sub download_file {
        my ( $filename, $mime ) = @_;
        if ( ! -e $filename ) {
            croak "$filename does not exist":
        }
        my $filesize = -s $filename;

        # print full header
        print "Content-disposition: attachment; filename=$filename\n";
        print "Content-Length: $filesize\n";
        print "Content-Type: $mime\n\n";
    
        # open in binmode
        open READ, "< $filename" or croak "Cannot open $filename for reading: $!";
        binmode READ;
    
        # stream it out
        binmode STDOUT;
        {
            local $/;
            print <READ>;
        }
        close(READ);
    
        # should always return true
        return(1);
    }