Provided by: libcgi-application-plugin-forward-perl_1.06-3_all 
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.
perl v5.34.0 2022-06-09 CGI::Application::Plugin::Forward(3pm)