get subtitles of coursera classes

sub.py

import os, urllib2

game_cookie = 'csrf_token=XXXX; session=XXXX;'

class Sub_downloader:

    def __init__(self, cookie):
        self.cookie = cookie # 'csrf_token=XXXX; session=XXXX;'

    def getname(self, response):
        content_type = response.headers['content-type']
        if 'download' not in content_type:
            return None # 404
        disposition = response.headers['content-disposition']
        st,ed = disposition.index('"'), disposition.rindex('"')
        return disposition[st+1:ed]


    def getsub(self, class_name, lecture_id, lang='en'):
        req = urllib2.Request(
              'https://www.coursera.org/%s/lecture/subtitles?q=%d_%s'
                      % (class_name, lecture_id, lang),
                      headers={'Cookie':self.cookie})
        response = urllib2.urlopen(req)
        name = self.getname(response)
        if not name:
            return None # 404
        if not os.path.exists(name):
            with file(name,'w') as f:
                f.write(response.read())
        return name
   
if __name__ == '__main__':
    sd = Sub_downloader(game_cookie)
    game_lst = [49,12,50,8,9,10,11]
    for i in game_lst:
        s='%d\t%s' %(i, sd.getsub('gametheory',i))
        print s