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72 lines
2.4 KiB
ReStructuredText
72 lines
2.4 KiB
ReStructuredText
Callable providers
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------------------
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.. currentmodule:: dependency_injector.providers
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:py:class:`Callable` provider calls wrapped callable on every call.
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Callable providers and injections
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:py:class:`Callable` provider takes a various number of positional and keyword
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arguments that are used as wrapped callable injections. Every time, when
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:py:class:`Callable` provider is called, positional and keyword argument
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injections would be passed as an callable arguments.
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Injections are done according to the next rules:
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+ All providers (instances of :py:class:`Provider`) are called every time
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when injection needs to be done.
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+ Providers could be injected "as is" (delegated), if it is defined obviously.
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Check out :ref:`callable_providers_delegation`.
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+ All other injectable values are provided *"as is"*.
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+ Positional context arguments will be appended after :py:class:`Callable`
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positional injections.
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+ Keyword context arguments have priority on :py:class:`Callable` keyword
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injections and will be merged over them.
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Example that shows usage of :py:class:`Callable` with positional argument
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injections:
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.. literalinclude:: ../../examples/providers/callable_args.py
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:language: python
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:linenos:
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Next one example shows usage of :py:class:`Callable` with keyword argument
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injections:
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.. image:: /images/providers/callable.png
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:width: 100%
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:align: center
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.. literalinclude:: ../../examples/providers/callable_kwargs.py
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:language: python
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:linenos:
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.. _callable_providers_delegation:
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Callable providers delegation
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:py:class:`Callable` provider could be delegated to any other provider via
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any kind of injection.
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Delegation of :py:class:`Callable` providers is the same as
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:py:class:`Factory` providers delegation, please follow
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:ref:`factory_providers_delegation` section for examples (with exception
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of using :py:class:`DelegatedCallable` instead of
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:py:class:`DelegatedFactory`).
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Abstract callable providers
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~~~~~~~~~~~~~~~~~~~~~~~~~~~
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:py:class:`AbstractCallable` provider is a :py:class:`Callable` provider that
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must be explicitly overridden before calling.
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Behaviour of :py:class:`AbstractCallable` providers is the same as of
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:py:class:`AbstractFactory`, please follow :ref:`abstract_factory_providers`
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section for examples (with exception of using :py:class:`AbstractCallable`
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provider instead of :py:class:`AbstractFactory`).
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.. disqus::
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