[Zope] extract complete filepath from HTML input file-tag

Hi! I need to extract the complete path of an <input type=file name="my_file"> because if a PDF file should be uploaded, I call a python script which uses the linux pdftotext command (which should to know where the file is) to convert the file to plain text and pass this plain text to ZCatalog indexing system to have stored in zope the searchible content of a PDF too. The only thing I get from REQUEST['my_file'].filename is the file name without the path 'cause I work under linux May be you have some other tip for me? I would appreciate your help greetings Andrei