44 lines
1.6 KiB
ReStructuredText
44 lines
1.6 KiB
ReStructuredText
.. _provider-overriding:
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Provider overriding
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===================
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.. meta::
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:keywords: Python,DI,Dependency injection,IoC,Inversion of Control,Override,Test,Unit
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:description: This page demonstrates how to implement providers overriding. This helps in
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testing and configuring the system for the multiple environments.
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.. currentmodule:: dependency_injector.providers
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You can override any provider with another provider.
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When provider is overridden it calls to the overriding provider instead of providing
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the object by its own.
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This helps in testing. This also helps in overriding API clients with stubs for the development
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or staging environment.
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To override a provider you need to call the ``Provider.override()`` method. This method receives
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a single argument called ``overriding``. If the ``overriding`` value is a provider, this provider
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is called instead of the original. If value is not a provider, this value is returned instead of
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calling the original provider.
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.. image:: images/overriding.png
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:width: 80%
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:align: center
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.. literalinclude:: ../../examples/providers/overriding.py
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:language: python
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:lines: 3-
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You can override a provider multiple times. In that case the latest ``overriding`` value will be
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used. The rest of the overriding values will form a stack.
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To reset an overriding you can use the ``Provider.reset_override()`` or
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``Provider.reset_last_overriding()`` methods.
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You can use a context manager for overriding a provider ``with Provider.override():``. The
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overriding will be reset when context closed.
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.. disqus::
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