NAME

       CGI::Application::Plugin::Forward - Pass control from one run mode to another

VERSION

       Version 1.06

SYNOPSIS

           use base 'CGI::Application';
           use CGI::Application::Plugin::Forward;

           sub setup {
               my $self = shift;
               $self->run_modes([qw(
                   start
                   second_runmode
               )]);
           }
           sub start {
               my $self = shift;
               return $self->forward('second_runmode');
           }
           sub second_runmode {
               my $self = shift;

               my $rm = $self->get_current_runmode;  # 'second_runmode'

           }

DESCRIPTION

       The forward method passes control to another run mode and returns its output.  This is
       equivalent to calling "$self->$other_runmode", except that CGI::Application's internal
       value of the current run mode is updated.

       This means that calling "$self->get_current_runmode" after calling "forward" will return
       the name of the new run mode.  This is useful for modules that depend on the name of the
       current run mode such as CGI::Application::Plugin::AnyTemplate.

       For example, here's how to pass control to a run mode named "other_action" from "start"
       while updating the value of "current_run_mode":

           sub setup {
               my $self = shift;
               $self->run_modes({
                   start         => 'start',
                   other_action  => 'other_method',
               });
           }
           sub start {
               my $self = shift;
               return $self->forward('other_action');
           }
           sub other_method {
               my $self = shift;

               my $rm = $self->get_current_runmode;  # 'other_action'
           }

       Note that forward accepts the name of the run mode (in this case 'other_action'), which
       might not be the same as the name of the method that handles the run mode (in this case
       'other_method')

       You can still call "$self->other_method" directly, but "current_run_mode" will not be
       updated:

           sub setup {
               my $self = shift;
               $self->run_modes({
                   start         => 'start',
                   other_action  => 'other_method',
               });
           }
           sub start {
               my $self = shift;
               return $self->other_method;
           }
           sub other_method {
               my $self = shift;

               my $rm = $self->get_current_runmode;  # 'start'
           }

       Forward will work with coderef-based runmodes as well:

           sub setup {
               my $self = shift;
               $self->run_modes({
                   start         => 'start',
                   anon_action   => sub {
                       my $self = shift;
                       my $rm = $self->get_current_runmode;  # 'anon_action'
                   },
               });
           }
           sub start {
               my $self = shift;
               return $self->forward('anon_action');
           }

FORWARD vs. REDIRECT

       Calling "forward" changes the run mode of your application, but it stays within the same
       HTTP request.

       To redirect to a new runmode using a completely new web request, you might consider using
       the "redirect" method provided by CGI::Application::Plugin::Redirect.

       The advantage of using an external redirect as opposed to an internal forward is that it
       provides a 'clean break' between pages.

       For instance, in a typical BREAD application (Browse, Read, Edit, Add, Delete), after the
       user completes an action, you usually return the user to the Browse list.  For instance,
       when the user adds a new record via a POST form, and your app returns them to the list of
       records.

       If you use "forward", then you are still in the same request as the original add record.
       The user might hit reload, expecting to refresh the list of records.  But in fact, reload
       will attempt to repost the add record form.  The user's browser might present a warning
       about reposting the same data.  The browser may refuse to redisplay the page, due for
       caching reasons.

       So in this case, it may make more sense to do a fresh HTTP redirect back to the Browse
       list.

METHODS

   forward
       Runs another run mode passing any parameters you supply.  Returns the output of the new
       run mode.

           return $self->forward('run_mode_name', @run_mode_params);

HOOKS

       Before the forwarded run mode is called, the "forward_prerun" hook is called. You can use
       this hook to do any prep work that you want to do before any new run mode gains control.

       This is similar to CGI::Application's built in "cgiapp_prerun" method, but it is called
       each time you call forward; not just the when your application starts.

           sub setup {
               my $self = shift;
               $self->add_callback('forward_prerun' => \&prepare_rm_stuff);
           }

           sub prepare_rm_stuff {
               my $self = shift;
               # do any necessary prep work here....
           }

       Note that your hooked method will only be called when you call forward.  If you never call
       "forward", the hook will not be called.  In particuar, the hook will not be called for
       your application's "start_mode".  For that, you still use "cgiapp_prerun".

       If you want to have a method run for every run mode including the "start_mode", then you
       can call the hook directly from "cgiapp_prerun".

           sub setup {
               my $self = shift;
               $self->add_callback('forward_prerun' => \&prepare_rm_stuff);
           }
           sub cgiapp_prerun {
               my $self = shift;
               $self->prepare_rm_stuff;
           }

           sub prepare_rm_stuff {
               my $self = shift;
               # do any necessary prep work here....
           }

       Alternately, you can hook "cgiapp_prerun" to the "forward_prerun" hook:

           sub setup {
               my $self = shift;
               $self->add_callback('forward_prerun' => \&cgiapp_prerun);
           }
           sub cgiapp_prerun {
               my $self = shift;
               # do any necessary prep work here....
           }

       This is a less flexible solution, since certain things that can be done in "cgiapp_prerun"
       (like setting "prerun_mode") won't work when the method is called from the
       "forward_prerun" hook.

AUTHOR

       Michael Graham, "<mag-perl@occamstoothbrush.com>"

BUGS

       Please report any bugs or feature requests to
       "bug-cgi-application-plugin-forward@rt.cpan.org", or through the web interface at
       <http://rt.cpan.org>.  I will be notified, and then you'll automatically be notified of
       progress on your bug as I make changes.

ACKNOWLEDGEMENTS

       Thanks to Mark Stosberg for the idea and...well...the implementation as well.

COPYRIGHT & LICENSE

       Copyright 2005 Michael Graham, All Rights Reserved.

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