show changes in twitter followers

followerdiff.py

#!/usr/bin/env python
"""Script to inform you of changes to your twitter followers.
ie: who just unfollowed you.

"""
from __future__ import with_statement
import bsddb
import contextlib
import functools
import pickle

import httplib2
#import lxml
import simplejson

USERNAME = 'edwardgeorge'
DBFILE = '.twitterdb'

def getfollowers(username):
    httpc = httplib2.Http()
    resp, content = httpc.request('http://twitter.com/followers/ids/%s.json' % username, 'GET')
    assert resp.status == 200
    data = simplejson.loads(content)
    return data

def getdiffandstore(db, key, username, data):
    dbkey = '%s:%s' % (key, username)
    existed = False
    additions, removals = [], []
    if dbkey in db:
        existed = True
        olddata = pickle.loads(db[dbkey])
        olddata = set(olddata)
        newdata = set(data)
        additions = newdata - olddata
        removals = olddata - newdata
    else:
        print 'no previous data found (%s)' % dbkey

    db[dbkey] = pickle.dumps(data)
    return additions, removals, existed

def getuserinfo(userid, cache):
    dbkey = 'user:%d' % userid
    if dbkey in cache:
        return cache[dbkey]

    try:
        httpc = httplib2.Http()
        resp, content = httpc.request('http://twitter.com/users/show/%s.json' % userid, 'GET')
        assert resp.status == 200
        data = simplejson.loads(content)
        screen_name = data['screen_name']
        cache[dbkey] = screen_name
        return screen_name
    except Exception, e:
        return 'user_id: %d' % userid


if __name__ == '__main__':
    with contextlib.closing(bsddb.hashopen(DBFILE, 'c')) as db:
        data = getfollowers(USERNAME)
        additions, removals, existed = getdiffandstore(db, 'followers', USERNAME, data)
        if existed:
            getuserinfo = functools.partial(getuserinfo, cache=db)
            if removals:
                print '\n'.join(map(lambda i: '-%s' % i, map(getuserinfo, removals)))
            if additions:
                print '\n'.join(map(lambda i: '+%s' % i, map(getuserinfo, additions)))
        db.sync()