[24341] in Perl-Users-Digest
Perl-Users Digest, Issue: 6530 Volume: 10
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Thu May 6 11:10:55 2004
Date: Thu, 6 May 2004 08:10:17 -0700 (PDT)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Thu, 6 May 2004 Volume: 10 Number: 6530
Today's topics:
Re: Strange DBI problem (Gil Vautour)
Re: Strange DBI problem <dwall@fastmail.fm>
Re: Text repetition operator (Anno Siegel)
Use of goto after an alarm? axel@white-eagle.co.uk
Re: Use of goto after an alarm? <for-spammers-only@web.de>
Re: Use of goto after an alarm? (Anno Siegel)
Re: Use of goto after an alarm? axel@white-eagle.co.uk
Re: Use of goto after an alarm? <for-spammers-only@web.de>
Re: Use of goto after an alarm? <for-spammers-only@web.de>
Re: win32::ole and excel VBA macro conversion: SmallScr <domenico_discepola@quadrachemicals.com>
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: 6 May 2004 05:03:48 -0700
From: vautour@unb.ca (Gil Vautour)
Subject: Re: Strange DBI problem
Message-Id: <7087ed01.0405060403.3b215570@posting.google.com>
"David K. Wall" <dwall@fastmail.fm> wrote in message news:<Xns94E0B01C72E79dkwwashere@216.168.3.30>...
> Gil Vautour <vautour@unb.ca> wrote:
>
> > I have a Perl CGI script that was failing with a Server 500 error
> > and I think I have traced it back to a DBI subroutine that is
> > inserting the form data into a MySql table. I can submit the form
> > with identical data except for one field (email) and it will work
> > sometimes and sometimes not depending on the email address that is
> > submitted. Has anyone seem anything like this or have any idea of
> > what I should be looking for?
>
> I have some guesses, but without code or error messages, guesses are
> all they would be.
>
> Check the server logs and see what the error is. If you don't have
> access to the server logs, put
>
> use CGI::Carp qw(fatalsToBrowser);
>
> in your program and try it again. That will send warnings and error
> messages to the browser. If you can't figure it out from that, post a
> *short* piece of code that exhibits the problem.
>
> OK, now the guess: I suspect you're not using placeholders and
> instead are constructing the SQL something like this:
>
> my $email = param('email');
> my $sql = "insert into TableName (email) values ($email)";
> my $dbh = DBI->connect( ... );
> $dbh->do($sql);
>
> Or maybe the '@' in the email address is being interpreted as the
> beginning of an array name. (not as likely, IMO, but possible)
Well I have been using Carp but it still only produces a 500 error. I
don't have direct access to the server logs, I had a sys admin take a
look for me. The only thing he could find was a mal-formed Header
problem, but it seemed like this was caused by the script failing in
general. Here is a snippet of the DBI code that I think is where the
problem occurs:
my $dbh = DBI->connect("DBI:mysql:$database:$hostname",$user,$password)||
die "Connect failed: $dbh->errstr\n";
my($query) = @_;
my(@form,$values,$key);
foreach $key ($query->param) {
if ($query->param($key) ne "") {
$values = $query->param($key);
$values = $dbh->quote($values);
push @form,$values;
} else {
$values = "null";
push @form,$values;
}
}
my $sql = "insert into Responses
values(null,$form[0],$form[1],$form[2],$form[3],$form[4],".
"$form[5],$form[6],$form[7],$form[8],$form[9],$form[10],$form[11],$form[12],$form[13],NOW());";
my $sth = $dbh->prepare($sql) || die "Can't prepare $sql:
$dbh->errstr\n";
my $rv = $sth->execute || die "Can't execute $sql: $sth->errstr\n";
my $rc = $sth->finish;
$rc = $dbh->disconnect;
}
Thanks,
------------------------------
Date: Thu, 06 May 2004 14:07:49 -0000
From: "David K. Wall" <dwall@fastmail.fm>
Subject: Re: Strange DBI problem
Message-Id: <Xns94E1670CEA42Fdkwwashere@216.168.3.30>
Gil Vautour <vautour@unb.ca> wrote:
> "David K. Wall" <dwall@fastmail.fm> wrote in message
> news:<Xns94E0B01C72E79dkwwashere@216.168.3.30>...
>> Gil Vautour <vautour@unb.ca> wrote:
>>
>> > I have a Perl CGI script that was failing with a Server 500
>> > error and I think I have traced it back to a DBI subroutine
>> > that is inserting the form data into a MySql table. I can
>> > submit the form with identical data except for one field
>> > (email) and it will work sometimes and sometimes not depending
>> > on the email address that is submitted. Has anyone seem
>> > anything like this or have any idea of what I should be looking
>> > for?
>>
>> I have some guesses, but without code or error messages, guesses
>> are all they would be.
>>
>> Check the server logs and see what the error is. If you don't
>> have access to the server logs, put
>>
>> use CGI::Carp qw(fatalsToBrowser);
>>
>> in your program and try it again. That will send warnings and
>> error messages to the browser. If you can't figure it out from
>> that, post a *short* piece of code that exhibits the problem.
>>
[snip my guess]
>
> Well I have been using Carp but it still only produces a 500
> error.
Not Carp. CGI::Carp. There *is* a difference; please be precise. Do
you mean you put the statement
use CGI::Carp qw(fatalsToBrowser);
in your program and you *still* get a 500 error?
What happens when you run it from the command line with the same
data?
> I don't have direct access to the server logs, I had a sys
> admin take a look for me. The only thing he could find was a
> mal-formed Header problem, but it seemed like this was caused by
> the script failing in general. Here is a snippet of the DBI code
> that I think is where the problem occurs:
>
> my $dbh =
> DBI->connect("DBI:mysql:$database:$hostname",$user,$password)||
> die "Connect failed: $dbh->errstr\n";
>
> my($query) = @_;
> my(@form,$values,$key);
>
> foreach $key ($query->param) {
It's better to confine $key to the loop, e.g.;
foreach my $key ( $query->param ) {
I'd put $values inside the loop, too.
my $values = $query->param($key);
if ($values ne '') {
# ...
> if ($query->param($key) ne "") {
^^
As a matter of style, single quotes are often preferred when there's
no variable interpolation happening.
> $values = $query->param($key);
> $values = $dbh->quote($values);
Hmm, the use of quote() makes my guess about placeholders wrong, as
placeholders implicitly use the quote method.
> push @form,$values;
> } else {
> $values = "null";
> push @form,$values;
> }
>}
>
> my $sql = "insert into Responses
> values(null,$form[0],$form[1],$form[2],$form[3],$form[4],".
> "$form[5],$form[6],$form[7],$form[8],$form[9],$form[10],$form[11],$
> form[12],$form[13],NOW());";
This seems to me a roundabout way of doing things. Someone please
correct me if I'm wrong, but I've generally done something like this:
# untested
my $sth = $dbh->prepare(q{
insert into Responses (colname1, colname2)
values (?,?)
})
or die $dbh->errstr;
$sth->execute( param('column1'), param('column2') )
or die $sth->errstr;
It seems odd that you never actually say which columns into which
you're inserting data, but a quick test shows that it works. I never
knew that. (and now that I know it, I don't really like it. it seems
sloppy.)
> my $sth = $dbh->prepare($sql) || die "Can't prepare $sql:
> $dbh->errstr\n";
>
> my $rv = $sth->execute || die "Can't execute $sql:
> $sth->errstr\n";
>
> my $rc = $sth->finish;
> $rc = $dbh->disconnect;
>
>}
I don't see anything obviously wrong, but I've been mistaken before.
As I said above, run the program from the command line with the same
data and see what happens. It's difficult to debug something without
error and warning messages.
------------------------------
Date: 6 May 2004 10:17:36 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Text repetition operator
Message-Id: <c7d3c0$6s1$5@mamenchi.zrz.TU-Berlin.DE>
Mark Clements <mark.clements@kcl.ac.uk> wrote in comp.lang.perl.misc:
> Anno Siegel wrote:
>
>
> > As Tony Curtis noted, "x" evaluates its argument only once, so the
> > result will always be a repetition of the same string, even if you
> > overload stringification (or tie a variable appropriately).
> sure - but it could probably be used to produce the required output in
> one fell swoop. You are
> right, though: it's unlikely that this is desirable.
>
> > But even if it worked, the result would be seriously obfuscated code.
> agreed.
>
> > Exploiting side effects is always sneaky; using a side effect that
> > happens on every *access* is doubly so.
> overloading should always be used with caution, similarly tie. I got the
> impression that the OP
> was more interested in playing "I thought it would be really cool if..."
use overload '""' => sub { ${ $_[ 0]} ++ };
my $x = bless \ (my $y = 'a');
print $x, $x, $x, "\n"; # abc
Abigail uses something ismilar in one of her japh's, and that is
where code like this belongs :)
Anno
------------------------------
Date: Thu, 06 May 2004 12:38:08 GMT
From: axel@white-eagle.co.uk
Subject: Use of goto after an alarm?
Message-Id: <Qkqmc.707$Ur7.528@nurse.blueyonder.net>
I am puzzled by the strange action of 'goto' (or lack of action) when
an alarm call is caught.
Code:
======================
print "Ready> ";
local $SIG{ALRM} = sub {
print "Nope\n";
goto LAB1;
print "Nope 2\n";
};
alarm 2;
eval { # XXX
$a = <STDIN>;
}; # XXX
$b = alarm (0);
if ($b > 0) {
print "OK: $b: $a";
} else {
print "Seems to have timed out: $a";
}
exit;
LAB1:
print "\nTimed out\n";
exit;
====================== produces:
Ready> Nope
Seems to have timed out:
======================
Removing the eval statements (marked with comments 'XXX' above),
produces:
======================
Ready> Nope
Can't find label LAB1 at ./q1.pl line 8.
======================
Please no flames about the use of 'goto'... I am just curious as to why
it seems to screw up in these circumstances.
Axel
------------------------------
Date: Thu, 06 May 2004 15:01:35 +0200
From: Toni Erdmann <for-spammers-only@web.de>
Subject: Re: Use of goto after an alarm?
Message-Id: <c7dcvk$ksu$1@news.mch.sbs.de>
axel@white-eagle.co.uk wrote:
> I am puzzled by the strange action of 'goto' (or lack of action) when
> an alarm call is caught.
>
> Code:
>
> ======================
> print "Ready> ";
> local $SIG{ALRM} = sub {
> print "Nope\n";
> goto LAB1;
> print "Nope 2\n";
> };
> alarm 2;
> eval { # XXX
> $a = <STDIN>;
> }; # XXX
> $b = alarm (0);
> if ($b > 0) {
> print "OK: $b: $a";
> } else {
> print "Seems to have timed out: $a";
> }
> exit;
>
> LAB1:
> print "\nTimed out\n";
> exit;
>
> ====================== produces:
> Ready> Nope
> Seems to have timed out:
> ======================
>
> Removing the eval statements (marked with comments 'XXX' above),
> produces:
> ======================
> Ready> Nope
> Can't find label LAB1 at ./q1.pl line 8.
> ======================
>
> Please no flames about the use of 'goto'... I am just curious as to why
> it seems to screw up in these circumstances.
LAB1 is a label, which is valid inside the "sub{}" only.
You can't 'goto' == exit out of a subroutine.
Toni
------------------------------
Date: 6 May 2004 13:12:12 GMT
From: anno4000@lublin.zrz.tu-berlin.de (Anno Siegel)
Subject: Re: Use of goto after an alarm?
Message-Id: <c7ddjc$ds8$1@mamenchi.zrz.TU-Berlin.DE>
Toni Erdmann <for-spammers-only@web.de> wrote in comp.lang.perl.misc:
[ in reply to a question by axel@white-eagle.co.uk about goto]
> LAB1 is a label, which is valid inside the "sub{}" only.
> You can't 'goto' == exit out of a subroutine.
If you answer questions, please look things up instead of making them up.
From "perldoc -f goto":
.... It can
be used to go almost anywhere else within the
dynamic scope, including out of subroutines...
Anno
------------------------------
Date: Thu, 06 May 2004 13:14:16 GMT
From: axel@white-eagle.co.uk
Subject: Re: Use of goto after an alarm?
Message-Id: <ISqmc.11970$f62.9545@pathologist.blueyonder.net>
Toni Erdmann <for-spammers-only@web.de> wrote:
> LAB1 is a label, which is valid inside the "sub{}" only.
> You can't 'goto' == exit out of a subroutine.
I had wondered about that, althought the Camel book explicitly says that
it is possible to use goto out of a subroutine... and I have tested
it to confirm:
====== code
xx();
print "Goto Failed\n";
exit;
LAB1:
print "'Goto' worked\n";
exit;
sub xx { goto LAB1; }
====== results
'Goto' worked
======
Axel
------------------------------
Date: Thu, 06 May 2004 16:50:35 +0200
From: Toni Erdmann <for-spammers-only@web.de>
Subject: Re: Use of goto after an alarm?
Message-Id: <c7djbr$f1a$1@news.mch.sbs.de>
axel@white-eagle.co.uk wrote:
> Toni Erdmann <for-spammers-only@web.de> wrote:
>
>>LAB1 is a label, which is valid inside the "sub{}" only.
>>You can't 'goto' == exit out of a subroutine.
>
>
> I had wondered about that, althought the Camel book explicitly says that
> it is possible to use goto out of a subroutine... and I have tested
> it to confirm:
>
> ====== code
>
> xx();
> print "Goto Failed\n";
> exit;
>
> LAB1:
> print "'Goto' worked\n";
> exit;
>
> sub xx { goto LAB1; }
> ====== results
> 'Goto' worked
> ======
Sorry, my fault.
The difference between your first posting and this one here is
that "LAB1:" here is declared/used before sub xx {} is defined.
Maybe this can explain the error?
Toni
------------------------------
Date: Thu, 06 May 2004 17:04:17 +0200
From: Toni Erdmann <for-spammers-only@web.de>
Subject: Re: Use of goto after an alarm?
Message-Id: <c7dk5i$hlf$1@news.mch.sbs.de>
Toni Erdmann wrote:
> axel@white-eagle.co.uk wrote:
>
>> Toni Erdmann <for-spammers-only@web.de> wrote:
>>
>>> LAB1 is a label, which is valid inside the "sub{}" only.
>>> You can't 'goto' == exit out of a subroutine.
>>
>>
>>
>> I had wondered about that, althought the Camel book explicitly says that
>> it is possible to use goto out of a subroutine... and I have tested
>> it to confirm:
>>
>> ====== code
>>
>> xx();
>> print "Goto Failed\n";
>> exit;
>>
>> LAB1: print "'Goto' worked\n";
>> exit;
>>
>> sub xx { goto LAB1; }
>> ====== results
>> 'Goto' worked
>> ======
>
>
> Sorry, my fault.
>
> The difference between your first posting and this one here is
> that "LAB1:" here is declared/used before sub xx {} is defined.
>
> Maybe this can explain the error?
No it does not explain the problem. I tried it.
Toni
------------------------------
Date: Thu, 6 May 2004 09:48:53 -0400
From: "Domenico Discepola" <domenico_discepola@quadrachemicals.com>
Subject: Re: win32::ole and excel VBA macro conversion: SmallScroll
Message-Id: <Jlrmc.37072$kc2.548331@nnrp1.uunet.ca>
"Bob Walton" <invalid-email@rochester.rr.com> wrote in message
news:4099940B.10103@rochester.rr.com...
> Domenico Discepola wrote:
>
> > Hello all. I'm trying to write some code to scroll my window pane (in
> > Microsoft Excel) & wish convert the following VBA macro to Perl format:
> > ActiveWindow.SmallScroll ToRight:=-3
> >
> > I have defined the following: $excel (excel object), $worksheet
(worksheet
> > object), $workbook (workbook object).
> >
> > I tried:
> > $excel->ActiveWindow->SmallScroll->{ToRight} = -3;
> > $workbook->ActiveWindow->SmallScroll->{ToRight} = -3;
> > $worksheet->ActiveWindow->SmallScroll->{ToRight} = -3;
> >
> > all without success... Any suggestions would be appreciated.
>
>
> Try:
>
> $excel->ActiveWindow->SmallScroll({ToRight=>-3});
>
> --
> Bob Walton
Thanks Bob - it worked like a charm. Now, here's my next question... I
find it very difficult to translate VBA into Perl. The existing
documentation is very basic. For instance, although Activestate's ASPN
provides a general example of how to translate VBA into Perl, it could not
provide me with the proper method that you did (as you can tell by my
trial-and-error approach). One trick I learned from someone in the
newsgroups is outlined in the following code. He suggested I print out all
key/values in the hash associated with each object. This way, you can drill
down and search through all methods available in each object. However, I
was still unable to find out how to scroll an Excel worksheet. My question
is, does anyone know of a good reference guide/book that gives lots of
concrete examples? I read the Win32 Perl Programming book by Dave Roth and
he does provide great examples but not enough of them. I would even go
about suggesting the development of some kind of module that helps
individuals drill down into various objects' methods and properties...
#!perl
use strict;
use warnings;
use Win32::OLE;
sub quitapp () {
my ( $ComObject ) = @_;
$ComObject->Quit();
}
sub main () {
my $class = "Excel.Application";
#Create application class called "$excel"
my $excel = Win32::OLE->GetActiveObject( $class );
if ( ! $excel ) {
$excel = new Win32::OLE( $class, \&quitapp ) || die "Could not create COM
${class} object\n";
}
$excel->{SheetsInNewWorkbook} = 1;
#create a new workbook
my $workbook = $excel->Workbooks->Add();
#create a new worksheet
my $worksheet = $workbook->WorkSheets(1);
$worksheet->{Name} = "test";
while ( my ($key, $value) = each %$excel ) {
#print "$key = $value\n";
if ( $key eq 'ActiveWindow' ) {
while ( my ( $key2, $value2 ) = each %$value ) {
#print "$key2 = $value2\n";
if ( $key2 eq 'Panes' ) {
while ( my ( $key3, $value3 ) = each %$value2 ) {
print "$key3 = $value3\n";
}
}
}
}
}
$workbook->Close();
sleep(2);
$excel->Quit();
}
&main();
exit 0;
------------------------------
Date: 6 Apr 2001 21:33:47 GMT (Last modified)
From: Perl-Users-Request@ruby.oce.orst.edu (Perl-Users-Digest Admin)
Subject: Digest Administrivia (Last modified: 6 Apr 01)
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------------------------------
End of Perl-Users Digest V10 Issue 6530
***************************************
