def shutdown():
    task = int(request.args.get("parameter").strip())
    showtext = {}
    if task in (0, 1):  # valid commandos received
        # close all database connections
        calibre_db.dispose()
        ub.dispose()

        if task == 0:
            showtext['text'] = _(u'Server restarted, please reload page')
        else:
            showtext['text'] = _(u'Performing shutdown of server, please close window')
        # stop gevent/tornado server
        web_server.stop(task == 0)
        return json.dumps(showtext)

    if task == 2:
        log.warning("reconnecting to calibre database")
        calibre_db.reconnect_db(config, ub.app_DB_path)
        showtext['text'] = _(u'Reconnect successful')
        return json.dumps(showtext)

    showtext['text'] = _(u'Unknown command')
    return json.dumps(showtext), 400
The web application does not, or can not, sufficiently verify whether a well-formed, valid, consistent request was intentionally provided by the user who submitted the request.