[30082] in Perl-Users-Digest
Perl-Users Digest, Issue: 1325 Volume: 11
daemon@ATHENA.MIT.EDU (Perl-Users Digest)
Sun Mar 2 00:14:14 2008
Date: Sat, 1 Mar 2008 21:14:06 -0800 (PST)
From: Perl-Users Digest <Perl-Users-Request@ruby.OCE.ORST.EDU>
To: Perl-Users@ruby.OCE.ORST.EDU (Perl-Users Digest)
Perl-Users Digest Sat, 1 Mar 2008 Volume: 11 Number: 1325
Today's topics:
Re: Tecnique and/or Modules for Perl and HTML <RedGrittyBrick@SpamWeary.foo>
Re: Tecnique and/or Modules for Perl and HTML <ben@morrow.me.uk>
Re: Tecnique and/or Modules for Perl and HTML <pgodfrin@gmail.com>
Re: Tecnique and/or Modules for Perl and HTML <pgodfrin@gmail.com>
use CGI::Carp qw(fatalsToBrowser) not sending file hand <bennett@peacefire.org>
Re: use CGI::Carp qw(fatalsToBrowser) not sending file xhoster@gmail.com
Digest Administrivia (Last modified: 6 Apr 01) (Perl-Users-Digest Admin)
----------------------------------------------------------------------
Date: Sat, 01 Mar 2008 19:26:57 +0000
From: RedGrittyBrick <RedGrittyBrick@SpamWeary.foo>
Subject: Re: Tecnique and/or Modules for Perl and HTML
Message-Id: <xIGdncEw2PuTM1TaRVnyhAA@bt.com>
pgodfrin wrote:
> On Mar 1, 10:42 am, Ron Bergin <r...@i.frys.com> wrote:
>> On Mar 1, 7:42 am, pgodfrin <pgodf...@gmail.com> wrote:
>>
>>
>>
>>> Greetings,
>>> Could someone point me in the right direction? I'm not a web developer
>>> - just a budding perl dude (who's really a database guy).
>>> I'd like to (at first) read from database (using DBI) and display the
>>> contents on a web page. The trick is I want to do it on the same page
>>> that the action button resides and pop the output of the perl program
>>> into a scrollable box. Nothing fancy - just output some data from a
>>> database call. Eventually I'd like to be able to pass variables from a
>>> form to the waiting perl program
>>> There is a bunch of confusing stuff out there everything from
>>> javascript to embperl and then Mason. And the unspeakable PHP of
>>> course...
>>> Can anyone offer some advice where I should go? (ok - no wisecracks...
>>> <grin>)
>>> thanks,
>>> pg
>> Have you looked at the CGI module? The synopsis section will give you
>> a hint on part of what you need. By the time you finish reading the
>> doc, you should have a pretty good idea where to start. After you've
>> made an attempt, post back with specific questions and example code
>> that demonstrates the problem that you're having.http://search.cpan.org/~lds/CGI.pm-3.33/CGI.pm
>
> Yep - I've even run the samples. Perhaps it's a conceptual thing, but
> it seems to me that the CGI module is all encompassing. When it's run
> - it must produce the entire web page. Which is not what I think I
> want.
>
> I'm not having a problem per se, but a conceptual quagmire - I have a
> web page, I just want to slap a table or text box in the middle of it
> with data from a perl DBI query. Maybe that's not how you do it...
> pg
Never having used DBI, but having Google to hand,
I'd try something like (untested):
---------------------- 8< ---------------------
#!perl
use strict;
use warnings;
use CGI qw/:standard/;
use CGI::Carp qw/warningsToBrowser fatalsToBrowser/;
use DBI
my $dbh = DBI->connect('dbi:DBMSNAME:whatever','pgodfrin','fred')
or die "Can't connect to database because $DBI::errstr";
my $sql = 'SELECT id, name, title, phone FROM employees';
my $sth = $dbh->prepare($sql);
$sth->execute();
my($id, $name, $title, $phone);
$sth->bind_columns(undef, \$id, \$name, \$title, \$phone);
my $rows;
while($sth->fetch()) {
$rows .= Tr(td($id),td($name),td($title),td($phone));
}
$sth->finish();
$dbh->disconnect();
print
header(),
start_html(),
h1('Employees'),
table($rows),
end_html();
---------------------- 8< ---------------------
What have you tried?
------------------------------
Date: Sat, 1 Mar 2008 19:29:10 +0000
From: Ben Morrow <ben@morrow.me.uk>
Subject: Re: Tecnique and/or Modules for Perl and HTML
Message-Id: <6dno95-i0b.ln1@osiris.mauzo.dyndns.org>
Quoth pgodfrin <pgodfrin@gmail.com>:
> On Mar 1, 10:42 am, Ron Bergin <r...@i.frys.com> wrote:
> > On Mar 1, 7:42 am, pgodfrin <pgodf...@gmail.com> wrote:
> >
> > > I'd like to (at first) read from database (using DBI) and display the
> > > contents on a web page. The trick is I want to do it on the same page
> > > that the action button resides and pop the output of the perl program
> > > into a scrollable box. Nothing fancy - just output some data from a
> > > database call. Eventually I'd like to be able to pass variables from a
> > > form to the waiting perl program
> >
> > Have you looked at the CGI module? The synopsis section will give you
> > a hint on part of what you need. By the time you finish reading the
> > doc, you should have a pretty good idea where to start. After you've
> > made an attempt, post back with specific questions and example code
> > that demonstrates the problem that you're
> having.http://search.cpan.org/~lds/CGI.pm-3.33/CGI.pm
>
> Yep - I've even run the samples. Perhaps it's a conceptual thing, but
> it seems to me that the CGI module is all encompassing. When it's run
> - it must produce the entire web page. Which is not what I think I
> want.
It is, though :). Except for modern JS-based techniques like Ajax, which
I would suggest you avoid for now, the way the web works is whole pages
at a time. If you re-read the docs for CGI.pm, you will find it has lots
of methods for re-requesting the current page with something slightly
different, and for preserving your program's state across several
invocations of the 'same' page.
Try this. It's not necessarily a good example of how to use CGI, the
HTML-generation is very simple-minded, and of course passing anything
to 'eval' is just downright stupid; but it should give you an idea of
how such programs work.
#!/usr/bin/perl -T
use strict;
use warnings;
use CGI;
my $Q = CGI->new;
my $url = $Q->url;
print $Q->header;
print <<HTML;
<html>
<head><title>Calculator</title></head>
<body>
<h2>Enter an arithmetic expression:</h2>
<form action="$url" method="POST">
<input name="eval"> <input type="submit" value="Eval">
</form>
HTML
if (my $expr = $Q->param('eval')) {
print <<HTML;
<!-- $expr -->
HTML
if (my ($safe) = $expr =~ m{^([-+/*()\d. ]+)$}) {
my $val = eval $safe;
if (defined $val) {
print <<HTML;
<p>Result: $val.</p>
HTML
}
else {
print <<HTML;
<p style="color: red;">Syntax error: $@</p>
HTML
}
}
else {
print <<HTML;
<p style="color: red;">Bad input.</p>
HTML
}
}
print <<HTML;
</body>
</html>
HTML
__END__
Ben
------------------------------
Date: Sat, 1 Mar 2008 14:36:23 -0800 (PST)
From: pgodfrin <pgodfrin@gmail.com>
Subject: Re: Tecnique and/or Modules for Perl and HTML
Message-Id: <9894764a-3387-41fa-a27e-545bf71e0bee@s12g2000prg.googlegroups.com>
On Mar 1, 1:29 pm, Ben Morrow <b...@morrow.me.uk> wrote:
> Quoth pgodfrin <pgodf...@gmail.com>:
>
>
>
> > On Mar 1, 10:42 am, Ron Bergin <r...@i.frys.com> wrote:
> > > On Mar 1, 7:42 am, pgodfrin <pgodf...@gmail.com> wrote:
>
> > > > I'd like to (at first) read from database (using DBI) and display the
> > > > contents on a web page. The trick is I want to do it on the same page
> > > > that the action button resides and pop the output of the perl program
> > > > into a scrollable box. Nothing fancy - just output some data from a
> > > > database call. Eventually I'd like to be able to pass variables from a
> > > > form to the waiting perl program
>
> > > Have you looked at the CGI module? The synopsis section will give you
> > > a hint on part of what you need. By the time you finish reading the
> > > doc, you should have a pretty good idea where to start. After you've
> > > made an attempt, post back with specific questions and example code
> > > that demonstrates the problem that you're
> > having.http://search.cpan.org/~lds/CGI.pm-3.33/CGI.pm
>
> > Yep - I've even run the samples. Perhaps it's a conceptual thing, but
> > it seems to me that the CGI module is all encompassing. When it's run
> > - it must produce the entire web page. Which is not what I think I
> > want.
>
> It is, though :). Except for modern JS-based techniques like Ajax, which
> I would suggest you avoid for now, the way the web works is whole pages
> at a time. If you re-read the docs for CGI.pm, you will find it has lots
> of methods for re-requesting the current page with something slightly
> different, and for preserving your program's state across several
> invocations of the 'same' page.
>
> Try this. It's not necessarily a good example of how to use CGI, the
> HTML-generation is very simple-minded, and of course passing anything
> to 'eval' is just downright stupid; but it should give you an idea of
> how such programs work.
>
> #!/usr/bin/perl -T
>
> use strict;
> use warnings;
> use CGI;
>
> my $Q = CGI->new;
> my $url = $Q->url;
>
> print $Q->header;
>
> print <<HTML;
> <html>
> <head><title>Calculator</title></head>
> <body>
> <h2>Enter an arithmetic expression:</h2>
> <form action="$url" method="POST">
> <input name="eval"> <input type="submit" value="Eval">
> </form>
> HTML
>
> if (my $expr = $Q->param('eval')) {
>
> print <<HTML;
> <!-- $expr -->
> HTML
>
> if (my ($safe) = $expr =~ m{^([-+/*()\d. ]+)$}) {
> my $val = eval $safe;
> if (defined $val) {
> print <<HTML;
> <p>Result: $val.</p>
> HTML
> }
> else {
> print <<HTML;
> <p style="color: red;">Syntax error: $@</p>
> HTML
> }
> }
> else {
> print <<HTML;
> <p style="color: red;">Bad input.</p>
> HTML
> }
>
> }
>
> print <<HTML;
> </body>
> </html>
> HTML
>
> __END__
>
> Ben
Hi Ben,
Always good to hear from you. I feel like - forgive the expression -
you're my fairy godmother... <grin>
I will read the docs a little closer - I must have been looking for a
silver bullet and peeked at the doc in a somewhat lazy manner.
thanks, as always,
pg
------------------------------
Date: Sat, 1 Mar 2008 19:16:35 -0800 (PST)
From: pgodfrin <pgodfrin@gmail.com>
Subject: Re: Tecnique and/or Modules for Perl and HTML
Message-Id: <70e5f6b3-c4a1-4b28-a9d8-3baedefab0ec@s13g2000prd.googlegroups.com>
On Mar 1, 4:36 pm, pgodfrin <pgodf...@gmail.com> wrote:
> On Mar 1, 1:29 pm, Ben Morrow <b...@morrow.me.uk> wrote:
>
>
>
> > Quoth pgodfrin <pgodf...@gmail.com>:
>
> > > On Mar 1, 10:42 am, Ron Bergin <r...@i.frys.com> wrote:
> > > > On Mar 1, 7:42 am, pgodfrin <pgodf...@gmail.com> wrote:
>
> > > > > I'd like to (at first) read from database (using DBI) and display the
> > > > > contents on a web page. The trick is I want to do it on the same page
> > > > > that the action button resides and pop the output of the perl program
> > > > > into a scrollable box. Nothing fancy - just output some data from a
> > > > > database call. Eventually I'd like to be able to pass variables from a
> > > > > form to the waiting perl program
>
> > > > Have you looked at the CGI module? The synopsis section will give you
> > > > a hint on part of what you need. By the time you finish reading the
> > > > doc, you should have a pretty good idea where to start. After you've
> > > > made an attempt, post back with specific questions and example code
> > > > that demonstrates the problem that you're
> > > having.http://search.cpan.org/~lds/CGI.pm-3.33/CGI.pm
>
> > > Yep - I've even run the samples. Perhaps it's a conceptual thing, but
> > > it seems to me that the CGI module is all encompassing. When it's run
> > > - it must produce the entire web page. Which is not what I think I
> > > want.
>
> > It is, though :). Except for modern JS-based techniques like Ajax, which
> > I would suggest you avoid for now, the way the web works is whole pages
> > at a time. If you re-read the docs for CGI.pm, you will find it has lots
> > of methods for re-requesting the current page with something slightly
> > different, and for preserving your program's state across several
> > invocations of the 'same' page.
>
> > Try this. It's not necessarily a good example of how to use CGI, the
> > HTML-generation is very simple-minded, and of course passing anything
> > to 'eval' is just downright stupid; but it should give you an idea of
> > how such programs work.
>
> > #!/usr/bin/perl -T
>
> > use strict;
> > use warnings;
> > use CGI;
>
> > my $Q = CGI->new;
> > my $url = $Q->url;
>
> > print $Q->header;
>
> > print <<HTML;
> > <html>
> > <head><title>Calculator</title></head>
> > <body>
> > <h2>Enter an arithmetic expression:</h2>
> > <form action="$url" method="POST">
> > <input name="eval"> <input type="submit" value="Eval">
> > </form>
> > HTML
>
> > if (my $expr = $Q->param('eval')) {
>
> > print <<HTML;
> > <!-- $expr -->
> > HTML
>
> > if (my ($safe) = $expr =~ m{^([-+/*()\d. ]+)$}) {
> > my $val = eval $safe;
> > if (defined $val) {
> > print <<HTML;
> > <p>Result: $val.</p>
> > HTML
> > }
> > else {
> > print <<HTML;
> > <p style="color: red;">Syntax error: $@</p>
> > HTML
> > }
> > }
> > else {
> > print <<HTML;
> > <p style="color: red;">Bad input.</p>
> > HTML
> > }
>
> > }
>
> > print <<HTML;
> > </body>
> > </html>
> > HTML
>
> > __END__
>
> > Ben
>
> Hi Ben,
> Always good to hear from you. I feel like - forgive the expression -
> you're my fairy godmother... <grin>
>
> I will read the docs a little closer - I must have been looking for a
> silver bullet and peeked at the doc in a somewhat lazy manner.
>
> thanks, as always,
> pg
sim-sala-bim...
I have seen the light...
I think I'm gonna start calling you Yoda...
pg
------------------------------
Date: Sat, 1 Mar 2008 15:17:28 -0800 (PST)
From: Bennett Haselton <bennett@peacefire.org>
Subject: use CGI::Carp qw(fatalsToBrowser) not sending file handle errors to browser
Message-Id: <0226b3d2-96c8-4933-9c00-008ed95fd519@d4g2000prg.googlegroups.com>
I wrote the following script to test whether, if I try writing to an
invalid filehandle, the error message would get sent to the browser:
>>>
#!/usr/bin/perl
use strict;
use IO::File;
use CGI::Carp qw(fatalsToBrowser);
print "Content-type: text/html\n\n";
# This will not open a valid filehandle since the script runs as
nobody
my $fh = IO::File->new("> doesnotexist.txt");
print $fh "foo";
die "Die here, if you get this far";
>>>
The line 'print $fh "foo";' does generate an error, however that error
gets written to /var/log/httpd/error_log where it says "Can't use an
undefined value as a symbol reference at /var/www/html/carptest/open-
wrong-file-with-carp-fatalstobrowser.cgi line 11". I want that sent
to the *browser*, not written to the log file. The line 'die "Die
here, if you get this far";' never gets executed.
The CGI::Carp page says that "Nonfatal errors will still be directed
to the log file only". But isn't the file handle error a *fatal*
error, since it caused the script to exit before getting to the 'die
"Die here, if you get this far";' line? And if it's a fatal error,
why didn't it get sent to the browser?
------------------------------
Date: 02 Mar 2008 02:57:51 GMT
From: xhoster@gmail.com
Subject: Re: use CGI::Carp qw(fatalsToBrowser) not sending file handle errors to browser
Message-Id: <20080301215754.859$TX@newsreader.com>
Bennett Haselton <bennett@peacefire.org> wrote:
> I wrote the following script to test whether, if I try writing to an
> invalid filehandle, the error message would get sent to the browser:
>
> >>>
> #!/usr/bin/perl
>
> use strict;
> use IO::File;
> use CGI::Carp qw(fatalsToBrowser);
>
> print "Content-type: text/html\n\n";
>
> # This will not open a valid filehandle since the script runs as
> nobody
> my $fh = IO::File->new("> doesnotexist.txt");
> print $fh "foo";
>
> die "Die here, if you get this far";
> >>>
>
> The line 'print $fh "foo";' does generate an error, however that error
> gets written to /var/log/httpd/error_log where it says "Can't use an
> undefined value as a symbol reference at /var/www/html/carptest/open-
> wrong-file-with-carp-fatalstobrowser.cgi line 11". I want that sent
> to the *browser*, not written to the log file. The line 'die "Die
> here, if you get this far";' never gets executed.
I can't replicate your problem.
perl -le 'use CGI::Carp; print $CGI::Carp::VERSION'
1.29
perl -le 'use CGI::Carp qw(fatalsToBrowser); use IO::File;
my $fh=IO::File->new("/fooasdf"); print $fh "foo"'
Content-type: text/html
<h1>Software error:</h1>
<pre>Can't use an undefined value as a symbol reference at -e line 1.
...
Xho
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Date: 6 Apr 2001 21:33:47 GMT (Last modified)
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------------------------------
End of Perl-Users Digest V11 Issue 1325
***************************************
