This allows you to use Amazon's SimpleDB as a backend for cherrypy sessions. It's not totally complete but it works for me (short example usage given below). It doesn't pass the unit tests, but I might need help figuring that out.
requires boto, you can do
easy_install boto
or get it from google code: http://code.google.com/p/boto/
make a file called simpledb.py
import datetime
import cherrypy
from cherrypy.lib.sessions import Session
import boto
try:
import cPickle as pickle
except ImportError:
import pickle
import unicodedata
class SimpledbSession(Session):
""" Implementation of the Amazon SimpleDB backend for sessions. It assumes
a table like this:
domain = sdb.get_domain('session')
item = domain.get_item(id)
item['data']
item['expiration_time']
use 'access_key' = 'your access key'
and 'secret_access_key' = 'your secret access key'
in your configuration
"""
pickle_protocol = pickle.HIGHEST_PROTOCOL
def __init__(self, id=None, **kwargs):
Session.__init__(self, id, **kwargs)
self.domain.new_item(self.id)
def setup(cls, **kwargs):
for k, v in kwargs.iteritems():
setattr(cls, k, v)
sdb = boto.connect_sdb(cls.access_key, cls.secret_access_key)
domain = sdb.get_domain('session')
cls.domain = domain
setup = classmethod(setup)
def __del__(self):
pass
def _exists(self):
item = self.domain.get_item(self.id)
return bool(item)
def _load(self):
item = self.domain.get_item(self.id)
if not item:
return None
try:
pickled_data = item['data'].decode('string_escape')
data = pickle.loads(pickled_data)
except:
data = {}
expiration_time = self.time_from_string(item['expiration_time'])
return data, expiration_time
def time_from_string(self, s):
d = s.split('.')
x = datetime.datetime.strptime(d[0], "%Y-%m-%d %H:%M:%S")
fractional = d[1]
if fractional is None:
fractional = '0'
fracpower = 6 - len(fractional)
fractional = float(fractional) * (10 ** fracpower)
x.replace(microsecond=int(fractional))
expiration_time = x
return expiration_time
def _save(self, expiration_time):
item = self.domain.get_item(self.id)
if not item:
item = self.domain.new_item(self.id)
item['expiration_time'] = expiration_time
pickled_data = pickle.dumps(self._data, self.pickle_protocol)
item['data'] = pickled_data.encode('string_escape')
def _delete(self):
item = self.domain.get_item(self.id)
self.get_domain().delete_item(item)
def acquire_lock(self):
"""(don't really) Acquire an exclusive lock on the currently-loaded session data."""
self.locked = True
def release_lock(self):
"""(don't really) Release the lock on the currently-loaded session data."""
self.locked = False
def clean_up(self):
"""Clean up expired sessions."""
for item in self.domain:
if self.time_from_string(item['expiration_time']) < datetime.datetime.now():
self.domain.delete_item(item)
You can try this self contained example: (make sure to put in your AWS credentials) sdbexample.py
import cherrypy
from cherrypy import _cperror
def handle_error():
cherrypy.response.status = 500
cherrypy.response.body = ["<html><body>Sorry, an error occured<br>%s</body></html>" % _cperror.format_exc()]
import simpledb
cherrypy.lib.sessions.SimpledbSession = simpledb.SimpledbSession
cherrypy.config.update({
#'server.socket_host': '0.0.0.0', #if you are running this on ec2, uncomment
#'server.socket_port': 8080, #so you can access by host address
'request.error_response': handle_error,
'tools.sessions.on': True,
'tools.sessions.storage_type': "simpledb",
'tools.sessions.timeout': 60,
'tools.sessions.access_key':"your access key",
'tools.sessions.secret_access_key':"your secret access key",
})
class SimpledbExample(object):
def __init__(self):
pass
def index(self):
return "index"
index.exposed = True
def report(self):
counter = cherrypy.session['counter']
return "count: %d" % counter
report.exposed = True
def add(self):
counter = cherrypy.session.get('counter', 0) + 1
cherrypy.session['counter'] = counter
return "added count: %d" % counter
add.exposed = True
cherrypy.quickstart(SimpledbExample())
run it with
python sdbexample.py
you can test like:
http://127.0.0.1/report and so on
If you need help or want to help contact ian@cloudcarpenters.com
