46 lines
1.9 KiB
ReStructuredText
46 lines
1.9 KiB
ReStructuredText
.. _create-provider:
|
|
|
|
Creating a custom provider
|
|
==========================
|
|
|
|
.. meta::
|
|
:keywords: Python,DI,Dependency injection,IoC,Inversion of Control,Custom provider, Create
|
|
:description: This page demonstrates how to create a custom provider.
|
|
|
|
.. currentmodule:: dependency_injector.providers
|
|
|
|
You can create a custom provider.
|
|
|
|
To create a custom provider you need to follow these rules:
|
|
|
|
1. New provider class should inherit :py:class:`Provider`.
|
|
2. You need to implement the ``Provider._provide()`` method.
|
|
3. You need to implement the ``Provider.__deepcopy__()`` method. It should return an
|
|
equivalent copy of a provider. All providers must be copied with a ``deepcopy()`` function
|
|
from the ``providers`` module. After the a new provider object is created use
|
|
``Provider._copy_overriding()`` method to copy all overriding providers. See the example
|
|
below.
|
|
4. If the new provider has a ``__init__()`` method, it should call the parent
|
|
``Provider.__init__()``.
|
|
|
|
.. literalinclude:: ../../examples/providers/custom_factory.py
|
|
:language: python
|
|
:lines: 3-
|
|
|
|
.. note::
|
|
1. Prefer delegation over inheritance. If you choose between inheriting a ``Factory`` or
|
|
inheriting a ``Provider`` and use ``Factory`` internally - the last is better.
|
|
2. When create a new provider follow the ``Factory``-like injections style. Consistency matters.
|
|
3. Use the ``__slots__`` attribute to make sure nothing could be attached to your provider. You
|
|
will also save some memory.
|
|
|
|
.. note::
|
|
If you don't find needed provider in the ``providers`` module and experience troubles creating
|
|
one by your own - open a
|
|
`Github Issue <https://github.com/ets-labs/python-dependency-injector/issues>`_.
|
|
|
|
I'll help you to resolve the issue if that's possible. If the new provider can be useful for
|
|
others I'll include it into the ``providers`` module.
|
|
|
|
.. disqus::
|