mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-11-26 19:43:58 +03:00
117 lines
3.1 KiB
Python
117 lines
3.1 KiB
Python
"""Injections module."""
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import sys
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import six
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from .utils import is_provider
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from .utils import ensure_is_injection
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from .utils import get_injectable_kwargs
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from .errors import Error
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IS_PYPY = '__pypy__' in sys.builtin_module_names
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if IS_PYPY or six.PY3: # pragma: no cover
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OBJECT_INIT = six.get_unbound_function(object.__init__)
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else: # pragma: no cover
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OBJECT_INIT = None
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class Injection(object):
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"""Base injection class."""
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__IS_INJECTION__ = True
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__slots__ = ('injectable', 'is_provider')
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def __init__(self, injectable):
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"""Initializer."""
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self.injectable = injectable
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self.is_provider = is_provider(injectable)
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@property
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def value(self):
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"""Return injectable value."""
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if self.is_provider:
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return self.injectable()
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return self.injectable
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class NamedInjection(Injection):
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"""Base class of named injections."""
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__slots__ = ('name',)
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def __init__(self, name, injectable):
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"""Initializer."""
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self.name = name
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super(NamedInjection, self).__init__(injectable)
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class Arg(Injection):
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"""Positional argument injection."""
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__IS_ARG_INJECTION__ = True
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class KwArg(NamedInjection):
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"""Keyword argument injection."""
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__IS_KWARG_INJECTION__ = True
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class Attribute(NamedInjection):
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"""Attribute injection."""
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__IS_ATTRIBUTE_INJECTION__ = True
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class Method(NamedInjection):
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"""Method injection."""
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__IS_METHOD_INJECTION__ = True
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def inject(*args, **kwargs):
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"""Dependency injection decorator.
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:type injection: Injection
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:return: (callable) -> (callable)
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"""
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injections = tuple(KwArg(name, value)
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for name, value in six.iteritems(kwargs))
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if args:
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injections += tuple(ensure_is_injection(injection)
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for injection in args)
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def decorator(callback_or_cls):
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"""Dependency injection decorator."""
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if isinstance(callback_or_cls, six.class_types):
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cls = callback_or_cls
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try:
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cls_init = six.get_unbound_function(cls.__init__)
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assert cls_init is not OBJECT_INIT
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except (AttributeError, AssertionError):
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raise Error(
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'Class {0}.{1} has no __init__() '.format(cls.__module__,
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cls.__name__) +
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'method and could not be decorated with @inject decorator')
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cls.__init__ = decorator(cls_init)
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return cls
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callback = callback_or_cls
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if hasattr(callback, 'injections'):
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callback.injections += injections
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return callback
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@six.wraps(callback)
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def decorated(*args, **kwargs):
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"""Decorated with dependency injection callback."""
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return callback(*args,
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**get_injectable_kwargs(kwargs,
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decorated.injections))
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decorated.injections = injections
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return decorated
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return decorator
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