[php]http post를 통해 json 데이터 보내기

function http_post_data($url, $data_string) {  
  
        $ch = curl_init();  
        curl_setopt($ch, CURLOPT_POST, 1);  
        curl_setopt($ch, CURLOPT_URL, $url);  
        curl_setopt($ch, CURLOPT_POSTFIELDS, $data_string);  
        curl_setopt($ch, CURLOPT_HTTPHEADER, array(  
            'Content-Type: application/json; charset=utf-8',  
            'Content-Length: ' . strlen($data_string))  
        );  
        ob_start();  
        curl_exec($ch);  
        $return_content = ob_get_contents();  
        ob_end_clean();  
  
        $return_code = curl_getinfo($ch, CURLINFO_HTTP_CODE);  
        return array($return_code, $return_content);  
    }  
  
$url  = "http://xx.xx.cn";  
$data = json_encode(array('a'=>1, 'b'=>2));   
  
list($return_code, $return_content) = http_post_data($url, $data);