54 lines
1.8 KiB
ReStructuredText
54 lines
1.8 KiB
ReStructuredText
Overriding of providers
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-----------------------
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.. module:: dependency_injector.providers
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Every provider could be overridden by another provider.
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This gives opportunity to make system behaviour more flexible in some points.
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The main feature is that while your code is using providers, it depends on
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providers, but not on the objects that providers provide. As a result of this,
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you can change providing by provider object to a different one, but still
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compatible one, without chaning your previously written code.
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Provider overriding functionality has such interface:
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.. image:: /images/providers/provider_override.png
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:width: 45%
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:align: center
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+ :py:meth:`Provider.override()` - takes another provider that will be used
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instead of current provider. This method could be called several times.
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In such case, last passed provider would be used as overriding one.
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+ :py:meth:`Provider.reset_override()` - resets all overriding providers.
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Provider starts to behave itself like usual.
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+ :py:attr:`Provider.is_overridden` - bool, ``True`` if provider is overridden.
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.. note::
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Actually, initial provider forms stack from overriding providers. There is
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some, not so common, but still usefull, functionality that could be used:
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+ :py:attr:`Provider.last_overriding` - always keeps reference to last
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overriding provider.
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+ :py:meth:`Provider.reset_last_overriding()` - remove last overriding
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provider from stack of overriding providers.
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Example:
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.. image:: /images/providers/overriding_simple.png
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:width: 80%
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:align: center
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.. literalinclude:: ../../examples/providers/overriding_simple.py
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:language: python
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Example:
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.. image:: /images/providers/overriding_users_model.png
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:width: 100%
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:align: center
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.. literalinclude:: ../../examples/providers/overriding_users_model.py
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:language: python
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