how to log in to otaku-streamers in python (vbulletin)

otaku-login.py

import cookielib
import md5
import sys
import urllib
import urllib2

username = 'your_username'
password = 'your_password'
login_url = 'http://otaku-streamers.com/community/login.php?do=login'
cookie_file = 'otaku.cookies'

#handy function to build a query string from a dictionary
def build_query(queries):
    return '&'.join([k+'='+urllib.quote(str(v)) for (k,v) in queries.items()])

#the onsubmit() javascript does this bit
password_md5 = md5.md5(password).hexdigest()

#build POST data (including hidden form fields)
post_data = build_query({'vb_login_username': username,
                         's': '',
                         'securitytoken': 'guest',
                         'do': 'login',
                         'vb_login_md5password': password_md5,
                         'vb_login_md5password_utf': password_md5,
                         })

#create cookiejar
cj = cookielib.LWPCookieJar()

#tell urllib2 to handle cookies
opener = urllib2.build_opener(urllib2.HTTPCookieProcessor(cj))
urllib2.install_opener(opener)

#try to load existing cookies
try:
    #ignore_discard=True loads session cookies too
    cj.load(cookie_file, ignore_discard=True)

    #check to see if login cookies already saved
    response = urllib2.urlopen('http://otaku-streamers.com/')
    html = response.read()

    if 'class="welcomelink"' in html:
        print 'already logged in as %s.' % username
        #lets get out of here!
        sys.exit()

#if cookie file does not exist we just keep going...
except IOError:
    pass

print 'logging in...'

#POST to login page
response = urllib2.urlopen(login_url, post_data)

#check for login string
html = response.read()

if 'Thank you for logging in, %s.' % username in html:
    print 'logged in to otaku-streamers as %s.' % username 
else:
    print 'login failed'

#save cookies to disk (ignore_discard=True saves session cookies)
cj.save(cookie_file, ignore_discard=True)