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# Copyright (C) 2007 by the Free Software Foundation, Inc.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301,
# USA.
"""Implementations of the IPendable and IPending interfaces."""
import time
import random
import hashlib
import datetime
from elixir import *
from zope.interface import implements
from zope.interface.verify import verifyObject
from Mailman.configuration import config
from Mailman.interfaces import IPending, IPendable
PEND_KIND = 'Mailman.database.model.pending.Pending'
class PendedKeyValue(Entity):
"""A pended key/value pair, tied to a token."""
has_field('key', Unicode)
has_field('value', Unicode)
# Relationships
belongs_to('pended', of_kind=PEND_KIND)
# Options
using_options(shortnames=True)
class Pending(Entity):
"""A pended event, tied to a token."""
has_field('token', Unicode)
has_field('expiration_date', DateTime)
# Options
using_options(shortnames=True)
class UnpendedPendable(dict):
implements(IPendable)
class Pendings(object):
"""Implementation of the IPending interface."""
implements(IPending)
def add(self, pendable, lifetime=None):
verifyObject(IPendable, pendable)
# Calculate the token and the lifetime.
if lifetime is None:
lifetime = config.PENDING_REQUEST_LIFE
# Calculate a unique token. Algorithm vetted by the Timbot. time()
# has high resolution on Linux, clock() on Windows. random gives us
# about 45 bits in Python 2.2, 53 bits on Python 2.3. The time and
# clock values basically help obscure the random number generator, as
# does the hash calculation. The integral parts of the time values
# are discarded because they're the most predictable bits.
while True:
now = time.time()
x = random.random() + now % 1.0 + time.clock() % 1.0
# Use sha1 because it produces shorter strings.
token = hashlib.sha1(repr(x)).hexdigest()
# In practice, we'll never get a duplicate, but we'll be anal
# about checking anyway.
if not Pending.select_by(token=token):
break
# Create the record, and then the individual key/value pairs.
pending = Pending(
token=token,
expiration_date=datetime.datetime.now() + lifetime)
for key, value in pendable.items():
PendedKeyValue(key=key, value=value, pended=pending)
return token
def confirm(self, token, expunge=True):
pendings = Pending.select_by(token=token)
assert 0 <= len(pendings) <= 1, 'Unexpected token search results'
if len(pendings) == 0:
return None
pending = pendings[0]
pendable = UnpendedPendable()
# Find all PendedKeyValue entries that are associated with the pending
# object's ID.
q = PendedKeyValue.filter(
PendedKeyValue.c.pended_id == Pending.c.id).filter(
Pending.c.id == pending.id)
for keyvalue in q.all():
pendable[keyvalue.key] = keyvalue.value
if expunge:
keyvalue.delete()
if expunge:
pending.delete()
return pendable
def evict(self):
now = datetime.datetime.now()
for pending in Pending.select():
if pending.expiration_date < now:
# Find all PendedKeyValue entries that are associated with the
# pending object's ID.
q = PendedKeyValue.filter(
PendedKeyValue.c.pended_id == Pending.c.id).filter(
Pending.c.id == pending.id)
for keyvalue in q:
keyvalue.delete()
pending.delete()
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