Redirect files to simple form before downloading

I am trying to redirect all links to any PDF file in my site to a page with a form in it that collects user info before they can proceed to download/view the PDF.

E.g.

I want to redirect *.pdf files in a web site to request.php?file=name_of_pdf_being_redirected where request.php is the page with the form on it asking for a few details before proceeding.

All PDFs in the site are held inside /pdf folder.

Any ideas?

I'm using Apache on the server.

You can try this:

• Move your files to a folder "outside" your web root so that no one can access it thru a browser
• Use sessions to detect whether a person has completed the form or not
• Use a php powered file download script. In its naivest form, it might look like this:

    if ( isset( $_SESSION[ 'OK_TO_DOWNLOAD' ] ) == false )
    {
        header( "Location: must_fill_this_first.php" );
        exit( 0 );
    }

    header( "Content-type: application/pdf" );
    // double check the above, google it as i am not sure

    echo file_get_contents( 'some_directory_inaccessible_thru_www/' . $_GET[ 'pdf_name' ] );
    // ideally a binary-safe function needs to be used above

This is a tried and tested technique I used on a website. The code example is a draft outline and needs refinement.