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 = $endpoint->list_extra_info->{Args};
101 my @parts = (defined($endpoint->attributes->{Args}[0]) ? (("*") 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, [ '', $name ]);
153 if($endpoint->has_args_constraints) {
154 my $tc = join ',', @{$endpoint->args_constraints};
155 $endpoint .= " ($tc)";
157 $endpoint .= defined($endpoint->attributes->{Args}[0]) ? " ($args)" : " (...)";
159 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : ''). ($scheme ? "$scheme: ":'')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
160 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
161 $rows[0][0] = join('/', '', @display_parts) || '/';
162 $paths->row(@$_) for @rows;
165 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
166 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
167 if $has_unattached_actions;
170 sub _list_extra_http_methods {
171 my ( $self, $action ) = @_;
172 return unless defined $action->list_extra_info->{HTTP_METHODS};
173 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
177 sub _list_extra_consumes {
178 my ( $self, $action ) = @_;
179 return unless defined $action->list_extra_info->{CONSUMES};
180 return join(', ', @{$action->list_extra_info->{CONSUMES}});
183 sub _list_extra_scheme {
184 my ( $self, $action ) = @_;
185 return unless defined $action->list_extra_info->{Scheme};
186 return uc $action->list_extra_info->{Scheme};
189 =head2 $self->match( $c, $path )
191 Calls C<recurse_match> to see if a chain matches the C<$path>.
196 my ( $self, $c, $path ) = @_;
198 my $request = $c->request;
199 return 0 if @{$request->args};
201 my @parts = split('/', $path);
203 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
205 if ($parts && @$parts) {
206 for my $arg (@$parts) {
207 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
208 push @{$request->args}, $arg;
212 return 0 unless $chain;
214 my $action = Catalyst::ActionChain->from_chain($chain);
216 $request->action("/${action}");
217 $request->match("/${action}");
218 $request->captures($captures);
220 $c->namespace( $action->namespace );
225 =head2 $self->recurse_match( $c, $parent, \@path_parts )
227 Recursive search for a matching chain.
232 my ( $self, $c, $parent, $path_parts ) = @_;
233 my $children = $self->_children_of->{$parent};
234 return () unless $children;
237 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
239 # $b then $a to try longest part first
240 my @parts = @$path_parts;
241 if (length $try_part) { # test and strip PathPart
243 ($try_part eq join('/', # assemble equal number of parts
244 splice( # and strip them off @parts as well
245 @parts, 0, scalar(@{[split('/', $try_part)]})
246 ))); # @{[]} to avoid split to @_
248 my @try_actions = @{$children->{$try_part}};
249 TRY_ACTION: foreach my $action (@try_actions) {
250 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
251 my $capture_count = $action->number_of_captures|| 0;
253 # Short-circuit if not enough remaining parts
254 next TRY_ACTION unless @parts >= $capture_count;
257 my @parts = @parts; # localise
259 # strip CaptureArgs into list
260 push(@captures, splice(@parts, 0, $capture_count));
262 # check if the action may fit, depending on a given test by the app
263 next TRY_ACTION unless $action->match_captures($c, \@captures);
265 # try the remaining parts against children of this action
266 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
267 $c, '/'.$action->reverse, \@parts
269 # No best action currently
270 # OR The action has less parts
271 # OR The action has equal parts but less captured data (ergo more defined)
274 $#$action_parts < $#{$best_action->{parts}} ||
275 ($#$action_parts == $#{$best_action->{parts}} &&
276 $#$captures < $#{$best_action->{captures}} &&
277 $n_pathparts > $best_action->{n_pathparts}))) {
278 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
280 actions => [ $action, @$actions ],
281 captures=> [ @captures, @$captures ],
282 parts => $action_parts,
283 n_pathparts => scalar(@pathparts) + $n_pathparts,
289 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
290 next TRY_ACTION unless $action->match($c);
292 my $args_attr = $action->attributes->{Args}->[0];
293 my $args_count = $action->normalized_arg_number;
294 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
295 # No best action currently
296 # OR This one matches with fewer parts left than the current best action,
297 # And therefore is a better match
298 # OR No parts and this expects 0
299 # The current best action might also be Args(0),
300 # but we couldn't chose between then anyway so we'll take the last seen
304 @parts < @{$best_action->{parts}} ||
307 defined($args_attr) &&
309 $args_count eq "0" &&
311 ($c->config->{use_chained_args_0_special_case}||0) ||
313 exists($best_action->{args_count}) && defined($best_action->{args_count}) ?
314 ($best_action->{args_count} ne 0) : 1
321 actions => [ $action ],
324 args_count => $args_count,
325 n_pathparts => scalar(@pathparts),
331 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
335 =head2 $self->register( $c, $action )
337 Calls register_path for every Path attribute for the given $action.
342 my ( $self, $c, $action ) = @_;
344 my @chained_attr = @{ $action->attributes->{Chained} || [] };
346 return 0 unless @chained_attr;
348 if (@chained_attr > 1) {
349 Catalyst::Exception->throw(
350 "Multiple Chained attributes not supported registering ${action}"
353 my $chained_to = $chained_attr[0];
355 Catalyst::Exception->throw(
356 "Actions cannot chain to themselves registering /${action}"
357 ) if ($chained_to eq '/' . $action);
359 my $children = ($self->_children_of->{ $chained_to } ||= {});
361 my @path_part = @{ $action->attributes->{PathPart} || [] };
363 my $part = $action->name;
365 if (@path_part == 1 && defined $path_part[0]) {
366 $part = $path_part[0];
367 } elsif (@path_part > 1) {
368 Catalyst::Exception->throw(
369 "Multiple PathPart attributes not supported registering " . $action->reverse()
373 if ($part =~ m(^/)) {
374 Catalyst::Exception->throw(
375 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
379 my $encoded_part = URI->new($part)->canonical;
380 $encoded_part =~ s{(?<=[^/])/+\z}{};
382 $action->attributes->{PathPart} = [ $encoded_part ];
384 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
386 $self->_actions->{'/'.$action->reverse} = $action;
388 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
389 Catalyst::Exception->throw(
390 "Combining Args and CaptureArgs attributes not supported registering " .
395 unless ($action->attributes->{CaptureArgs}) {
396 unshift(@{ $self->_endpoints }, $action);
402 =head2 $self->uri_for_action($action, $captures)
404 Get the URI part for the action, using C<$captures> to fill
410 my ( $self, $action, $captures ) = @_;
412 return undef unless ($action->attributes->{Chained}
413 && !$action->attributes->{CaptureArgs});
416 my @captures = @$captures;
417 my $parent = "DUMMY";
419 # If this is an action chain get the last action in the chain
420 if($curr->can('chain') ) {
421 $curr = ${$curr->chain}[-1];
424 if (my $cap = $curr->number_of_captures) {
425 return undef unless @captures >= $cap; # not enough captures
427 unshift(@parts, splice(@captures, -$cap));
430 if (my $pp = $curr->attributes->{PathPart}) {
431 unshift(@parts, $pp->[0])
432 if (defined($pp->[0]) && length($pp->[0]));
434 $parent = $curr->attributes->{Chained}->[0];
435 $curr = $self->_actions->{$parent};
438 return undef unless $parent eq '/'; # fail for dangling action
440 return undef if @captures; # fail for too many captures
442 return join('/', '', @parts);
446 =head2 $c->expand_action($action)
448 Return a list of actions that represents a chained action. See
449 L<Catalyst::Dispatcher> for more info. You probably want to
450 use the expand_action it provides rather than this directly.
455 my ($self, $action) = @_;
457 return unless $action->attributes && $action->attributes->{Chained};
464 my $parent = $curr->attributes->{Chained}->[0];
465 $curr = $self->_actions->{$parent};
468 return Catalyst::ActionChain->from_chain([reverse @chain]);
471 __PACKAGE__->meta->make_immutable;
478 The C<Chained> attribute allows you to chain public path parts together
479 by their private names. A chain part's path can be specified with
480 C<PathPart> and can be declared to expect an arbitrary number of
481 arguments. The endpoint of the chain specifies how many arguments it
482 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
483 C<:Args> without an integer would be unlimited. The path parts that
484 aren't endpoints are using C<CaptureArgs> to specify how many parameters
485 they expect to receive. As an example setup:
487 package MyApp::Controller::Greeting;
488 use base qw/ Catalyst::Controller /;
490 # this is the beginning of our chain
491 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
492 my ( $self, $c, $integer ) = @_;
493 $c->stash->{ message } = "Hello ";
494 $c->stash->{ arg_sum } = $integer;
497 # this is our endpoint, because it has no :CaptureArgs
498 sub world : PathPart('world') Chained('hello') Args(1) {
499 my ( $self, $c, $integer ) = @_;
500 $c->stash->{ message } .= "World!";
501 $c->stash->{ arg_sum } += $integer;
503 $c->response->body( join "<br/>\n" =>
504 $c->stash->{ message }, $c->stash->{ arg_sum } );
507 The debug output provides a separate table for chained actions, showing
508 the whole chain as it would match and the actions it contains. Here's an
509 example of the startup output with our actions above:
512 [debug] Loaded Path Part actions:
513 .-----------------------+------------------------------.
514 | Path Spec | Private |
515 +-----------------------+------------------------------+
516 | /hello/*/world/* | /greeting/hello (1) |
517 | | => /greeting/world |
518 '-----------------------+------------------------------'
521 As you can see, Catalyst only deals with chains as whole paths and
522 builds one for each endpoint, which are the actions with C<:Chained> but
523 without C<:CaptureArgs>.
525 Let's assume this application gets a request at the path
526 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
527 to the C<hello> action and pass the value C<23> as an argument to it
528 after the context. It does so because we have previously used
529 C<:CaptureArgs(1)> to declare that it has one path part after itself as
530 its argument. We told Catalyst that this is the beginning of the chain
531 by specifying C<:Chained('/')>. Also note that instead of saying
532 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
533 defaults to the name of the action.
535 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
536 action. This is the last action to be called: Catalyst knows this is an
537 endpoint because we did not specify a C<:CaptureArgs>
538 attribute. Nevertheless we specify that this action expects an argument,
539 but at this point we're using C<:Args(1)> to do that. We could also have
540 said C<:Args> or left it out altogether, which would mean this action
541 would get all arguments that are there. This action's C<:Chained>
542 attribute says C<hello> and tells Catalyst that the C<hello> action in
543 the current controller is its parent.
545 With this we have built a chain consisting of two public path parts.
546 C<hello> captures one part of the path as its argument, and also
547 specifies the path root as its parent. So this part is
548 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
549 argument. It sums up to the path part C<world/$arg>. This leads to a
550 complete chain of C</hello/$arg/world/$arg> which is matched against the
553 This example application would, if run and called by e.g.
554 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
555 value C<arg_sum> to "23". The C<world> action would then append "World!"
556 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
557 sake of simplicity no view is shown. Instead we just put the values of
558 the stash into our body. So the output would look like:
563 And our test server would have given us this debugging output for the
567 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
568 [debug] Path is "/greeting/world"
569 [debug] Arguments are "12"
570 [info] Request took 0.164113s (6.093/s)
571 .------------------------------------------+-----------.
573 +------------------------------------------+-----------+
574 | /greeting/hello | 0.000029s |
575 | /greeting/world | 0.000024s |
576 '------------------------------------------+-----------'
579 What would be common uses of this dispatch technique? It gives the
580 possibility to split up logic that contains steps that each depend on
581 each other. An example would be, for example, a wiki path like
582 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
585 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
586 my ( $self, $c, $page_name ) = @_;
587 # load the page named $page_name and put the object
591 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
592 my ( $self, $c, $revision_id ) = @_;
593 # use the page object in the stash to get at its
594 # revision with number $revision_id
597 sub view : PathPart Chained('rev') Args(0) {
598 my ( $self, $c ) = @_;
599 # display the revision in our stash. Another option
600 # would be to forward a compatible object to the action
601 # that displays the default wiki pages, unless we want
602 # a different interface here, for example restore
606 It would now be possible to add other endpoints, for example C<restore>
607 to restore this specific revision as the current state.
609 You don't have to put all the chained actions in one controller. The
610 specification of the parent through C<:Chained> also takes an absolute
611 action path as its argument. Just specify it with a leading C</>.
613 If you want, for example, to have actions for the public paths
614 C</foo/12/edit> and C</foo/12>, just specify two actions with
615 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
616 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
617 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
618 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
619 this debugging output:
622 [debug] Loaded Path Part actions:
623 .-----------------------+------------------------------.
624 | Path Spec | Private |
625 +-----------------------+------------------------------+
626 | /foo/* | /controller/foo_view |
627 | /foo/*/edit | /controller/foo_load (1) |
628 | | => /controller/edit |
629 '-----------------------+------------------------------'
632 Here's a more detailed specification of the attributes belonging to
641 Sets the name of this part of the chain. If it is specified without
642 arguments, it takes the name of the action as default. So basically
643 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
644 This can also contain slashes to bind to a deeper level. An action
645 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
646 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
647 effect as using C<:PathPart>, it would default to the action name.
651 Sets PathPart to the path_prefix of the current controller.
655 Has to be specified for every child in the chain. Possible values are
656 absolute and relative private action paths or a single slash C</> to
657 tell Catalyst that this is the root of a chain. The attribute
658 C<:Chained> without arguments also defaults to the C</> behavior.
659 Relative action paths may use C<../> to refer to actions in parent
662 Because you can specify an absolute path to the parent action, it
663 doesn't matter to Catalyst where that parent is located. So, if your
664 design requests it, you can redispatch a chain through any controller or
667 Another interesting possibility gives C<:Chained('.')>, which chains
668 itself to an action with the path of the current controller's namespace.
671 # in MyApp::Controller::Foo
672 sub bar : Chained CaptureArgs(1) { ... }
674 # in MyApp::Controller::Foo::Bar
675 sub baz : Chained('.') Args(1) { ... }
677 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
678 as the argument to Chained here chains the C<baz> action to an action
679 with the path of the current controller namespace, namely
680 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
681 chain comes out as the end product.
685 Chains an action to another action with the same name in the parent
686 controller. For Example:
688 # in MyApp::Controller::Foo
689 sub bar : Chained CaptureArgs(1) { ... }
691 # in MyApp::Controller::Foo::Moo
692 sub bar : ChainedParent Args(1) { ... }
694 This builds a chain like C</bar/*/bar/*>.
698 Must be specified for every part of the chain that is not an
699 endpoint. With this attribute Catalyst knows how many of the following
700 parts of the path (separated by C</>) this action wants to capture as
701 its arguments. If it doesn't expect any, just specify
702 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
703 after the context, but you can also find them as array references in
704 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
705 level of the action in the chain that captured the parts of the path.
707 An action that is part of a chain (that is, one that has a C<:Chained>
708 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
711 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
712 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
713 named constraint such as CaptureArgs(Int,Str) would require two args with
714 the first being a Integer and the second a string. You may declare your own
715 custom type constraints and import them into the controller namespace:
717 package MyApp::Controller::Root;
720 use MooseX::MethodAttributes;
721 use MyApp::Types qw/Int/;
723 extends 'Catalyst::Controller';
725 sub chain_base :Chained(/) CaptureArgs(1) { }
727 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
729 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
731 See L<Catalyst::RouteMatching> for more.
735 By default, endpoints receive the rest of the arguments in the path. You
736 can tell Catalyst through C<:Args> explicitly how many arguments your
737 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
738 also affects whether this chain is invoked on a request. A chain with an
739 endpoint specifying one argument will only match if exactly one argument
742 You can specify an exact number of arguments like C<:Args(3)>, including
743 C<0>. If you just say C<:Args> without any arguments, it is the same as
744 leaving it out altogether: The chain is matched regardless of the number
745 of path parts after the endpoint.
747 Just as with C<:CaptureArgs>, the arguments get passed to the action in
748 C<@_> after the context object. They can also be reached through
749 C<$c-E<gt>request-E<gt>arguments>.
753 =head2 Auto actions, dispatching and forwarding
755 Note that the list of C<auto> actions called depends on the private path
756 of the endpoint of the chain, not on the chained actions way. The
757 C<auto> actions will be run before the chain dispatching begins. In
758 every other aspect, C<auto> actions behave as documented.
760 The C<forward>ing to other actions does just what you would expect. i.e.
761 only the target action is run. The actions that that action is chained
763 If you C<detach> out of a chain, the rest of the chain will not get
764 called after the C<detach>.
766 =head2 match_captures
768 A method which can optionally be implemented by actions to
771 See L<Catalyst::Action> for further details.
775 Catalyst Contributors, see Catalyst.pm
779 This library is free software. You can redistribute it and/or modify it under
780 the same terms as Perl itself.