mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-11-22 09:36:48 +03:00
155 lines
3.7 KiB
Python
155 lines
3.7 KiB
Python
"""
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Standard providers.
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"""
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from .injections import InitArg, Attribute, Method
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class Provider(object):
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"""
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Base provider class.
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"""
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__is_objects_provider__ = True
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__overridden_by__ = list()
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def __init__(self):
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"""
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Initializer.
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"""
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self.__overridden_by__ = list()
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def __call__(self, *args, **kwargs):
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"""
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Returns provided instance.
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"""
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raise NotImplementedError()
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def __override__(self, provider):
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"""
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Overrides provider with another provider.
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"""
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self.__overridden_by__.append(provider)
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def prepare_injections(injections):
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"""
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Prepares injections list to injection.
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"""
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return [(injection.name, injection.value) for injection in injections]
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def fetch_injections(injections, injection_type):
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"""
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Fetches injections of injection type from list.
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"""
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return tuple([injection
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for injection in injections
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if isinstance(injection, injection_type)])
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class NewInstance(Provider):
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"""
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New instance providers will create and return new instance on every call.
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"""
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def __init__(self, provides, *injections):
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"""
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Initializer.
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"""
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self.provides = provides
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self.init_injections = fetch_injections(injections, InitArg)
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self.attribute_injections = fetch_injections(injections, Attribute)
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self.method_injections = fetch_injections(injections, Method)
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super(NewInstance, self).__init__()
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def __call__(self, *args, **kwargs):
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"""
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Returns provided instance.
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"""
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if self.__overridden_by__:
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return self.__overridden_by__[-1].__call__(*args, **kwargs)
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init_injections = prepare_injections(self.init_injections)
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init_injections = dict(init_injections)
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init_injections.update(kwargs)
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provided = self.provides(*args, **init_injections)
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attribute_injections = prepare_injections(self.attribute_injections)
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for name, injectable in attribute_injections:
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setattr(provided, name, injectable)
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method_injections = prepare_injections(self.method_injections)
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for name, injectable in method_injections:
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getattr(provided, name)(injectable)
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return provided
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class Singleton(NewInstance):
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"""
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Singleton provider will create instance once and return it on every call.
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"""
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def __init__(self, *args, **kwargs):
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"""
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Initializer.
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"""
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self.instance = None
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super(Singleton, self).__init__(*args, **kwargs)
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def __call__(self, *args, **kwargs):
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"""
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Returns provided instance.
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"""
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if not self.instance:
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self.instance = super(Singleton, self).__call__(*args, **kwargs)
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return self.instance
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class _StaticProvider(Provider):
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"""
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Static provider is base implementation that provides exactly the same as
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it got on input.
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"""
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def __init__(self, provides):
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"""
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Initializer.
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"""
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self.provides = provides
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super(_StaticProvider, self).__init__()
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def __call__(self):
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"""
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Returns provided instance.
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"""
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if self.__overridden_by__:
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return self.__overridden_by__[-1].__call__()
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return self.provides
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class Class(_StaticProvider):
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"""
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Class provider provides class.
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"""
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class Object(_StaticProvider):
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"""
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Object provider provides object.
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"""
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class Function(_StaticProvider):
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"""
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Function provider provides function.
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"""
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class Value(_StaticProvider):
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"""
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Value provider provides value.
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"""
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