class SessionContainer(object):
""" Session container object. """
def __init__(self):
self._items = dict()
self._queue = PriorityQueue()
def add(self, session):
""" Add session to the container.
@param session: Session object
"""
self._items[session.session_id] = session
if session.expiry is not None:
self._queue.push(session)
def get(self, session_id):
""" Return session object or None if it is not available
@param session_id: Session identifier
"""
return self._items.get(session_id, None)
def remove(self, session_id):
""" Remove session object from the container
@param session_id: Session identifier
"""
session = self._items.get(session_id, None)
if session is not None:
session.promoted = -1
session.on_delete(True)
del self._items[session_id]
return True
return False
def expire(self, current_time=None):
""" Expire any old entries
@param current_time: Optional time to be used to clean up queue (can be
used in unit tests)
"""
if self._queue.is_empty():
return
if current_time is None:
current_time = time.time()
while not self._queue.is_empty():
# Get top most item
top = self._queue.peek()
# Early exit if item was not promoted and its expiration time
# is greater than now.
if top.promoted is None and top.expiry_date > current_time:
break
# Pop item from the stack
top = self._queue.pop()
need_reschedule = (top.promoted is not None
and top.promoted > current_time)
# Give chance to reschedule
if not need_reschedule:
top.promoted = None
top.on_delete(False)
need_reschedule = (top.promoted is not None
and top.promoted > current_time)
# If item is promoted and expiration time somewhere in future
# just reschedule it
if need_reschedule:
top.expiry_date = top.promoted
top.promoted = None
self._queue.push(top)
else:
del self._items[top.session_id]
class PriorityQueueTest(unittest.TestCase):
def setUp(self):
self.q = PriorityQueue()
def test_is_empty(self):
self.assertTrue(self.q.is_empty())
self.q.push(1)
self.assertFalse(self.q.is_empty())
self.q.pop()
self.assertTrue(self.q.is_empty())
def test_push(self):
self.q.push(1)
self.assertEquals(self.q.pop(), 1)
def test_pop_from_empty_queue_raises_indexerror(self):
self.assertRaises(IndexError, self.q.pop)
def test_peek_doesnt_pop(self):
self.q.push(1)
self.assertEquals(self.q.peek(), 1)
self.assertFalse(self.q.is_empty())
def test_insertion_order_is_preserved_for_same_priority_elements(self):
class El(object):
def __init__(self, id, val):
self.id = id
self.val = val
def __cmp__(self, other):
return cmp(self.val, other.val)
self.q.push(El('other', 2))
self.q.push(El('first', 1))
self.q.push(El('second', 1))
self.q.push(El('third', 1))
self.assertEquals(self.q.pop().id, 'first')
self.assertEquals(self.q.pop().id, 'second')
self.assertEquals(self.q.pop().id, 'third')
self.assertEquals(self.q.pop().id, 'other')
def test_contains(self):
self.assertFalse(1 in self.q)
self.q.push(1)
self.assertTrue(1 in self.q)
self.q.pop()
self.assertFalse(1 in self.q)
def test_len(self):
self.assertEquals(len(self.q), 0)
self.q.push(1)
self.assertEquals(len(self.q), 1)
self.q.pop()
self.assertEquals(len(self.q), 0)