This works. I'm not sure if it's proper for what you're doing or not, but maybe it helps.
Code:
$cmd=$_GET['cmd'];
$url=$_GET['url'];
$title=$_GET['title'];
$blogs=$_GET['blogs'];
$types=$_GET['types'];
$check=is_string($url)&&($title)&&($blogs)&&($types);
if(($cmd=='go')&&($check != FALSE)){
echo "YAY!";
}else{
echo "BOOO!";
}