Php curl post数据参数有时会发送为空

Question

I am trying to call service with three parameters: uri, code and type. But sometimes "type" parameter posting empty, sometimes posting correct. So service call sometimes successfull, sometimes fail. I don't change anything but parameter "type" sometimes empty. How can ı solve this problem ?

$curl_post_data = array(   
        "uri" => $uri,
        "code" => $code,
        "type" => $type
    );

$post_data = http_build_query($curl_post_data);
$curl = curl_init($service_url);
curl_setopt($curl, CURLOPT_CONNECTTIMEOUT, 60);
curl_setopt($curl, CURLOPT_TIMEOUT, 10);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYHOST, false);
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $post_data);
curl_setopt($curl, CURLOPT_HEADER, false);
curl_setopt($curl, CURLOPT_HTTPAUTH, xxx);
curl_setopt($curl, CURLOPT_USERPWD, xxx);
curl_setopt($curl, CURLOPT_PROXY, 'xxx');
curl_setopt($curl, CURLOPT_PROXYUSERPWD, 'xxxx');
curl_setopt($curl, CURLOPT_PROXYPORT, xxx);
curl_setopt($curl, CURLOPT_PROXYAUTH, xxx);
$curl_response = curl_exec($curl);
if (false === $curl_response) {
     return null;
}

Answer 1

http_build_query will remove null values.. see first comment: http://php.net/manual/en/function.http-build-query.php