requests gevent demo

reqeusts_bug.py

"""
requests uses a singleton AuthManager, which when used with gevent's monkey patching
(or presumably, the threading module) can be set by one thread, and read by another.
The AuthManager maps urls to credentials which assumes for any url you will always
request it with the same credentials.  This turned out to be false for us, and thus,
the bug.  Here's code to reliably reproduce it.
"""

import base64
import gevent.monkey
from gevent.pywsgi import WSGIServer
gevent.monkey.patch_all()
import requests

port = 8899

def cycle_auths(n):
    # cycle between user1 and user2
    auths = [('user1', 'pass1', 'forced_basic'), ('user2', 'pass2', 'forced_basic')]
    for i in xrange(n):
        yield auths[i % len(auths)]

def app(env, start_response):
    if not env.get('HTTP_AUTHORIZATION'):
        # force requests to send the auth!
        start_response("401 Unauthorized", [])
        return ""
    start_response("200 OK", [])
    b64auth = env['HTTP_AUTHORIZATION'][6:]
    user, password = base64.b64decode(b64auth).split(':')
    print user, password, "should be", env['wsgi.input'].read()
    return ""

g = gevent.Greenlet(WSGIServer(('', port), app).serve_forever).start()
gevent.sleep(2) # wait for the server to start

def mk_request(auth):
    r = requests.post('http://localhost:{port}'.format(port=port),
            data=auth[0], auth=auth)

threads = [gevent.spawn(mk_request, auth) for auth in cycle_auths(20)]
gevent.joinall(threads)

gevent.sleep(2)

# show that in a non-race situation, the auth will be correct
thread = [gevent.spawn(mk_request, ('user3', 'pass3'))]
gevent.joinall(thread)