I find HTML::Template great and in my personal mission to encourage people not to embed HTML in perl scripts, here is a few examples to get you started. I've tried to cover things I didn't get when I first started and could have saved me some work.

Lazy form handling with associate

HTML::Template has a cunning feature which I didn't notice in my first few passes through the documentation. You can give it your CGI object and it will fill in template values with them.

color1.tmpl:


<form action="color.pl" method="post">
<p>Your name: <input type="text" name="name" 
  value="<TMPL_VAR NAME=NAME>"></p>
<p>Your favorite color: <input type="text" name="color"
  value="<TMPL_VAR NAME=COLOR>"></p>
<p><input type="submit"></p>
</form>

color2.tmpl:


<p>Hello, <b><TMPL_VAR NAME=NAME></b>. A little
birdy told me your favorite color is <b><TMPL_VAR NAME=COLOR></b>.

color.pl:


use CGI;
use HTML::Template;

my $cgi = CGI->new; 
my $template;

print $cgi->header;

if ($cgi->param('name') && $cgi->param('color')) {
    $template = 'color2';
} else {
    $template = 'color1';
}

my $t = HTML::Template->new(filename => "$template.tmpl", associate =>
+ $cgi);
print $t->output;

Cheap Database Output

You want to output a table but are too lazy to code something? HTML::Template to the rescue! param() needs hashrefs and arrayrefs and the DBI functions selectall_hashref and fetchrow_hashref come in very handy.

Perl code:


use DBI;
use CGI;
use HTML::Template;

my $cgi = CGI->new;
my $dbh = DBI->connect('dbi:mysql:xxxx:localhost', 'xxxx', 'xxxx');
my $t = HTML::Template->new(filename => 'db.tmpl');

$t->param(ROWS => $dbh->selectall_hashref('select id, name, price from
+ products'));

$dbh->disconnect;

print $cgi->header;
print $t->output;

Template code:


<table border="1">
<tr><th>ID</th><th>NAME</th><th>PRICE</th></tr>

<TMPL_LOOP ROWS>
    <tr>
        <td><TMPL_VAR NAME=ID></td>
        <td><TMPL_VAR NAME=NAME></td>
        <td><TMPL_VAR NAME=PRICE></td>
    </tr>
</TMPL_LOOP>

</table>

Doing a little bit more...

Perl code:


[snip]

my $rows = $dbh->selectall_hashref('select id, name, price from produc
+ts');
$dbh->disconnect;

my $sum = 0; 
my $i = 0;

foreach (@$rows) {
    $_->{odd} = $i++ % 2;
    $sum += $_->{price};
}

$t->param(ROWS => $rows, TOTAL => $sum);

Template:


<table border="1">
<tr><th>ID</th><th>NAME</th><th>PRICE</th></tr>

<TMPL_LOOP ROWS>
    <tr bgcolor="#<TMPL_IF ODD>666666<TMPL_ELSE>EEEEEE</TMPL_IF>">
        <td><TMPL_VAR NAME=ID></td>
        <td><TMPL_VAR NAME=NAME></td>
        <td><TMPL_VAR NAME=PRICE></td>
    </tr>
</TMPL_LOOP>

</table>

<p>The total is <TMPL_VAR NAME=TOTAL></p>

But I need to process my db output!

I often find I need to do a little work on what's in the database and handling it row by row is easier.

Note the array created so I can pass the same thing every time I create a template. I usually have cache on as I am running under mod_perl and this speeds things up a bit, I tend to turn off strict and die_on_bad_params as I'd rather things looked a bit funky than the script die (especially if it isn't me editing it).

Perl code:


use DBI;
use CGI;
use HTML::Template;

my $cgi = CGI->new;
my $dbh = DBI->connect('dbi:mysql:xxxx:localhost', 'xxxxx', 'xxxx');

my @tmpl_opts = (cache => 1, die_on_bad_params => 0, associate => $cgi
+);

my $sth = $dbh->prepare('select id, name, price, saleprice from produc
+ts');

my ($id, $name, $price, $saleprice);

my $i = 0;
my $sum = 0;

$sth->execute;
$sth->bind_columns(\($id, $name, $price, $saleprice));

while ($sth->fetch) {
    my $real_price = $price < $saleprice ? $price : $saleprice;
    $name =~ s/\b(\w)(\w+)\b/\U$1\L$2/g;
    push @rows, { ID => lc($id), PRICE => $real_price, NAME => $name, 
+ODD => $i++ %2 };
    $sum += $real_price;
}

$sth->finish;

my $t = HTML::Template->new(filename => 'db2.tmpl', @tmpl_opts);
$t->param(ROWS => \@rows, TOTAL => $sum);

print $cgi->header;
print $t->output;

$dbh->disconnect;

Fin

Hope you liked it :)

gav^

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