how to model a follower stream in appengine?
- by molicule
I am trying to design tables to buildout a follower relationship.
Say I have a stream of 140char records that have user, hashtag and other text.
Users follow other users, and can also follow hashtags.
I am outlining the way I've designed this below, but there are two limitaions in my design. I was wondering if others had smarter ways to accomplish the same goal.
The issues with this are
The list of followers is copied in for each record
If a new follower is added or one removed, 'all' the
records have to be updated.
The code
class HashtagFollowers(db.Model):
"""
This table contains the followers for each hashtag
"""
hashtag = db.StringProperty()
followers = db.StringListProperty()
class UserFollowers(db.Model):
"""
This table contains the followers for each user
"""
username = db.StringProperty()
followers = db.StringListProperty()
class stream(db.Model):
"""
This table contains the data stream
"""
username = db.StringProperty()
hashtag = db.StringProperty()
text = db.TextProperty()
def save(self):
"""
On each save all the followers for each hashtag and user
are added into a another table with this record as the parent
"""
super(stream, self).save()
hfs = HashtagFollowers.all().filter("hashtag =", self.hashtag).fetch(10)
for hf in hfs:
sh = streamHashtags(parent=self, followers=hf.followers)
sh.save()
ufs = UserFollowers.all().filter("username =", self.username).fetch(10)
for uf in ufs:
uh = streamUsers(parent=self, followers=uf.followers)
uh.save()
class streamHashtags(db.Model):
"""
The stream record is the parent of this record
"""
followers = db.StringListProperty()
class streamUsers(db.Model):
"""
The stream record is the parent of this record
"""
followers = db.StringListProperty()
Now, to get the stream of followed hastags
indexes = db.GqlQuery("""SELECT __key__ from streamHashtags where followers = 'myusername'""")
keys = [k,parent() for k in indexes[offset:numresults]]
return db.get(keys)
Is there a smarter way to do this?
