CGI::Ajax

This Ajax stuff is really quite easy :-)

Dominic Mitchell (dom@happygiraffe.net)

London JavaScript Night, May 2006

happygiraffe.net/presentations/cgi-ajax-lightning

$Id: index.html 796 2006-05-24 23:30:02Z dom $

Bob, we need Ajax!

• Yet another random buzzword from on high.
• No time to learn vast new frameworks.

What is Ajax?

• Really simple: updating bits of your page.
• Whilst leaving most of it untouched.
• All done with JavaScript.

How can I implement it?

• Easy!
• Retro-fit your existing Perl CGI scripts with CGI::Ajax.
• Dead simple: turns Perl functions into JavaScript functions.

This is your CGI

  #!perl -w
  use strict;
  use CGI;

  my $cgi = CGI->new();
  print $cgi->header();
  # ... exercise for the reader ...
  print $template->output();

  # Do something dynamic.
  sub uptime { `uptime` }

This is your CGI on Ajax

  #!perl -w
  use strict;
  use CGI;
  use CGI::Ajax;

  my $cgi = CGI->new();
  my $ajax = CGI::Ajax->new( uptime => \&uptime );
  print $ajax->build_html( $cgi, \&main );

  sub main {
    print $cgi->header();
    # ...
    print $template->output();
  }

  # Do something dynamic.
  sub uptime { `uptime` }

Serve with a dash of JavaScript

  <div>
    <input type="button" name="uptime" value="Uptime?" 
      onclick="uptime([],['overhere'])" />
    <span id="overhere"/>
  </div>

• Each exposed function has two args:
  • A list of id’s of form inputs.
  • A list of id’s to update with the results.
• Please excuse the onclick, Jeremy.

CGI::Ajax

• Dead simple.
• On CPAN
  • search.cpan.org/dist/CGI-Ajax
• Give it a try.

More Details

• An extensive walkthrough is available at:

perl.com/pub/a/2006/03/02/ajax_and_perl.html