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 = $endpoint->list_extra_info->{Args};
103 if($endpoint->has_args_constraints) {
104 @parts = map { "{$_}" } $endpoint->all_args_constraints;
105 } elsif(defined $endpoint->attributes->{Args}) {
106 @parts = (defined($endpoint->attributes->{Args}[0]) ? (("*") x $args) : '...');
110 my $parent = "DUMMY";
111 my $extra = $self->_list_extra_http_methods($endpoint);
112 my $consumes = $self->_list_extra_consumes($endpoint);
113 my $scheme = $self->_list_extra_scheme($endpoint);
114 my $curr = $endpoint;
116 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
117 if($curr->has_captures_constraints) {
118 my $names = join '/', map { "{$_}" } $curr->all_captures_constraints;
119 unshift(@parts, $names);
121 unshift(@parts, (("*") x $cap));
124 if (my $pp = $curr->attributes->{PathPart}) {
125 unshift(@parts, $pp->[0])
126 if (defined $pp->[0] && length $pp->[0]);
128 $parent = $curr->attributes->{Chained}->[0];
129 $curr = $self->_actions->{$parent};
130 unshift(@parents, $curr) if $curr;
132 if ($parent ne '/') {
133 $has_unattached_actions = 1;
134 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
138 foreach my $p (@parents) {
141 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
142 $name = "${extra} ${name}";
144 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
145 if($p->has_captures_constraints) {
146 my $tc = join ',', @{$p->captures_constraints};
152 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
155 if (defined(my $s = $p->list_extra_info->{Scheme})) {
159 unless ($p eq $parents[0]) {
160 $name = "-> ${name}";
162 push(@rows, [ '', $name ]);
165 my $endpoint_arg_info = $endpoint;
166 if($endpoint->has_args_constraints) {
167 my $tc = join ',', @{$endpoint->args_constraints};
168 $endpoint_arg_info .= " ($tc)";
170 $endpoint_arg_info .= defined($endpoint->attributes->{Args}[0]) ? " ($args)" : " (...)";
172 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : ''). ($scheme ? "$scheme: ":'')."/${endpoint_arg_info}". ($consumes ? " :$consumes":"" ) ]);
173 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
174 $rows[0][0] = join('/', '', @display_parts) || '/';
175 $paths->row(@$_) for @rows;
178 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
179 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
180 if $has_unattached_actions;
183 sub _list_extra_http_methods {
184 my ( $self, $action ) = @_;
185 return unless defined $action->list_extra_info->{HTTP_METHODS};
186 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
190 sub _list_extra_consumes {
191 my ( $self, $action ) = @_;
192 return unless defined $action->list_extra_info->{CONSUMES};
193 return join(', ', @{$action->list_extra_info->{CONSUMES}});
196 sub _list_extra_scheme {
197 my ( $self, $action ) = @_;
198 return unless defined $action->list_extra_info->{Scheme};
199 return uc $action->list_extra_info->{Scheme};
202 =head2 $self->match( $c, $path )
204 Calls C<recurse_match> to see if a chain matches the C<$path>.
209 my ( $self, $c, $path ) = @_;
211 my $request = $c->request;
212 return 0 if @{$request->args};
214 my @parts = split('/', $path);
216 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
218 if ($parts && @$parts) {
219 for my $arg (@$parts) {
220 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
221 push @{$request->args}, $arg;
225 return 0 unless $chain;
227 my $action = Catalyst::ActionChain->from_chain($chain);
229 $request->action("/${action}");
230 $request->match("/${action}");
231 $request->captures($captures);
233 $c->namespace( $action->namespace );
238 =head2 $self->recurse_match( $c, $parent, \@path_parts )
240 Recursive search for a matching chain.
245 my ( $self, $c, $parent, $path_parts ) = @_;
246 my $children = $self->_children_of->{$parent};
247 return () unless $children;
250 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
252 # $b then $a to try longest part first
253 my @parts = @$path_parts;
254 if (length $try_part) { # test and strip PathPart
256 ($try_part eq join('/', # assemble equal number of parts
257 splice( # and strip them off @parts as well
258 @parts, 0, scalar(@{[split('/', $try_part)]})
259 ))); # @{[]} to avoid split to @_
261 my @try_actions = @{$children->{$try_part}};
262 TRY_ACTION: foreach my $action (@try_actions) {
265 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
266 my $capture_count = $action->number_of_captures|| 0;
268 # Short-circuit if not enough remaining parts
269 next TRY_ACTION unless @parts >= $capture_count;
272 my @parts = @parts; # localise
274 # strip CaptureArgs into list
275 push(@captures, splice(@parts, 0, $capture_count));
277 # check if the action may fit, depending on a given test by the app
278 next TRY_ACTION unless $action->match_captures($c, \@captures);
280 # try the remaining parts against children of this action
281 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
282 $c, '/'.$action->reverse, \@parts
284 # No best action currently
285 # OR The action has less parts
286 # OR The action has equal parts but less captured data (ergo more defined)
289 $#$action_parts < $#{$best_action->{parts}} ||
290 ($#$action_parts == $#{$best_action->{parts}} &&
291 $#$captures < $#{$best_action->{captures}} &&
292 $n_pathparts > $best_action->{n_pathparts}))) {
293 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
295 actions => [ $action, @$actions ],
296 captures=> [ @captures, @$captures ],
297 parts => $action_parts,
298 n_pathparts => scalar(@pathparts) + $n_pathparts,
304 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
305 next TRY_ACTION unless $action->match($c);
307 my $args_attr = $action->attributes->{Args}->[0];
308 my $args_count = $action->comparable_arg_number;
309 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
310 # No best action currently
311 # OR This one matches with fewer parts left than the current best action,
312 # And therefore is a better match
313 # OR No parts and this expects 0
314 # The current best action might also be Args(0),
315 # but we couldn't chose between then anyway so we'll take the last seen
318 @parts < @{$best_action->{parts}} ||
321 defined($args_attr) &&
323 $args_count eq "0" &&
325 ($c->config->{use_chained_args_0_special_case}||0) ||
327 exists($best_action->{args_count}) && defined($best_action->{args_count}) ?
328 ($best_action->{args_count} ne 0) : 1
335 actions => [ $action ],
338 args_count => $args_count,
339 n_pathparts => scalar(@pathparts),
345 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
349 =head2 $self->register( $c, $action )
351 Calls register_path for every Path attribute for the given $action.
356 my ( $self, $c, $action ) = @_;
358 my @chained_attr = @{ $action->attributes->{Chained} || [] };
360 return 0 unless @chained_attr;
362 if (@chained_attr > 1) {
363 Catalyst::Exception->throw(
364 "Multiple Chained attributes not supported registering ${action}"
367 my $chained_to = $chained_attr[0];
369 Catalyst::Exception->throw(
370 "Actions cannot chain to themselves registering /${action}"
371 ) if ($chained_to eq '/' . $action);
373 my $children = ($self->_children_of->{ $chained_to } ||= {});
375 my @path_part = @{ $action->attributes->{PathPart} || [] };
377 my $part = $action->name;
379 if (@path_part == 1 && defined $path_part[0]) {
380 $part = $path_part[0];
381 } elsif (@path_part > 1) {
382 Catalyst::Exception->throw(
383 "Multiple PathPart attributes not supported registering " . $action->reverse()
387 if ($part =~ m(^/)) {
388 Catalyst::Exception->throw(
389 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
393 my $encoded_part = URI->new($part)->canonical;
394 $encoded_part =~ s{(?<=[^/])/+\z}{};
396 $action->attributes->{PathPart} = [ $encoded_part ];
398 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
400 $self->_actions->{'/'.$action->reverse} = $action;
402 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
403 Catalyst::Exception->throw(
404 "Combining Args and CaptureArgs attributes not supported registering " .
409 unless ($action->attributes->{CaptureArgs}) {
410 unshift(@{ $self->_endpoints }, $action);
416 =head2 $self->uri_for_action($action, $captures)
418 Get the URI part for the action, using C<$captures> to fill
424 my ( $self, $action, $captures ) = @_;
426 return undef unless ($action->attributes->{Chained}
427 && !$action->attributes->{CaptureArgs});
430 my @captures = @$captures;
431 my $parent = "DUMMY";
433 # If this is an action chain get the last action in the chain
434 if($curr->can('chain') ) {
435 $curr = ${$curr->chain}[-1];
438 if (my $cap = $curr->number_of_captures) {
439 return undef unless @captures >= $cap; # not enough captures
441 unshift(@parts, splice(@captures, -$cap));
444 if (my $pp = $curr->attributes->{PathPart}) {
445 unshift(@parts, $pp->[0])
446 if (defined($pp->[0]) && length($pp->[0]));
448 $parent = $curr->attributes->{Chained}->[0];
449 $curr = $self->_actions->{$parent};
452 return undef unless $parent eq '/'; # fail for dangling action
454 return undef if @captures; # fail for too many captures
456 return join('/', '', @parts);
460 =head2 $c->expand_action($action)
462 Return a list of actions that represents a chained action. See
463 L<Catalyst::Dispatcher> for more info. You probably want to
464 use the expand_action it provides rather than this directly.
469 my ($self, $action) = @_;
471 return unless $action->attributes && $action->attributes->{Chained};
478 my $parent = $curr->attributes->{Chained}->[0];
479 $curr = $self->_actions->{$parent};
482 return Catalyst::ActionChain->from_chain([reverse @chain]);
485 __PACKAGE__->meta->make_immutable;
492 The C<Chained> attribute allows you to chain public path parts together
493 by their private names. A chain part's path can be specified with
494 C<PathPart> and can be declared to expect an arbitrary number of
495 arguments. The endpoint of the chain specifies how many arguments it
496 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
497 C<:Args> without an integer would be unlimited. The path parts that
498 aren't endpoints are using C<CaptureArgs> to specify how many parameters
499 they expect to receive. As an example setup:
501 package MyApp::Controller::Greeting;
502 use base qw/ Catalyst::Controller /;
504 # this is the beginning of our chain
505 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
506 my ( $self, $c, $integer ) = @_;
507 $c->stash->{ message } = "Hello ";
508 $c->stash->{ arg_sum } = $integer;
511 # this is our endpoint, because it has no :CaptureArgs
512 sub world : PathPart('world') Chained('hello') Args(1) {
513 my ( $self, $c, $integer ) = @_;
514 $c->stash->{ message } .= "World!";
515 $c->stash->{ arg_sum } += $integer;
517 $c->response->body( join "<br/>\n" =>
518 $c->stash->{ message }, $c->stash->{ arg_sum } );
521 The debug output provides a separate table for chained actions, showing
522 the whole chain as it would match and the actions it contains. Here's an
523 example of the startup output with our actions above:
526 [debug] Loaded Path Part actions:
527 .-----------------------+------------------------------.
528 | Path Spec | Private |
529 +-----------------------+------------------------------+
530 | /hello/*/world/* | /greeting/hello (1) |
531 | | => /greeting/world |
532 '-----------------------+------------------------------'
535 As you can see, Catalyst only deals with chains as whole paths and
536 builds one for each endpoint, which are the actions with C<:Chained> but
537 without C<:CaptureArgs>.
539 Let's assume this application gets a request at the path
540 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
541 to the C<hello> action and pass the value C<23> as an argument to it
542 after the context. It does so because we have previously used
543 C<:CaptureArgs(1)> to declare that it has one path part after itself as
544 its argument. We told Catalyst that this is the beginning of the chain
545 by specifying C<:Chained('/')>. Also note that instead of saying
546 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
547 defaults to the name of the action.
549 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
550 action. This is the last action to be called: Catalyst knows this is an
551 endpoint because we did not specify a C<:CaptureArgs>
552 attribute. Nevertheless we specify that this action expects an argument,
553 but at this point we're using C<:Args(1)> to do that. We could also have
554 said C<:Args> or left it out altogether, which would mean this action
555 would get all arguments that are there. This action's C<:Chained>
556 attribute says C<hello> and tells Catalyst that the C<hello> action in
557 the current controller is its parent.
559 With this we have built a chain consisting of two public path parts.
560 C<hello> captures one part of the path as its argument, and also
561 specifies the path root as its parent. So this part is
562 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
563 argument. It sums up to the path part C<world/$arg>. This leads to a
564 complete chain of C</hello/$arg/world/$arg> which is matched against the
567 This example application would, if run and called by e.g.
568 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
569 value C<arg_sum> to "23". The C<world> action would then append "World!"
570 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
571 sake of simplicity no view is shown. Instead we just put the values of
572 the stash into our body. So the output would look like:
577 And our test server would have given us this debugging output for the
581 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
582 [debug] Path is "/greeting/world"
583 [debug] Arguments are "12"
584 [info] Request took 0.164113s (6.093/s)
585 .------------------------------------------+-----------.
587 +------------------------------------------+-----------+
588 | /greeting/hello | 0.000029s |
589 | /greeting/world | 0.000024s |
590 '------------------------------------------+-----------'
593 What would be common uses of this dispatch technique? It gives the
594 possibility to split up logic that contains steps that each depend on
595 each other. An example would be, for example, a wiki path like
596 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
599 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
600 my ( $self, $c, $page_name ) = @_;
601 # load the page named $page_name and put the object
605 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
606 my ( $self, $c, $revision_id ) = @_;
607 # use the page object in the stash to get at its
608 # revision with number $revision_id
611 sub view : PathPart Chained('rev') Args(0) {
612 my ( $self, $c ) = @_;
613 # display the revision in our stash. Another option
614 # would be to forward a compatible object to the action
615 # that displays the default wiki pages, unless we want
616 # a different interface here, for example restore
620 It would now be possible to add other endpoints, for example C<restore>
621 to restore this specific revision as the current state.
623 You don't have to put all the chained actions in one controller. The
624 specification of the parent through C<:Chained> also takes an absolute
625 action path as its argument. Just specify it with a leading C</>.
627 If you want, for example, to have actions for the public paths
628 C</foo/12/edit> and C</foo/12>, just specify two actions with
629 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
630 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
631 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
632 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
633 this debugging output:
636 [debug] Loaded Path Part actions:
637 .-----------------------+------------------------------.
638 | Path Spec | Private |
639 +-----------------------+------------------------------+
640 | /foo/* | /controller/foo_view |
641 | /foo/*/edit | /controller/foo_load (1) |
642 | | => /controller/edit |
643 '-----------------------+------------------------------'
646 Here's a more detailed specification of the attributes belonging to
655 Sets the name of this part of the chain. If it is specified without
656 arguments, it takes the name of the action as default. So basically
657 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
658 This can also contain slashes to bind to a deeper level. An action
659 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
660 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
661 effect as using C<:PathPart>, it would default to the action name.
665 Sets PathPart to the path_prefix of the current controller.
669 Has to be specified for every child in the chain. Possible values are
670 absolute and relative private action paths or a single slash C</> to
671 tell Catalyst that this is the root of a chain. The attribute
672 C<:Chained> without arguments also defaults to the C</> behavior.
673 Relative action paths may use C<../> to refer to actions in parent
676 Because you can specify an absolute path to the parent action, it
677 doesn't matter to Catalyst where that parent is located. So, if your
678 design requests it, you can redispatch a chain through any controller or
681 Another interesting possibility gives C<:Chained('.')>, which chains
682 itself to an action with the path of the current controller's namespace.
685 # in MyApp::Controller::Foo
686 sub bar : Chained CaptureArgs(1) { ... }
688 # in MyApp::Controller::Foo::Bar
689 sub baz : Chained('.') Args(1) { ... }
691 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
692 as the argument to Chained here chains the C<baz> action to an action
693 with the path of the current controller namespace, namely
694 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
695 chain comes out as the end product.
699 Chains an action to another action with the same name in the parent
700 controller. For Example:
702 # in MyApp::Controller::Foo
703 sub bar : Chained CaptureArgs(1) { ... }
705 # in MyApp::Controller::Foo::Bar
706 sub bar : ChainedParent Args(1) { ... }
708 This builds a chain like C</bar/*/bar/*>.
712 Must be specified for every part of the chain that is not an
713 endpoint. With this attribute Catalyst knows how many of the following
714 parts of the path (separated by C</>) this action wants to capture as
715 its arguments. If it doesn't expect any, just specify
716 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
717 after the context, but you can also find them as array references in
718 C<< $c->request->captures->[$level] >>. The C<$level> is the
719 level of the action in the chain that captured the parts of the path.
721 An action that is part of a chain (that is, one that has a C<:Chained>
722 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
725 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
726 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
727 named constraint such as CaptureArgs(Int,Str) would require two args with
728 the first being a Integer and the second a string. You may declare your own
729 custom type constraints and import them into the controller namespace:
731 package MyApp::Controller::Root;
734 use MooseX::MethodAttributes;
735 use MyApp::Types qw/Int/;
737 extends 'Catalyst::Controller';
739 sub chain_base :Chained(/) CaptureArgs(1) { }
741 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
743 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
745 If you use a reference type constraint in CaptureArgs, it must be a type
746 like Tuple in L<Types::Standard> that allows us to determine the number of
747 args to match. Otherwise this will raise an error during startup.
749 See L<Catalyst::RouteMatching> for more.
753 By default, endpoints receive the rest of the arguments in the path. You
754 can tell Catalyst through C<:Args> explicitly how many arguments your
755 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
756 also affects whether this chain is invoked on a request. A chain with an
757 endpoint specifying one argument will only match if exactly one argument
760 You can specify an exact number of arguments like C<:Args(3)>, including
761 C<0>. If you just say C<:Args> without any arguments, it is the same as
762 leaving it out altogether: The chain is matched regardless of the number
763 of path parts after the endpoint.
765 Just as with C<:CaptureArgs>, the arguments get passed to the action in
766 C<@_> after the context object. They can also be reached through
767 C<< $c->request->arguments >>.
769 You should see 'Args' in L<Catalyst::Controller> for more details on using
770 type constraints in your Args declarations.
774 =head2 Auto actions, dispatching and forwarding
776 Note that the list of C<auto> actions called depends on the private path
777 of the endpoint of the chain, not on the chained actions way. The
778 C<auto> actions will be run before the chain dispatching begins. In
779 every other aspect, C<auto> actions behave as documented.
781 The C<forward>ing to other actions does just what you would expect. i.e.
782 only the target action is run. The actions that that action is chained
784 If you C<detach> out of a chain, the rest of the chain will not get
785 called after the C<detach>.
787 =head2 match_captures
789 A method which can optionally be implemented by actions to
792 See L<Catalyst::Action> for further details.
796 Catalyst Contributors, see Catalyst.pm
800 This library is free software. You can redistribute it and/or modify it under
801 the same terms as Perl itself.