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56 lines
2.1 KiB
ReStructuredText
56 lines
2.1 KiB
ReStructuredText
Advanced usage
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==============
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Current section of documentation describes advanced usage of
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*Dependency Injector*.
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@inject decorator
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-----------------
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``@di.inject()`` decorator can be used for making *inline* dependency
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injections. It *patches* decorated callable in such way that dependency
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injection will be done during every call of decorated callable.
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``di.inject()`` takes a various number of positional and keyword arguments
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that are used as decorated callable injections. Every time, when
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``di.inject()`` is called, positional and keyword argument injections would be
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passed as an callable arguments.
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Such behaviour is very similar to the standard Python ``functools.partial``
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object, except of one thing: all injectable values are provided
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*"as is"*, except of providers (subclasses of ``di.Provider``). Providers
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will be called every time, when injection needs to be done. For example,
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if injectable value of injection is a ``di.Factory``, it will provide new one
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instance (as a result of its call) every time, when injection needs to be done.
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``di.inject()`` behaviour with context positional and keyword arguments is
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very like a standard Python ``functools.partial``:
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- Positional context arguments will be appended after ``di.inject()``
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positional injections.
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- Keyword context arguments have priority on ``di.inject()`` keyword
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injections and will be merged over them.
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Example:
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.. literalinclude:: ../../examples/advanced_usage/inject_simple.py
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:language: python
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Example of usage ``@di.inject()`` decorator with Flask:
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.. literalinclude:: ../../examples/advanced_usage/inject_flask.py
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:language: python
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@inject decorator with classes
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~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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``@di.inject()`` could be applied for classes. In such case, it will look for
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class ``__init__()`` method and pass injection to it. If decorated class has
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no ``__init__()`` method, appropriate ``di.Error`` will be raised.
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Example of usage ``@di.inject()`` with Flask class-based view:
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.. literalinclude:: ../../examples/advanced_usage/inject_flask_class_based.py
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:language: python
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