def get_app_url(self):
        """
        Returns the application URL as defined in the INI section
        `server:main`. Defaults to `http://0.0.0.0/6543`.
        """
        section = 'server:main'
        if self.has_setting(section, 'host'):
            host = self.get_setting(section, 'host')
        else:
            host = '0.0.0.0'
        if self.has_setting(section, 'port'):
            port = int(self.get_setting(section, 'port'))
        else:
            port = 6543
        return 'http://%s:%d' % (host, port)
Returns the application URL as defined in the INI section
        `server:main`. Defaults to `http://0.0.0.0/6543`.