/**
  * Function to fetch the actual file content of a document
  * 
  * @return $content the document file content 
  */
 function get_document_content()
 {
     // fetch the content
     $content = KTDocumentUtil::getDocumentContent($this->document);
     // TODO what if the file could not be found?
     // Log the transaction
     $this->download();
     // return the document content
     return $content;
 }