1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
11 use Encode 2.21 'decode_utf8';
36 # please don't perltidy this. hairy code within.
40 Catalyst::DispatchType::Chained - Path Part DispatchType
44 Path part matching, allowing several actions to sequentially take care of processing a request:
46 # root action - captures one argument after it
47 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
48 my ( $self, $c, $foo_arg ) = @_;
52 # child action endpoint - takes one argument
53 sub bar : Chained('foo_setup') Args(1) {
54 my ( $self, $c, $bar_arg ) = @_;
60 Dispatch type managing default behaviour. For more information on
65 =item * L<Catalyst::Manual::Intro> for how they affect application authors
67 =item * L<Catalyst::DispatchType> for implementation information.
73 =head2 $self->list($c)
75 Debug output for Path Part dispatch points
80 my ( $self, $c ) = @_;
82 return unless $self->_endpoints;
84 my $avail_width = Catalyst::Utils::term_width() - 9;
85 my $col1_width = ($avail_width * .50) < 35 ? 35 : int($avail_width * .50);
86 my $col2_width = $avail_width - $col1_width;
87 my $paths = Text::SimpleTable->new(
88 [ $col1_width, 'Path Spec' ], [ $col2_width, 'Private' ],
91 my $has_unattached_actions;
92 my $unattached_actions = Text::SimpleTable->new(
93 [ $col1_width, 'Private' ], [ $col2_width, 'Missing parent' ],
96 ENDPOINT: foreach my $endpoint (
97 sort { $a->reverse cmp $b->reverse }
98 @{ $self->_endpoints }
100 my $args = $endpoint->list_extra_info->{Args};
101 my @parts = (defined($args) ? (("*") x $args) : '...');
103 my $parent = "DUMMY";
104 my $extra = $self->_list_extra_http_methods($endpoint);
105 my $consumes = $self->_list_extra_consumes($endpoint);
106 my $scheme = $self->_list_extra_scheme($endpoint);
107 my $curr = $endpoint;
109 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
110 unshift(@parts, (("*") x $cap));
112 if (my $pp = $curr->attributes->{PathPart}) {
113 unshift(@parts, $pp->[0])
114 if (defined $pp->[0] && length $pp->[0]);
116 $parent = $curr->attributes->{Chained}->[0];
117 $curr = $self->_actions->{$parent};
118 unshift(@parents, $curr) if $curr;
120 if ($parent ne '/') {
121 $has_unattached_actions = 1;
122 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
126 foreach my $p (@parents) {
129 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
130 $name = "${extra} ${name}";
132 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
133 if($p->has_captures_constraints) {
134 my $tc = join ',', @{$p->captures_constraints};
140 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
143 if (defined(my $s = $p->list_extra_info->{Scheme})) {
147 unless ($p eq $parents[0]) {
148 $name = "-> ${name}";
150 push(@rows, [ '', $name ]);
153 if(defined $endpoint->number_of_args) {
154 if($endpoint->has_args_constraints) {
155 my $tc = join ',', @{$endpoint->args_constraints};
156 $endpoint .= " ($tc)";
158 $endpoint .= " (${\$endpoint->number_of_args})";
161 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : ''). ($scheme ? "$scheme: ":'')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
162 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
163 $rows[0][0] = join('/', '', @display_parts) || '/';
164 $paths->row(@$_) for @rows;
167 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
168 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
169 if $has_unattached_actions;
172 sub _list_extra_http_methods {
173 my ( $self, $action ) = @_;
174 return unless defined $action->list_extra_info->{HTTP_METHODS};
175 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
179 sub _list_extra_consumes {
180 my ( $self, $action ) = @_;
181 return unless defined $action->list_extra_info->{CONSUMES};
182 return join(', ', @{$action->list_extra_info->{CONSUMES}});
185 sub _list_extra_scheme {
186 my ( $self, $action ) = @_;
187 return unless defined $action->list_extra_info->{Scheme};
188 return uc $action->list_extra_info->{Scheme};
191 =head2 $self->match( $c, $path )
193 Calls C<recurse_match> to see if a chain matches the C<$path>.
198 my ( $self, $c, $path ) = @_;
200 my $request = $c->request;
201 return 0 if @{$request->args};
203 my @parts = split('/', $path);
205 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
207 if ($parts && @$parts) {
208 for my $arg (@$parts) {
209 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
210 push @{$request->args}, $arg;
214 return 0 unless $chain;
216 my $action = Catalyst::ActionChain->from_chain($chain);
218 $request->action("/${action}");
219 $request->match("/${action}");
220 $request->captures($captures);
222 $c->namespace( $action->namespace );
227 =head2 $self->recurse_match( $c, $parent, \@path_parts )
229 Recursive search for a matching chain.
234 my ( $self, $c, $parent, $path_parts ) = @_;
235 my $children = $self->_children_of->{$parent};
236 return () unless $children;
239 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
241 # $b then $a to try longest part first
242 my @parts = @$path_parts;
243 if (length $try_part) { # test and strip PathPart
245 ($try_part eq join('/', # assemble equal number of parts
246 splice( # and strip them off @parts as well
247 @parts, 0, scalar(@{[split('/', $try_part)]})
248 ))); # @{[]} to avoid split to @_
250 my @try_actions = @{$children->{$try_part}};
251 TRY_ACTION: foreach my $action (@try_actions) {
252 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
253 my $capture_count = $action->number_of_captures|| 0;
255 # Short-circuit if not enough remaining parts
256 next TRY_ACTION unless @parts >= $capture_count;
259 my @parts = @parts; # localise
261 # strip CaptureArgs into list
262 push(@captures, splice(@parts, 0, $capture_count));
264 # check if the action may fit, depending on a given test by the app
265 next TRY_ACTION unless $action->match_captures($c, \@captures);
267 # try the remaining parts against children of this action
268 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
269 $c, '/'.$action->reverse, \@parts
271 # No best action currently
272 # OR The action has less parts
273 # OR The action has equal parts but less captured data (ergo more defined)
276 $#$action_parts < $#{$best_action->{parts}} ||
277 ($#$action_parts == $#{$best_action->{parts}} &&
278 $#$captures < $#{$best_action->{captures}} &&
279 $n_pathparts > $best_action->{n_pathparts}))) {
280 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
282 actions => [ $action, @$actions ],
283 captures=> [ @captures, @$captures ],
284 parts => $action_parts,
285 n_pathparts => scalar(@pathparts) + $n_pathparts,
291 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
292 next TRY_ACTION unless $action->match($c);
294 my $args_attr = $action->attributes->{Args}->[0];
295 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
296 # No best action currently
297 # OR This one matches with fewer parts left than the current best action,
298 # And therefore is a better match
299 # OR No parts and this expects 0
300 # The current best action might also be Args(0),
301 # but we couldn't chose between then anyway so we'll take the last seen
304 @parts < @{$best_action->{parts}} ||
305 (!@parts && defined($args_attr) && $args_attr eq "0")){
307 actions => [ $action ],
310 n_pathparts => scalar(@pathparts),
316 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
320 =head2 $self->register( $c, $action )
322 Calls register_path for every Path attribute for the given $action.
327 my ( $self, $c, $action ) = @_;
329 my @chained_attr = @{ $action->attributes->{Chained} || [] };
331 return 0 unless @chained_attr;
333 if (@chained_attr > 1) {
334 Catalyst::Exception->throw(
335 "Multiple Chained attributes not supported registering ${action}"
338 my $chained_to = $chained_attr[0];
340 Catalyst::Exception->throw(
341 "Actions cannot chain to themselves registering /${action}"
342 ) if ($chained_to eq '/' . $action);
344 my $children = ($self->_children_of->{ $chained_to } ||= {});
346 my @path_part = @{ $action->attributes->{PathPart} || [] };
348 my $part = $action->name;
350 if (@path_part == 1 && defined $path_part[0]) {
351 $part = $path_part[0];
352 } elsif (@path_part > 1) {
353 Catalyst::Exception->throw(
354 "Multiple PathPart attributes not supported registering " . $action->reverse()
358 if ($part =~ m(^/)) {
359 Catalyst::Exception->throw(
360 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
364 my $encoded_part = URI->new($part)->canonical;
365 $encoded_part =~ s{(?<=[^/])/+\z}{};
367 $action->attributes->{PathPart} = [ $encoded_part ];
369 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
371 $self->_actions->{'/'.$action->reverse} = $action;
373 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
374 Catalyst::Exception->throw(
375 "Combining Args and CaptureArgs attributes not supported registering " .
380 unless ($action->attributes->{CaptureArgs}) {
381 unshift(@{ $self->_endpoints }, $action);
387 =head2 $self->uri_for_action($action, $captures)
389 Get the URI part for the action, using C<$captures> to fill
395 my ( $self, $action, $captures ) = @_;
397 return undef unless ($action->attributes->{Chained}
398 && !$action->attributes->{CaptureArgs});
401 my @captures = @$captures;
402 my $parent = "DUMMY";
404 # If this is an action chain get the last action in the chain
405 if($curr->can('chain') ) {
406 $curr = ${$curr->chain}[-1];
409 if (my $cap = $curr->number_of_captures) {
410 return undef unless @captures >= $cap; # not enough captures
412 unshift(@parts, splice(@captures, -$cap));
415 if (my $pp = $curr->attributes->{PathPart}) {
416 unshift(@parts, $pp->[0])
417 if (defined($pp->[0]) && length($pp->[0]));
419 $parent = $curr->attributes->{Chained}->[0];
420 $curr = $self->_actions->{$parent};
423 return undef unless $parent eq '/'; # fail for dangling action
425 return undef if @captures; # fail for too many captures
427 return join('/', '', @parts);
431 =head2 $c->expand_action($action)
433 Return a list of actions that represents a chained action. See
434 L<Catalyst::Dispatcher> for more info. You probably want to
435 use the expand_action it provides rather than this directly.
440 my ($self, $action) = @_;
442 return unless $action->attributes && $action->attributes->{Chained};
449 my $parent = $curr->attributes->{Chained}->[0];
450 $curr = $self->_actions->{$parent};
453 return Catalyst::ActionChain->from_chain([reverse @chain]);
456 __PACKAGE__->meta->make_immutable;
463 The C<Chained> attribute allows you to chain public path parts together
464 by their private names. A chain part's path can be specified with
465 C<PathPart> and can be declared to expect an arbitrary number of
466 arguments. The endpoint of the chain specifies how many arguments it
467 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
468 C<:Args> without an integer would be unlimited. The path parts that
469 aren't endpoints are using C<CaptureArgs> to specify how many parameters
470 they expect to receive. As an example setup:
472 package MyApp::Controller::Greeting;
473 use base qw/ Catalyst::Controller /;
475 # this is the beginning of our chain
476 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
477 my ( $self, $c, $integer ) = @_;
478 $c->stash->{ message } = "Hello ";
479 $c->stash->{ arg_sum } = $integer;
482 # this is our endpoint, because it has no :CaptureArgs
483 sub world : PathPart('world') Chained('hello') Args(1) {
484 my ( $self, $c, $integer ) = @_;
485 $c->stash->{ message } .= "World!";
486 $c->stash->{ arg_sum } += $integer;
488 $c->response->body( join "<br/>\n" =>
489 $c->stash->{ message }, $c->stash->{ arg_sum } );
492 The debug output provides a separate table for chained actions, showing
493 the whole chain as it would match and the actions it contains. Here's an
494 example of the startup output with our actions above:
497 [debug] Loaded Path Part actions:
498 .-----------------------+------------------------------.
499 | Path Spec | Private |
500 +-----------------------+------------------------------+
501 | /hello/*/world/* | /greeting/hello (1) |
502 | | => /greeting/world |
503 '-----------------------+------------------------------'
506 As you can see, Catalyst only deals with chains as whole paths and
507 builds one for each endpoint, which are the actions with C<:Chained> but
508 without C<:CaptureArgs>.
510 Let's assume this application gets a request at the path
511 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
512 to the C<hello> action and pass the value C<23> as an argument to it
513 after the context. It does so because we have previously used
514 C<:CaptureArgs(1)> to declare that it has one path part after itself as
515 its argument. We told Catalyst that this is the beginning of the chain
516 by specifying C<:Chained('/')>. Also note that instead of saying
517 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
518 defaults to the name of the action.
520 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
521 action. This is the last action to be called: Catalyst knows this is an
522 endpoint because we did not specify a C<:CaptureArgs>
523 attribute. Nevertheless we specify that this action expects an argument,
524 but at this point we're using C<:Args(1)> to do that. We could also have
525 said C<:Args> or left it out altogether, which would mean this action
526 would get all arguments that are there. This action's C<:Chained>
527 attribute says C<hello> and tells Catalyst that the C<hello> action in
528 the current controller is its parent.
530 With this we have built a chain consisting of two public path parts.
531 C<hello> captures one part of the path as its argument, and also
532 specifies the path root as its parent. So this part is
533 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
534 argument. It sums up to the path part C<world/$arg>. This leads to a
535 complete chain of C</hello/$arg/world/$arg> which is matched against the
538 This example application would, if run and called by e.g.
539 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
540 value C<arg_sum> to "23". The C<world> action would then append "World!"
541 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
542 sake of simplicity no view is shown. Instead we just put the values of
543 the stash into our body. So the output would look like:
548 And our test server would have given us this debugging output for the
552 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
553 [debug] Path is "/greeting/world"
554 [debug] Arguments are "12"
555 [info] Request took 0.164113s (6.093/s)
556 .------------------------------------------+-----------.
558 +------------------------------------------+-----------+
559 | /greeting/hello | 0.000029s |
560 | /greeting/world | 0.000024s |
561 '------------------------------------------+-----------'
564 What would be common uses of this dispatch technique? It gives the
565 possibility to split up logic that contains steps that each depend on
566 each other. An example would be, for example, a wiki path like
567 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
570 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
571 my ( $self, $c, $page_name ) = @_;
572 # load the page named $page_name and put the object
576 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
577 my ( $self, $c, $revision_id ) = @_;
578 # use the page object in the stash to get at its
579 # revision with number $revision_id
582 sub view : PathPart Chained('rev') Args(0) {
583 my ( $self, $c ) = @_;
584 # display the revision in our stash. Another option
585 # would be to forward a compatible object to the action
586 # that displays the default wiki pages, unless we want
587 # a different interface here, for example restore
591 It would now be possible to add other endpoints, for example C<restore>
592 to restore this specific revision as the current state.
594 You don't have to put all the chained actions in one controller. The
595 specification of the parent through C<:Chained> also takes an absolute
596 action path as its argument. Just specify it with a leading C</>.
598 If you want, for example, to have actions for the public paths
599 C</foo/12/edit> and C</foo/12>, just specify two actions with
600 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
601 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
602 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
603 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
604 this debugging output:
607 [debug] Loaded Path Part actions:
608 .-----------------------+------------------------------.
609 | Path Spec | Private |
610 +-----------------------+------------------------------+
611 | /foo/* | /controller/foo_view |
612 | /foo/*/edit | /controller/foo_load (1) |
613 | | => /controller/edit |
614 '-----------------------+------------------------------'
617 Here's a more detailed specification of the attributes belonging to
626 Sets the name of this part of the chain. If it is specified without
627 arguments, it takes the name of the action as default. So basically
628 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
629 This can also contain slashes to bind to a deeper level. An action
630 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
631 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
632 effect as using C<:PathPart>, it would default to the action name.
636 Sets PathPart to the path_prefix of the current controller.
640 Has to be specified for every child in the chain. Possible values are
641 absolute and relative private action paths or a single slash C</> to
642 tell Catalyst that this is the root of a chain. The attribute
643 C<:Chained> without arguments also defaults to the C</> behavior.
644 Relative action paths may use C<../> to refer to actions in parent
647 Because you can specify an absolute path to the parent action, it
648 doesn't matter to Catalyst where that parent is located. So, if your
649 design requests it, you can redispatch a chain through any controller or
652 Another interesting possibility gives C<:Chained('.')>, which chains
653 itself to an action with the path of the current controller's namespace.
656 # in MyApp::Controller::Foo
657 sub bar : Chained CaptureArgs(1) { ... }
659 # in MyApp::Controller::Foo::Bar
660 sub baz : Chained('.') Args(1) { ... }
662 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
663 as the argument to Chained here chains the C<baz> action to an action
664 with the path of the current controller namespace, namely
665 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
666 chain comes out as the end product.
670 Chains an action to another action with the same name in the parent
671 controller. For Example:
673 # in MyApp::Controller::Foo
674 sub bar : Chained CaptureArgs(1) { ... }
676 # in MyApp::Controller::Foo::Moo
677 sub bar : ChainedParent Args(1) { ... }
679 This builds a chain like C</bar/*/bar/*>.
683 Must be specified for every part of the chain that is not an
684 endpoint. With this attribute Catalyst knows how many of the following
685 parts of the path (separated by C</>) this action wants to capture as
686 its arguments. If it doesn't expect any, just specify
687 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
688 after the context, but you can also find them as array references in
689 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
690 level of the action in the chain that captured the parts of the path.
692 An action that is part of a chain (that is, one that has a C<:Chained>
693 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
696 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
697 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
698 named constraint such as CaptureArgs(Int,Str) would require two args with
699 the first being a Integer and the second a string. You may declare your own
700 custom type constraints and import them into the controller namespace:
702 package MyApp::Controller::Root;
705 use MooseX::MethodAttributes;
706 use MyApp::Types qw/Int/;
708 extends 'Catalyst::Controller';
710 sub chain_base :Chained(/) CaptureArgs(1) { }
712 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
714 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
716 See L<Catalyst::RouteMatching> for more.
720 By default, endpoints receive the rest of the arguments in the path. You
721 can tell Catalyst through C<:Args> explicitly how many arguments your
722 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
723 also affects whether this chain is invoked on a request. A chain with an
724 endpoint specifying one argument will only match if exactly one argument
727 You can specify an exact number of arguments like C<:Args(3)>, including
728 C<0>. If you just say C<:Args> without any arguments, it is the same as
729 leaving it out altogether: The chain is matched regardless of the number
730 of path parts after the endpoint.
732 Just as with C<:CaptureArgs>, the arguments get passed to the action in
733 C<@_> after the context object. They can also be reached through
734 C<$c-E<gt>request-E<gt>arguments>.
738 =head2 Auto actions, dispatching and forwarding
740 Note that the list of C<auto> actions called depends on the private path
741 of the endpoint of the chain, not on the chained actions way. The
742 C<auto> actions will be run before the chain dispatching begins. In
743 every other aspect, C<auto> actions behave as documented.
745 The C<forward>ing to other actions does just what you would expect. i.e.
746 only the target action is run. The actions that that action is chained
748 If you C<detach> out of a chain, the rest of the chain will not get
749 called after the C<detach>.
751 =head2 match_captures
753 A method which can optionally be implemented by actions to
756 See L<Catalyst::Action> for further details.
760 Catalyst Contributors, see Catalyst.pm
764 This library is free software. You can redistribute it and/or modify it under
765 the same terms as Perl itself.