๐ Async pathlib for Python
aiopath is a complete implementation of Python's pathlib that's compatible with asyncio, trio, and the async/await syntax.
All I/O performed by aiopath is asynchronous and awaitable.
Check out ๐ app_paths for an example of an app that uses aiopath, as well as the pyclean script here.
Use case
If you're writing asynchronous Python code and want to take advantage of pathlib's conveniences, but don't want to mix blocking and non-blocking I/O, then you can reach for aiopath.
For example, if you're writing an async web scraping script, you might want to make several concurrent requests to websites and save the responses to persistent storage:
from asyncio import run, gather
from aiohttp import ClientSession
from aiopath import AsyncPath
async def save_page(url: str, name: str):
path = AsyncPath(name)
if await path.exists():
return
async with ClientSession() as session:
async with session.get(url) as response:
content: bytes = await response.read()
await path.write_bytes(content)
async def main():
urls = [
'https://example.com',
'https://github.com/alexdelorenzo/aiopath',
'https://alexdelorenzo.dev',
'https://dupebot.firstbyte.dev'
]
tasks = (
save_page(url, f'{index}.html')
for index, url in enumerate(urls)
)
await gather(*tasks)
run(main())If you used pathlib instead of aiopath, tasks accessing the disk would block the event loop, and async tasks accessing the network would suspend until the event loop was unblocked.
By using aiopath, the script can access the network and disk concurrently.
Implementation
aiopath is a direct reimplementation of CPython's pathlib.py and shares some of its code. aiopath's class hierarchy directly matches the one from pathlib, where Path inherits from PurePath, AsyncPath inherits from AsyncPurePath, and so on.
With aiopath, methods that perform I/O are asynchronous and awaitable, and methods that perform I/O and return iterators in pathlib now return async generators. aiopath goes one step further, and wraps os.scandir() and DirEntry to make AsyncPath.glob() completely async.
aiopath is typed with Python type annotations, and if using the aiofile back end, it takes advantage of libaio for async I/O on Linux.
Usage
aiopath's API directly matches pathlib, so check out the standard library documentation for PurePath and Path.
Running examples
To run the following examples with top-level await expressions, launch an asynchronous Python REPL using python3 -m asyncio or an IPython shell.
You'll also need to install asynctempfile via PyPI, like so python3 -m pip install asynctempfile.
Replacing pathlib
All of pathlib.Path's methods that perform synchronous I/O are reimplemented as asynchronous methods. PurePath methods are not asynchronous because they don't perform I/O.
from pathlib import Path
from asynctempfile import NamedTemporaryFile
from aiopath import AsyncPath
async with NamedTemporaryFile() as temp:
path = Path(temp.name)
apath = AsyncPath(temp.name)
# check existence
## sync
assert path.exists()
## async
assert await apath.exists()
# check if file
## sync
assert path.is_file()
## async
assert await apath.is_file()
# touch
path.touch()
await apath.touch()
# PurePath methods are not async
assert path.is_absolute() == apath.is_absolute()
assert path.as_uri() == apath.as_uri()
# read and write text
text: str = 'example'
await apath.write_text(text)
assert await apath.read_text() == text
assert not path.exists()
assert not await apath.exists()You can convert pathlib.Path objects to aiopath.AsyncPath objects, and vice versa:
from pathlib import Path
from aiopath import AsyncPath
home: Path = Path.home()
ahome: AsyncPath = AsyncPath(home)
path: Path = Path(ahome)
assert isinstance(home, Path)
assert isinstance(ahome, AsyncPath)
assert isinstance(path, Path)
# AsyncPath and Path objects can point to the same file
assert str(home) == str(ahome) == str(path)
# but AsyncPath and Path objects are not equivalent
assert not home == ahomeAsyncPath is a subclass of Path and PurePath, and a subclass of AsyncPurePath:
from pathlib import Path, PurePath
from aiopath import AsyncPath, AsyncPurePath
assert issubclass(AsyncPath, Path)
assert issubclass(AsyncPath, PurePath)
assert issubclass(AsyncPath, AsyncPurePath)
assert issubclass(AsyncPurePath, PurePath)
path: AsyncPath = await AsyncPath.home()
assert isinstance(path, Path)
assert isinstance(path, PurePath)
assert isinstance(path, AsyncPurePath) Check out the test files in the tests directory for more examples of how aiopath compares to pathlib.
Opening a file
You can get an asynchronous file-like object handle by using asynchronous context managers.
AsyncPath.open()'s async context manager yields an anyio.AsyncFile object.
from asynctempfile import NamedTemporaryFile
from aiopath import AsyncPath
text: str = 'example'
# you can access a file with async context managers
async with NamedTemporaryFile() as temp:
path = AsyncPath(temp.name)
async with path.open(mode='w') as file:
await file.write(text)
async with path.open(mode='r') as file:
result: str = await file.read()
assert result == text
# or you can use the read/write convenience methods
async with NamedTemporaryFile() as temp:
path = AsyncPath(temp.name)
await path.write_text(text)
result: str = await path.read_text()
assert result == text
content: bytes = text.encode()
await path.write_bytes(content)
result: bytes = await path.read_bytes()
assert result == contentGlobbing
aiopath implements pathlib globbing using async I/O and async generators.
from aiopath import AsyncPath
home: AsyncPath = await AsyncPath.home()
async for path in home.glob('*'):
assert isinstance(path, AsyncPath)
print(path)
downloads: AsyncPath = home / 'Downloads'
if await downloads.exists():
# this might take a while
paths: list[AsyncPath] = \
[path async for path in downloads.glob('**/*')]Installation
Dependencies
- A POSIX compliant OS, or Windows
- Python 3.7+
requirements.txt
PyPI
$ python3 -m pip install aiopathPython 3.9 and older
aiopath for Python 3.9 and older is available on PyPI under versions 0.5.x and lower.
Python 3.10 and newer
aiopath for Python 3.10 and newer is available on PyPI under versions 0.6.x and higher.
GitHub
Download a release archive for your Python version from the releases page.
Then to install, run:
$ python3 -m pip install -r requirements.txt
$ python3 setup.py installPython 3.9 and older
aiopath for Python 3.9 and older is developed on the Python-3.9 branch.
Python 3.10 and newer
aiopath for Python 3.10 and newer is developed on the Python-3.10 branch.
Support
Want to support this project and other open-source projects like it?
License
See LICENSE. If you'd like to use this project with a different license, please get in touch.
Credit
See CREDIT.md.