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 ];
294 next TRY_ACTION unless $action->match($c);
296 my $args_attr = $action->attributes->{Args}->[0];
297 my $args_count = $action->normalized_arg_number;
298 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
299 # No best action currently
300 # OR This one matches with fewer parts left than the current best action,
301 # And therefore is a better match
302 # OR No parts and this expects 0
303 # The current best action might also be Args(0),
304 # but we couldn't chose between then anyway so we'll take the last seen
307 @parts < @{$best_action->{parts}} ||
310 defined($args_attr) &&
312 $args_count eq "0" &&
314 ($c->config->{use_chained_args_0_special_case}||0) ||
316 exists($best_action->{args_count}) && defined($best_action->{args_count}) ?
317 ($best_action->{args_count} ne 0) : 1
324 actions => [ $action ],
327 args_count => $args_count,
328 n_pathparts => scalar(@pathparts),
334 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
338 =head2 $self->register( $c, $action )
340 Calls register_path for every Path attribute for the given $action.
345 my ( $self, $c, $action ) = @_;
347 my @chained_attr = @{ $action->attributes->{Chained} || [] };
349 return 0 unless @chained_attr;
351 if (@chained_attr > 1) {
352 Catalyst::Exception->throw(
353 "Multiple Chained attributes not supported registering ${action}"
356 my $chained_to = $chained_attr[0];
358 Catalyst::Exception->throw(
359 "Actions cannot chain to themselves registering /${action}"
360 ) if ($chained_to eq '/' . $action);
362 my $children = ($self->_children_of->{ $chained_to } ||= {});
364 my @path_part = @{ $action->attributes->{PathPart} || [] };
366 my $part = $action->name;
368 if (@path_part == 1 && defined $path_part[0]) {
369 $part = $path_part[0];
370 } elsif (@path_part > 1) {
371 Catalyst::Exception->throw(
372 "Multiple PathPart attributes not supported registering " . $action->reverse()
376 if ($part =~ m(^/)) {
377 Catalyst::Exception->throw(
378 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
382 my $encoded_part = URI->new($part)->canonical;
383 $encoded_part =~ s{(?<=[^/])/+\z}{};
385 $action->attributes->{PathPart} = [ $encoded_part ];
387 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
389 $self->_actions->{'/'.$action->reverse} = $action;
391 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
392 Catalyst::Exception->throw(
393 "Combining Args and CaptureArgs attributes not supported registering " .
398 unless ($action->attributes->{CaptureArgs}) {
399 unshift(@{ $self->_endpoints }, $action);
405 =head2 $self->uri_for_action($action, $captures)
407 Get the URI part for the action, using C<$captures> to fill
413 my ( $self, $action, $captures ) = @_;
415 return undef unless ($action->attributes->{Chained}
416 && !$action->attributes->{CaptureArgs});
419 my @captures = @$captures;
420 my $parent = "DUMMY";
422 # If this is an action chain get the last action in the chain
423 if($curr->can('chain') ) {
424 $curr = ${$curr->chain}[-1];
427 if (my $cap = $curr->number_of_captures) {
428 return undef unless @captures >= $cap; # not enough captures
430 unshift(@parts, splice(@captures, -$cap));
433 if (my $pp = $curr->attributes->{PathPart}) {
434 unshift(@parts, $pp->[0])
435 if (defined($pp->[0]) && length($pp->[0]));
437 $parent = $curr->attributes->{Chained}->[0];
438 $curr = $self->_actions->{$parent};
441 return undef unless $parent eq '/'; # fail for dangling action
443 return undef if @captures; # fail for too many captures
445 return join('/', '', @parts);
449 =head2 $c->expand_action($action)
451 Return a list of actions that represents a chained action. See
452 L<Catalyst::Dispatcher> for more info. You probably want to
453 use the expand_action it provides rather than this directly.
458 my ($self, $action) = @_;
460 return unless $action->attributes && $action->attributes->{Chained};
467 my $parent = $curr->attributes->{Chained}->[0];
468 $curr = $self->_actions->{$parent};
471 return Catalyst::ActionChain->from_chain([reverse @chain]);
474 __PACKAGE__->meta->make_immutable;
481 The C<Chained> attribute allows you to chain public path parts together
482 by their private names. A chain part's path can be specified with
483 C<PathPart> and can be declared to expect an arbitrary number of
484 arguments. The endpoint of the chain specifies how many arguments it
485 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
486 C<:Args> without an integer would be unlimited. The path parts that
487 aren't endpoints are using C<CaptureArgs> to specify how many parameters
488 they expect to receive. As an example setup:
490 package MyApp::Controller::Greeting;
491 use base qw/ Catalyst::Controller /;
493 # this is the beginning of our chain
494 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
495 my ( $self, $c, $integer ) = @_;
496 $c->stash->{ message } = "Hello ";
497 $c->stash->{ arg_sum } = $integer;
500 # this is our endpoint, because it has no :CaptureArgs
501 sub world : PathPart('world') Chained('hello') Args(1) {
502 my ( $self, $c, $integer ) = @_;
503 $c->stash->{ message } .= "World!";
504 $c->stash->{ arg_sum } += $integer;
506 $c->response->body( join "<br/>\n" =>
507 $c->stash->{ message }, $c->stash->{ arg_sum } );
510 The debug output provides a separate table for chained actions, showing
511 the whole chain as it would match and the actions it contains. Here's an
512 example of the startup output with our actions above:
515 [debug] Loaded Path Part actions:
516 .-----------------------+------------------------------.
517 | Path Spec | Private |
518 +-----------------------+------------------------------+
519 | /hello/*/world/* | /greeting/hello (1) |
520 | | => /greeting/world |
521 '-----------------------+------------------------------'
524 As you can see, Catalyst only deals with chains as whole paths and
525 builds one for each endpoint, which are the actions with C<:Chained> but
526 without C<:CaptureArgs>.
528 Let's assume this application gets a request at the path
529 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
530 to the C<hello> action and pass the value C<23> as an argument to it
531 after the context. It does so because we have previously used
532 C<:CaptureArgs(1)> to declare that it has one path part after itself as
533 its argument. We told Catalyst that this is the beginning of the chain
534 by specifying C<:Chained('/')>. Also note that instead of saying
535 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
536 defaults to the name of the action.
538 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
539 action. This is the last action to be called: Catalyst knows this is an
540 endpoint because we did not specify a C<:CaptureArgs>
541 attribute. Nevertheless we specify that this action expects an argument,
542 but at this point we're using C<:Args(1)> to do that. We could also have
543 said C<:Args> or left it out altogether, which would mean this action
544 would get all arguments that are there. This action's C<:Chained>
545 attribute says C<hello> and tells Catalyst that the C<hello> action in
546 the current controller is its parent.
548 With this we have built a chain consisting of two public path parts.
549 C<hello> captures one part of the path as its argument, and also
550 specifies the path root as its parent. So this part is
551 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
552 argument. It sums up to the path part C<world/$arg>. This leads to a
553 complete chain of C</hello/$arg/world/$arg> which is matched against the
556 This example application would, if run and called by e.g.
557 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
558 value C<arg_sum> to "23". The C<world> action would then append "World!"
559 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
560 sake of simplicity no view is shown. Instead we just put the values of
561 the stash into our body. So the output would look like:
566 And our test server would have given us this debugging output for the
570 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
571 [debug] Path is "/greeting/world"
572 [debug] Arguments are "12"
573 [info] Request took 0.164113s (6.093/s)
574 .------------------------------------------+-----------.
576 +------------------------------------------+-----------+
577 | /greeting/hello | 0.000029s |
578 | /greeting/world | 0.000024s |
579 '------------------------------------------+-----------'
582 What would be common uses of this dispatch technique? It gives the
583 possibility to split up logic that contains steps that each depend on
584 each other. An example would be, for example, a wiki path like
585 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
588 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
589 my ( $self, $c, $page_name ) = @_;
590 # load the page named $page_name and put the object
594 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
595 my ( $self, $c, $revision_id ) = @_;
596 # use the page object in the stash to get at its
597 # revision with number $revision_id
600 sub view : PathPart Chained('rev') Args(0) {
601 my ( $self, $c ) = @_;
602 # display the revision in our stash. Another option
603 # would be to forward a compatible object to the action
604 # that displays the default wiki pages, unless we want
605 # a different interface here, for example restore
609 It would now be possible to add other endpoints, for example C<restore>
610 to restore this specific revision as the current state.
612 You don't have to put all the chained actions in one controller. The
613 specification of the parent through C<:Chained> also takes an absolute
614 action path as its argument. Just specify it with a leading C</>.
616 If you want, for example, to have actions for the public paths
617 C</foo/12/edit> and C</foo/12>, just specify two actions with
618 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
619 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
620 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
621 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
622 this debugging output:
625 [debug] Loaded Path Part actions:
626 .-----------------------+------------------------------.
627 | Path Spec | Private |
628 +-----------------------+------------------------------+
629 | /foo/* | /controller/foo_view |
630 | /foo/*/edit | /controller/foo_load (1) |
631 | | => /controller/edit |
632 '-----------------------+------------------------------'
635 Here's a more detailed specification of the attributes belonging to
644 Sets the name of this part of the chain. If it is specified without
645 arguments, it takes the name of the action as default. So basically
646 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
647 This can also contain slashes to bind to a deeper level. An action
648 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
649 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
650 effect as using C<:PathPart>, it would default to the action name.
654 Sets PathPart to the path_prefix of the current controller.
658 Has to be specified for every child in the chain. Possible values are
659 absolute and relative private action paths or a single slash C</> to
660 tell Catalyst that this is the root of a chain. The attribute
661 C<:Chained> without arguments also defaults to the C</> behavior.
662 Relative action paths may use C<../> to refer to actions in parent
665 Because you can specify an absolute path to the parent action, it
666 doesn't matter to Catalyst where that parent is located. So, if your
667 design requests it, you can redispatch a chain through any controller or
670 Another interesting possibility gives C<:Chained('.')>, which chains
671 itself to an action with the path of the current controller's namespace.
674 # in MyApp::Controller::Foo
675 sub bar : Chained CaptureArgs(1) { ... }
677 # in MyApp::Controller::Foo::Bar
678 sub baz : Chained('.') Args(1) { ... }
680 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
681 as the argument to Chained here chains the C<baz> action to an action
682 with the path of the current controller namespace, namely
683 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
684 chain comes out as the end product.
688 Chains an action to another action with the same name in the parent
689 controller. For Example:
691 # in MyApp::Controller::Foo
692 sub bar : Chained CaptureArgs(1) { ... }
694 # in MyApp::Controller::Foo::Moo
695 sub bar : ChainedParent Args(1) { ... }
697 This builds a chain like C</bar/*/bar/*>.
701 Must be specified for every part of the chain that is not an
702 endpoint. With this attribute Catalyst knows how many of the following
703 parts of the path (separated by C</>) this action wants to capture as
704 its arguments. If it doesn't expect any, just specify
705 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
706 after the context, but you can also find them as array references in
707 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
708 level of the action in the chain that captured the parts of the path.
710 An action that is part of a chain (that is, one that has a C<:Chained>
711 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
714 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
715 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
716 named constraint such as CaptureArgs(Int,Str) would require two args with
717 the first being a Integer and the second a string. You may declare your own
718 custom type constraints and import them into the controller namespace:
720 package MyApp::Controller::Root;
723 use MooseX::MethodAttributes;
724 use MyApp::Types qw/Int/;
726 extends 'Catalyst::Controller';
728 sub chain_base :Chained(/) CaptureArgs(1) { }
730 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
732 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
734 If you use a reference type constraint in CaptureArgs, it must be a type
735 like Tuple in L<Types::Standard> that allows us to determine the number of
736 args to match. Otherwise this will raise an error during startup.
738 See L<Catalyst::RouteMatching> for more.
742 By default, endpoints receive the rest of the arguments in the path. You
743 can tell Catalyst through C<:Args> explicitly how many arguments your
744 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
745 also affects whether this chain is invoked on a request. A chain with an
746 endpoint specifying one argument will only match if exactly one argument
749 You can specify an exact number of arguments like C<:Args(3)>, including
750 C<0>. If you just say C<:Args> without any arguments, it is the same as
751 leaving it out altogether: The chain is matched regardless of the number
752 of path parts after the endpoint.
754 Just as with C<:CaptureArgs>, the arguments get passed to the action in
755 C<@_> after the context object. They can also be reached through
756 C<$c-E<gt>request-E<gt>arguments>.
758 You should see 'Args' in L<Catalyst::Controller> for more details on using
759 type constraints in your Args declarations.
763 =head2 Auto actions, dispatching and forwarding
765 Note that the list of C<auto> actions called depends on the private path
766 of the endpoint of the chain, not on the chained actions way. The
767 C<auto> actions will be run before the chain dispatching begins. In
768 every other aspect, C<auto> actions behave as documented.
770 The C<forward>ing to other actions does just what you would expect. i.e.
771 only the target action is run. The actions that that action is chained
773 If you C<detach> out of a chain, the rest of the chain will not get
774 called after the C<detach>.
776 =head2 match_captures
778 A method which can optionally be implemented by actions to
781 See L<Catalyst::Action> for further details.
785 Catalyst Contributors, see Catalyst.pm
789 This library is free software. You can redistribute it and/or modify it under
790 the same terms as Perl itself.