# -*- coding: utf-8 -*- """ Copyright (c) 2008, appengine-utilities project All rights reserved. Redistribution and use in source and binary forms, with or without modification, are permitted provided that the following conditions are met: - Redistributions of source code must retain the above copyright notice, this list of conditions and the following disclaimer. - Redistributions in binary form must reproduce the above copyright notice, this list of conditions and the following disclaimer in the documentation and/or other materials provided with the distribution. - Neither the name of the appengine-utilities project nor the names of its contributors may be used to endorse or promote products derived from this software without specific prior written permission. THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. """ # main python imports import os import time import datetime import random import md5 import Cookie import pickle import __main__ from time import strftime import logging # google appengine imports from google.appengine.ext import db from google.appengine.api import memcache #django simplejson import, used for flash from django.utils import simplejson from rotmodel import ROTModel # settings, if you have these set elsewhere, such as your django settings file, # you'll need to adjust the values to pull from there. class _AppEngineUtilities_Session(db.Model): """ Model for the sessions in the datastore. This contains the identifier and validation information for the session. """ sid = db.StringListProperty() session_key = db.FloatProperty() ip = db.StringProperty() ua = db.StringProperty() last_activity = db.DateTimeProperty() dirty = db.BooleanProperty(default=False) working = db.BooleanProperty(default=False) deleted = db.BooleanProperty(default=False) # used for cases where # datastore delete doesn't # work def put(self): """ Extend put so that it writes vaules to memcache as well as the datastore, and keeps them in sync, even when datastore writes fails. """ if self.session_key: memcache.set("_AppEngineUtilities_Session_" + str(self.session_key), self) else: # new session, generate a new key, which will handle the put and set the memcache self.create_key() self.last_activity = datetime.datetime.now() try: self.dirty = False logging.info("doing a put") db.put(self) memcache.set("_AppEngineUtilities_Session_" + str(self.session_key), self) except: self.dirty = True memcache.set("_AppEngineUtilities_Session_" + str(self.session_key), self) return self @classmethod def get_session(cls, session_obj=None): """ Uses the passed sid to get a session object from memcache, or datastore if a valid one exists. """ if session_obj.sid == None: return None session_key = session_obj.sid.split('_')[0] session = memcache.get("_AppEngineUtilities_Session_" + str(session_key)) if session: if session.deleted == True: session.delete() return None if session.dirty == True and session.working != False: # the working bit is used to make sure multiple requests, which can happen # with ajax oriented sites, don't try to put at the same time session.working = True memcache.set("_AppEngineUtilities_Session_" + str(session_key), session) session.put() if session_obj.sid in session.sid: logging.info('grabbed session from memcache') sessionAge = datetime.datetime.now() - session.last_activity if sessionAge.seconds > session_obj.session_expire_time: session.delete() return None return session else: return None # Not in memcache, check datastore query = _AppEngineUtilities_Session.all() query.filter("sid = ", session_obj.sid) results = query.fetch(1) if len(results) > 0: sessionAge = datetime.datetime.now() - results[0].last_activity if sessionAge.seconds > self.session_expire_time: results[0].delete() return None memcache.set("_AppEngineUtilities_Session_" + str(session_key), results[0]) memcache.set("_AppEngineUtilities_SessionData_" + str(session_key), results[0].get_items_ds()) logging.info('grabbed session from datastore') return results[0] else: return None def get_items(self): """ Returns all the items stored in a session """ items = memcache.get("_AppEngineUtilities_SessionData_" + str(self.session_key)) if items: for item in items: if item.deleted == True: item.delete() items.remove(item) return items query = _AppEngineUtilities_SessionData.all() query.filter('session_key', self.session_key) results = query.fetch(1000) return results def get_item(self, keyname = None): """ Returns a single item from the memcache or datastore """ mc = memcache.get("_AppEngineUtilities_SessionData_" + str(self.session_key)) if mc: for item in mc: if item.keyname == keyname: if item.deleted == True: item.delete() return None return item query = _AppEngineUtilities_SessionData.all() query.filter("session_key = ", self.session_key) query.filter("keyname = ", keyname) results = query.fetch(1) if len(results) > 0: memcache.set("_AppEngineUtilities_SessionData_" + str(self.session_key), self.get_items_ds()) return results[0] return None def get_items_ds(self): """ This gets all the items straight from the datastore, does not interact with the memcache. """ query = _AppEngineUtilities_SessionData.all() query.filter('session_key', self.session_key) results = query.fetch(1000) return results def delete(self): try: query = _AppEngineUtilities_SessionData.all() query.filter("session_key = ", self.session_key) results = query.fetch(1000) db.delete(results) db.delete(self) memcache.delete_multi(["_AppEngineUtilities_Session_" + str(self.session_key), "_AppEngineUtilities_SessionData_" + str(self.session_key)]) except: mc = memcache.get("_AppEngineUtilities_Session_" + str(self.session_key)) mc.deleted = True memcache.set("_AppEngineUtilities_Session_" + str(self.session_key), mc) def create_key(self): """ Creates a unique key for the session. """ self.session_key = time.time() valid = False while valid == False: # verify session_key is unique if memcache.get("_AppEngineUtilities_Session_" + str(self.session_key)): self.session_key = self.session_key + 0.001 else: query = _AppEngineUtilities_Session.all() query.filter("session_key = ", self.session_key) results = query.fetch(1) if len(results) > 0: self.session_key = self.session_key + 0.001 else: try: self.put() memcache.set("_AppEngineUtilities_Session_" + str(self.session_key), self) except: self.dirty = True memcache.set("_AppEngineUtilities_Session_" + str(self.session_key), self) valid = True class _AppEngineUtilities_SessionData(db.Model): """ Model for the session data in the datastore. """ session_key = db.FloatProperty() keyname = db.StringProperty() content = db.BlobProperty() dirty = db.BooleanProperty(default=False) deleted = db.BooleanProperty(default=False) def put(self): """ Adds a keyname/value for session to the datastore and memcache """ # update or insert in datastore try: db.put(self) self.dirty = False except: self.dirty = True # update or insert in memcache mc_items = memcache.get("_AppEngineUtilities_SessionData_" + str(self.session_key)) if mc_items: value_updated = False for item in mc_items: if value_updated == True: break if item.keyname == self.keyname: logging.info("updating " + self.keyname) item.content = self.content memcache.set("_AppEngineUtilities_SessionData_" + str(self.session_key), mc_items) value_updated = True break if value_updated == False: #logging.info("adding " + self.keyname) mc_items.append(self) memcache.set("_AppEngineUtilities_SessionData_" + str(self.session_key), mc_items) def delete(self): """ Deletes an entity from the session in memcache and the datastore """ try: db.delete(self) except: self.deleted = True mc_items = memcache.get("_AppEngineUtilities_SessionData_" + str(self.session_key)) value_handled = False for item in mc_items: if value_handled == True: break if item.keyname == self.keyname: if self.deleted == True: item.deleted = True else: mc_items.remove(item) memcache.set("_AppEngineUtilities_SessionData_" + str(self.session_key), mc_items) class _DatastoreWriter(object): def put(self, keyname, value, session): """ Insert a keyname/value pair into the datastore for the session. Args: keyname: The keyname of the mapping. value: The value of the mapping. """ keyname = session._validate_key(keyname) if value is None: raise ValueError('You must pass a value to put.') # datestore write trumps cookie. If there is a cookie value # with this keyname, delete it so we don't have conflicting # entries. if session.cookie_vals.has_key(keyname): del(session.cookie_vals[keyname]) session.output_cookie[session.cookie_name + '_data'] = \ simplejson.dumps(session.cookie_vals) print session.output_cookie.output() sessdata = session._get(keyname=keyname) if sessdata is None: sessdata = _AppEngineUtilities_SessionData() sessdata.session_key = session.session.session_key sessdata.keyname = keyname sessdata.content = pickle.dumps(value) # UNPICKLING CACHE session.cache[keyname] = pickle.dumps(value) session.cache[keyname] = value sessdata.put() # todo _set_memcache() should be going away when this is done # session._set_memcache() class _CookieWriter(object): def put(self, keyname, value, session): """ Insert a keyname/value pair into the datastore for the session. Args: keyname: The keyname of the mapping. value: The value of the mapping. """ keyname = session._validate_key(keyname) if value is None: raise ValueError('You must pass a value to put.') # Use simplejson for cookies instead of pickle. session.cookie_vals[keyname] = value # update the requests session cache as well. session.cache[keyname] = value session.output_cookie[session.cookie_name + '_data'] = \ simplejson.dumps(session.cookie_vals) print session.output_cookie.output() class Session(object): """ Sessions used to maintain user presence between requests. Sessions store a unique id as a cookie in the browser and referenced in a datastore object. This maintains user presence by validating requests as visits from the same browser. You can add extra data to the session object by using it as a dictionary object. Values can be any python object that can be pickled. For extra performance, session objects are also store in memcache and kept consistent with the datastore. This increases the performance of read requests to session data. """ COOKIE_NAME = 'appengine-utilities-session-sid' # session token DEFAULT_COOKIE_PATH = '/' SESSION_EXPIRE_TIME = 7200 # sessions are valid for 7200 seconds (2 hours) CLEAN_CHECK_PERCENT = 50 # By default, 50% of all requests will clean the database INTEGRATE_FLASH = True # integrate functionality from flash module? CHECK_IP = True # validate sessions by IP CHECK_USER_AGENT = True # validate sessions by user agent SET_COOKIE_EXPIRES = True # Set to True to add expiration field to cookie SESSION_TOKEN_TTL = 5 # Number of seconds a session token is valid for. UPDATE_LAST_ACTIVITY = 60 # Number of seconds that may pass before # last_activity is updated WRITER = "datastore" # Use the datastore writer by default. cookie is the # other option. def __init__(self, cookie_path=DEFAULT_COOKIE_PATH, cookie_name=COOKIE_NAME, session_expire_time=SESSION_EXPIRE_TIME, clean_check_percent=CLEAN_CHECK_PERCENT, integrate_flash=INTEGRATE_FLASH, check_ip=CHECK_IP, check_user_agent=CHECK_USER_AGENT, set_cookie_expires=SET_COOKIE_EXPIRES, session_token_ttl=SESSION_TOKEN_TTL, last_activity_update=UPDATE_LAST_ACTIVITY, writer=WRITER): """ Initializer Args: cookie_name: The name for the session cookie stored in the browser. session_expire_time: The amount of time between requests before the session expires. clean_check_percent: The percentage of requests the will fire off a cleaning routine that deletes stale session data. integrate_flash: If appengine-utilities flash utility should be integrated into the session object. check_ip: If browser IP should be used for session validation check_user_agent: If the browser user agent should be used for sessoin validation. set_cookie_expires: True adds an expires field to the cookie so it saves even if the browser is closed. session_token_ttl: Number of sessions a session token is valid for before it should be regenerated. """ self.cookie_path = cookie_path self.cookie_name = cookie_name self.session_expire_time = session_expire_time self.integrate_flash = integrate_flash self.check_user_agent = check_user_agent self.check_ip = check_ip self.set_cookie_expires = set_cookie_expires self.session_token_ttl = session_token_ttl self.last_activity_update = last_activity_update self.writer = writer # make sure the page is not cached in the browser self.no_cache_headers() # Check the cookie and, if necessary, create a new one. self.cache = {} string_cookie = os.environ.get('HTTP_COOKIE', '') self.cookie = Cookie.SimpleCookie() self.output_cookie = Cookie.SimpleCookie() self.cookie.load(string_cookie) try: self.cookie_vals = \ simplejson.loads(self.cookie[self.cookie_name + '_data'].value) # sync self.cache and self.cookie_vals which will make those # values available for all gets immediately. for k in self.cookie_vals: self.cache[k] = self.cookie_vals[k] self.output_cookie[self.cookie_name + '_data'] = self.cookie[self.cookie_name + '_data'] # sync the input cookie with the output cookie except: self.cookie_vals = {} if writer == "cookie": pass else: self.sid = None new_session = True # do_put is used to determine if a datastore write should # happen on this request. do_put = False # check for existing cookie if self.cookie.get(cookie_name): self.sid = self.cookie[cookie_name].value self.session = _AppEngineUtilities_Session.get_session(self) # will return None if # sid expired if self.session: new_session = False if new_session: # start a new session self.session = _AppEngineUtilities_Session() self.session.put() self.sid = self.new_sid() if 'HTTP_USER_AGENT' in os.environ: self.session.ua = os.environ['HTTP_USER_AGENT'] else: self.session.ua = None if 'REMOTE_ADDR' in os.environ: self.session.ip = os.environ['REMOTE_ADDR'] else: self.session.ip = None self.session.sid = [self.sid] # do put() here to get the session key self.session.put() else: # check the age of the token to determine if a new one # is required duration = datetime.timedelta(seconds=self.session_token_ttl) session_age_limit = datetime.datetime.now() - duration if self.session.last_activity < session_age_limit: logging.info("UPDATING SID LA = " + str(self.session.last_activity) + " - TL = " + str(session_age_limit)) self.sid = self.new_sid() if len(self.session.sid) > 2: self.session.sid.remove(self.session.sid[0]) self.session.sid.append(self.sid) do_put = True else: self.sid = self.session.sid[-1] # check if last_activity needs updated ula = datetime.timedelta(seconds=self.last_activity_update) if datetime.datetime.now() > self.session.last_activity + ula: do_put = True self.output_cookie[cookie_name] = self.sid self.output_cookie[cookie_name]['path'] = cookie_path # UNPICKLING CACHE self.cache['sid'] = pickle.dumps(self.sid) self.cache['sid'] = self.sid if do_put: if self.sid != None or self.sid != "": logging.info("doing put") self.session.put() if self.set_cookie_expires: if not self.output_cookie.has_key(cookie_name + '_data'): self.output_cookie[cookie_name + '_data'] = "" self.output_cookie[cookie_name + '_data']['expires'] = \ self.session_expire_time print self.output_cookie.output() # fire up a Flash object if integration is enabled if self.integrate_flash: import flash self.flash = flash.Flash(cookie=self.cookie) # randomly delete old stale sessions in the datastore (see # CLEAN_CHECK_PERCENT variable) if random.randint(1, 100) < clean_check_percent: self._clean_old_sessions() def new_sid(self): """ Create a new session id. """ sid = str(self.session.session_key) + "_" +md5.new(repr(time.time()) + \ str(random.random())).hexdigest() return sid ''' # removed as model now has get_session classmethod def _get_session(self): """ Get the user's session from the datastore """ query = _AppEngineUtilities_Session.all() query.filter('sid', self.sid) if self.check_user_agent: query.filter('ua', os.environ['HTTP_USER_AGENT']) if self.check_ip: query.filter('ip', os.environ['REMOTE_ADDR']) results = query.fetch(1) if len(results) is 0: return None else: sessionAge = datetime.datetime.now() - results[0].last_activity if sessionAge.seconds > self.session_expire_time: results[0].delete() return None return results[0] ''' def _get(self, keyname=None): """ Return all of the SessionData object data from the datastore onlye, unless keyname is specified, in which case only that instance of SessionData is returned. Important: This does not interact with memcache and pulls directly from the datastore. This also does not get items from the cookie store. Args: keyname: The keyname of the value you are trying to retrieve. """ if keyname != None: return self.session.get_item(keyname) return self.session.get_items() """ OLD query = _AppEngineUtilities_SessionData.all() query.filter('session', self.session) if keyname != None: query.filter('keyname =', keyname) results = query.fetch(1000) if len(results) is 0: return None if keyname != None: return results[0] return results """ def _validate_key(self, keyname): """ Validate the keyname, making sure it is set and not a reserved name. """ if keyname is None: raise ValueError('You must pass a keyname for the session' + \ ' data content.') elif keyname in ('sid', 'flash'): raise ValueError(keyname + ' is a reserved keyname.') if type(keyname) != type([str, unicode]): return str(keyname) return keyname def _put(self, keyname, value): """ Insert a keyname/value pair into the datastore for the session. Args: keyname: The keyname of the mapping. value: The value of the mapping. """ if self.writer == "datastore": writer = _DatastoreWriter() else: writer = _CookieWriter() writer.put(keyname, value, self) def _delete_session(self): """ Delete the session and all session data. """ if hasattr(self, "session"): self.session.delete() self.cookie_vals = {} self.cache = {} self.output_cookie[self.cookie_name + '_data'] = \ simplejson.dumps(self.cookie_vals) print self.output_cookie.output() """ OLD if hasattr(self, "session"): sessiondata = self._get() # delete from datastore if sessiondata is not None: for sd in sessiondata: sd.delete() # delete from memcache memcache.delete('sid-'+str(self.session.key())) # delete the session now that all items that reference it are deleted. self.session.delete() # unset any cookie values that may exist self.cookie_vals = {} self.cache = {} self.output_cookie[self.cookie_name + '_data'] = \ simplejson.dumps(self.cookie_vals) print self.output_cookie.output() """ # if the event class has been loaded, fire off the sessionDeleted event if 'AEU_Events' in __main__.__dict__: __main__.AEU_Events.fire_event('sessionDelete') def delete(self): """ Delete the current session and start a new one. This is useful for when you need to get rid of all data tied to a current session, such as when you are logging out a user. """ self._delete_session() @classmethod def delete_all_sessions(cls): """ Deletes all sessions and session data from the data store and memcache: NOTE: This is not fully developed. It also will not delete any cookie data as this does not work for each incoming request. Keep this in mind if you are using the cookie writer. """ all_sessions_deleted = False all_data_deleted = False while not all_sessions_deleted: query = _AppEngineUtilities_Session.all() results = query.fetch(75) if len(results) is 0: all_sessions_deleted = True else: for result in results: result.delete() def _clean_old_sessions(self): """ Delete expired sessions from the datastore. This is only called for CLEAN_CHECK_PERCENT percent of requests because it could be rather intensive. """ duration = datetime.timedelta(seconds=self.session_expire_time) session_age = datetime.datetime.now() - duration query = _AppEngineUtilities_Session.all() query.filter('last_activity <', session_age) results = query.fetch(50) for result in results: """ OLD data_query = _AppEngineUtilities_SessionData.all() data_query.filter('session', result) data_results = data_query.fetch(1000) for data_result in data_results: data_result.delete() memcache.delete('sid-'+str(result.key())) """ result.delete() # Implement Python container methods def __getitem__(self, keyname): """ Get item from session data. keyname: The keyname of the mapping. """ # flash messages don't go in the datastore if self.integrate_flash and (keyname == 'flash'): return self.flash.msg if keyname in self.cache: # UNPICKLING CACHE return pickle.loads(str(self.cache[keyname])) return self.cache[keyname] if keyname in self.cookie_vals: return self.cookie_vals[keyname] if hasattr(self, "session"): data = self._get(keyname) if data: #UNPICKLING CACHE self.cache[keyname] = data.content self.cache[keyname] = pickle.loads(data.content) return pickle.loads(data.content) else: raise KeyError(str(keyname)) raise KeyError(str(keyname)) def __setitem__(self, keyname, value): """ Set item in session data. Args: keyname: They keyname of the mapping. value: The value of mapping. """ if self.integrate_flash and (keyname == 'flash'): self.flash.msg = value else: keyname = self._validate_key(keyname) self.cache[keyname] = value # self._set_memcache() # commented out because this is done in the datestore put return self._put(keyname, value) def delete_item(self, keyname, throw_exception=False): """ Delete item from session data, ignoring exceptions if necessary. Args: keyname: The keyname of the object to delete. throw_exception: false if exceptions are to be ignored. Returns: Nothing. """ if throw_exception: self.__delitem__(keyname) return None else: try: self.__delitem__(keyname) except KeyError: return None def __delitem__(self, keyname): """ Delete item from session data. Args: keyname: The keyname of the object to delete. """ bad_key = False sessdata = self._get(keyname = keyname) if sessdata is None: bad_key = True else: sessdata.delete() if keyname in self.cookie_vals: del self.cookie_vals[keyname] bad_key = False self.output_cookie[self.cookie_name + '_data'] = \ simplejson.dumps(self.cookie_vals) print self.output_cookie.output() if bad_key: raise KeyError(str(keyname)) if keyname in self.cache: del self.cache[keyname] def __len__(self): """ Return size of session. """ # check memcache first if hasattr(self, "session"): results = self._get() if results is not None: return len(results) + len(self.cookie_vals) else: return 0 return len(self.cookie_vals) def __contains__(self, keyname): """ Check if an item is in the session data. Args: keyname: The keyname being searched. """ try: r = self.__getitem__(keyname) except KeyError: return False return True def __iter__(self): """ Iterate over the keys in the session data. """ # try memcache first if hasattr(self, "session"): for k in self._get(): yield k.keyname for k in self.cookie_vals: yield k def __str__(self): """ Return string representation. """ #if self._get(): return '{' + ', '.join(['"%s" = "%s"' % (k, self[k]) for k in self]) + '}' #else: # return [] ''' OLD def _set_memcache(self): """ Set a memcache object with all the session data. Optionally you can add a key and value to the memcache for put operations. """ # Pull directly from the datastore in order to ensure that the # information is as up to date as possible. if self.writer == "datastore": data = {} sessiondata = self._get() if sessiondata is not None: for sd in sessiondata: data[sd.keyname] = pickle.loads(sd.content) memcache.set('sid-'+str(self.session.key()), data, \ self.session_expire_time) ''' def cycle_key(self): """ Changes the session id. """ self.sid = self.new_sid() if len(self.session.sid) > 2: self.session.sid.remove(self.session.sid[0]) self.session.sid.append(self.sid) def flush(self): """ Delete's the current session, creating a new one. """ self._delete_session() self.__init__() def no_cache_headers(self): """ Adds headers, avoiding any page caching in the browser. Useful for highly dynamic sites. """ print "Expires: Tue, 03 Jul 2001 06:00:00 GMT" print strftime("Last-Modified: %a, %d %b %y %H:%M:%S %Z") print "Cache-Control: no-store, no-cache, must-revalidate, max-age=0" print "Cache-Control: post-check=0, pre-check=0" print "Pragma: no-cache" def clear(self): """ Remove all items """ sessiondata = self._get() # delete from datastore if sessiondata is not None: for sd in sessiondata: sd.delete() # delete from memcache self.cache = {} self.cookie_vals = {} self.output_cookie[self.cookie_name + '_data'] = \ simplejson.dumps(self.cookie_vals) print self.output_cookie.output() def has_key(self, keyname): """ Equivalent to k in a, use that form in new code """ return self.__contains__(keyname) def items(self): """ A copy of list of (key, value) pairs """ op = {} for k in self: op[k] = self[k] return op def keys(self): """ List of keys. """ l = [] for k in self: l.append(k) return l def update(*dicts): """ Updates with key/value pairs from b, overwriting existing keys, returns None """ for dict in dicts: for k in dict: self._put(k, dict[k]) return None def values(self): """ A copy list of values. """ v = [] for k in self: v.append(self[k]) return v def get(self, keyname, default = None): """ a[k] if k in a, else x """ try: return self.__getitem__(keyname) except KeyError: if default is not None: return default return None def setdefault(self, keyname, default = None): """ a[k] if k in a, else x (also setting it) """ try: return self.__getitem__(keyname) except KeyError: if default is not None: self.__setitem__(keyname, default) return default return None @classmethod def check_token(cls, cookie_name=COOKIE_NAME, delete_invalid=True): """ Retrieves the token from a cookie and validates that it is a valid token for an existing cookie. Cookie validation is based on the token existing on a session that has not expired. This is useful for determining if datastore or cookie writer should be used in hybrid implementations. Args: cookie_name: Name of the cookie to check for a token. delete_invalid: If the token is not valid, delete the session cookie, to avoid datastore queries on future requests. Returns True/False NOTE: TODO This currently only works when the datastore is working, which of course is pointless for applications using the django middleware. This needs to be resolved before merging back into the main project. """ string_cookie = os.environ.get('HTTP_COOKIE', '') cookie = Cookie.SimpleCookie() cookie.load(string_cookie) if cookie.has_key(cookie_name): query = _AppEngineUtilities_Session.all() query.filter('sid', cookie[cookie_name].value) results = query.fetch(1) if len(results) > 0: return True else: if delete_invalid: output_cookie = Cookie.SimpleCookie() output_cookie[cookie_name] = cookie[cookie_name] output_cookie[cookie_name]['expires'] = 0 print output_cookie.output() return False