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Python decorator for async properties.
To install async_property, run this command in your terminal:
.. code-block:: console
$ pip install async-property
Or if you have pipenv:
.. code-block:: console
$ pipenv install async-property
Or alternatively with conda:
.. code-block:: console
$ conda install -c ryananguiano async-property
You can use @async_property
just as you would with @property
, but on an async function.
.. code-block:: python
class Foo:
@async_property
async def remote_value(self):
return await get_remote_value()
The property remote_value
now returns an awaitable coroutine.
.. code-block:: python
instance = Foo()
await instance.remote_value
Cached Properties
``@async_cached_property`` will call the function only once. Subsequent awaits to the property will return a cached value.
.. code-block:: python
class Foo:
@async_cached_property
async def value(self):
print('loading value')
return 123
>>> instance = Foo()
>>> instance.value
<AwaitableOnly "Foo.value">
>>> await instance.value
loading value
123
>>> await instance.value
123
>>> instance.value
123
>>> instance.value = 'abc'
>>> instance.value
'abc'
>>> await instance.value
'abc'
>>> del instance.value
>>> await instance.value
loading value
123
AwaitLoader
If you have an object with multiple cached properties, you can subclass AwaitLoader
. This will make your class instances awaitable and will load all @async_cached_property
fields concurrently. AwaitLoader
will call await instance.load()
, if it exists, before loading properties.
.. code-block:: python
class Foo(AwaitLoader):
async def load(self):
print('load called')
@async_cached_property
async def db_lookup(self):
return 'success'
@async_cached_property
async def api_call(self):
print('calling api')
return 'works every time'
>>> instance = await Foo()
load called
calling api
>>> instance.db_lookup
'success'
>>> instance.api_call
'works every time'
This package was created with Cookiecutter and the audreyr/cookiecutter-pypackage
project template.
.. Cookiecutter: https://github.com/audreyr/cookiecutter
.. audreyr/cookiecutter-pypackage
: https://github.com/audreyr/cookiecutter-pypackage
The ObjectProxy class was taken from wrapt library by Graham Dumpleton.
.. _ObjectProxy: https://github.com/GrahamDumpleton/wrapt/blob/master/src/wrapt/wrappers.py .. _wrapt: https://github.com/GrahamDumpleton/wrapt