Crochet is an MIT-licensed library that makes it easier to use Twisted from regular blocking code. Some use cases include:
* Easily use Twisted from a blocking framework like Django or Flask. * Write a library that provides a blocking API, but uses Twisted for its implementation. * Port blocking code to Twisted more easily, by keeping a backwards compatibility layer. * Allow normal Twisted programs that use threads to interact with Twisted more cleanly from their threaded parts. For example this can be useful when using Twisted as a WSGI container.
This is a bugfix release, recommended for all users of Crochet.
Crochet can be downloaded from https://pypi.python.org/pypi/crochet or by running:
$ pip install crochet
Bugs and feature requests should be filed at the project https://github.com/itamarst/crochet
Here’s an example of a program using Crochet. Notice that you get a completely blocking interface to Twisted and do not need to run the Twisted reactor, the event loop, yourself.
#!/usr/bin/python """ Do a DNS lookup using Twisted's APIs. """ from __future__ import print_function
# The Twisted code we'll be using: from twisted.names import client
from crochet import setup, wait_for setup()
# Crochet layer, wrapping Twisted's DNS library in a blocking call. @wait_for(timeout=5.0) def gethostbyname(name): """Lookup the IP of a given hostname.
Unlike socket.gethostbyname() which can take an arbitrary amount of time to finish, this function will raise crochet.TimeoutError if more than 5 seconds elapse without an answer being received. """ d = client.lookupAddress(name) d.addCallback(lambda result: result.payload.dottedQuad()) return d
if __name__ == '__main__': # Application code using the public API - notice it works in a normal # blocking manner, with no event loop visible: import sys name = sys.argv ip = gethostbyname(name) print(name, "->", ip)
Run on the command line:
$ python blockingdns.py twistedmatrix.com twistedmatrix.com -> 220.127.116.11