObjectB(object):
|
|
def __init__(self, a, db):
|
|
self.a = a
|
|
self.db = db
|
|
|
|
|
|
# Catalog of objects providers.
|
|
class Catalog(AbstractCatalog):
|
|
"""
|
|
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 """
|
|
|
|
object_b = NewInstance(ObjectB,
|
|
InitArg('a', object_a),
|
|
InitArg('db', database))
|
|
""" :type: (objects.Provider) -> ObjectB """
|
|
|
|
|
|
# Catalog static provides.
|
|
a1, a2 = Catalog.object_a(), Catalog.object_a()
|
|
b1, b2 = Catalog.object_b(), Catalog.object_b()
|
|
|
|
# Some asserts.
|
|
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()
|
|
|
|
|
|
# Dependencies injection (The Python Way) into class.
|
|
class Consumer(object):
|
|
|
|
dependencies = Catalog(Catalog.object_a,
|
|
Catalog.object_b)
|
|
|
|
def test(self):
|
|
a1 = self.dependencies.object_a()
|
|
a2 = self.dependencies.object_a()
|
|
|
|
b1 = self.dependencies.object_b()
|
|
b2 = self.dependencies.object_b()
|
|
|
|
# Some asserts.
|
|
assert a1 is not a2
|
|
assert b1 is not b2
|
|
assert a1.db is a2.db is b1.db is b2.db
|
|
|
|
try:
|
|
self.dependencies.database()
|
|
except AttributeError:
|
|
pass
|
|
else:
|
|
raise Exception('Database is not listed as a dependency')
|
|
|
|
Consumer().test()
|
|
|
|
|
|
# Dependencies injection (The Python Way) into a callback.
|
|
def consumer_callback(dependencies=Catalog(Catalog.object_a,
|
|
Catalog.object_b)):
|
|
a1 = dependencies.object_a()
|
|
a2 = dependencies.object_a()
|
|
|
|
b1 = dependencies.object_b()
|
|
b2 = dependencies.object_b()
|
|
|
|
# Some asserts.
|
|
assert a1 is not a2
|
|
assert b1 is not b2
|
|
assert a1.db is a2.db is b1.db is b2.db
|
|
|
|
try:
|
|
dependencies.database()
|
|
except AttributeError:
|
|
pass
|
|
else:
|
|
raise Exception('Database is not listed as a dependency')
|
|
```
|
|
|
|
Example of overriding object providers:
|
|
|
|
```python
|
|
"""
|
|
Concept example of objects overrides.
|
|
"""
|
|
|
|
|
|
from objects import AbstractCatalog, overrides
|
|
from objects.providers import Singleton, NewInstance
|
|
from objects.injections import InitArg, Attribute
|
|
|
|
import sqlite3
|
|
|
|
|
|
# Some example class.
|
|
class ObjectA(object):
|
|
def __init__(self, db):
|
|
self.db = db
|
|
|
|
|
|
class ObjectAMock(ObjectA):
|
|
pass
|
|
|
|
|
|
# Catalog of objects providers.
|
|
class Catalog(AbstractCatalog):
|
|
"""
|
|
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 """
|
|
|
|
|
|
# Overriding Catalog by SandboxCatalog with some mocks.
|
|
@overrides(Catalog)
|
|
class SandboxCatalog(Catalog):
|
|
"""
|
|
Sandbox objects catalog with some mocks.
|
|
"""
|
|
|
|
object_a = NewInstance(ObjectAMock,
|
|
InitArg('db', Catalog.database))
|
|
""" :type: (objects.Provider) -> ObjectA """
|
|
|
|
|
|
# Catalog static provides.
|
|
a1 = Catalog.object_a()
|
|
a2 = Catalog.object_a()
|
|
|
|
# Some asserts.
|
|
assert isinstance(a1, ObjectAMock)
|
|
assert isinstance(a2, ObjectAMock)
|
|
assert a1 is not a2
|
|
assert a1.db is a2.db is Catalog.database()
|
|
```
|
|
|
|
Example of objects catalog external dependency:
|
|
|
|
```python
|
|
"""
|
|
Concept example of objects catalogs.
|
|
"""
|
|
|
|
from objects import AbstractCatalog
|
|
from objects.providers import Singleton, NewInstance, ExternalDependency
|
|
from objects.injections import InitArg, Attribute
|
|
|
|
import sqlite3
|
|
|
|
|
|
# Some example classes.
|
|
class ObjectA(object):
|
|
def __init__(self, db):
|
|
self.db = db
|
|
|
|
|
|
class ObjectB(object):
|
|
def __init__(self, a, db):
|
|
self.a = a
|
|
self.db = db
|
|
|
|
|
|
# Catalog of objects providers.
|
|
class Catalog(AbstractCatalog):
|
|
"""
|
|
Objects catalog.
|
|
"""
|
|
|
|
database = ExternalDependency(instance_of=sqlite3.Connection)
|
|
""" :type: (objects.Provider) -> sqlite3.Connection """
|
|
|
|
object_a = NewInstance(ObjectA,
|
|
InitArg('db', database))
|
|
""" :type: (objects.Provider) -> ObjectA """
|
|
|
|
object_b = NewInstance(ObjectB,
|
|
InitArg('a', object_a),
|
|
InitArg('db', database))
|
|
""" :type: (objects.Provider) -> ObjectB """
|
|
|
|
|
|
# Satisfaction of external dependency.
|
|
Catalog.database.satisfy(Singleton(sqlite3.Connection,
|
|
InitArg('database', ':memory:'),
|
|
Attribute('row_factory', sqlite3.Row)))
|
|
|
|
# Catalog static provides.
|
|
a1, a2 = Catalog.object_a(), Catalog.object_a()
|
|
b1, b2 = Catalog.object_b(), Catalog.object_b()
|
|
|
|
# Some asserts.
|
|
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 objects catalog with scoped provider:
|
|
|
|
```python
|
|
"""
|
|
Scoped provider examples.
|
|
"""
|
|
|
|
from objects import AbstractCatalog
|
|
from objects.providers import Singleton, Scoped
|
|
from objects.injections import InitArg, Attribute
|
|
|
|
import sqlite3
|
|
|
|
|
|
class ObjectA(object):
|
|
def __init__(self, db):
|
|
self.db = db
|
|
|
|
|
|
# Catalog of objects providers.
|
|
class Catalog(AbstractCatalog):
|
|
"""
|
|
Objects catalog.
|
|
"""
|
|
|
|
database = Singleton(sqlite3.Connection,
|
|
InitArg('database', ':memory:'),
|
|
Attribute('row_factory', sqlite3.Row))
|
|
""" :type: (objects.Provider) -> sqlite3.Connection """
|
|
|
|
object_a = Scoped(ObjectA,
|
|
InitArg('db', database))
|
|
""" :type: (objects.Provider) -> ObjectA """
|
|
|
|
|
|
# Making scope using `with` statement.
|
|
with Catalog.object_a as object_a_provider:
|
|
object_a1 = object_a_provider()
|
|
object_a2 = object_a_provider()
|
|
|
|
assert object_a1 is object_a2
|
|
assert object_a1.db is object_a2.db
|
|
|
|
# Making another one scope using `with` statement.
|
|
with Catalog.object_a as object_a_provider:
|
|
object_a3 = object_a_provider()
|
|
object_a4 = object_a_provider()
|
|
|
|
assert object_a3 is object_a4
|
|
assert object_a3.db is object_a4.db
|
|
|
|
assert (object_a1 is not object_a3) and \
|
|
(object_a1 is not object_a4)
|
|
assert (object_a2 is not object_a3) and \
|
|
(object_a2 is not object_a4)
|
|
|
|
|
|
# Making one more scope using provider methods.
|
|
Catalog.object_a.in_scope()
|
|
|
|
object_a5 = Catalog.object_a()
|
|
object_a6 = Catalog.object_a()
|
|
|
|
assert object_a5 is object_a6
|
|
assert object_a5.db is object_a6.db
|
|
|
|
assert (object_a1 is not object_a3) and \
|
|
(object_a1 is not object_a4) and \
|
|
(object_a1 is not object_a5) and \
|
|
(object_a1 is not object_a6)
|
|
assert (object_a2 is not object_a3) and \
|
|
(object_a2 is not object_a4) and \
|
|
(object_a2 is not object_a5) and \
|
|
(object_a2 is not object_a6)
|
|
```
|
|
|
|
Example of objects catalog with callable provider:
|
|
|
|
```python
|
|
"""
|
|
Callable provider examples.
|
|
"""
|
|
|
|
from objects import AbstractCatalog
|
|
from objects.providers import Singleton, Callable
|
|
from objects.injections import Injection, InitArg, Attribute
|
|
|
|
import sqlite3
|
|
|
|
|
|
# Some example function.
|
|
def consuming_function(arg, db):
|
|
return arg, db
|
|
|
|
|
|
# Catalog of objects providers.
|
|
class Catalog(AbstractCatalog):
|
|
"""
|
|
Objects catalog.
|
|
"""
|
|
|
|
database = Singleton(sqlite3.Connection,
|
|
InitArg('database', ':memory:'),
|
|
Attribute('row_factory', sqlite3.Row))
|
|
""" :type: (objects.Provider) -> sqlite3.Connection """
|
|
|
|
consuming_function = Callable(consuming_function,
|
|
Injection('db', database))
|
|
""" :type: (objects.Provider) -> consuming_function """
|
|
|
|
|
|
# Some calls.
|
|
arg1, db1 = Catalog.consuming_function(1)
|
|
arg2, db2 = Catalog.consuming_function(2)
|
|
arg3, db3 = Catalog.consuming_function(3)
|
|
|
|
# Some asserts.
|
|
assert db1 is db2 is db3
|
|
assert arg1 == 1
|
|
assert arg2 == 2
|
|
assert arg3 == 3
|
|
```
|