I don't like Yii much. Maybe it's cause of the overbloatedness of PHP.
$_POST object in Yii from which you can conveniently partake of your desired data.
After spending some time trying to figure out why that is so, I came upon this post. It's annoying but basically you have to just do a low-level PHP read using.
$post = file_get_contents("php://input");
Oh Yii !! How I hate thee...