aiofiles: file support for asyncio

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:alt: Supported Python versions

aiofiles is an Apache2 licensed library, written in Python, for handling local
disk files in asyncio applications.

Ordinary local file IO is blocking, and cannot easily and portably made
asynchronous. This means doing file IO may interfere with asyncio applications,
which shouldn't block the executing thread. aiofiles helps with this by
introducing asynchronous versions of files that support delegating operations to
a separate thread pool.

.. code-block:: python

async with aiofiles.open('filename', mode='r') as f:
    contents = await f.read()
print(contents)
'My file contents'

Asynchronous iteration is also supported.

.. code-block:: python

async with aiofiles.open('filename') as f:
    async for line in f:
        ...

Asynchronous interface to tempfile module.

.. code-block:: python

async with aiofiles.tempfile.TemporaryFile('wb') as f:
    await f.write(b'Hello, World!')

Features

• a file API very similar to Python's standard, blocking API


• support for buffered and unbuffered binary files, and buffered text files


• support for async/await (:PEP:492) constructs


• async interface to tempfile module

Installation

To install aiofiles, simply:

.. code-block:: bash

$ pip install aiofiles

Usage

Files are opened using the aiofiles.open() coroutine, which in addition to
mirroring the builtin open accepts optional loop and executor
arguments. If loop is absent, the default loop will be used, as per the
set asyncio policy. If executor is not specified, the default event loop
executor will be used.

In case of success, an asynchronous file object is returned with an
API identical to an ordinary file, except the following methods are coroutines
and delegate to an executor:

• close


• flush


• isatty


• read


• readall


• read1


• readinto


• readline


• readlines


• seek


• seekable


• tell


• truncate


• writable


• write


• writelines

In case of failure, one of the usual exceptions will be raised.

The aiofiles.os module contains executor-enabled coroutine versions of
several useful os functions that deal with files:

• stat


• sendfile


• rename


• replace


• remove


• mkdir


• rmdir


• path.exists


• path.isfile


• path.isdir


• path.getsize


• path.getatime


• path.getctime


• path.samefile


• path.sameopenfile

Tempfile
~~~~~~~~

aiofiles.tempfile implements the following interfaces:

• TemporaryFile


• NamedTemporaryFile


• SpooledTemporaryFile


• TemporaryDirectory

Results return wrapped with a context manager allowing use with async with and async for.

.. code-block:: python

async with aiofiles.tempfile.NamedTemporaryFile('wb+') as f:
    await f.write(b'Line1\n Line2')
    await f.seek(0)
    async for line in f:
        print(line)

async with aiofiles.tempfile.TemporaryDirectory() as d:
 filename = os.path.join(d, "file.ext")

Writing tests for aiofiles
~~~~~~~~~~~~~~~~~~~~~~~~~~

Real file IO can be mocked by patching aiofiles.threadpool.sync_open
as desired. The return type also needs to be registered with the
aiofiles.threadpool.wrap dispatcher:

.. code-block:: python

aiofiles.threadpool.wrap.register(mock.MagicMock)(
    lambda *args, **kwargs: threadpool.AsyncBufferedIOBase(*args, **kwargs))

async def test_stuff():
 data = 'data'
 mock_file = mock.MagicMock()
 with mock.patch('aiofiles.threadpool.sync_open', return_value=mock_file) as mock_open:
 async with aiofiles.open('filename', 'w') as f:
 await f.write(data)
 mock_file.write.assert_called_once_with(data)

History
~~~~~~~
0.8.0 (UNRELEASED)
````````````````
* aiofiles is now tested on Python 3.10.
* Addedaiofiles.os.replace.
`#107 <https://github.com/Tinche/aiofiles/pull/107>`_
* Addedaiofiles.os.path.{exists, isfile, isdir, getsize, getatime, getctime, samefile, sameopenfile}`.#63 https://github.com/Tinche/aiofiles/pull/63`_

0.7.0 (2021-05-17)
````````````````
- Added theaiofiles.tempfile` module for async temporary files.#56 https://github.com/Tinche/aiofiles/pull/56`_
- Switched to Poetry and GitHub actions.
- Dropped 3.5 support.

0.6.0 (2020-10-27)
`````````````````
-aiofilesis now tested on ppc64le.
- Addednameandmodeproperties to async file objects.#82 https://github.com/Tinche/aiofiles/pull/82_
- Fixed a DeprecationWarning internally.#75 https://github.com/Tinche/aiofiles/pull/75`_
- Python 3.9 support and tests.

0.5.0 (2020-04-12)
````````````````
- Python 3.8 support. Code base modernization (usingasync/awaitinstead ofasyncio.coroutine/yield from).
- Addedaiofiles.os.remove,aiofiles.os.rename,aiofiles.os.mkdir,aiofiles.os.rmdir`.#62 https://github.com/Tinche/aiofiles/pull/62`_

0.4.0 (2018-08-11)
``````````````````
- Python 3.7 support.
- Removed Python 3.3/3.4 support. If you use these versions, stick to aiofiles 0.3.x.

0.3.2 (2017-09-23)
`````````````````
- The LICENSE is now included in the sdist.#31 https://github.com/Tinche/aiofiles/pull/31`_

0.3.1 (2017-03-10)
``````````````````

• Introduced a changelog.


• aiofiles.os.sendfile will now work if the standard os module contains a sendfile function.

Contributing
~~~~~~~~~~~~
Contributions are very welcome. Tests can be run with tox, please ensure
the coverage at least stays the same before you submit a pull request.