pyasynchat

1.0.5 · active · verified Wed Apr 15

pyasynchat is a re-implementation of Python's `asynchat` standard library module, which was removed in Python 3.12. It provides a compatible API for asynchronous event-driven network communication, built upon `pyasyncore`. The current version is 1.0.5, and releases are made as needed to ensure compatibility with newer Python versions or address bugs.

Warnings

breaking The original `asynchat` standard library module was removed from Python 3.12 and later versions.
Fix: Migrate applications to use `pyasynchat` (and `pyasyncore`) as external packages.
breaking Applications using `asynchat` must update their import statements to use `pyasynchat`.
Fix: Change `import asynchat` to `import pyasynchat` or `from asynchat import ...` to `from pyasynchat import ...`.
gotcha `pyasynchat` relies on `pyasyncore` for the underlying asynchronous event loop (`asyncore.loop`). Both packages must be installed for `pyasynchat` to function correctly.
Fix: Ensure `pip install pyasynchat pyasyncore` is run, and update any `asyncore.loop()` calls to `pyasyncore.loop()` if `asyncore` itself was previously imported directly.
gotcha As a re-implementation of a removed standard library module, while aiming for high compatibility, subtle behavioral differences might exist compared to the original CPython standard library versions of `asynchat` and `asyncore`.
Fix: Thoroughly test existing applications after migration to `pyasynchat` and `pyasyncore` to ensure no unexpected behavior changes.

Install

pip install pyasynchat Install pyasynchat
pip install pyasynchat pyasyncore Install with its core dependency

Imports

async_chat
```
from pyasynchat import async_chat
```
The original `asynchat` module was removed in Python 3.12+. This library provides the functionality under its own namespace.
simple_producer
```
from pyasynchat import simple_producer
```
The original `asynchat` module was removed in Python 3.12+. This library provides the functionality under its own namespace.

Quickstart

This quickstart demonstrates a simple asynchronous echo server using `pyasynchat` for handling client communication and `pyasyncore` for the main event loop. It mirrors the functionality of a classic `asynchat` example.

import socket
import pyasyncore
from pyasynchat import async_chat, simple_producer # simple_producer is imported but not used for brevity in this example

class EchoHandler(async_chat):
    def __init__(self, sock):
        super().__init__(sock)
        self.set_terminator(b'\n')
        self.data = []

    def collect_incoming_data(self, data):
        self.data.append(data)

    def found_terminator(self):
        message = b"".join(self.data).strip()
        print(f"Received: {message.decode()}")
        self.push(message + b'\n') # Echo back with a newline
        self.data = []

class EchoServer(pyasyncore.dispatcher):
    def __init__(self, host, port):
        super().__init__()
        self.create_socket(socket.AF_INET, socket.SOCK_STREAM)
        self.set_reuse_addr()
        self.bind((host, port))
        self.listen(5)
        print(f"Listening on {host}:{port}")

    def handle_accept(self):
        pair = self.accept()
        if pair is not None:
            sock, addr = pair
            print(f"Incoming connection from {addr}")
            EchoHandler(sock)

if __name__ == "__main__":
    # The loop function must be imported from pyasyncore, not pyasynchat.
    # Ensure pyasyncore is also installed: pip install pyasyncore
    server = EchoServer('localhost', 8080)
    try:
        pyasyncore.loop()
    except KeyboardInterrupt:
        print("Server stopped.")

# To test: In another terminal, run: nc localhost 8080

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