CODEWITHSUNDEEP
python
victor n.
victor n.

Reputation: 668

AppEngine: how do cursors work?

i have the following code

def get(self):
    date = datetime.date.today()
    loc_query = Location.all()

    last_cursor = memcache.get('location_cursor')
    if last_cursor: loc_query.with_cursor(last_cursor)
    loc_result = loc_query.fetch(1)

    for loc in loc_result:
        self.record(loc, date)
        taskqueue.add(
            url='/task/query/simplegeo',
            params={'date':date, 'locid':loc.key().id()}
        )

    if len(loc_result):
        memcache.add('location_cursor', loc_query.cursor())
        taskqueue.add(url='/task/count/', method='GET')
    else:
        memcache.add('location_cursor', None)

i don't know what i'm doing wrong, but i am getting the same cursor which is not the effect i wanted. why isn't the cursor moving?

Upvotes: 0

Views: 334

Answers (1)

Alex Martelli
Alex Martelli

Reputation: 881675

You're misusing memcache.add, which is documented here as:

Sets a key's value, if and only if the item is not already in memcache.

So you're never storing any cursor different from the first one. Use memcache.set instead, which

Sets a key's value, regardless of previous contents in cache.

Note that this has nothing to do with cursors -- it's all about proper use of memcache!

Upvotes: 5

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