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 = $endpoint->list_extra_info->{Args};
101 my @parts = (defined($args) ? (("*") 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 $curr = $endpoint;
108 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
109 unshift(@parts, (("*") x $cap));
111 if (my $pp = $curr->attributes->{PathPart}) {
112 unshift(@parts, $pp->[0])
113 if (defined $pp->[0] && length $pp->[0]);
115 $parent = $curr->attributes->{Chained}->[0];
116 $curr = $self->_actions->{$parent};
117 unshift(@parents, $curr) if $curr;
119 if ($parent ne '/') {
120 $has_unattached_actions = 1;
121 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
125 foreach my $p (@parents) {
128 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
129 $name = "${extra} ${name}";
131 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
132 $name .= ' ('.$cap.')';
134 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
138 unless ($p eq $parents[0]) {
139 $name = "-> ${name}";
141 push(@rows, [ '', $name ]);
143 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : '')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
144 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
145 $rows[0][0] = join('/', '', @display_parts) || '/';
146 $paths->row(@$_) for @rows;
149 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
150 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
151 if $has_unattached_actions;
154 sub _list_extra_http_methods {
155 my ( $self, $action ) = @_;
156 return unless defined $action->list_extra_info->{HTTP_METHODS};
157 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
161 sub _list_extra_consumes {
162 my ( $self, $action ) = @_;
163 return unless defined $action->list_extra_info->{CONSUMES};
164 return join(', ', @{$action->list_extra_info->{CONSUMES}});
168 =head2 $self->match( $c, $path )
170 Calls C<recurse_match> to see if a chain matches the C<$path>.
175 my ( $self, $c, $path ) = @_;
177 my $request = $c->request;
178 return 0 if @{$request->args};
180 my @parts = split('/', $path);
182 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
184 if ($parts && @$parts) {
185 for my $arg (@$parts) {
186 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
187 push @{$request->args}, $arg;
191 return 0 unless $chain;
193 my $action = Catalyst::ActionChain->from_chain($chain);
195 $request->action("/${action}");
196 $request->match("/${action}");
197 $request->captures($captures);
199 $c->namespace( $action->namespace );
204 =head2 $self->recurse_match( $c, $parent, \@path_parts )
206 Recursive search for a matching chain.
211 my ( $self, $c, $parent, $path_parts ) = @_;
212 my $children = $self->_children_of->{$parent};
213 return () unless $children;
216 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
218 # $b then $a to try longest part first
219 my @parts = @$path_parts;
220 if (length $try_part) { # test and strip PathPart
222 ($try_part eq join('/', # assemble equal number of parts
223 splice( # and strip them off @parts as well
224 @parts, 0, scalar(@{[split('/', $try_part)]})
225 ))); # @{[]} to avoid split to @_
227 my @try_actions = @{$children->{$try_part}};
228 TRY_ACTION: foreach my $action (@try_actions) {
229 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
230 my $capture_count = $capture_attr->[0] || 0;
232 # Short-circuit if not enough remaining parts
233 next TRY_ACTION unless @parts >= $capture_count;
236 my @parts = @parts; # localise
238 # strip CaptureArgs into list
239 push(@captures, splice(@parts, 0, $capture_count));
241 # check if the action may fit, depending on a given test by the app
242 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
244 # try the remaining parts against children of this action
245 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
246 $c, '/'.$action->reverse, \@parts
248 # No best action currently
249 # OR The action has less parts
250 # OR The action has equal parts but less captured data (ergo more defined)
253 $#$action_parts < $#{$best_action->{parts}} ||
254 ($#$action_parts == $#{$best_action->{parts}} &&
255 $#$captures < $#{$best_action->{captures}} &&
256 $n_pathparts > $best_action->{n_pathparts}))) {
257 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
259 actions => [ $action, @$actions ],
260 captures=> [ @captures, @$captures ],
261 parts => $action_parts,
262 n_pathparts => scalar(@pathparts) + $n_pathparts,
268 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
269 next TRY_ACTION unless $action->match($c);
271 my $args_attr = $action->attributes->{Args}->[0];
272 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
273 # No best action currently
274 # OR This one matches with fewer parts left than the current best action,
275 # And therefore is a better match
276 # OR No parts and this expects 0
277 # The current best action might also be Args(0),
278 # but we couldn't chose between then anyway so we'll take the last seen
281 @parts < @{$best_action->{parts}} ||
282 (!@parts && defined($args_attr) && $args_attr eq "0")){
284 actions => [ $action ],
287 n_pathparts => scalar(@pathparts),
293 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
297 =head2 $self->register( $c, $action )
299 Calls register_path for every Path attribute for the given $action.
303 sub _check_args_attr {
304 my ( $self, $action, $name ) = @_;
306 return unless exists $action->attributes->{$name};
308 if (@{$action->attributes->{$name}} > 1) {
309 Catalyst::Exception->throw(
310 "Multiple $name attributes not supported registering " . $action->reverse()
313 my $args = $action->attributes->{$name}->[0];
314 if (defined($args) and not (
315 Scalar::Util::looks_like_number($args) and
316 int($args) == $args and $args >= 0
318 require Data::Dumper;
319 local $Data::Dumper::Terse = 1;
320 local $Data::Dumper::Indent = 0;
321 $args = Data::Dumper::Dumper($args);
322 Catalyst::Exception->throw(
323 "Invalid $name($args) for action " . $action->reverse() .
324 " (use '$name' or '$name(<number>)')"
330 my ( $self, $c, $action ) = @_;
332 my @chained_attr = @{ $action->attributes->{Chained} || [] };
334 return 0 unless @chained_attr;
336 if (@chained_attr > 1) {
337 Catalyst::Exception->throw(
338 "Multiple Chained attributes not supported registering ${action}"
341 my $chained_to = $chained_attr[0];
343 Catalyst::Exception->throw(
344 "Actions cannot chain to themselves registering /${action}"
345 ) if ($chained_to eq '/' . $action);
347 my $children = ($self->_children_of->{ $chained_to } ||= {});
349 my @path_part = @{ $action->attributes->{PathPart} || [] };
351 my $part = $action->name;
353 if (@path_part == 1 && defined $path_part[0]) {
354 $part = $path_part[0];
355 } elsif (@path_part > 1) {
356 Catalyst::Exception->throw(
357 "Multiple PathPart attributes not supported registering " . $action->reverse()
361 if ($part =~ m(^/)) {
362 Catalyst::Exception->throw(
363 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
367 my $encoded_part = URI->new($part)->canonical;
368 $encoded_part =~ s{(?<=[^/])/+\z}{};
370 $action->attributes->{PathPart} = [ $encoded_part ];
372 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
374 $self->_actions->{'/'.$action->reverse} = $action;
376 foreach my $name (qw(Args CaptureArgs)) {
377 $self->_check_args_attr($action, $name);
380 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
381 Catalyst::Exception->throw(
382 "Combining Args and CaptureArgs attributes not supported registering " .
387 unless ($action->attributes->{CaptureArgs}) {
388 unshift(@{ $self->_endpoints }, $action);
394 =head2 $self->uri_for_action($action, $captures)
396 Get the URI part for the action, using C<$captures> to fill
402 my ( $self, $action, $captures ) = @_;
404 return undef unless ($action->attributes->{Chained}
405 && !$action->attributes->{CaptureArgs});
408 my @captures = @$captures;
409 my $parent = "DUMMY";
412 if (my $cap = $curr->attributes->{CaptureArgs}) {
413 return undef unless @captures >= ($cap->[0]||0); # not enough captures
415 unshift(@parts, splice(@captures, -$cap->[0]));
418 if (my $pp = $curr->attributes->{PathPart}) {
419 unshift(@parts, $pp->[0])
420 if (defined($pp->[0]) && length($pp->[0]));
422 $parent = $curr->attributes->{Chained}->[0];
423 $curr = $self->_actions->{$parent};
426 return undef unless $parent eq '/'; # fail for dangling action
428 return undef if @captures; # fail for too many captures
430 return join('/', '', @parts);
434 =head2 $c->expand_action($action)
436 Return a list of actions that represents a chained action. See
437 L<Catalyst::Dispatcher> for more info. You probably want to
438 use the expand_action it provides rather than this directly.
443 my ($self, $action) = @_;
445 return unless $action->attributes && $action->attributes->{Chained};
452 my $parent = $curr->attributes->{Chained}->[0];
453 $curr = $self->_actions->{$parent};
456 return Catalyst::ActionChain->from_chain([reverse @chain]);
459 __PACKAGE__->meta->make_immutable;
466 The C<Chained> attribute allows you to chain public path parts together
467 by their private names. A chain part's path can be specified with
468 C<PathPart> and can be declared to expect an arbitrary number of
469 arguments. The endpoint of the chain specifies how many arguments it
470 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
471 C<:Args> without an integer would be unlimited. The path parts that
472 aren't endpoints are using C<CaptureArgs> to specify how many parameters
473 they expect to receive. As an example setup:
475 package MyApp::Controller::Greeting;
476 use base qw/ Catalyst::Controller /;
478 # this is the beginning of our chain
479 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
480 my ( $self, $c, $integer ) = @_;
481 $c->stash->{ message } = "Hello ";
482 $c->stash->{ arg_sum } = $integer;
485 # this is our endpoint, because it has no :CaptureArgs
486 sub world : PathPart('world') Chained('hello') Args(1) {
487 my ( $self, $c, $integer ) = @_;
488 $c->stash->{ message } .= "World!";
489 $c->stash->{ arg_sum } += $integer;
491 $c->response->body( join "<br/>\n" =>
492 $c->stash->{ message }, $c->stash->{ arg_sum } );
495 The debug output provides a separate table for chained actions, showing
496 the whole chain as it would match and the actions it contains. Here's an
497 example of the startup output with our actions above:
500 [debug] Loaded Path Part actions:
501 .-----------------------+------------------------------.
502 | Path Spec | Private |
503 +-----------------------+------------------------------+
504 | /hello/*/world/* | /greeting/hello (1) |
505 | | => /greeting/world |
506 '-----------------------+------------------------------'
509 As you can see, Catalyst only deals with chains as whole paths and
510 builds one for each endpoint, which are the actions with C<:Chained> but
511 without C<:CaptureArgs>.
513 Let's assume this application gets a request at the path
514 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
515 to the C<hello> action and pass the value C<23> as an argument to it
516 after the context. It does so because we have previously used
517 C<:CaptureArgs(1)> to declare that it has one path part after itself as
518 its argument. We told Catalyst that this is the beginning of the chain
519 by specifying C<:Chained('/')>. Also note that instead of saying
520 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
521 defaults to the name of the action.
523 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
524 action. This is the last action to be called: Catalyst knows this is an
525 endpoint because we did not specify a C<:CaptureArgs>
526 attribute. Nevertheless we specify that this action expects an argument,
527 but at this point we're using C<:Args(1)> to do that. We could also have
528 said C<:Args> or left it out altogether, which would mean this action
529 would get all arguments that are there. This action's C<:Chained>
530 attribute says C<hello> and tells Catalyst that the C<hello> action in
531 the current controller is its parent.
533 With this we have built a chain consisting of two public path parts.
534 C<hello> captures one part of the path as its argument, and also
535 specifies the path root as its parent. So this part is
536 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
537 argument. It sums up to the path part C<world/$arg>. This leads to a
538 complete chain of C</hello/$arg/world/$arg> which is matched against the
541 This example application would, if run and called by e.g.
542 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
543 value C<arg_sum> to "23". The C<world> action would then append "World!"
544 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
545 sake of simplicity no view is shown. Instead we just put the values of
546 the stash into our body. So the output would look like:
551 And our test server would have given us this debugging output for the
555 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
556 [debug] Path is "/greeting/world"
557 [debug] Arguments are "12"
558 [info] Request took 0.164113s (6.093/s)
559 .------------------------------------------+-----------.
561 +------------------------------------------+-----------+
562 | /greeting/hello | 0.000029s |
563 | /greeting/world | 0.000024s |
564 '------------------------------------------+-----------'
567 What would be common uses of this dispatch technique? It gives the
568 possibility to split up logic that contains steps that each depend on
569 each other. An example would be, for example, a wiki path like
570 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
573 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
574 my ( $self, $c, $page_name ) = @_;
575 # load the page named $page_name and put the object
579 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
580 my ( $self, $c, $revision_id ) = @_;
581 # use the page object in the stash to get at its
582 # revision with number $revision_id
585 sub view : PathPart Chained('rev') Args(0) {
586 my ( $self, $c ) = @_;
587 # display the revision in our stash. Another option
588 # would be to forward a compatible object to the action
589 # that displays the default wiki pages, unless we want
590 # a different interface here, for example restore
594 It would now be possible to add other endpoints, for example C<restore>
595 to restore this specific revision as the current state.
597 You don't have to put all the chained actions in one controller. The
598 specification of the parent through C<:Chained> also takes an absolute
599 action path as its argument. Just specify it with a leading C</>.
601 If you want, for example, to have actions for the public paths
602 C</foo/12/edit> and C</foo/12>, just specify two actions with
603 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
604 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
605 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
606 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
607 this debugging output:
610 [debug] Loaded Path Part actions:
611 .-----------------------+------------------------------.
612 | Path Spec | Private |
613 +-----------------------+------------------------------+
614 | /foo/* | /controller/foo_view |
615 | /foo/*/edit | /controller/foo_load (1) |
616 | | => /controller/edit |
617 '-----------------------+------------------------------'
620 Here's a more detailed specification of the attributes belonging to
629 Sets the name of this part of the chain. If it is specified without
630 arguments, it takes the name of the action as default. So basically
631 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
632 This can also contain slashes to bind to a deeper level. An action
633 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
634 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
635 effect as using C<:PathPart>, it would default to the action name.
639 Sets PathPart to the path_prefix of the current controller.
643 Has to be specified for every child in the chain. Possible values are
644 absolute and relative private action paths or a single slash C</> to
645 tell Catalyst that this is the root of a chain. The attribute
646 C<:Chained> without arguments also defaults to the C</> behavior.
647 Relative action paths may use C<../> to refer to actions in parent
650 Because you can specify an absolute path to the parent action, it
651 doesn't matter to Catalyst where that parent is located. So, if your
652 design requests it, you can redispatch a chain through any controller or
655 Another interesting possibility gives C<:Chained('.')>, which chains
656 itself to an action with the path of the current controller's namespace.
659 # in MyApp::Controller::Foo
660 sub bar : Chained CaptureArgs(1) { ... }
662 # in MyApp::Controller::Foo::Bar
663 sub baz : Chained('.') Args(1) { ... }
665 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
666 as the argument to Chained here chains the C<baz> action to an action
667 with the path of the current controller namespace, namely
668 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
669 chain comes out as the end product.
673 Chains an action to another action with the same name in the parent
674 controller. For Example:
676 # in MyApp::Controller::Foo
677 sub bar : Chained CaptureArgs(1) { ... }
679 # in MyApp::Controller::Foo::Moo
680 sub bar : ChainedParent Args(1) { ... }
682 This builds a chain like C</bar/*/bar/*>.
686 Must be specified for every part of the chain that is not an
687 endpoint. With this attribute Catalyst knows how many of the following
688 parts of the path (separated by C</>) this action wants to capture as
689 its arguments. If it doesn't expect any, just specify
690 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
691 after the context, but you can also find them as array references in
692 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
693 level of the action in the chain that captured the parts of the path.
695 An action that is part of a chain (that is, one that has a C<:Chained>
696 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
701 By default, endpoints receive the rest of the arguments in the path. You
702 can tell Catalyst through C<:Args> explicitly how many arguments your
703 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
704 also affects whether this chain is invoked on a request. A chain with an
705 endpoint specifying one argument will only match if exactly one argument
708 You can specify an exact number of arguments like C<:Args(3)>, including
709 C<0>. If you just say C<:Args> without any arguments, it is the same as
710 leaving it out altogether: The chain is matched regardless of the number
711 of path parts after the endpoint.
713 Just as with C<:CaptureArgs>, the arguments get passed to the action in
714 C<@_> after the context object. They can also be reached through
715 C<$c-E<gt>request-E<gt>arguments>.
719 =head2 Auto actions, dispatching and forwarding
721 Note that the list of C<auto> actions called depends on the private path
722 of the endpoint of the chain, not on the chained actions way. The
723 C<auto> actions will be run before the chain dispatching begins. In
724 every other aspect, C<auto> actions behave as documented.
726 The C<forward>ing to other actions does just what you would expect. i.e.
727 only the target action is run. The actions that that action is chained
729 If you C<detach> out of a chain, the rest of the chain will not get
730 called after the C<detach>.
732 =head2 match_captures
734 A method which can optionally be implemented by actions to
737 See L<Catalyst::Action> for further details.
741 Catalyst Contributors, see Catalyst.pm
745 This library is free software. You can redistribute it and/or modify it under
746 the same terms as Perl itself.