[Dancer-users] generating client side code on the server

8 Jan 2011

      Consider the most basic of workflows

     ## Perl
     get '/:foo_id.:format' => sub {
         my $foo_id = params->{foo_id};

         ## SQL
         my $sth = $dbh->prepare(qq{
             SELECT foo FROM table WHERE foo_id = ?
         });
         $sth->execute($foo_id);
         my ($foo) = $sth->fetchrow_array;

         to_json({data => $foo});
     };

     foo.tt
     ======
     <p>You got <span id="foo">[% foo %]</span></p>
     enter a number <input type="text" id="foo_id" name="foo_id">
     <input type="button" onclick="foo();">

     JavaScript
     ==========
     foo = function() {
         $.ajax({
             url     : "/server/" + $("#foo_id").val() + ".json",
             type    : "GET",
             data    : "",
             dataType: "json",
             error   : function() { alert("Error"); },
             success : function(data) {
                 $("#foo").html(data.foo);
             }
         });
     }

If I change the table column 'foo' to 'bar' and 'foo_id' to 'bar_id', I 
have to change my Perl code (which includes SQL), my template and 
JavaScript. Obviously, this can get untenable very quickly as the 
application becomes complex. The obvious solution is to generate the 
template and the JavaScript on the server side, thereby having to 
declare all the names in just one place. I have recently learned of the 
Perl module Jemplate that might enable me to do this. But before I 
commit any cycles to it, I want to know how the other Dancers handle 
something like this.

Puneet.

-- 
Puneet Kishor http://punkish.org
Carbon Model http://carbonmodel.org
Charter Member, Open Source Geospatial Foundation http://www.osgeo.org
Science Fellow http://creativecommons.org/about/people/fellows#puneetkishor
Nelson Institute, UW-Madison http://www.nelson.wisc.edu
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