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Template Toolkit - passing hashes

by punch_card_don (Curate)
on Apr 02, 2007 at 13:05 UTC ( #607815=perlquestion: print w/replies, xml ) Need Help??

punch_card_don has asked for the wisdom of the Perl Monks concerning the following question:

Monday Monks,

Why isn't my hash passed to TT for processing? When I run this, I get one iteration of the template html and with no values inserted.

In the script (snippet):

use DBI; use Template; #get users list from database $sql = "SELECT user_id, ufname, ulname FROM users"; $sth = $dbh->prepare($sql) or die("Could not prepare!" . $dbh->errstr) +; $sth->execute() or die("Could not execute!" . $dbh->errstr); # build data structure while (($user_id, $ufname, $ulname) = $sth->fetchrow_array()) { $data{$user_id} = { ufname => $ufname, ulname => $ulname } } $sth->finish; #prep variables for TT $vars = { data => %data, today => $today }; $template_file = "./template/my_file.htm"; #process file $template->process($template_file, $vars);

and in the template
Call list for [% today %] <p> [% FOREACH user IN data %] Be sure to call [% user.ulname %], [% user.ufname %] [% END %]

I suspect there's something wrong with the way I'm passing the data hash?

Thanks.

updated for typo in code unrelated to question




Forget that fear of gravity,
Get a little savagery in your life.

Replies are listed 'Best First'.
Re: Template Toolkit - passing hashes
by imp (Priest) on Apr 02, 2007 at 13:17 UTC
    Replace this:
    $vars = { data => %data, today => $today };
    With:
    $vars = { data => \%data, today => $today };
    Otherwise perl will expand the %data hash into a list.

    Another problem is that you are building a hash of hashes, but your template seems to expect a list of hashes.

    You should always use both strict and warnings by the way.

      Thanks.

      Another problem is that you are building a hash of hashes, but your template seems to expect a list of hashes.

      But I thought:
      http://www.template-toolkit.org/docs/plain/Manual/Variables.html#Hash_Array_References

      Members of hash arrays are accessed by specifying the hash reference a +nd key separated by the dot '.' operator. my $vars = { 'home' => 'http://www.myserver.com/homepage.html', 'page' => { 'this' => 'mypage.html', 'next' => 'nextpage.html', 'prev' => 'prevpage.html', }, }; template: <a href="[% home %]">Home</a> <a href="[% page.prev %]">Previous Page</a> <a href="[% page.next %]">Next Page</a>




      Forget that fear of gravity,
      Get a little savagery in your life.
        You're not reproducing the same setup. Instead of:
        Call list for [% today %] <p> [% FOREACH user IN data %] Be sure to call [% user.ulname %], [% user.ufname %] [% END %]
        you should use the values virtual method:
        Call list for [% today %] <p> [% FOREACH user IN data.values %] Be sure to call [% user.ulname %], [% user.ufname %] [% END %]
        which gives you back the list that FOREACH iterates on.

        As an alternative, you should modify your Perl code:

        # build data structure my @data; while (($user_id, $ufname, $ulname) = $sth->fetchrow_array()) { push @data, { ufname => $ufname, ulname => $ulname } }
        and then pass \@data instead of \%data.

        Which way to go is up to you, but keep in mind that using the hash will destroy record order (which does not seem an issue in your case, you don't specify any ORDER BY clause in your SQL query) and using an array won't let you address every record by user_id. Just to name a few differences.

        Flavio
        perl -ple'$_=reverse' <<<ti.xittelop@oivalf

        Don't fool yourself.
Re: Template Toolkit - passing hashes
by Herkum (Parson) on Apr 02, 2007 at 13:33 UTC
      Yes, that did it. Thanks




      Forget that fear of gravity,
      Get a little savagery in your life.
Re: Template Toolkit - passing hashes
by punch_card_don (Curate) on Apr 02, 2007 at 13:44 UTC
    Just to recap - it took both fixes:
    • add the backslash to data => \%data
    • use the keys method in the template



    Forget that fear of gravity,
    Get a little savagery in your life.

      (just to recap) If you already know the key, you can use it directly too with [% thing.hashkey %]

      like this:

      @_=qw; ask f00li5h to appear and remain for a moment of pretend better than a lifetime;;s;;@_[map hex,split'',B204316D8C2A4516DE];;y/05/os/&print;

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