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) {
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 $args_count = $action->normalized_arg_number;
296 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
297 # No best action currently
298 # OR This one matches with fewer parts left than the current best action,
299 # And therefore is a better match
300 # OR No parts and this expects 0
301 # The current best action might also be Args(0),
302 # but we couldn't chose between then anyway so we'll take the last seen
305 @parts < @{$best_action->{parts}} ||
308 defined($args_attr) &&
310 $args_count eq "0" &&
312 ($c->config->{use_chained_args_0_special_case}||0) ||
314 exists($best_action->{args_count}) && defined($best_action->{args_count}) ?
315 ($best_action->{args_count} ne 0) : 1
322 actions => [ $action ],
325 args_count => $args_count,
326 n_pathparts => scalar(@pathparts),
332 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
336 =head2 $self->register( $c, $action )
338 Calls register_path for every Path attribute for the given $action.
343 my ( $self, $c, $action ) = @_;
345 my @chained_attr = @{ $action->attributes->{Chained} || [] };
347 return 0 unless @chained_attr;
349 if (@chained_attr > 1) {
350 Catalyst::Exception->throw(
351 "Multiple Chained attributes not supported registering ${action}"
354 my $chained_to = $chained_attr[0];
356 Catalyst::Exception->throw(
357 "Actions cannot chain to themselves registering /${action}"
358 ) if ($chained_to eq '/' . $action);
360 my $children = ($self->_children_of->{ $chained_to } ||= {});
362 my @path_part = @{ $action->attributes->{PathPart} || [] };
364 my $part = $action->name;
366 if (@path_part == 1 && defined $path_part[0]) {
367 $part = $path_part[0];
368 } elsif (@path_part > 1) {
369 Catalyst::Exception->throw(
370 "Multiple PathPart attributes not supported registering " . $action->reverse()
374 if ($part =~ m(^/)) {
375 Catalyst::Exception->throw(
376 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
380 my $encoded_part = URI->new($part)->canonical;
381 $encoded_part =~ s{(?<=[^/])/+\z}{};
383 $action->attributes->{PathPart} = [ $encoded_part ];
385 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
387 $self->_actions->{'/'.$action->reverse} = $action;
389 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
390 Catalyst::Exception->throw(
391 "Combining Args and CaptureArgs attributes not supported registering " .
396 unless ($action->attributes->{CaptureArgs}) {
397 unshift(@{ $self->_endpoints }, $action);
403 =head2 $self->uri_for_action($action, $captures)
405 Get the URI part for the action, using C<$captures> to fill
411 my ( $self, $action, $captures ) = @_;
413 return undef unless ($action->attributes->{Chained}
414 && !$action->attributes->{CaptureArgs});
417 my @captures = @$captures;
418 my $parent = "DUMMY";
420 # If this is an action chain get the last action in the chain
421 if($curr->can('chain') ) {
422 $curr = ${$curr->chain}[-1];
425 if (my $cap = $curr->number_of_captures) {
426 return undef unless @captures >= $cap; # not enough captures
428 unshift(@parts, splice(@captures, -$cap));
431 if (my $pp = $curr->attributes->{PathPart}) {
432 unshift(@parts, $pp->[0])
433 if (defined($pp->[0]) && length($pp->[0]));
435 $parent = $curr->attributes->{Chained}->[0];
436 $curr = $self->_actions->{$parent};
439 return undef unless $parent eq '/'; # fail for dangling action
441 return undef if @captures; # fail for too many captures
443 return join('/', '', @parts);
447 =head2 $c->expand_action($action)
449 Return a list of actions that represents a chained action. See
450 L<Catalyst::Dispatcher> for more info. You probably want to
451 use the expand_action it provides rather than this directly.
456 my ($self, $action) = @_;
458 return unless $action->attributes && $action->attributes->{Chained};
465 my $parent = $curr->attributes->{Chained}->[0];
466 $curr = $self->_actions->{$parent};
469 return Catalyst::ActionChain->from_chain([reverse @chain]);
472 __PACKAGE__->meta->make_immutable;
479 The C<Chained> attribute allows you to chain public path parts together
480 by their private names. A chain part's path can be specified with
481 C<PathPart> and can be declared to expect an arbitrary number of
482 arguments. The endpoint of the chain specifies how many arguments it
483 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
484 C<:Args> without an integer would be unlimited. The path parts that
485 aren't endpoints are using C<CaptureArgs> to specify how many parameters
486 they expect to receive. As an example setup:
488 package MyApp::Controller::Greeting;
489 use base qw/ Catalyst::Controller /;
491 # this is the beginning of our chain
492 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
493 my ( $self, $c, $integer ) = @_;
494 $c->stash->{ message } = "Hello ";
495 $c->stash->{ arg_sum } = $integer;
498 # this is our endpoint, because it has no :CaptureArgs
499 sub world : PathPart('world') Chained('hello') Args(1) {
500 my ( $self, $c, $integer ) = @_;
501 $c->stash->{ message } .= "World!";
502 $c->stash->{ arg_sum } += $integer;
504 $c->response->body( join "<br/>\n" =>
505 $c->stash->{ message }, $c->stash->{ arg_sum } );
508 The debug output provides a separate table for chained actions, showing
509 the whole chain as it would match and the actions it contains. Here's an
510 example of the startup output with our actions above:
513 [debug] Loaded Path Part actions:
514 .-----------------------+------------------------------.
515 | Path Spec | Private |
516 +-----------------------+------------------------------+
517 | /hello/*/world/* | /greeting/hello (1) |
518 | | => /greeting/world |
519 '-----------------------+------------------------------'
522 As you can see, Catalyst only deals with chains as whole paths and
523 builds one for each endpoint, which are the actions with C<:Chained> but
524 without C<:CaptureArgs>.
526 Let's assume this application gets a request at the path
527 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
528 to the C<hello> action and pass the value C<23> as an argument to it
529 after the context. It does so because we have previously used
530 C<:CaptureArgs(1)> to declare that it has one path part after itself as
531 its argument. We told Catalyst that this is the beginning of the chain
532 by specifying C<:Chained('/')>. Also note that instead of saying
533 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
534 defaults to the name of the action.
536 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
537 action. This is the last action to be called: Catalyst knows this is an
538 endpoint because we did not specify a C<:CaptureArgs>
539 attribute. Nevertheless we specify that this action expects an argument,
540 but at this point we're using C<:Args(1)> to do that. We could also have
541 said C<:Args> or left it out altogether, which would mean this action
542 would get all arguments that are there. This action's C<:Chained>
543 attribute says C<hello> and tells Catalyst that the C<hello> action in
544 the current controller is its parent.
546 With this we have built a chain consisting of two public path parts.
547 C<hello> captures one part of the path as its argument, and also
548 specifies the path root as its parent. So this part is
549 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
550 argument. It sums up to the path part C<world/$arg>. This leads to a
551 complete chain of C</hello/$arg/world/$arg> which is matched against the
554 This example application would, if run and called by e.g.
555 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
556 value C<arg_sum> to "23". The C<world> action would then append "World!"
557 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
558 sake of simplicity no view is shown. Instead we just put the values of
559 the stash into our body. So the output would look like:
564 And our test server would have given us this debugging output for the
568 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
569 [debug] Path is "/greeting/world"
570 [debug] Arguments are "12"
571 [info] Request took 0.164113s (6.093/s)
572 .------------------------------------------+-----------.
574 +------------------------------------------+-----------+
575 | /greeting/hello | 0.000029s |
576 | /greeting/world | 0.000024s |
577 '------------------------------------------+-----------'
580 What would be common uses of this dispatch technique? It gives the
581 possibility to split up logic that contains steps that each depend on
582 each other. An example would be, for example, a wiki path like
583 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
586 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
587 my ( $self, $c, $page_name ) = @_;
588 # load the page named $page_name and put the object
592 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
593 my ( $self, $c, $revision_id ) = @_;
594 # use the page object in the stash to get at its
595 # revision with number $revision_id
598 sub view : PathPart Chained('rev') Args(0) {
599 my ( $self, $c ) = @_;
600 # display the revision in our stash. Another option
601 # would be to forward a compatible object to the action
602 # that displays the default wiki pages, unless we want
603 # a different interface here, for example restore
607 It would now be possible to add other endpoints, for example C<restore>
608 to restore this specific revision as the current state.
610 You don't have to put all the chained actions in one controller. The
611 specification of the parent through C<:Chained> also takes an absolute
612 action path as its argument. Just specify it with a leading C</>.
614 If you want, for example, to have actions for the public paths
615 C</foo/12/edit> and C</foo/12>, just specify two actions with
616 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
617 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
618 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
619 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
620 this debugging output:
623 [debug] Loaded Path Part actions:
624 .-----------------------+------------------------------.
625 | Path Spec | Private |
626 +-----------------------+------------------------------+
627 | /foo/* | /controller/foo_view |
628 | /foo/*/edit | /controller/foo_load (1) |
629 | | => /controller/edit |
630 '-----------------------+------------------------------'
633 Here's a more detailed specification of the attributes belonging to
642 Sets the name of this part of the chain. If it is specified without
643 arguments, it takes the name of the action as default. So basically
644 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
645 This can also contain slashes to bind to a deeper level. An action
646 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
647 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
648 effect as using C<:PathPart>, it would default to the action name.
652 Sets PathPart to the path_prefix of the current controller.
656 Has to be specified for every child in the chain. Possible values are
657 absolute and relative private action paths or a single slash C</> to
658 tell Catalyst that this is the root of a chain. The attribute
659 C<:Chained> without arguments also defaults to the C</> behavior.
660 Relative action paths may use C<../> to refer to actions in parent
663 Because you can specify an absolute path to the parent action, it
664 doesn't matter to Catalyst where that parent is located. So, if your
665 design requests it, you can redispatch a chain through any controller or
668 Another interesting possibility gives C<:Chained('.')>, which chains
669 itself to an action with the path of the current controller's namespace.
672 # in MyApp::Controller::Foo
673 sub bar : Chained CaptureArgs(1) { ... }
675 # in MyApp::Controller::Foo::Bar
676 sub baz : Chained('.') Args(1) { ... }
678 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
679 as the argument to Chained here chains the C<baz> action to an action
680 with the path of the current controller namespace, namely
681 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
682 chain comes out as the end product.
686 Chains an action to another action with the same name in the parent
687 controller. For Example:
689 # in MyApp::Controller::Foo
690 sub bar : Chained CaptureArgs(1) { ... }
692 # in MyApp::Controller::Foo::Moo
693 sub bar : ChainedParent Args(1) { ... }
695 This builds a chain like C</bar/*/bar/*>.
699 Must be specified for every part of the chain that is not an
700 endpoint. With this attribute Catalyst knows how many of the following
701 parts of the path (separated by C</>) this action wants to capture as
702 its arguments. If it doesn't expect any, just specify
703 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
704 after the context, but you can also find them as array references in
705 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
706 level of the action in the chain that captured the parts of the path.
708 An action that is part of a chain (that is, one that has a C<:Chained>
709 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
712 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
713 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
714 named constraint such as CaptureArgs(Int,Str) would require two args with
715 the first being a Integer and the second a string. You may declare your own
716 custom type constraints and import them into the controller namespace:
718 package MyApp::Controller::Root;
721 use MooseX::MethodAttributes;
722 use MyApp::Types qw/Int/;
724 extends 'Catalyst::Controller';
726 sub chain_base :Chained(/) CaptureArgs(1) { }
728 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
730 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
732 If you use a reference type constraint in CaptureArgs, it must be a type
733 like Tuple in L<Types::Standard> that allows us to determine the number of
734 args to match. Otherwise this will raise an error during startup.
736 See L<Catalyst::RouteMatching> for more.
740 By default, endpoints receive the rest of the arguments in the path. You
741 can tell Catalyst through C<:Args> explicitly how many arguments your
742 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
743 also affects whether this chain is invoked on a request. A chain with an
744 endpoint specifying one argument will only match if exactly one argument
747 You can specify an exact number of arguments like C<:Args(3)>, including
748 C<0>. If you just say C<:Args> without any arguments, it is the same as
749 leaving it out altogether: The chain is matched regardless of the number
750 of path parts after the endpoint.
752 Just as with C<:CaptureArgs>, the arguments get passed to the action in
753 C<@_> after the context object. They can also be reached through
754 C<$c-E<gt>request-E<gt>arguments>.
756 You should see 'Args' in L<Catalyst::Controller> for more details on using
757 type constraints in your Args declarations.
761 =head2 Auto actions, dispatching and forwarding
763 Note that the list of C<auto> actions called depends on the private path
764 of the endpoint of the chain, not on the chained actions way. The
765 C<auto> actions will be run before the chain dispatching begins. In
766 every other aspect, C<auto> actions behave as documented.
768 The C<forward>ing to other actions does just what you would expect. i.e.
769 only the target action is run. The actions that that action is chained
771 If you C<detach> out of a chain, the rest of the chain will not get
772 called after the C<detach>.
774 =head2 match_captures
776 A method which can optionally be implemented by actions to
779 See L<Catalyst::Action> for further details.
783 Catalyst Contributors, see Catalyst.pm
787 This library is free software. You can redistribute it and/or modify it under
788 the same terms as Perl itself.