public function fileExists()
    {
        if (!$this->hasRequestParameter('uri') || !$this->hasRequestParameter('path') || !$this->hasRequestParameter('lang')) {
            throw new common_exception_MissingParameter();
        }

        $item = $this->getResource($this->getRequestParameter('uri'));
        $itemLang = $this->getRequestParameter('lang');

        try {
            $resolver = new ItemMediaResolver($item, $itemLang);
            $asset = $resolver->resolve($this->getRequestParameter('path'));
            $asset->getMediaSource()->getFileInfo($asset->getMediaIdentifier());
            $found = true;
        } catch (tao_models_classes_FileNotFoundException $exception) {
            $found = false;
        }
        return $this->returnJson(array(
            'exists' => $found
        ));
    }