Perl write to file returns huge weird stacktrace

Question

I have the following problem: when I try to save the file that contains a semicolon in the name it returns a huge and weird stacktrace of the characters on the page. I've tried to escape, to trim and to replace those semicolons, but the result is still the same. I use the following regex:

$value =~ s/([^a-zA-Z0-9_\-.]|;)/uc sprintf("%%%02x",ord($1))/eg;

(I've even added the |; part separately..)

So, when I open the file to write and call the print function it returns lots of weird stuff, like that:

PK!}�3y�[Content_Types].xml ��/�h9\�?�0��cz��:� �s_��o��>�T�� (it is a huge one, this is just a part of it).

Is there any way I could avoid this?

Thank you in advance!

EDIT:

Just interested - what is the PK responsible of in this string? I mean I can understand that those chars are just contents of the file, but what is PK ? And why does it show the content type?

EDIT 2.0:

I'm uploading the .docx file - when the name doesn't contain the semicolon it works all fine. This is the code for the file saving:

open (QSTR,">", "$dest_file") or die "can't open output file: $qstring_file";
print QSTR $value;
close (QSTR);

EDIT 3.0

This is a .cgi script, that is called after posting some data to the server. It has to save some info about the uploading file to a temp file (name, contents, size) in the manner of key-value pairs. So any file that contains the semicolon causes this error.

EDIT 4.0 Found the cause:

The CGI param function while uploading the params counts semicolon as the delimiter! Is there any way to escape it in the file header?

Can you show us the code that you're using to save the file? I suspect that it's actually working properly, but the data that you're writing to the file simply isn't plain text - it's something like Postscript or PDF. I don't know what format the PK! marker actually indicates, but using your shell's file command might identify the format. In any case, I highly doubt that the filename is relevant to this. — Dave Sherohman
Sure. The edit is done. The file is not just text, you are right. — user
What about a bit more of context? You mention "the page". So is this some sort of web-app? Based on what framework? You say "I'm uploading the .docx file". What file? Uploading it where? And when? Does this trigger the error? What does PK mean? — innaM

user1126070 user1126070 · Accepted Answer · 2013-07-15T09:09:55

The PK in file header it means it is compressed ZIP like file, like docx.

One guess: The ; is not valid character in filename at the destination?

Your regexp is not good: (the dot alone is applicable to any character...)

$value =~ s/([^a-zA-Z0-9_\-.]|;)/uc sprintf("%%%02x",ord($1))/eg;

Try this:

#replace evey non valid char to underscore
$value =~ s/([^a-zA-Z0-9_\-\.\;])/_/g;

Perl write to file returns huge weird stacktrace

1 Answers