query_es.php

    function request_es($param, $use_post=false)
    {
        /* send request to es */
        $es_server = '';
        $ch = curl_init($es_server);
        curl_setopt_array(
            $ch,
            array(CURLOPT_POST => TRUE,
                  CURLOPT_RETURNTRANSFER => TRUE,
                  CURLOPT_HTTPHEADER => array(
                      'Content-Type: application/json'
                      ),
                  CURLOPT_POSTFIELDS => json_encode($param)
                ));
        $resp = curl_exec($ch);
        if ($resp === false)
        {
            return null;
        }
        return json_decode($resp, true);
    }