"""`Gravatar <https://en.gravatar.com/site/implement/>`_""" # import code for encoding urls and generating md5 hashes import urllib2, hashlib # Make response slow if verify whether default avatar or not. # So let js do it, see `/static/js/article.js`. def gravatar_url(email, size=40, verify_default=False):     """Construct the gravatar url."""     gravatar_url = ''.join(['http://www.gravatar.com/avatar/',         hashlib.md5(email.lower()).hexdigest(), '?s=%d' % size])     # if default return None     if (verify_default):         gravatar_url += '&d=404'         try:             urllib2.urlopen(gravatar_url)         except urllib2.URLError, e:             return None     return gravatar_url if __name__ == '__main__':     import webbrowser as wb     for email in ['xxx@gmail.com']:         url = gravatar_url(email)         print(url)         if url:             wb.open(url)