.. Injector documentation master file, created by sphinx-quickstart on Mon Sep 16 02:58:17 2013. You can adapt this file completely to your liking, but it should at least contain the root `toctree` directive. Welcome to Injector's documentation! ==================================== .. image:: https://travis-ci.org/alecthomas/injector.png?branch=master :alt: Build status :target: https://travis-ci.org/alecthomas/injector .. image:: https://coveralls.io/repos/github/alecthomas/injector/badge.svg?branch=master :alt: Covergage status :target: https://coveralls.io/github/alecthomas/injector?branch=master GitHub (code repository, issues): https://github.com/alecthomas/injector PyPI (installable, stable distributions): https://pypi.org/project/injector. You can install Injector using pip:: pip install injector Injector works with CPython 3.5+ and PyPy 3 implementing Python 3.5+. Introduction ------------ While dependency injection is easy to do in Python due to its support for keyword arguments, the ease with which objects can be mocked and its dynamic natura, a framework for assisting in this process can remove a lot of boiler-plate from larger applications. That's where Injector can help. It automatically and transitively provides dependencies for you. As an added benefit, Injector encourages nicely compartmentalised code through the use of :ref:`modules `. If you're not sure what dependency injection is or you'd like to learn more about it see: * `The Clean Code Talks - Don't Look For Things! (a talk by Miško Hevery) `_ * `Inversion of Control Containers and the Dependency Injection pattern (an article by Martin Fowler) `_ The core values of Injector are: * Simplicity - while being inspired by Guice, Injector does not slavishly replicate its API. Providing a Pythonic API trumps faithfulness. Additionally some features are ommitted because supporting them would be cumbersome and introduce a little bit too much "magic" (member injection, method injection). Connected to this, Injector tries to be as nonintrusive as possible. For example while you may declare a class' constructor to expect some injectable parameters, the class' constructor remains a standard constructor – you may instaniate the class just the same manually, if you want. * No global state – you can have as many :class:`Injector` instances as you like, each with a different configuration and each with different objects in different scopes. Code like this won't work for this very reason:: class MyClass: @inject def __init__(t: SomeType): # ... MyClass() This is simply because there's no global :class:`Injector` to use. You need to be explicit and use :meth:`Injector.get `, :meth:`Injector.create_object ` or inject `MyClass` into the place that needs it. * Cooperation with static type checking infrastructure – the API provides as much static type safety as possible and only breaks it where there's no other option. For example the :meth:`Injector.get ` method is typed such that `injector.get(SomeType)` is statically declared to return an instance of `SomeType`, therefore making it possible for tools such as `mypy `_ to type-check correctly the code using it. Quick start ----------- See `the project's README `_ for an example of Injector use. Contents -------- .. toctree:: :maxdepth: 1 changelog terminology testing scopes logging api faq practices