Shows how to "extend" CUploadedFile (difficult to do classically because of private static $_files property) using a small Factory component and a behavior

UploadedFileBehavior.php

<?php

//Class to provide factory methods for seamless use

class UploadedFile extends CComponent
{
    public function init()
    {
        parent::init();
    }
    
    public static function getInstanceByName($name)
    {
        $file = CUploadedFile::getInstanceByName($name);
        $file->attachBehavior('uploadedFile', new UploadedFileBehavior());
        return $file;
    }
}

//Actual behavior class


class UploadedFileBehavior extends CBehavior
{
    
    public function init()
    {
        parent::init();
    }
    
    private function incrementFileName($file)
    {
        //do stuff to ensure filename is unique in target folder and return modified path
    }
    
    public function saveAsUnique($file, $deleteTempFile=true)
    {
        if (file_exists($file))
            return $this->saveAsUnique($this->incrementFileName($file), $deleteTempFile);
        return $this->owner->saveAs($file, $deleteTempFile);
    }
    
}

//example use

$file = UploadedFile::getInstanceByName('upload')
$file->saveAsUnique('/destination/path/and/file.jpg');

Thanks for sharing, this helped me out today.