lnked

json_encode( $arr, 					JSON_UNESCAPED_UNICODE				)

$json = json_decode( file_get_contents('json.txt'), true );
$json = sortmulti( $json, 'username',  'asc',  );

foreach ($json->data as $item) {
    echo $item->username;
    echo '<br>';
}
?>

function sortmulti ($array, $index, $order, $natsort=FALSE, $case_sensitive=FALSE) 
{
    if(is_array($array) && count($array)>0)
    {
        foreach(array_keys($array) as $key)
        $temp[$key]=$array[$key][$index];
        if(!$natsort)
        {
            if ($order=='asc')
                asort($temp);
            else   
                arsort($temp);
        }
        else
        {
            if ($case_sensitive===true)
                natsort($temp);
            else
                natcasesort($temp);
                
            if($order!='asc')
                $temp=array_reverse($temp,TRUE);
        }
        foreach(array_keys($temp) as $key)
            if (is_numeric($key))
                $sorted[]=$array[$key];
            else   
                $sorted[$key]=$array[$key];
        return $sorted;
    }
    
    return $sorted;
}