I can't validate array in json.

You need to json_decode the json array to an associated array first.

He get the data with getJSON(), so no need to call json_decode, it’s already done by getJSON().

PHP Code:

$json = $this->request->getJSON(true); 


PHP Code:

public function getJSON(bool $assoc = false, int $depth = 512, int $options = 0)
{
    return json_decode($this->body, $assoc, $depth, $options);
}