https://github.com/sethmlarson/selectors2
Backported, durable, and portable selectors designed to replace the standard library selectors module.
https://github.com/sethmlarson/selectors2
async devpoll epoll io kqueue poll python python2 python3 select selector
Last synced: 3 months ago
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Backported, durable, and portable selectors designed to replace the standard library selectors module.
- Host: GitHub
- URL: https://github.com/sethmlarson/selectors2
- Owner: sethmlarson
- License: mit
- Archived: true
- Created: 2016-10-25T14:16:42.000Z (over 8 years ago)
- Default Branch: master
- Last Pushed: 2020-07-21T22:39:10.000Z (almost 5 years ago)
- Last Synced: 2025-01-11T19:07:37.957Z (4 months ago)
- Topics: async, devpoll, epoll, io, kqueue, poll, python, python2, python3, select, selector
- Language: Python
- Homepage: https://twitter.com/sethmlarson
- Size: 75.2 KB
- Stars: 14
- Watchers: 2
- Forks: 6
- Open Issues: 0
-
Metadata Files:
- Readme: README.rst
- Changelog: CHANGELOG.rst
- License: LICENSE
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README
Selectors2
==========
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:target: https://travis-ci.org/SethMichaelLarson/selectors2
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:target: https://ci.appveyor.com/project/SethMichaelLarson/selectors2
.. image:: https://img.shields.io/pypi/v/selectors2.svg?style=flat-square
:target: https://pypi.python.org/pypi/selectors2
.. image:: https://img.shields.io/badge/say-thanks-ff69b4.svg?style=flat-square
:target: https://saythanks.io/to/SethMichaelLarson
Backported, durable, and portable selectors designed to replace
the standard library selectors module.
Features
--------
* Support for all major platforms. (Linux, Mac OS, Windows)
* Support for Python 2.6 or later and **Jython**.
* Support many different selectors
* ``select.kqueue`` (BSD, Mac OS)
* ``select.devpoll`` (Solaris)
* ``select.epoll`` (Linux 2.5.44+)
* ``select.poll`` (Linux, Mac OS)
* ``select.select`` - (Linux, Mac OS, Windows)
* Support for `PEP 475 `_ (Retries system calls on interrupt)
* Support for modules which monkey-patch the standard library after import (like greenlet, gevent)
* Support for systems which define a selector being available but don't actually implement it. ()
About
-----
This module was originally written by me for the `urllib3 `_ project
(history in PR `#1001 `_) but it was decided that it would
be beneficial for everyone to have access to this work.
All the additional features that ``selectors2`` provides are real-world problems that have occurred
and been reported during the lifetime of its maintenance and use within ``urllib3``.
If this work is useful to you, `feel free to say thanks `_,
takes only a little time and really brightens my day! :cake:
Can this module be used in place of ``selectors``?
--------------------------------------------------
Yes! This module is a 1-to-1 drop-in replacement for ``selectors`` and
provides all selector types that would be available in ``selectors`` including
``DevpollSelector``, ``KqueueSelector``, ``EpollSelector``, ``PollSelector``, and ``SelectSelector``.
What is different between `selectors2` and `selectors34`?
---------------------------------------------------------
This module is similar to ``selectors34`` in that it supports Python 2.6 - 3.3
but differs in that this module also implements PEP 475 for the backported selectors.
This allows similar behaviour between Python 3.5+ selectors and selectors from before PEP 475.
In ``selectors34``, an interrupted system call would result in an incorrect return of no events, which
for some use cases is not an acceptable behavior.
I will also add here that ``selectors2`` also makes large improvements on the test suite surrounding it
providing 100% test coverage for each selector. The test suite is also more robust and tests durability
of the selectors in many different situations that aren't tested in ``selectors34``.
What types of objects are supported?
------------------------------------
At this current time ``selectors2`` only support the ``SelectSelector`` for Windows which cannot select on non-socket objects.
On Linux and Mac OS, both sockets and pipes are supported (some other types may be supported as well, such as fifos or special file devices).
What if I have to support a platform without ``select.select``?
---------------------------------------------------------------
There are a few platforms that don't have a selector available, notably
Google AppEngine. When running on those platforms any call to ``DefaultSelector()``
will raise a ``RuntimeError`` explaining that there are no selectors available.
License
-------
This module is dual-licensed under MIT and PSF License.
Installation
------------
``$ python -m pip install selectors2``
Usage
-----
.. code-block:: python
import sys
import selectors2 as selectors
# Use DefaultSelector, it picks the best
# selector available for your platform! :)
s = selectors.DefaultSelector()
import socket
# We're going to use Google as an example.
sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
sock.connect(("www.google.com", 80))
# Register the file to be watched for write availibility.
s.register(sock, selectors.EVENT_WRITE)
# Give a timeout in seconds or no
# timeout to block until an event happens.
events = s.select(timeout=1.0)
# Loop over all events that happened.
for key, event in events:
if event & selectors.EVENT_WRITE:
key.fileobj.send(b'HEAD / HTTP/1.1\r\n\r\n')
# Change what event you're waiting for.
s.modify(sock, selectors.EVENT_READ)
# Timeout of None let's the selector wait as long as it needs to.
events = s.select(timeout=None)
for key, event in events:
if event & selectors.EVENT_READ:
data = key.fileobj.recv(4096)
print(data)
# Stop watching the socket.
s.unregister(sock)
sock.close()