1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
34 # please don't perltidy this. hairy code within.
38 Catalyst::DispatchType::Chained - Path Part DispatchType
42 Path part matching, allowing several actions to sequentially take care of processing a request:
44 # root action - captures one argument after it
45 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
46 my ( $self, $c, $foo_arg ) = @_;
50 # child action endpoint - takes one argument
51 sub bar : Chained('foo_setup') Args(1) {
52 my ( $self, $c, $bar_arg ) = @_;
58 Dispatch type managing default behaviour. For more information on
63 =item * L<Catalyst::Manual::Intro> for how they affect application authors
65 =item * L<Catalyst::DispatchType> for implementation information.
71 =head2 $self->list($c)
73 Debug output for Path Part dispatch points
78 my ( $self, $c ) = @_;
80 return unless $self->_endpoints;
82 my $column_width = Catalyst::Utils::term_width() - 35 - 9;
83 my $paths = Text::SimpleTable->new(
84 [ 35, 'Path Spec' ], [ $column_width, 'Private' ],
87 my $has_unattached_actions;
88 my $unattached_actions = Text::SimpleTable->new(
89 [ 35, 'Private' ], [ 36, 'Missing parent' ],
92 ENDPOINT: foreach my $endpoint (
93 sort { $a->reverse cmp $b->reverse }
94 @{ $self->_endpoints }
96 my $args = $endpoint->attributes->{Args}->[0];
97 my @parts = (defined($args) ? (("*") x $args) : '...');
100 my $curr = $endpoint;
102 if (my $cap = $curr->attributes->{CaptureArgs}) {
103 unshift(@parts, (("*") x $cap->[0]));
105 if (my $pp = $curr->attributes->{PartPath}) {
106 unshift(@parts, $pp->[0])
107 if (defined $pp->[0] && length $pp->[0]);
109 $parent = $curr->attributes->{Chained}->[0];
110 $curr = $self->_actions->{$parent};
111 unshift(@parents, $curr) if $curr;
113 if ($parent ne '/') {
114 $has_unattached_actions = 1;
115 $unattached_actions->row('/'.$parents[0]->reverse, $parent);
119 foreach my $p (@parents) {
121 if (my $cap = $p->attributes->{CaptureArgs}) {
122 $name .= ' ('.$cap->[0].')';
124 unless ($p eq $parents[0]) {
125 $name = "-> ${name}";
127 push(@rows, [ '', $name ]);
129 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
130 $rows[0][0] = join('/', '', @parts);
131 $paths->row(@$_) for @rows;
134 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
135 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
136 if $has_unattached_actions;
139 =head2 $self->match( $c, $path )
141 Calls C<recurse_match> to see if a chain matches the C<$path>.
146 my ( $self, $c, $path ) = @_;
148 my $request = $c->request;
149 return 0 if @{$request->args};
151 my @parts = split('/', $path);
153 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
154 push @{$request->args}, @$parts if $parts && @$parts;
156 return 0 unless $chain;
158 my $action = Catalyst::ActionChain->from_chain($chain);
160 $request->action("/${action}");
161 $request->match("/${action}");
162 $request->captures($captures);
164 $c->namespace( $action->namespace );
169 =head2 $self->recurse_match( $c, $parent, \@path_parts )
171 Recursive search for a matching chain.
176 my ( $self, $c, $parent, $path_parts ) = @_;
177 my $children = $self->_children_of->{$parent};
178 return () unless $children;
181 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
183 # $b then $a to try longest part first
184 my @parts = @$path_parts;
185 if (length $try_part) { # test and strip PathPart
187 ($try_part eq join('/', # assemble equal number of parts
188 splice( # and strip them off @parts as well
189 @parts, 0, scalar(@{[split('/', $try_part)]})
190 ))); # @{[]} to avoid split to @_
192 my @try_actions = @{$children->{$try_part}};
193 TRY_ACTION: foreach my $action (@try_actions) {
194 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
196 # Short-circuit if not enough remaining parts
197 next TRY_ACTION unless @parts >= $capture_attr->[0];
200 my @parts = @parts; # localise
202 # strip CaptureArgs into list
203 push(@captures, splice(@parts, 0, $capture_attr->[0]));
205 # try the remaining parts against children of this action
206 my ($actions, $captures, $action_parts) = $self->recurse_match(
207 $c, '/'.$action->reverse, \@parts
209 # No best action currently
210 # OR The action has less parts
211 # OR The action has equal parts but less captured data (ergo more defined)
214 $#$action_parts < $#{$best_action->{parts}} ||
215 ($#$action_parts == $#{$best_action->{parts}} &&
216 $#$captures < $#{$best_action->{captures}}))){
218 actions => [ $action, @$actions ],
219 captures=> [ @captures, @$captures ],
220 parts => $action_parts
226 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
227 next TRY_ACTION unless $action->match($c);
229 my $args_attr = $action->attributes->{Args}->[0];
231 # No best action currently
232 # OR This one matches with fewer parts left than the current best action,
233 # And therefore is a better match
234 # OR No parts and this expects 0
235 # The current best action might also be Args(0),
236 # but we couldn't chose between then anyway so we'll take the last seen
239 @parts < @{$best_action->{parts}} ||
240 (!@parts && $args_attr eq 0)){
242 actions => [ $action ],
250 return @$best_action{qw/actions captures parts/} if $best_action;
254 =head2 $self->register( $c, $action )
256 Calls register_path for every Path attribute for the given $action.
261 my ( $self, $c, $action ) = @_;
263 my @chained_attr = @{ $action->attributes->{Chained} || [] };
265 return 0 unless @chained_attr;
267 if (@chained_attr > 1) {
268 Catalyst::Exception->throw(
269 "Multiple Chained attributes not supported registering ${action}"
272 my $chained_to = $chained_attr[0];
274 Catalyst::Exception->throw(
275 "Actions cannot chain to themselves registering /${action}"
276 ) if ($chained_to eq '/' . $action);
278 my $children = ($self->_children_of->{ $chained_to } ||= {});
280 my @path_part = @{ $action->attributes->{PathPart} || [] };
282 my $part = $action->name;
284 if (@path_part == 1 && defined $path_part[0]) {
285 $part = $path_part[0];
286 } elsif (@path_part > 1) {
287 Catalyst::Exception->throw(
288 "Multiple PathPart attributes not supported registering " . $action->reverse()
292 if ($part =~ m(^/)) {
293 Catalyst::Exception->throw(
294 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
298 $action->attributes->{PartPath} = [ $part ];
300 unshift(@{ $children->{$part} ||= [] }, $action);
302 $self->_actions->{'/'.$action->reverse} = $action;
304 unless ($action->attributes->{CaptureArgs}) {
305 unshift(@{ $self->_endpoints }, $action);
311 =head2 $self->uri_for_action($action, $captures)
313 Get the URI part for the action, using C<$captures> to fill
319 my ( $self, $action, $captures ) = @_;
321 return undef unless ($action->attributes->{Chained}
322 && !$action->attributes->{CaptureArgs});
325 my @captures = @$captures;
326 my $parent = "DUMMY";
329 if (my $cap = $curr->attributes->{CaptureArgs}) {
330 return undef unless @captures >= $cap->[0]; # not enough captures
332 unshift(@parts, splice(@captures, -$cap->[0]));
335 if (my $pp = $curr->attributes->{PartPath}) {
336 unshift(@parts, $pp->[0])
337 if (defined($pp->[0]) && length($pp->[0]));
339 $parent = $curr->attributes->{Chained}->[0];
340 $curr = $self->_actions->{$parent};
343 return undef unless $parent eq '/'; # fail for dangling action
345 return undef if @captures; # fail for too many captures
347 return join('/', '', @parts);
351 =head2 $c->expand_action($action)
353 Return a list of actions that represents a chained action. See
354 L<Catalyst::Dispatcher> for more info. You probably want to
355 use the expand_action it provides rather than this directly.
360 my ($self, $action) = @_;
362 return unless $action->attributes && $action->attributes->{Chained};
369 my $parent = $curr->attributes->{Chained}->[0];
370 $curr = $self->_actions->{$parent};
373 return Catalyst::ActionChain->from_chain([reverse @chain]);
376 __PACKAGE__->meta->make_immutable;
382 The C<Chained> attribute allows you to chain public path parts together
383 by their private names. A chain part's path can be specified with
384 C<PathPart> and can be declared to expect an arbitrary number of
385 arguments. The endpoint of the chain specifies how many arguments it
386 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
387 C<:Args> without an integer would be unlimited. The path parts that
388 aren't endpoints are using C<CaptureArgs> to specify how many parameters
389 they expect to receive. As an example setup:
391 package MyApp::Controller::Greeting;
392 use base qw/ Catalyst::Controller /;
394 # this is the beginning of our chain
395 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
396 my ( $self, $c, $integer ) = @_;
397 $c->stash->{ message } = "Hello ";
398 $c->stash->{ arg_sum } = $integer;
401 # this is our endpoint, because it has no :CaptureArgs
402 sub world : PathPart('world') Chained('hello') Args(1) {
403 my ( $self, $c, $integer ) = @_;
404 $c->stash->{ message } .= "World!";
405 $c->stash->{ arg_sum } += $integer;
407 $c->response->body( join "<br/>\n" =>
408 $c->stash->{ message }, $c->stash->{ arg_sum } );
411 The debug output provides a separate table for chained actions, showing
412 the whole chain as it would match and the actions it contains. Here's an
413 example of the startup output with our actions above:
416 [debug] Loaded Path Part actions:
417 .-----------------------+------------------------------.
418 | Path Spec | Private |
419 +-----------------------+------------------------------+
420 | /hello/*/world/* | /greeting/hello (1) |
421 | | => /greeting/world |
422 '-----------------------+------------------------------'
425 As you can see, Catalyst only deals with chains as whole paths and
426 builds one for each endpoint, which are the actions with C<:Chained> but
427 without C<:CaptureArgs>.
429 Let's assume this application gets a request at the path
430 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
431 to the C<hello> action and pass the value C<23> as an argument to it
432 after the context. It does so because we have previously used
433 C<:CaptureArgs(1)> to declare that it has one path part after itself as
434 its argument. We told Catalyst that this is the beginning of the chain
435 by specifying C<:Chained('/')>. Also note that instead of saying
436 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
437 defaults to the name of the action.
439 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
440 action. This is the last action to be called: Catalyst knows this is an
441 endpoint because we did not specify a C<:CaptureArgs>
442 attribute. Nevertheless we specify that this action expects an argument,
443 but at this point we're using C<:Args(1)> to do that. We could also have
444 said C<:Args> or left it out altogether, which would mean this action
445 would get all arguments that are there. This action's C<:Chained>
446 attribute says C<hello> and tells Catalyst that the C<hello> action in
447 the current controller is its parent.
449 With this we have built a chain consisting of two public path parts.
450 C<hello> captures one part of the path as its argument, and also
451 specifies the path root as its parent. So this part is
452 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
453 argument. It sums up to the path part C<world/$arg>. This leads to a
454 complete chain of C</hello/$arg/world/$arg> which is matched against the
457 This example application would, if run and called by e.g.
458 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
459 value C<arg_sum> to "23". The C<world> action would then append "World!"
460 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
461 sake of simplicity no view is shown. Instead we just put the values of
462 the stash into our body. So the output would look like:
467 And our test server would have given us this debugging output for the
471 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
472 [debug] Path is "/greeting/world"
473 [debug] Arguments are "12"
474 [info] Request took 0.164113s (6.093/s)
475 .------------------------------------------+-----------.
477 +------------------------------------------+-----------+
478 | /greeting/hello | 0.000029s |
479 | /greeting/world | 0.000024s |
480 '------------------------------------------+-----------'
483 What would be common uses of this dispatch technique? It gives the
484 possibility to split up logic that contains steps that each depend on
485 each other. An example would be, for example, a wiki path like
486 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
489 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
490 my ( $self, $c, $page_name ) = @_;
491 # load the page named $page_name and put the object
495 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
496 my ( $self, $c, $revision_id ) = @_;
497 # use the page object in the stash to get at its
498 # revision with number $revision_id
501 sub view : PathPart Chained('rev') Args(0) {
502 my ( $self, $c ) = @_;
503 # display the revision in our stash. Another option
504 # would be to forward a compatible object to the action
505 # that displays the default wiki pages, unless we want
506 # a different interface here, for example restore
510 It would now be possible to add other endpoints, for example C<restore>
511 to restore this specific revision as the current state.
513 You don't have to put all the chained actions in one controller. The
514 specification of the parent through C<:Chained> also takes an absolute
515 action path as its argument. Just specify it with a leading C</>.
517 If you want, for example, to have actions for the public paths
518 C</foo/12/edit> and C</foo/12>, just specify two actions with
519 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
520 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
521 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
522 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
523 this debugging output:
526 [debug] Loaded Path Part actions:
527 .-----------------------+------------------------------.
528 | Path Spec | Private |
529 +-----------------------+------------------------------+
530 | /foo/* | /controller/foo_view |
531 | /foo/*/edit | /controller/foo_load (1) |
532 | | => /controller/edit |
533 '-----------------------+------------------------------'
536 Here's a more detailed specification of the attributes belonging to
545 Sets the name of this part of the chain. If it is specified without
546 arguments, it takes the name of the action as default. So basically
547 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
548 This can also contain slashes to bind to a deeper level. An action
549 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
550 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
551 effect as using C<:PathPart>, it would default to the action name.
555 Sets PathPart to the path_prefix of the current controller.
559 Has to be specified for every child in the chain. Possible values are
560 absolute and relative private action paths or a single slash C</> to
561 tell Catalyst that this is the root of a chain. The attribute
562 C<:Chained> without arguments also defaults to the C</> behavior.
563 Relative action paths may use C<../> to refer to actions in parent
566 Because you can specify an absolute path to the parent action, it
567 doesn't matter to Catalyst where that parent is located. So, if your
568 design requests it, you can redispatch a chain through any controller or
571 Another interesting possibility gives C<:Chained('.')>, which chains
572 itself to an action with the path of the current controller's namespace.
575 # in MyApp::Controller::Foo
576 sub bar : Chained CaptureArgs(1) { ... }
578 # in MyApp::Controller::Foo::Bar
579 sub baz : Chained('.') Args(1) { ... }
581 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
582 as the argument to Chained here chains the C<baz> action to an action
583 with the path of the current controller namespace, namely
584 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
585 chain comes out as the end product.
589 Chains an action to another action with the same name in the parent
590 controller. For Example:
592 # in MyApp::Controller::Foo
593 sub bar : Chained CaptureArgs(1) { ... }
595 # in MyApp::Controller::Foo::Moo
596 sub bar : ChainedParent Args(1) { ... }
598 This builds a chain like C</bar/*/bar/*>.
602 Must be specified for every part of the chain that is not an
603 endpoint. With this attribute Catalyst knows how many of the following
604 parts of the path (separated by C</>) this action wants to capture as
605 its arguments. If it doesn't expect any, just specify
606 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
607 after the context, but you can also find them as array references in
608 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
609 level of the action in the chain that captured the parts of the path.
611 An action that is part of a chain (that is, one that has a C<:Chained>
612 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
617 By default, endpoints receive the rest of the arguments in the path. You
618 can tell Catalyst through C<:Args> explicitly how many arguments your
619 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
620 also affects whether this chain is invoked on a request. A chain with an
621 endpoint specifying one argument will only match if exactly one argument
624 You can specify an exact number of arguments like C<:Args(3)>, including
625 C<0>. If you just say C<:Args> without any arguments, it is the same as
626 leaving it out altogether: The chain is matched regardless of the number
627 of path parts after the endpoint.
629 Just as with C<:CaptureArgs>, the arguments get passed to the action in
630 C<@_> after the context object. They can also be reached through
631 C<$c-E<gt>request-E<gt>arguments>.
635 =head2 Auto actions, dispatching and forwarding
637 Note that the list of C<auto> actions called depends on the private path
638 of the endpoint of the chain, not on the chained actions way. The
639 C<auto> actions will be run before the chain dispatching begins. In
640 every other aspect, C<auto> actions behave as documented.
642 The C<forward>ing to other actions does just what you would expect. But if
643 you C<detach> out of a chain, the rest of the chain will not get called
648 Catalyst Contributors, see Catalyst.pm
652 This program is free software, you can redistribute it and/or modify it under
653 the same terms as Perl itself.