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 @pathparts = split /\//, $action->attributes->{PathPart}->[0];
294 # No best action currently
295 # OR This one matches with fewer parts left than the current best action,
296 # And therefore is a better match
297 # OR No parts and this expects 0
298 # The current best action might also be Args(0),
299 # but we couldn't chose between then anyway so we'll take the last seen
303 @parts < @{$best_action->{parts}} ||
306 defined($args_attr) &&
310 ($c->config->{use_chained_args_0_special_case}||0) ||
312 exists($best_action->{args_attr}) && defined($best_action->{args_attr}) ?
313 ($best_action->{args_attr} ne 0) : 1
320 actions => [ $action ],
323 args_attr => $args_attr,
324 n_pathparts => scalar(@pathparts),
330 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
334 =head2 $self->register( $c, $action )
336 Calls register_path for every Path attribute for the given $action.
341 my ( $self, $c, $action ) = @_;
343 my @chained_attr = @{ $action->attributes->{Chained} || [] };
345 return 0 unless @chained_attr;
347 if (@chained_attr > 1) {
348 Catalyst::Exception->throw(
349 "Multiple Chained attributes not supported registering ${action}"
352 my $chained_to = $chained_attr[0];
354 Catalyst::Exception->throw(
355 "Actions cannot chain to themselves registering /${action}"
356 ) if ($chained_to eq '/' . $action);
358 my $children = ($self->_children_of->{ $chained_to } ||= {});
360 my @path_part = @{ $action->attributes->{PathPart} || [] };
362 my $part = $action->name;
364 if (@path_part == 1 && defined $path_part[0]) {
365 $part = $path_part[0];
366 } elsif (@path_part > 1) {
367 Catalyst::Exception->throw(
368 "Multiple PathPart attributes not supported registering " . $action->reverse()
372 if ($part =~ m(^/)) {
373 Catalyst::Exception->throw(
374 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
378 my $encoded_part = URI->new($part)->canonical;
379 $encoded_part =~ s{(?<=[^/])/+\z}{};
381 $action->attributes->{PathPart} = [ $encoded_part ];
383 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
385 $self->_actions->{'/'.$action->reverse} = $action;
387 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
388 Catalyst::Exception->throw(
389 "Combining Args and CaptureArgs attributes not supported registering " .
394 unless ($action->attributes->{CaptureArgs}) {
395 unshift(@{ $self->_endpoints }, $action);
401 =head2 $self->uri_for_action($action, $captures)
403 Get the URI part for the action, using C<$captures> to fill
409 my ( $self, $action, $captures ) = @_;
411 return undef unless ($action->attributes->{Chained}
412 && !$action->attributes->{CaptureArgs});
415 my @captures = @$captures;
416 my $parent = "DUMMY";
418 # If this is an action chain get the last action in the chain
419 if($curr->can('chain') ) {
420 $curr = ${$curr->chain}[-1];
423 if (my $cap = $curr->number_of_captures) {
424 return undef unless @captures >= $cap; # not enough captures
426 unshift(@parts, splice(@captures, -$cap));
429 if (my $pp = $curr->attributes->{PathPart}) {
430 unshift(@parts, $pp->[0])
431 if (defined($pp->[0]) && length($pp->[0]));
433 $parent = $curr->attributes->{Chained}->[0];
434 $curr = $self->_actions->{$parent};
437 return undef unless $parent eq '/'; # fail for dangling action
439 return undef if @captures; # fail for too many captures
441 return join('/', '', @parts);
445 =head2 $c->expand_action($action)
447 Return a list of actions that represents a chained action. See
448 L<Catalyst::Dispatcher> for more info. You probably want to
449 use the expand_action it provides rather than this directly.
454 my ($self, $action) = @_;
456 return unless $action->attributes && $action->attributes->{Chained};
463 my $parent = $curr->attributes->{Chained}->[0];
464 $curr = $self->_actions->{$parent};
467 return Catalyst::ActionChain->from_chain([reverse @chain]);
470 __PACKAGE__->meta->make_immutable;
477 The C<Chained> attribute allows you to chain public path parts together
478 by their private names. A chain part's path can be specified with
479 C<PathPart> and can be declared to expect an arbitrary number of
480 arguments. The endpoint of the chain specifies how many arguments it
481 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
482 C<:Args> without an integer would be unlimited. The path parts that
483 aren't endpoints are using C<CaptureArgs> to specify how many parameters
484 they expect to receive. As an example setup:
486 package MyApp::Controller::Greeting;
487 use base qw/ Catalyst::Controller /;
489 # this is the beginning of our chain
490 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
491 my ( $self, $c, $integer ) = @_;
492 $c->stash->{ message } = "Hello ";
493 $c->stash->{ arg_sum } = $integer;
496 # this is our endpoint, because it has no :CaptureArgs
497 sub world : PathPart('world') Chained('hello') Args(1) {
498 my ( $self, $c, $integer ) = @_;
499 $c->stash->{ message } .= "World!";
500 $c->stash->{ arg_sum } += $integer;
502 $c->response->body( join "<br/>\n" =>
503 $c->stash->{ message }, $c->stash->{ arg_sum } );
506 The debug output provides a separate table for chained actions, showing
507 the whole chain as it would match and the actions it contains. Here's an
508 example of the startup output with our actions above:
511 [debug] Loaded Path Part actions:
512 .-----------------------+------------------------------.
513 | Path Spec | Private |
514 +-----------------------+------------------------------+
515 | /hello/*/world/* | /greeting/hello (1) |
516 | | => /greeting/world |
517 '-----------------------+------------------------------'
520 As you can see, Catalyst only deals with chains as whole paths and
521 builds one for each endpoint, which are the actions with C<:Chained> but
522 without C<:CaptureArgs>.
524 Let's assume this application gets a request at the path
525 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
526 to the C<hello> action and pass the value C<23> as an argument to it
527 after the context. It does so because we have previously used
528 C<:CaptureArgs(1)> to declare that it has one path part after itself as
529 its argument. We told Catalyst that this is the beginning of the chain
530 by specifying C<:Chained('/')>. Also note that instead of saying
531 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
532 defaults to the name of the action.
534 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
535 action. This is the last action to be called: Catalyst knows this is an
536 endpoint because we did not specify a C<:CaptureArgs>
537 attribute. Nevertheless we specify that this action expects an argument,
538 but at this point we're using C<:Args(1)> to do that. We could also have
539 said C<:Args> or left it out altogether, which would mean this action
540 would get all arguments that are there. This action's C<:Chained>
541 attribute says C<hello> and tells Catalyst that the C<hello> action in
542 the current controller is its parent.
544 With this we have built a chain consisting of two public path parts.
545 C<hello> captures one part of the path as its argument, and also
546 specifies the path root as its parent. So this part is
547 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
548 argument. It sums up to the path part C<world/$arg>. This leads to a
549 complete chain of C</hello/$arg/world/$arg> which is matched against the
552 This example application would, if run and called by e.g.
553 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
554 value C<arg_sum> to "23". The C<world> action would then append "World!"
555 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
556 sake of simplicity no view is shown. Instead we just put the values of
557 the stash into our body. So the output would look like:
562 And our test server would have given us this debugging output for the
566 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
567 [debug] Path is "/greeting/world"
568 [debug] Arguments are "12"
569 [info] Request took 0.164113s (6.093/s)
570 .------------------------------------------+-----------.
572 +------------------------------------------+-----------+
573 | /greeting/hello | 0.000029s |
574 | /greeting/world | 0.000024s |
575 '------------------------------------------+-----------'
578 What would be common uses of this dispatch technique? It gives the
579 possibility to split up logic that contains steps that each depend on
580 each other. An example would be, for example, a wiki path like
581 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
584 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
585 my ( $self, $c, $page_name ) = @_;
586 # load the page named $page_name and put the object
590 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
591 my ( $self, $c, $revision_id ) = @_;
592 # use the page object in the stash to get at its
593 # revision with number $revision_id
596 sub view : PathPart Chained('rev') Args(0) {
597 my ( $self, $c ) = @_;
598 # display the revision in our stash. Another option
599 # would be to forward a compatible object to the action
600 # that displays the default wiki pages, unless we want
601 # a different interface here, for example restore
605 It would now be possible to add other endpoints, for example C<restore>
606 to restore this specific revision as the current state.
608 You don't have to put all the chained actions in one controller. The
609 specification of the parent through C<:Chained> also takes an absolute
610 action path as its argument. Just specify it with a leading C</>.
612 If you want, for example, to have actions for the public paths
613 C</foo/12/edit> and C</foo/12>, just specify two actions with
614 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
615 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
616 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
617 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
618 this debugging output:
621 [debug] Loaded Path Part actions:
622 .-----------------------+------------------------------.
623 | Path Spec | Private |
624 +-----------------------+------------------------------+
625 | /foo/* | /controller/foo_view |
626 | /foo/*/edit | /controller/foo_load (1) |
627 | | => /controller/edit |
628 '-----------------------+------------------------------'
631 Here's a more detailed specification of the attributes belonging to
640 Sets the name of this part of the chain. If it is specified without
641 arguments, it takes the name of the action as default. So basically
642 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
643 This can also contain slashes to bind to a deeper level. An action
644 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
645 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
646 effect as using C<:PathPart>, it would default to the action name.
650 Sets PathPart to the path_prefix of the current controller.
654 Has to be specified for every child in the chain. Possible values are
655 absolute and relative private action paths or a single slash C</> to
656 tell Catalyst that this is the root of a chain. The attribute
657 C<:Chained> without arguments also defaults to the C</> behavior.
658 Relative action paths may use C<../> to refer to actions in parent
661 Because you can specify an absolute path to the parent action, it
662 doesn't matter to Catalyst where that parent is located. So, if your
663 design requests it, you can redispatch a chain through any controller or
666 Another interesting possibility gives C<:Chained('.')>, which chains
667 itself to an action with the path of the current controller's namespace.
670 # in MyApp::Controller::Foo
671 sub bar : Chained CaptureArgs(1) { ... }
673 # in MyApp::Controller::Foo::Bar
674 sub baz : Chained('.') Args(1) { ... }
676 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
677 as the argument to Chained here chains the C<baz> action to an action
678 with the path of the current controller namespace, namely
679 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
680 chain comes out as the end product.
684 Chains an action to another action with the same name in the parent
685 controller. For Example:
687 # in MyApp::Controller::Foo
688 sub bar : Chained CaptureArgs(1) { ... }
690 # in MyApp::Controller::Foo::Moo
691 sub bar : ChainedParent Args(1) { ... }
693 This builds a chain like C</bar/*/bar/*>.
697 Must be specified for every part of the chain that is not an
698 endpoint. With this attribute Catalyst knows how many of the following
699 parts of the path (separated by C</>) this action wants to capture as
700 its arguments. If it doesn't expect any, just specify
701 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
702 after the context, but you can also find them as array references in
703 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
704 level of the action in the chain that captured the parts of the path.
706 An action that is part of a chain (that is, one that has a C<:Chained>
707 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
710 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
711 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
712 named constraint such as CaptureArgs(Int,Str) would require two args with
713 the first being a Integer and the second a string. You may declare your own
714 custom type constraints and import them into the controller namespace:
716 package MyApp::Controller::Root;
719 use MooseX::MethodAttributes;
720 use MyApp::Types qw/Int/;
722 extends 'Catalyst::Controller';
724 sub chain_base :Chained(/) CaptureArgs(1) { }
726 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
728 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
730 See L<Catalyst::RouteMatching> for more.
734 By default, endpoints receive the rest of the arguments in the path. You
735 can tell Catalyst through C<:Args> explicitly how many arguments your
736 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
737 also affects whether this chain is invoked on a request. A chain with an
738 endpoint specifying one argument will only match if exactly one argument
741 You can specify an exact number of arguments like C<:Args(3)>, including
742 C<0>. If you just say C<:Args> without any arguments, it is the same as
743 leaving it out altogether: The chain is matched regardless of the number
744 of path parts after the endpoint.
746 Just as with C<:CaptureArgs>, the arguments get passed to the action in
747 C<@_> after the context object. They can also be reached through
748 C<$c-E<gt>request-E<gt>arguments>.
752 =head2 Auto actions, dispatching and forwarding
754 Note that the list of C<auto> actions called depends on the private path
755 of the endpoint of the chain, not on the chained actions way. The
756 C<auto> actions will be run before the chain dispatching begins. In
757 every other aspect, C<auto> actions behave as documented.
759 The C<forward>ing to other actions does just what you would expect. i.e.
760 only the target action is run. The actions that that action is chained
762 If you C<detach> out of a chain, the rest of the chain will not get
763 called after the C<detach>.
765 =head2 match_captures
767 A method which can optionally be implemented by actions to
770 See L<Catalyst::Action> for further details.
774 Catalyst Contributors, see Catalyst.pm
778 This library is free software. You can redistribute it and/or modify it under
779 the same terms as Perl itself.