class Reader(QonPersistent):
"""Represents a single user/reader of a Blog.
Uses a conflict-avoiding IO BTree:
self.read_items[item_id] = (datetime, count)
"""
persistenceVersion = 2
def __init__(self, user):
self.user = user
self.read_items = ConflictAvoidingIOBTree()
def upgradeToVersion2(self):
for k,v in self.read_items.iteritems():
self.read_items[k] = (v, 0)
self.version_upgrade_done()
def upgradeToVersion1(self):
newbt = ConflictAvoidingIOBTree()
for k,v in self.read_items.iteritems():
newbt[k] = v
del self.read_items
self.read_items = newbt
self.version_upgrade_done()
def read_item(self, item_id, now=None):
"""Notice that I have read item number item_id. Returns self as a convenience."""
now = now or datetime.utcnow()
dt, count = self.read_items.get(item_id, (never, 0))
# don't allow changing last_read to anything earlier than it is now
now = max(now, dt)
self.read_items[item_id] = (now, count + 1)
return self
def has_read_item(self, item_id, updated=None):
"""Have I read item_id, which was optionally updated at updated?"""
last_read, count = self.read_items.get(item_id, (None, 0))
if last_read:
if updated:
return last_read >= updated
else:
return True
return False
def last_read(self, item_id):
"""Return the datetime of the last time that the user read a BlogItem"""
dt, count = self.read_items.get(item_id, (never, 0))
return dt
def last_read_count(self, item_id):
"""Return (last read datetime, count int)."""
return self.read_items.get(item_id, (never, 0))
def __init__(self, user):
self.user = user
self.read_items = ConflictAvoidingIOBTree()
