asyncfile 1.0.0

Purpose

Operating on files in Python is a synchronous activity. When normally operating on file this does not cause any problems. However, when files are tampered with in code that also runs the asyncio event loop, this can cause the asyncio event loop to block. This negatively effects the program’s performance and should therefore be avoided. The asyncfile module avoids this problem by running the file operations in a separate thread so that the event loop is not as harshly affected.

Features

• async and await syntax is used

• There is almost complete coverage of the io module’s classes

• The syntax and utility is similar to the built-in Python open function and the built-in io module

• Lightweight in speed and memory

Installation

Installing asyncfile should be done through PIP:

pip install asyncfile

Open Examples

If you were to have regular, blocking code, you can easily transition it to asyncfile

Blocking:

with open('fake_file', 'r') as f:
    print(f.read())

Non-Blocking:

import asyncfile
import asyncio

custom_loop = asyncio.get_event_loop() # You can pass in your own loop

async def open_file():
    async with asyncfile.open('fake_file', 'r', loop=custom_loop) as f:
        print(await f.read())

custom_loop.run_until_complete(open_file())

These both produce the same results, but one is better suited for asyncio-based code.

IO Examples

Blocking:

import io

wrap = io.FileIO('fake_file.txt', 'wb')

buff = io.BufferedReader(wrap)
buff.write(b'Random bytes')
print(buff.fileno())
print(buff.raw)
print(buff.readable())
buff.close()

Non-Blocking:

import asyncfile
import asyncio

async def no_block(file_path):
    wrap = asyncfile.AsyncFileIO(file_path, 'rb')
    buff = asyncfile.AsyncBufferedReader(wrap)
    await buff.read(-1)
    print(await buff.fileno())
    print(buff.raw)
    print(await buff.readable())
    await buff.close()

loop = asyncio.get_event_loop()
loop.run_until_complete(no_block('fake_file.txt'))

Blocking:

import io

for i in io.FileIO('fake_file.txt'):
    print(i)

Non-Blocking:

import asyncfile
import asyncio

async def async_iteration():
    async for i in asyncfile.AsyncFileIO('fake_file.txt'):
        print(i)