<file_allegati>
  <allegato id="0" planimetria="0" type="foto">
    <id>0</id>
    <file_path>https://##.jpg </file_path>
  </allegato>
  <allegato id="1" planimetria="1" type="planimetria">
    <id>1</id>
    <file_path>https://##.jpg </file_path>
  </allegato>
</file_allegati>

function set_planimetrie( $allegati ) {
    $result="";
    $xml = new SimpleXMLElement($allegati);

    foreach($xml->children() as $allegato)
    {
        if($allegato['type']=='planimetria' && $allegato['planimetria']==1){
            if( $result != ''){$result .=',';}
            $result.= $allegato->file_path;
        }
    return $result;
    }
}