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# (c) 2005 Ian Bicking and contributors; written for Paste (http://pythonpaste.org)
# Licensed under the MIT license: http://www.opensource.org/licenses/mit-license.php
"""
Creates a session object; then in your application, use::
environ['paste.session.factory']()
This will return a dictionary. The contents of this dictionary will
be saved to disk when the request is completed. The session will be
created when you first fetch the session dictionary, and a cookie will
be sent in that case. There's current no way to use sessions without
cookies, and there's no way to delete a session except to clear its
data.
@@: This doesn't do any locking, and may cause problems when a single
session is accessed concurrently. Also, it loads and saves the
session for each request, with no caching. Also, sessions aren't
expired.
"""
from Cookie import SimpleCookie
import time
import random
import os
import md5
try:
import cPickle
except ImportError:
import pickle as cPickle
import wsgilib
class SessionMiddleware(object):
def __init__(self, application, global_conf=None, **factory_kw):
self.application = application
self.factory_kw = factory_kw
def __call__(self, environ, start_response):
session_factory = SessionFactory(environ, **self.factory_kw)
environ['paste.session.factory'] = session_factory
def session_start_response(status, headers, exc_info=None):
if not session_factory.created:
return start_response(status, headers)
headers.append(session_factory.set_cookie_header())
return start_response(status, headers, exc_info)
app_iter = self.application(environ, session_start_response)
if session_factory.used:
return wsgilib.add_close(app_iter, session_factory.close)
else:
return app_iter
class SessionFactory(object):
def __init__(self, environ, cookie_name='_SID_',
session_class=None, **session_class_kw):
self.created = False
self.used = False
self.environ = environ
self.cookie_name = cookie_name
self.session = None
self.session_class = session_class or FileSession
self.session_class_kw = session_class_kw
def __call__(self):
self.used = True
if self.session is not None:
return self.session.data()
cookies = wsgilib.get_cookies(self.environ)
session = None
if cookies.has_key(self.cookie_name):
self.sid = cookies[self.cookie_name].value
try:
session = self.session_class(self.sid, create=False,
**self.session_class_kw)
except KeyError:
# Invalid SID
pass
if session is None:
self.created = True
self.sid = self.make_sid()
session = self.session_class(self.sid, create=True,
**self.session_class_kw)
self.session = session
return session.data()
def make_sid(self):
# @@: need better algorithm
return (''.join(['%02d' % x for x in time.localtime(time.time())[:6]])
+ '-' + self.unique_id())
def unique_id(self, for_object=None):
"""
Generates an opaque, identifier string that is practically
guaranteed to be unique. If an object is passed, then its
id() is incorporated into the generation. Relies on md5 and
returns a 32 character long string.
"""
r = [time.time(), random.random(), os.times()]
if for_object is not None:
r.append(id(for_object))
md5_hash = md5.new(str(r))
try:
return md5_hash.hexdigest()
except AttributeError:
# Older versions of Python didn't have hexdigest, so we'll
# do it manually
hexdigest = []
for char in md5_hash.digest():
hexdigest.append('%02x' % ord(char))
return ''.join(hexdigest)
def set_cookie_header(self):
c = SimpleCookie()
c[self.cookie_name] = self.sid
c[self.cookie_name]['path'] = '/'
name, value = str(c).split(': ', 1)
return (name, value)
def close(self):
if self.session is not None:
self.session.close()
class FileSession(object):
def __init__(self, sid, create=False, session_file_path='/tmp'):
self.session_file_path = session_file_path
self.sid = sid
if not create:
if not os.path.exists(self.filename()):
raise KeyError
self._data = None
def filename(self):
return os.path.join(self.session_file_path, self.sid)
def data(self):
if self._data is not None:
return self._data
if os.path.exists(self.filename()):
f = open(self.filename(), 'rb')
self._data = cPickle.load(f)
f.close()
else:
self._data = {}
return self._data
def close(self):
if self._data is not None:
filename = self.filename()
if not self._data:
if os.path.exists(filename):
os.unlink(filename)
else:
f = open(self.filename(), 'wb')
cPickle.dump(self._data, f)
f.close()
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