$options = array(

    CURLOPT_URL => 'http://www.example.com/',

    CURLOPT_RETURNTRANSFER => true,  // boolean

    CURLOPT_HEADER => false,         // boolean

    CURLOPT_USERAGENT => ''          // empty string, will be filtered

);

// Filter only non-empty strings

$options = array_filter($options, fn($v) => gettype($v) === 'string' && strlen($v) > 0);

$ch = curl_init();

foreach($options as $opt => $val){

    curl_setopt($ch, $opt, $val);

}

$response = curl_exec($ch);

curl_close($ch);