mirror of
https://github.com/ets-labs/python-dependency-injector.git
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116 lines
3.2 KiB
Python
116 lines
3.2 KiB
Python
"""Dependency injector callable providers."""
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import six
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from dependency_injector.providers.base import Provider
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from dependency_injector.injections import Arg, KwArg
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from dependency_injector.utils import represent_provider
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from dependency_injector.errors import Error
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@six.python_2_unicode_compatible
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class Callable(Provider):
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r""":py:class:`Callable` provider calls wrapped callable on every call.
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:py:class:`Callable` provider provides callable that is called on every
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provider call with some predefined dependency injections.
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:py:class:`Callable` supports positional and keyword argument injections:
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.. code-block:: python
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some_function = Callable(some_function) \
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.args('arg1', 'arg2') \
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.kwargs(arg3=3, arg4=4)
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"""
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__slots__ = ('_provides', '_args', '_kwargs')
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def __init__(self, provides):
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"""Initializer.
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:param provides: Wrapped callable.
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:type provides: callable
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"""
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if not callable(provides):
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raise Error('Provider {0} expected to get callable, '
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'got {0}'.format('.'.join((self.__class__.__module__,
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self.__class__.__name__)),
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provides))
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self._provides = provides
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self._args = tuple()
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self._kwargs = tuple()
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super(Callable, self).__init__()
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@property
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def injections(self):
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"""Read-only tuple of all injections.
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:rtype: tuple[:py:class:`dependency_injector.injections.Injection`]
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"""
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return self._args + self._kwargs
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def args(self, *args):
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"""Add postional argument injections.
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:param args: Tuple of injections.
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:type args: tuple
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:return: Reference ``self``
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"""
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self._args += tuple(Arg(value) for value in args)
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return self
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def kwargs(self, **kwargs):
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"""Add keyword argument injections.
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:param kwargs: Dictionary of injections.
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:type kwargs: dict
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:return: Reference ``self``
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"""
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self._kwargs += tuple(KwArg(name, value)
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for name, value in six.iteritems(kwargs))
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return self
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def _provide(self, *args, **kwargs):
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"""Return provided instance.
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:param args: Tuple of context positional arguments.
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:type args: tuple[object]
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:param kwargs: Dictionary of context keyword arguments.
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:type kwargs: dict[str, object]
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:rtype: object
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"""
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if self._args:
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args = tuple(arg.value for arg in self._args) + args
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for kwarg in self._kwargs:
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if kwarg.name not in kwargs:
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kwargs[kwarg.name] = kwarg.value
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return self._provides(*args, **kwargs)
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def __str__(self):
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"""Return string representation of provider.
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:rtype: str
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"""
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return represent_provider(provider=self, provides=self._provides)
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__repr__ = __str__
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class DelegatedCallable(Callable):
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""":py:class:`DelegatedCallable` is a delegated :py:class:`Callable`.
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:py:class:`DelegatedCallable` is a :py:class:`Callable`, that is injected
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"as is".
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"""
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__IS_DELEGATED__ = True
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