mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2025-11-04 01:47:36 +03:00
34 lines
1.4 KiB
ReStructuredText
34 lines
1.4 KiB
ReStructuredText
.. _selector-provider:
|
|
|
|
Selector provider
|
|
=================
|
|
|
|
.. meta::
|
|
:keywords: Python,DI,Dependency injection,IoC,Inversion of Control,Configuration,Injection,
|
|
Selector,Polymorphism,Environment Variable,Flexibility
|
|
:description: Selector selects provider based on a configuration value or another callable.
|
|
This page demonstrates how to implement the polymorphism and increase the
|
|
flexibility of your application using the Selector provider.
|
|
|
|
.. currentmodule:: dependency_injector.providers
|
|
|
|
:py:class:`Selector` provider selects provider based on a configuration value or another callable.
|
|
|
|
.. literalinclude:: ../../examples/providers/selector.py
|
|
:language: python
|
|
:lines: 3-
|
|
:emphasize-lines: 16-20
|
|
|
|
The first argument of the ``Selector`` provider is called ``selector``. It can be an option of
|
|
a ``Configuration`` provider or any other callable. The ``selector`` callable has to return a
|
|
string value. This value is used as a key for selecting the provider.
|
|
|
|
The providers are provided as keyword arguments. Argument name is used as a key for selecting the
|
|
provider.
|
|
|
|
When a ``Selector`` provider is called, it gets a ``selector`` value and delegates the work to
|
|
the provider with a matching name. The ``selector`` callable works as a switch: when the returned
|
|
value is changed the ``Selector`` provider will delegate the work to another provider.
|
|
|
|
.. disqus::
|