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 $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 $name .= ' ('.$cap.')';
135 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
138 if (defined(my $s = $p->list_extra_info->{Scheme})) {
142 unless ($p eq $parents[0]) {
143 $name = "-> ${name}";
145 push(@rows, [ '', $name ]);
147 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : ''). ($scheme ? "$scheme: ":'')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
148 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
149 $rows[0][0] = join('/', '', @display_parts) || '/';
150 $paths->row(@$_) for @rows;
153 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
154 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
155 if $has_unattached_actions;
158 sub _list_extra_http_methods {
159 my ( $self, $action ) = @_;
160 return unless defined $action->list_extra_info->{HTTP_METHODS};
161 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
165 sub _list_extra_consumes {
166 my ( $self, $action ) = @_;
167 return unless defined $action->list_extra_info->{CONSUMES};
168 return join(', ', @{$action->list_extra_info->{CONSUMES}});
171 sub _list_extra_scheme {
172 my ( $self, $action ) = @_;
173 return unless defined $action->list_extra_info->{Scheme};
174 return uc $action->list_extra_info->{Scheme};
177 =head2 $self->match( $c, $path )
179 Calls C<recurse_match> to see if a chain matches the C<$path>.
184 my ( $self, $c, $path ) = @_;
186 my $request = $c->request;
187 return 0 if @{$request->args};
189 my @parts = split('/', $path);
191 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
193 if ($parts && @$parts) {
194 for my $arg (@$parts) {
195 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
196 push @{$request->args}, $arg;
200 return 0 unless $chain;
202 my $action = Catalyst::ActionChain->from_chain($chain);
204 $request->action("/${action}");
205 $request->match("/${action}");
206 $request->captures($captures);
208 $c->namespace( $action->namespace );
213 =head2 $self->recurse_match( $c, $parent, \@path_parts )
215 Recursive search for a matching chain.
220 my ( $self, $c, $parent, $path_parts ) = @_;
221 my $children = $self->_children_of->{$parent};
222 return () unless $children;
225 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
227 # $b then $a to try longest part first
228 my @parts = @$path_parts;
229 if (length $try_part) { # test and strip PathPart
231 ($try_part eq join('/', # assemble equal number of parts
232 splice( # and strip them off @parts as well
233 @parts, 0, scalar(@{[split('/', $try_part)]})
234 ))); # @{[]} to avoid split to @_
236 my @try_actions = @{$children->{$try_part}};
237 TRY_ACTION: foreach my $action (@try_actions) {
238 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
239 my $capture_count = $capture_attr->[0] || 0;
241 # Short-circuit if not enough remaining parts
242 next TRY_ACTION unless @parts >= $capture_count;
245 my @parts = @parts; # localise
247 # strip CaptureArgs into list
248 push(@captures, splice(@parts, 0, $capture_count));
250 # check if the action may fit, depending on a given test by the app
251 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
253 # try the remaining parts against children of this action
254 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
255 $c, '/'.$action->reverse, \@parts
257 # No best action currently
258 # OR The action has less parts
259 # OR The action has equal parts but less captured data (ergo more defined)
262 $#$action_parts < $#{$best_action->{parts}} ||
263 ($#$action_parts == $#{$best_action->{parts}} &&
264 $#$captures < $#{$best_action->{captures}} &&
265 $n_pathparts > $best_action->{n_pathparts}))) {
266 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
268 actions => [ $action, @$actions ],
269 captures=> [ @captures, @$captures ],
270 parts => $action_parts,
271 n_pathparts => scalar(@pathparts) + $n_pathparts,
277 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
278 next TRY_ACTION unless $action->match($c);
280 my $args_attr = $action->attributes->{Args}->[0];
281 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
282 # No best action currently
283 # OR This one matches with fewer parts left than the current best action,
284 # And therefore is a better match
285 # OR No parts and this expects 0
286 # The current best action might also be Args(0),
287 # but we couldn't chose between then anyway so we'll take the last seen
291 @parts < @{$best_action->{parts}} ||
294 defined($args_attr) &&
298 ($c->config->{use_chained_args_0_special_case}||0) ||
300 exists($best_action->{args_attr}) && defined($best_action->{args_attr}) ?
301 ($best_action->{args_attr} ne 0) : 1
308 actions => [ $action ],
311 args_attr => $args_attr,
312 n_pathparts => scalar(@pathparts),
318 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
322 =head2 $self->register( $c, $action )
324 Calls register_path for every Path attribute for the given $action.
328 sub _check_args_attr {
329 my ( $self, $action, $name ) = @_;
331 return unless exists $action->attributes->{$name};
333 if (@{$action->attributes->{$name}} > 1) {
334 Catalyst::Exception->throw(
335 "Multiple $name attributes not supported registering " . $action->reverse()
338 my $args = $action->attributes->{$name}->[0];
339 if (defined($args) and not (
340 Scalar::Util::looks_like_number($args) and
341 int($args) == $args and $args >= 0
343 require Data::Dumper;
344 local $Data::Dumper::Terse = 1;
345 local $Data::Dumper::Indent = 0;
346 $args = Data::Dumper::Dumper($args);
347 Catalyst::Exception->throw(
348 "Invalid $name($args) for action " . $action->reverse() .
349 " (use '$name' or '$name(<number>)')"
355 my ( $self, $c, $action ) = @_;
357 my @chained_attr = @{ $action->attributes->{Chained} || [] };
359 return 0 unless @chained_attr;
361 if (@chained_attr > 1) {
362 Catalyst::Exception->throw(
363 "Multiple Chained attributes not supported registering ${action}"
366 my $chained_to = $chained_attr[0];
368 Catalyst::Exception->throw(
369 "Actions cannot chain to themselves registering /${action}"
370 ) if ($chained_to eq '/' . $action);
372 my $children = ($self->_children_of->{ $chained_to } ||= {});
374 my @path_part = @{ $action->attributes->{PathPart} || [] };
376 my $part = $action->name;
378 if (@path_part == 1 && defined $path_part[0]) {
379 $part = $path_part[0];
380 } elsif (@path_part > 1) {
381 Catalyst::Exception->throw(
382 "Multiple PathPart attributes not supported registering " . $action->reverse()
386 if ($part =~ m(^/)) {
387 Catalyst::Exception->throw(
388 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
392 my $encoded_part = URI->new($part)->canonical;
393 $encoded_part =~ s{(?<=[^/])/+\z}{};
395 $action->attributes->{PathPart} = [ $encoded_part ];
397 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
399 $self->_actions->{'/'.$action->reverse} = $action;
401 foreach my $name (qw(Args CaptureArgs)) {
402 $self->_check_args_attr($action, $name);
405 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
406 Catalyst::Exception->throw(
407 "Combining Args and CaptureArgs attributes not supported registering " .
412 unless ($action->attributes->{CaptureArgs}) {
413 unshift(@{ $self->_endpoints }, $action);
419 =head2 $self->uri_for_action($action, $captures)
421 Get the URI part for the action, using C<$captures> to fill
427 my ( $self, $action, $captures ) = @_;
429 return undef unless ($action->attributes->{Chained}
430 && !$action->attributes->{CaptureArgs});
433 my @captures = @$captures;
434 my $parent = "DUMMY";
437 if (my $cap = $curr->attributes->{CaptureArgs}) {
438 return undef unless @captures >= ($cap->[0]||0); # not enough captures
440 unshift(@parts, splice(@captures, -$cap->[0]));
443 if (my $pp = $curr->attributes->{PathPart}) {
444 unshift(@parts, $pp->[0])
445 if (defined($pp->[0]) && length($pp->[0]));
447 $parent = $curr->attributes->{Chained}->[0];
448 $curr = $self->_actions->{$parent};
451 return undef unless $parent eq '/'; # fail for dangling action
453 return undef if @captures; # fail for too many captures
455 return join('/', '', @parts);
459 =head2 $c->expand_action($action)
461 Return a list of actions that represents a chained action. See
462 L<Catalyst::Dispatcher> for more info. You probably want to
463 use the expand_action it provides rather than this directly.
468 my ($self, $action) = @_;
470 return unless $action->attributes && $action->attributes->{Chained};
477 my $parent = $curr->attributes->{Chained}->[0];
478 $curr = $self->_actions->{$parent};
481 return Catalyst::ActionChain->from_chain([reverse @chain]);
484 __PACKAGE__->meta->make_immutable;
491 The C<Chained> attribute allows you to chain public path parts together
492 by their private names. A chain part's path can be specified with
493 C<PathPart> and can be declared to expect an arbitrary number of
494 arguments. The endpoint of the chain specifies how many arguments it
495 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
496 C<:Args> without an integer would be unlimited. The path parts that
497 aren't endpoints are using C<CaptureArgs> to specify how many parameters
498 they expect to receive. As an example setup:
500 package MyApp::Controller::Greeting;
501 use base qw/ Catalyst::Controller /;
503 # this is the beginning of our chain
504 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
505 my ( $self, $c, $integer ) = @_;
506 $c->stash->{ message } = "Hello ";
507 $c->stash->{ arg_sum } = $integer;
510 # this is our endpoint, because it has no :CaptureArgs
511 sub world : PathPart('world') Chained('hello') Args(1) {
512 my ( $self, $c, $integer ) = @_;
513 $c->stash->{ message } .= "World!";
514 $c->stash->{ arg_sum } += $integer;
516 $c->response->body( join "<br/>\n" =>
517 $c->stash->{ message }, $c->stash->{ arg_sum } );
520 The debug output provides a separate table for chained actions, showing
521 the whole chain as it would match and the actions it contains. Here's an
522 example of the startup output with our actions above:
525 [debug] Loaded Path Part actions:
526 .-----------------------+------------------------------.
527 | Path Spec | Private |
528 +-----------------------+------------------------------+
529 | /hello/*/world/* | /greeting/hello (1) |
530 | | => /greeting/world |
531 '-----------------------+------------------------------'
534 As you can see, Catalyst only deals with chains as whole paths and
535 builds one for each endpoint, which are the actions with C<:Chained> but
536 without C<:CaptureArgs>.
538 Let's assume this application gets a request at the path
539 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
540 to the C<hello> action and pass the value C<23> as an argument to it
541 after the context. It does so because we have previously used
542 C<:CaptureArgs(1)> to declare that it has one path part after itself as
543 its argument. We told Catalyst that this is the beginning of the chain
544 by specifying C<:Chained('/')>. Also note that instead of saying
545 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
546 defaults to the name of the action.
548 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
549 action. This is the last action to be called: Catalyst knows this is an
550 endpoint because we did not specify a C<:CaptureArgs>
551 attribute. Nevertheless we specify that this action expects an argument,
552 but at this point we're using C<:Args(1)> to do that. We could also have
553 said C<:Args> or left it out altogether, which would mean this action
554 would get all arguments that are there. This action's C<:Chained>
555 attribute says C<hello> and tells Catalyst that the C<hello> action in
556 the current controller is its parent.
558 With this we have built a chain consisting of two public path parts.
559 C<hello> captures one part of the path as its argument, and also
560 specifies the path root as its parent. So this part is
561 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
562 argument. It sums up to the path part C<world/$arg>. This leads to a
563 complete chain of C</hello/$arg/world/$arg> which is matched against the
566 This example application would, if run and called by e.g.
567 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
568 value C<arg_sum> to "23". The C<world> action would then append "World!"
569 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
570 sake of simplicity no view is shown. Instead we just put the values of
571 the stash into our body. So the output would look like:
576 And our test server would have given us this debugging output for the
580 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
581 [debug] Path is "/greeting/world"
582 [debug] Arguments are "12"
583 [info] Request took 0.164113s (6.093/s)
584 .------------------------------------------+-----------.
586 +------------------------------------------+-----------+
587 | /greeting/hello | 0.000029s |
588 | /greeting/world | 0.000024s |
589 '------------------------------------------+-----------'
592 What would be common uses of this dispatch technique? It gives the
593 possibility to split up logic that contains steps that each depend on
594 each other. An example would be, for example, a wiki path like
595 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
598 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
599 my ( $self, $c, $page_name ) = @_;
600 # load the page named $page_name and put the object
604 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
605 my ( $self, $c, $revision_id ) = @_;
606 # use the page object in the stash to get at its
607 # revision with number $revision_id
610 sub view : PathPart Chained('rev') Args(0) {
611 my ( $self, $c ) = @_;
612 # display the revision in our stash. Another option
613 # would be to forward a compatible object to the action
614 # that displays the default wiki pages, unless we want
615 # a different interface here, for example restore
619 It would now be possible to add other endpoints, for example C<restore>
620 to restore this specific revision as the current state.
622 You don't have to put all the chained actions in one controller. The
623 specification of the parent through C<:Chained> also takes an absolute
624 action path as its argument. Just specify it with a leading C</>.
626 If you want, for example, to have actions for the public paths
627 C</foo/12/edit> and C</foo/12>, just specify two actions with
628 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
629 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
630 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
631 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
632 this debugging output:
635 [debug] Loaded Path Part actions:
636 .-----------------------+------------------------------.
637 | Path Spec | Private |
638 +-----------------------+------------------------------+
639 | /foo/* | /controller/foo_view |
640 | /foo/*/edit | /controller/foo_load (1) |
641 | | => /controller/edit |
642 '-----------------------+------------------------------'
645 Here's a more detailed specification of the attributes belonging to
654 Sets the name of this part of the chain. If it is specified without
655 arguments, it takes the name of the action as default. So basically
656 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
657 This can also contain slashes to bind to a deeper level. An action
658 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
659 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
660 effect as using C<:PathPart>, it would default to the action name.
664 Sets PathPart to the path_prefix of the current controller.
668 Has to be specified for every child in the chain. Possible values are
669 absolute and relative private action paths or a single slash C</> to
670 tell Catalyst that this is the root of a chain. The attribute
671 C<:Chained> without arguments also defaults to the C</> behavior.
672 Relative action paths may use C<../> to refer to actions in parent
675 Because you can specify an absolute path to the parent action, it
676 doesn't matter to Catalyst where that parent is located. So, if your
677 design requests it, you can redispatch a chain through any controller or
680 Another interesting possibility gives C<:Chained('.')>, which chains
681 itself to an action with the path of the current controller's namespace.
684 # in MyApp::Controller::Foo
685 sub bar : Chained CaptureArgs(1) { ... }
687 # in MyApp::Controller::Foo::Bar
688 sub baz : Chained('.') Args(1) { ... }
690 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
691 as the argument to Chained here chains the C<baz> action to an action
692 with the path of the current controller namespace, namely
693 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
694 chain comes out as the end product.
698 Chains an action to another action with the same name in the parent
699 controller. For Example:
701 # in MyApp::Controller::Foo
702 sub bar : Chained CaptureArgs(1) { ... }
704 # in MyApp::Controller::Foo::Moo
705 sub bar : ChainedParent Args(1) { ... }
707 This builds a chain like C</bar/*/bar/*>.
711 Must be specified for every part of the chain that is not an
712 endpoint. With this attribute Catalyst knows how many of the following
713 parts of the path (separated by C</>) this action wants to capture as
714 its arguments. If it doesn't expect any, just specify
715 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
716 after the context, but you can also find them as array references in
717 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
718 level of the action in the chain that captured the parts of the path.
720 An action that is part of a chain (that is, one that has a C<:Chained>
721 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
726 By default, endpoints receive the rest of the arguments in the path. You
727 can tell Catalyst through C<:Args> explicitly how many arguments your
728 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
729 also affects whether this chain is invoked on a request. A chain with an
730 endpoint specifying one argument will only match if exactly one argument
733 You can specify an exact number of arguments like C<:Args(3)>, including
734 C<0>. If you just say C<:Args> without any arguments, it is the same as
735 leaving it out altogether: The chain is matched regardless of the number
736 of path parts after the endpoint.
738 Just as with C<:CaptureArgs>, the arguments get passed to the action in
739 C<@_> after the context object. They can also be reached through
740 C<$c-E<gt>request-E<gt>arguments>.
744 =head2 Auto actions, dispatching and forwarding
746 Note that the list of C<auto> actions called depends on the private path
747 of the endpoint of the chain, not on the chained actions way. The
748 C<auto> actions will be run before the chain dispatching begins. In
749 every other aspect, C<auto> actions behave as documented.
751 The C<forward>ing to other actions does just what you would expect. i.e.
752 only the target action is run. The actions that that action is chained
754 If you C<detach> out of a chain, the rest of the chain will not get
755 called after the C<detach>.
757 =head2 match_captures
759 A method which can optionally be implemented by actions to
762 See L<Catalyst::Action> for further details.
766 Catalyst Contributors, see Catalyst.pm
770 This library is free software. You can redistribute it and/or modify it under
771 the same terms as Perl itself.