Python: Moodle login with urllib2

I am trying to log in to a Moodle website, but it returns the "you haven't logged in yet" page, which means authentication wasn't successful. What am I doing wrong? Am I forgetting to set a parameter? Please don't recommend *mechanize*. I want to understand how it works without a library. My code: import cookielib, urllib, urllib2, getpass # not the actual site, but still a Moodle example theurl = 'https://moodle.pucrs.br/login/index.php' username= raw_input("\tusername: ") password= getpass.getpass("\tpassword: ") passman = urllib2.HTTPPasswordMgrWithDefaultRealm() passman.add_password(None, theurl, username, password) cj = cookielib.CookieJar() opener = urllib2.build_opener( urllib2.HTTPRedirectHandler(), urllib2.HTTPBasicAuthHandler(passman), urllib2.HTTPHandler(debuglevel=0), urllib2.HTTPSHandler(debuglevel=0), urllib2.HTTPCookieProcessor(cj), ) urllib2.install_opener(opener) # set headers opener.addheaders = [ ('User-agent', ('Mozilla/4.0 (compatible; MSIE 6.0; ' 'Windows NT 5.2; .NET CLR 1.1.4322)')) ] try: #req = opener.open(theurl, data) req = opener.open(theurl) except IOError, e: print "It looks like the username or password is wrong." # == test == # visit "my courses": req = opener.open("https://moodle.pucrs.br/my/‎") content = ''.join(req.readlines()) print(content)