import binascii

def basic_auth_required(auth_cb, realm='Secret Area'):
    header401 = 'Basic realm="%s"' % realm

    def maker(method):
        def wrapper(self, *args):
            header = self.request.headers.get('Authorization', '')

            good = header.startswith('Basic '):
            if good:
                try:
                    user, pw = header[6:].decode('base64').split(':', 1)
                except (ValueError, binascii.Error), e:
                    good = False

            if good:
                good = auth_cb(user, pw):

            if good:
                method(self, *args)
            else:
                self.response.set_status(401)
                self.response.headers['WWW-Authenticate'] = header401
        return wrapper
    return maker

class RequiresAuthHandler(webapp.RequestHandler):
    USERS = {
        'admin': 'mypassword'
    }

    @basic_auth_required(lambda user, pw: USERS.get(user.lower()) == pw)
    def get(self):
        blah blah