man > CGI::Application::Plugin::ErrorPage(3pm)

NAME
    CGI::Application::Plugin::ErrorPage - A simple error page plugin for CGI::Application

SYNOPSIS
      use CGI::Application::Plugin::ErrorPage 'error';

      sub my_run_mode {
        my $self = shift;

        eval { .... };

        if ($@) {
            # Send the gory details to the log for the developers
            warn "$@";

            # Send a comprehensible message to the users
            return $self->error(
                title => "Technical Failure',
                msg   => "There was a techical failure during the operation.",
            );
        }

      }

DESCRIPTION
    This plugin provides a shortcut for the common need of returning a simple error message to the
    user.

    You are encouraged to provide a template file so that the error messages can be presented with a
    design consistent with the rest of your application.

    A simple design is provided below to get to you started.

  A better default error page.
    If you don't install an AUTOLOAD run mode in the normal way in "setup", this plugin will
    automatically install a reasonable default at the "prerun" stage, which returns an error page
    like this:

      return $c->error(
          title => 'The requested page was not found.',
          msg => "(The page tried was: ".$c->get_current_runmode.")"
      );

  Relation to error_mode()
    CGI::Application includes "error_mode()" to provide custom handling when the application dies.
    This error() routine provides a shortcut for displaying error messages to the user. So, they
    both have a place on their own, and it could make sense to use them together. In your
    'error_mode' routine, you might call error() to return a message to the user:

        $self->error( title => 'Technical Failure', msg => 'There was a technical failure' );

  Suggested Uses
    Some common cases for returning error messages to the user include:

      * "Technical Failure" - The software failed unexpectedly
      * "Insufficient Information" - some required query parameter was missing
      * "Request Not Understood" - Some value we received in the query just didn't make sense.

  Silliness
      [22:36] <rjbs> Techno Failure.  We were cruising along and rocking out while fulfilling your request, but then the music stopped and we sort of got distracted.
      [22:36] <rjbs> Tek Failure.  Too busy reading Shatner novels to respond to your request.

METHODS
  error()
            return $self->error(
                title => "Technical Failure',
                msg   => "There was a techical failure during the operation",
            );

    Nothing fancy, just a shortcut to load a template meant to display errors. I've used it for the
    past several years, and it's been very handy to always have around on projects to quickly write
    error handling code.

    It tries to load a template file named 'error.html' to display the error page.

    If you want to use a different location, I recommend putting something like this in your base
    class, so you only have to provide your error template location once.

     # In this case, intentionally *don't* import 'error' to avoid a "redefined" warning.
     use CGI::Application::Plugin::ErrorPage;
     sub error {
          my $c = shift;
          return $c->CGI::Application::Plugin::ErrorPage::error(
              tmpl => $self->cfg('ROOT_URI').'/path/to/my/alternate/error/file.html',
              @_,
          );
     }

    This module intentionally ignores any "tmpl_path()" set by application, since this is usually an
    indication of where the intended file is located, not the error template. This exceptional
    handling of the "tmpl_path()" is one of the only value added bits of logic that this plugin
    adds. The rest of it is primarily a simple recommendation for error page handling wrapped up as
    a module.

    If you don't want this behavior, it's simple enough just to roll your own error() page method
    and skip using this plugin. Here's the simple essential code:

        use Params::Validate ':all';
        sub error {
            my $self  = shift;
            my %p = validate(@_, { title => SCALAR, msg => SCALAR });
            my $t = $self->load_tmpl;
            $t->param( title => $p{title}, msg => $p{msg} );
            return $t->output;
        }

  Example error.html
    Here's a very basic example of an "error.html" file to get you started.

     <!DOCTYPE html
             PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
              "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
     <html xmlns="http://www.w3.org/1999/xhtml" lang="en-US" xml:lang="en-US">
     <head>
     <title><!-- tmpl_var title escape=HTML --></title>
     <meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
     </head>
     <body>
     <h1><!-- tmpl_var title escape=HTML--></h1>
     <p><!-- tmpl_var msg escape=HTML --></p>
     </body>
     </html>

    We manage site-wide designs with Dreamweaver and keep a basic 'error.html' that uses a generic
    Dreamweaver 'page.dwt' template with standard EditableRegion names. That way, we can copy this
    error.html into a new Dreamweaver-managed project and have the new design applied to it easily
    through Dreamweaver.

SUPPORT
    Ask for help on the CGI::Application mailing list. Report bugs and wishes through the
    rt.cpan.org bug tracker.

AUTHOR
        Mark Stosberg
        CPAN ID: MARKSTOS
        mark AT summersault.com

COPYRIGHT
    This program is free software; you can redistribute it and/or modify it under the same terms as
    Perl itself.

    The full text of the license can be found in the LICENSE file included with this module.

SEE ALSO
    perl(1).