python-dependency-injector/dependency_injector/providers/callable.py
Roman Mogilatov c5518e0ec3 Update callable provider docs
+ Add providers class diagram
2016-06-09 01:43:25 +03:00

128 lines
3.5 KiB
Python

"""Dependency injector callable providers."""
import six
from dependency_injector.providers.base import (
Provider,
_parse_positional_injections,
_parse_keyword_injections,
)
from dependency_injector.utils import represent_provider
from dependency_injector.errors import Error
@six.python_2_unicode_compatible
class Callable(Provider):
r""":py:class:`Callable` provider calls wrapped callable on every call.
:py:class:`Callable` supports positional and keyword argument injections:
.. code-block:: python
some_function = Callable(some_function,
'positional_arg1', 'positional_arg2',
keyword_argument1=3, keyword_argument=4)
# or
some_function = Callable(some_function) \
.add_args('positional_arg1', 'positional_arg2') \
.add_kwargs(keyword_argument1=3, keyword_argument=4)
# or
some_function = Callable(some_function)
some_function.add_args('positional_arg1', 'positional_arg2')
some_function.add_kwargs(keyword_argument1=3, keyword_argument=4)
"""
__slots__ = ('provides', 'args', 'kwargs')
def __init__(self, provides, *args, **kwargs):
"""Initializer.
:param provides: Wrapped callable.
:type provides: callable
"""
if not callable(provides):
raise Error('Provider {0} expected to get callable, '
'got {0}'.format('.'.join((self.__class__.__module__,
self.__class__.__name__)),
provides))
self.provides = provides
self.args = tuple()
self.kwargs = dict()
self.add_args(*args)
self.add_kwargs(**kwargs)
super(Callable, self).__init__()
def add_args(self, *args):
"""Add postional argument injections.
:param args: Tuple of injections.
:type args: tuple
:return: Reference ``self``
"""
self.args += _parse_positional_injections(args)
return self
def add_kwargs(self, **kwargs):
"""Add keyword argument injections.
:param kwargs: Dictionary of injections.
:type kwargs: dict
:return: Reference ``self``
"""
self.kwargs.update(_parse_keyword_injections(kwargs))
return self
def _provide(self, *args, **kwargs):
"""Return provided instance.
:param args: Tuple of context positional arguments.
:type args: tuple[object]
:param kwargs: Dictionary of context keyword arguments.
:type kwargs: dict[str, object]
:rtype: object
"""
if self.args:
args = tuple(arg.provide_injection() for arg in self.args) + args
for name, arg in six.iteritems(self.kwargs):
if name not in kwargs:
kwargs[name] = arg.provide_injection()
return self.provides(*args, **kwargs)
def __str__(self):
"""Return string representation of provider.
:rtype: str
"""
return represent_provider(provider=self, provides=self.provides)
__repr__ = __str__
class DelegatedCallable(Callable):
""":py:class:`DelegatedCallable` is a delegated :py:class:`Callable`.
:py:class:`DelegatedCallable` is a :py:class:`Callable`, that is injected
"as is".
"""
def provide_injection(self):
"""Injection strategy implementation.
:rtype: object
"""
return self