获取微信 JS-SDK ticket

        该方法会通过 session 对象自动缓存管理 ticket

        :return: ticket

def get_jsapi_ticket(self):
        """
        获取微信 JS-SDK ticket

        该方法会通过 session 对象自动缓存管理 ticket

        :return: ticket
        """
        ticket_key = '{}_jsapi_ticket'.format(self._client.corp_id)
        expires_at_key = '{}_jsapi_ticket_expires_at'.format(self._client.corp_id)
        ticket = self.session.get(ticket_key)
        expires_at = self.session.get(expires_at_key, 0)
        if not ticket or expires_at < int(time.time()):
            jsapi_ticket = self.get_ticket()
            ticket = jsapi_ticket['ticket']
            expires_at = int(time.time()) + int(jsapi_ticket['expires_in'])
            self.session.set(ticket_key, ticket)
            self.session.set(expires_at_key, expires_at)
        return ticket