CGI.pm gives you low-level access to file upload management through a file upload hook. You can use this feature to completely turn off the temp file storage of file uploads, or potentially write your own file upload progress meter.

This is much like the UPLOAD_HOOK facility available in Apache::Request, with the exception that the first argument to the callback is an Apache::Upload object, here it’s the remote filename.

$q = CGI->new(\&hook [,$data [,$use_tempfile]]);
sub hook {
my ($filename, $buffer, $bytes_read, $data) = @_;
print “Read $bytes_read bytes of $filename\n”;
}

The $data field is optional; it lets you pass configuration information (e.g. a database handle) to your hook callback.

The $use_tempfile field is a flag that lets you turn on and off CGI.pm‘s use of a temporary disk-based file during file upload. If you set this to a FALSE value (default true) then $q->param(‘uploaded_file’) will no longer work, and the only way to get at the uploaded data is via the hook you provide.

If using the function-oriented interface, call the CGI::upload_hook() method before calling param() or any other CGI functions:

CGI::upload_hook(\&hook [,$data [,$use_tempfile]]);

This method is not exported by default. You will have to import it explicitly if you wish to use it without the CGI:: prefix.