yapp
User
Apr 18, 2002, 9:57 AM
Views: 281
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Re: [alalleyn] Obtaining information forms
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- There are single quotes arround your filename!! open() fails! The script returns an error. The webserver doesn't send the message to the browser, since it's not a HTTP header. Bad luck i'd say. 
use #!/usr/bin/perl -w
This is a great debugging tool!
If you have problems with understanding the error messages:
- use diagnostics;
It's recommended to declare all variables with my() first
use strict; forces you to do that!
my($x) = value;
use CGI::Carp qw(fatalsToBrowser)
- You'll see a lot of compiler messages (if you had any problems)
use: open(...) or die "can't open the file: $!";
- Not checking the result of any IO isn't good.
Don't forget the lock the file!
use Fcntl qw(:flock);
- before reading do:
flock(TXT, LOCK_SH);
- before writing do:
flock(TXT, LOCK_EX);
- before appending do:
flock(TXT, LOCK_EX);
seek(TXT, 0, 2) or die "Can't seek new EOF: $!"; # File size might changed after lock was released!
You're using the CGI module, why not using the header() method??? print $query->header('text/html');
So in other words:
#!/usr/bin/perl -w
use strict;
use diagnostics;
use CGI();
use CGI::Carp qw(fatalsToBrowser);
use Fcntl qw(:flock);
my $query = new CGI;
my $file = $query -> param('file');
open (TXT, $file) or die "Can't open $file: $!";
flock(TXT, LOCK_SH); # no one can edit the file now.
my @text = <TXT>;
close (TXT);
open (DATA, ">>xmlWeave.xml") or die "Can't open xml: $!";
lock(DATA, LOCK_EX); # waits until no-one uses the file, and blocks it then.
seek(DATA, 0,0) or die "Can't seek new EOF: $!";
print DATA @text; # all in once; print can handle array's
close(DATA);
print $query -> header('text/html');
print <<HTML_PAGE; # nice <<HERE; block
<html><h1>
A Documentation file has been created!</h1>
Please open xmlWeave in a broswer to see complete documentation file
</html>
HTML_PAGE
Voila! 
PS. what will happen if your users call your script like this:
script.cgi?file=/etc/passwd
This might be something you want to watch out for! Good luck!
Yet Another Perl Programmer
_________________________________
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More then 3500 X-Forum [url=http://www.codingdomain.com/cgi-perl/downloads/x-forum]Downloads! 
(This post was edited by yapp on Apr 18, 2002, 10:00 AM)
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