Traitement XML en PHP (récupération de certains attributs)

$aContext = array(
    'http' => array(
        'proxy' => 'proxy:8080',
        'request_fulluri' => true,
    ),
);
$cxContext = stream_context_create($aContext);

$xml = file_get_contents("https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml", False, $cxContext);

$doc = new DOMDocument();
$tab = array();
 
if(@$doc->loadXML($xml))
{
	$domliste = $doc->getElementsByTagName('Cube');
 
	foreach($domliste as $c) 
	{
		if($c->hasAttributes() && $c->getAttribute('currency'))
		{
			$tab[$c->getAttribute('currency')] = $c->getAttribute('rate');
		}
	}
}
else
{
	echo "le document xml n'a pas pu être chargé";
}
 
echo '<pre>';
print_r($tab);
echo '</pre>';
?>