As a spin-off from this thread, I've got a problem with CGI.pm and file uploads from utf8 html pages. On larger uploads (valid binary files like mp3s etc) I get a "CGI.pm: Server closed socket during multipart read (client aborted?)." on the client/browser side and in apache2's error.log multiple lines with "Malformed UTF-8 character (unexpected continuation byte ..."

To replicate the error I use the script from http://www.perlfect.com/articles/upload.shtml 

<FORM ENCTYPE="multipart/form-data" ACTION="/cgi-bin/upload.pl" METHOD
+="POST"> Please choose directory to upload to:<br> <SELECT NAME="dir"
+> <OPTION VALUE="images">images</OPTION> <OPTION VALUE="sounds">sound
+s</OPTION> </SELECT> <p> Please select a file to upload: <BR> <INPUT 
+TYPE="FILE" NAME="file"> <p> <INPUT TYPE="submit"> </FORM>

[download]
which is served as "Content-Encoding: utf8;"

Then I upload a file of approx. 800K (on smaller files like 300K I manage to get them up despite of errors...) to this script: 
#!/usr/bin/perl -CS
use CGI::Carp qw(fatalsToBrowser);
use CGI;
my $cgi = new CGI;

my $file = $cgi->param('file');

$file=~m/^.*(\\|\/)(.*)/; # strip the remote path and keep the filenam
+e

my $name = $2;

open(LOCAL, ">/var/www/mypath/$file") or die "$!: path: /var/www/mypat
+h/$name file: $file";
while(<$file>) {
        print LOCAL $_;
}

print $cgi->header();
print "$file has been successfully uploaded... thank you.\n";

[download]


Now, the important part is the #!/usr/bin/perl -CS switch! It tells perl to perate in utf8 mode on input, output and stderror. A method I also had in effect with different approaches, i.e. with binmode STDIN, STDOUT etc. set to utf8.

I need this functionality as I use CGI::Application to serve pages in utf8. But what it also seems to do is treating file-uploads as utf8 which leads to the error I am describing.
For example, setting the switch to #!/usr/bin/perl -COE (= utf8 for output and stderror) will not yield the error.

1. Now, is this behaviour an error of CGI.pm (not differentiating between form-(text)-data and file-uploads or intended behaviour?

2.And what is the correct application design? Should I use the switch -COE so output and err is utf8 while input stays :raw - which I then convert on selected form-fields via my $param_f = decode("utf8", $q->param("f") )?

In reply to CGI.pm: "Malformed UTF-8 character" in apache's error.log by isync

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