NAME
Catalyst::Plugin::Continuation - Catalyst Continuation Plugin
SYNOPSIS
# Make sure to load session plugins too!
package MyApp;
use Catalyst qw/Session Session::Store::File
Session::State::Cookie Continuation/;
# Create a controller
package MyApp::Controller::Test;
use base 'Catalyst::Controller';
# Add a action with attached action class
sub counter : Global {
my ( $self, $c ) = @_;
my $up = $c->continue('up');
my $down = $c->continue('down');
my $counter = $c->stash->{counter} || 0;
$c->res->body(<<"EOF");
Counter: $counter<br/>
<a href="$up">++</a>
<a href="$down">--</a>
EOF
}
# Add private actions for continuations
sub up : Private { $_[1]->stash->{counter}++ }
sub down : Private { $_[1]->stash->{counter}-- }DESCRIPTION
Catalyst Continuation Plugin.
OVERLOADED METHODS
prepare_action
dispatch
These methods are overridden to allow the special continuation dispatch.
METHODS
continuation
Contains the continuation object that was restored.
set_continuation $id, $structure
get_continuation $id
delete_continuation $id
active_continuations
clear_continuations
generate_continuation_id
These are internal methods which you can override.
They default to storing inside $c->session, and using "generate_session_id" in Catalyst::Plugin::Session.
If you want your continuations to be garbage collected in some way you need to override this to store the data in some other backend.
Note that active_continuations returns a hash reference which you can edit. Be careful.
$c->continuation_expired( $id )
This handler is called when the continuation with the ID $id tried to get invoked but did not exist
$c->resume_continuation( $cont_or_id );
Resume a continuation based on an ID or an object.
This is a convenience method intended on saving you the need to load and execute the continuation yourself.
$c->continue($method)
$c->cont($method)
Returns the Catalyst::Continuation object for given method.
Takes the same arguments as "forward" in Catalyst and it's relatives.
$c->caller_continuation
A pseudo-cc - a continuation to your caller.
Note that this does NOT honor the call stack in any way - it is ONLY to reinvoke the immediate caller. See the NeedsLogin test controller in the test suite for an example of how to use this effectively.
$c->cont_class
Returns the string Catalyst::Continuation by default. You may override this to replace the continuation class.
CAVEATS
Continuations take up space, and are by default stored in the session.
When invoked a session will delete itself by default, but anything else will leak, until the session expires.
If this is a concern for you, override the get_continuation family of functions to have a better scheme for storage.
Some approaches you could implement, depending on how you use continuations:
- size limiting
-
Store up to $x continuations, and toss out old ones once this starts to overflow. This is essentially an LRU policy.
- continuation grouping
-
Group all the continuations saved in a single request together. When one of them is deleted, all the rest go with it.
- use the fine grained session expiry feature
-
Catalyst::Plugin::Session allows you to expire some session keys before the entire session expired. You can associate each session with it's own unique key, and avoid extending the continuation's time-to-live.
If you override all these functions then you don't need the Catalyst::Plugin::Session dependency.
SEE ALSO
Catalyst, Seaside (http://www.seaside.st/), Jifty, Coro::Cont, psychiatrist(1).
AUTHOR
Sebastian Riedel, sri@oook.de Yuval Kogman, nothingmuch@woobling.org
LICENSE
This library is free software, you can redistribute it and/or modify it under the same terms as Perl itself.