mirror of
https://github.com/ets-labs/python-dependency-injector.git
synced 2024-12-01 22:14:04 +03:00
81 lines
2.8 KiB
ReStructuredText
81 lines
2.8 KiB
ReStructuredText
Callable providers
|
|
------------------
|
|
|
|
.. currentmodule:: dependency_injector.providers
|
|
|
|
:py:class:`Callable` provider is a provider that wraps particular callable with
|
|
some injections. Every call of this provider returns result of call of initial
|
|
callable.
|
|
|
|
Callable providers and injections
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
:py:class:`Callable` takes a various number of positional and keyword
|
|
arguments that are used as decorated callable injections. Every time, when
|
|
:py:class:`Callable` is called, positional and keyword argument injections
|
|
would be passed as an callable arguments.
|
|
|
|
Such behaviour is very similar to the standard Python ``functools.partial``
|
|
object with several more things:
|
|
|
|
+ All providers (instances of :py:class:`Provider`) are called every time
|
|
when injection needs to be done.
|
|
+ Providers could be injected "as is" (delegated), if it is defined obviously.
|
|
Check out `Callable providers delegation`_.
|
|
+ All other injectable values are provided *"as is"*
|
|
|
|
For example, if injectable value of injection is a :py:class:`Factory`, it
|
|
will provide new one instance (as a result of its call) every time, when
|
|
injection needs to be done.
|
|
|
|
:py:class:`Callable` behaviour with context positional and keyword arguments
|
|
is very like a standard Python ``functools.partial``:
|
|
|
|
- Positional context arguments will be appended after :py:class:`Callable`
|
|
positional injections.
|
|
- Keyword context arguments have priority on :py:class:`Callable` keyword
|
|
injections and will be merged over them.
|
|
|
|
Example that shows usage of :py:class:`Callable` with positional argument
|
|
injections:
|
|
|
|
.. literalinclude:: ../../examples/providers/callable_args.py
|
|
:language: python
|
|
|
|
Next one example shows usage of :py:class:`Callable` with keyword argument
|
|
injections:
|
|
|
|
.. image:: /images/providers/callable.png
|
|
:width: 100%
|
|
:align: center
|
|
|
|
.. literalinclude:: ../../examples/providers/callable_kwargs.py
|
|
:language: python
|
|
|
|
.. _callable_delegation:
|
|
|
|
Callable providers delegation
|
|
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
|
|
|
|
:py:class:`Callable` provider could be delegated to any other provider via any
|
|
kind of injection. Delegation of :py:class:`Callable` providers is the same as
|
|
:py:class:`Factory` and :py:class:`Singleton` providers delegation, please
|
|
follow *Factory providers delegation* section for example.
|
|
|
|
:py:class:`Callable` delegate could be created obviously using
|
|
``Delegate(Callable(...))`` or by calling ``Callable(...).delegate()`` method.
|
|
|
|
Example:
|
|
|
|
.. literalinclude:: ../../examples/providers/callable_delegation.py
|
|
:language: python
|
|
|
|
Alternative way of doing :py:class:`Callable` delegation is an usage of
|
|
:py:class:`DelegatedCallable`. :py:class:`DelegatedCallable` is a
|
|
:py:class:`Callable` that is always injected "as is".
|
|
|
|
Example:
|
|
|
|
.. literalinclude:: ../../examples/providers/delegated_callable.py
|
|
:language: python
|