1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
35 # please don't perltidy this. hairy code within.
39 Catalyst::DispatchType::Chained - Path Part DispatchType
43 Path part matching, allowing several actions to sequentially take care of processing a request:
45 # root action - captures one argument after it
46 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
47 my ( $self, $c, $foo_arg ) = @_;
51 # child action endpoint - takes one argument
52 sub bar : Chained('foo_setup') Args(1) {
53 my ( $self, $c, $bar_arg ) = @_;
59 Dispatch type managing default behaviour. For more information on
64 =item * L<Catalyst::Manual::Intro> for how they affect application authors
66 =item * L<Catalyst::DispatchType> for implementation information.
72 =head2 $self->list($c)
74 Debug output for Path Part dispatch points
79 my ( $self, $c ) = @_;
81 return unless $self->_endpoints;
83 my $avail_width = Catalyst::Utils::term_width() - 9;
84 my $col1_width = ($avail_width * .50) < 35 ? 35 : int($avail_width * .50);
85 my $col2_width = $avail_width - $col1_width;
86 my $paths = Text::SimpleTable->new(
87 [ $col1_width, 'Path Spec' ], [ $col2_width, 'Private' ],
90 my $has_unattached_actions;
91 my $unattached_actions = Text::SimpleTable->new(
92 [ $col1_width, 'Private' ], [ $col2_width, 'Missing parent' ],
95 ENDPOINT: foreach my $endpoint (
96 sort { $a->reverse cmp $b->reverse }
97 @{ $self->_endpoints }
99 my $args = $endpoint->list_extra_info->{Args};
100 my @parts = (defined($args) ? (("*") x $args) : '...');
102 my $parent = "DUMMY";
103 my $extra = $self->_list_extra_http_methods($endpoint);
104 my $curr = $endpoint;
106 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
107 unshift(@parts, (("*") x $cap));
109 if (my $pp = $curr->attributes->{PathPart}) {
110 unshift(@parts, $pp->[0])
111 if (defined $pp->[0] && length $pp->[0]);
113 $parent = $curr->attributes->{Chained}->[0];
114 $curr = $self->_actions->{$parent};
115 unshift(@parents, $curr) if $curr;
117 if ($parent ne '/') {
118 $has_unattached_actions = 1;
119 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
123 foreach my $p (@parents) {
126 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
127 $name = "${extra} ${name}";
129 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
130 $name .= ' ('.$cap.')';
132 unless ($p eq $parents[0]) {
133 $name = "-> ${name}";
135 push(@rows, [ '', $name ]);
137 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : '')."/${endpoint}" ]);
138 $rows[0][0] = join('/', '', @parts) || '/';
139 $paths->row(@$_) for @rows;
142 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
143 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
144 if $has_unattached_actions;
147 sub _list_extra_http_methods {
148 my ( $self, $action ) = @_;
149 return unless defined $action->list_extra_info->{HTTP_METHODS};
150 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
153 =head2 $self->match( $c, $path )
155 Calls C<recurse_match> to see if a chain matches the C<$path>.
160 my ( $self, $c, $path ) = @_;
162 my $request = $c->request;
163 return 0 if @{$request->args};
165 my @parts = split('/', $path);
167 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
169 if ($parts && @$parts) {
170 for my $arg (@$parts) {
171 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
172 push @{$request->args}, $arg;
176 return 0 unless $chain;
178 my $action = Catalyst::ActionChain->from_chain($chain);
180 $request->action("/${action}");
181 $request->match("/${action}");
182 $request->captures($captures);
184 $c->namespace( $action->namespace );
189 =head2 $self->recurse_match( $c, $parent, \@path_parts )
191 Recursive search for a matching chain.
196 my ( $self, $c, $parent, $path_parts ) = @_;
197 my $children = $self->_children_of->{$parent};
198 return () unless $children;
201 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
203 # $b then $a to try longest part first
204 my @parts = @$path_parts;
205 if (length $try_part) { # test and strip PathPart
207 ($try_part eq join('/', # assemble equal number of parts
208 splice( # and strip them off @parts as well
209 @parts, 0, scalar(@{[split('/', $try_part)]})
210 ))); # @{[]} to avoid split to @_
212 my @try_actions = @{$children->{$try_part}};
213 TRY_ACTION: foreach my $action (@try_actions) {
214 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
215 my $capture_count = $capture_attr->[0] || 0;
217 # Short-circuit if not enough remaining parts
218 next TRY_ACTION unless @parts >= $capture_count;
221 my @parts = @parts; # localise
223 # strip CaptureArgs into list
224 push(@captures, splice(@parts, 0, $capture_count));
226 # check if the action may fit, depending on a given test by the app
227 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
229 # try the remaining parts against children of this action
230 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
231 $c, '/'.$action->reverse, \@parts
233 # No best action currently
234 # OR The action has less parts
235 # OR The action has equal parts but less captured data (ergo more defined)
238 $#$action_parts < $#{$best_action->{parts}} ||
239 ($#$action_parts == $#{$best_action->{parts}} &&
240 $#$captures < $#{$best_action->{captures}} &&
241 $n_pathparts > $best_action->{n_pathparts}))) {
242 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
244 actions => [ $action, @$actions ],
245 captures=> [ @captures, @$captures ],
246 parts => $action_parts,
247 n_pathparts => scalar(@pathparts) + $n_pathparts,
253 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
254 next TRY_ACTION unless $action->match($c);
256 my $args_attr = $action->attributes->{Args}->[0];
257 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
258 # No best action currently
259 # OR This one matches with fewer parts left than the current best action,
260 # And therefore is a better match
261 # OR No parts and this expects 0
262 # The current best action might also be Args(0),
263 # but we couldn't chose between then anyway so we'll take the last seen
266 @parts < @{$best_action->{parts}} ||
267 (!@parts && defined($args_attr) && $args_attr eq "0")){
269 actions => [ $action ],
272 n_pathparts => scalar(@pathparts),
278 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
282 =head2 $self->register( $c, $action )
284 Calls register_path for every Path attribute for the given $action.
288 sub _check_args_attr {
289 my ( $self, $action, $name ) = @_;
291 return unless exists $action->attributes->{$name};
293 if (@{$action->attributes->{$name}} > 1) {
294 Catalyst::Exception->throw(
295 "Multiple $name attributes not supported registering " . $action->reverse()
298 my $args = $action->attributes->{$name}->[0];
299 if (defined($args) and not (
300 Scalar::Util::looks_like_number($args) and
301 int($args) == $args and $args >= 0
303 require Data::Dumper;
304 local $Data::Dumper::Terse = 1;
305 local $Data::Dumper::Indent = 0;
306 $args = Data::Dumper::Dumper($args);
307 Catalyst::Exception->throw(
308 "Invalid $name($args) for action " . $action->reverse() .
309 " (use '$name' or '$name(<number>)')"
315 my ( $self, $c, $action ) = @_;
317 my @chained_attr = @{ $action->attributes->{Chained} || [] };
319 return 0 unless @chained_attr;
321 if (@chained_attr > 1) {
322 Catalyst::Exception->throw(
323 "Multiple Chained attributes not supported registering ${action}"
326 my $chained_to = $chained_attr[0];
328 Catalyst::Exception->throw(
329 "Actions cannot chain to themselves registering /${action}"
330 ) if ($chained_to eq '/' . $action);
332 my $children = ($self->_children_of->{ $chained_to } ||= {});
334 my @path_part = @{ $action->attributes->{PathPart} || [] };
336 my $part = $action->name;
338 if (@path_part == 1 && defined $path_part[0]) {
339 $part = $path_part[0];
340 } elsif (@path_part > 1) {
341 Catalyst::Exception->throw(
342 "Multiple PathPart attributes not supported registering " . $action->reverse()
346 if ($part =~ m(^/)) {
347 Catalyst::Exception->throw(
348 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
352 $action->attributes->{PathPart} = [ $part ];
354 unshift(@{ $children->{$part} ||= [] }, $action);
356 $self->_actions->{'/'.$action->reverse} = $action;
358 foreach my $name (qw(Args CaptureArgs)) {
359 $self->_check_args_attr($action, $name);
362 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
363 Catalyst::Exception->throw(
364 "Combining Args and CaptureArgs attributes not supported registering " .
369 unless ($action->attributes->{CaptureArgs}) {
370 unshift(@{ $self->_endpoints }, $action);
376 =head2 $self->uri_for_action($action, $captures)
378 Get the URI part for the action, using C<$captures> to fill
384 my ( $self, $action, $captures ) = @_;
386 return undef unless ($action->attributes->{Chained}
387 && !$action->attributes->{CaptureArgs});
390 my @captures = @$captures;
391 my $parent = "DUMMY";
394 if (my $cap = $curr->attributes->{CaptureArgs}) {
395 return undef unless @captures >= ($cap->[0]||0); # not enough captures
397 unshift(@parts, splice(@captures, -$cap->[0]));
400 if (my $pp = $curr->attributes->{PathPart}) {
401 unshift(@parts, $pp->[0])
402 if (defined($pp->[0]) && length($pp->[0]));
404 $parent = $curr->attributes->{Chained}->[0];
405 $curr = $self->_actions->{$parent};
408 return undef unless $parent eq '/'; # fail for dangling action
410 return undef if @captures; # fail for too many captures
412 return join('/', '', @parts);
416 =head2 $c->expand_action($action)
418 Return a list of actions that represents a chained action. See
419 L<Catalyst::Dispatcher> for more info. You probably want to
420 use the expand_action it provides rather than this directly.
425 my ($self, $action) = @_;
427 return unless $action->attributes && $action->attributes->{Chained};
434 my $parent = $curr->attributes->{Chained}->[0];
435 $curr = $self->_actions->{$parent};
438 return Catalyst::ActionChain->from_chain([reverse @chain]);
441 __PACKAGE__->meta->make_immutable;
448 The C<Chained> attribute allows you to chain public path parts together
449 by their private names. A chain part's path can be specified with
450 C<PathPart> and can be declared to expect an arbitrary number of
451 arguments. The endpoint of the chain specifies how many arguments it
452 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
453 C<:Args> without an integer would be unlimited. The path parts that
454 aren't endpoints are using C<CaptureArgs> to specify how many parameters
455 they expect to receive. As an example setup:
457 package MyApp::Controller::Greeting;
458 use base qw/ Catalyst::Controller /;
460 # this is the beginning of our chain
461 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
462 my ( $self, $c, $integer ) = @_;
463 $c->stash->{ message } = "Hello ";
464 $c->stash->{ arg_sum } = $integer;
467 # this is our endpoint, because it has no :CaptureArgs
468 sub world : PathPart('world') Chained('hello') Args(1) {
469 my ( $self, $c, $integer ) = @_;
470 $c->stash->{ message } .= "World!";
471 $c->stash->{ arg_sum } += $integer;
473 $c->response->body( join "<br/>\n" =>
474 $c->stash->{ message }, $c->stash->{ arg_sum } );
477 The debug output provides a separate table for chained actions, showing
478 the whole chain as it would match and the actions it contains. Here's an
479 example of the startup output with our actions above:
482 [debug] Loaded Path Part actions:
483 .-----------------------+------------------------------.
484 | Path Spec | Private |
485 +-----------------------+------------------------------+
486 | /hello/*/world/* | /greeting/hello (1) |
487 | | => /greeting/world |
488 '-----------------------+------------------------------'
491 As you can see, Catalyst only deals with chains as whole paths and
492 builds one for each endpoint, which are the actions with C<:Chained> but
493 without C<:CaptureArgs>.
495 Let's assume this application gets a request at the path
496 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
497 to the C<hello> action and pass the value C<23> as an argument to it
498 after the context. It does so because we have previously used
499 C<:CaptureArgs(1)> to declare that it has one path part after itself as
500 its argument. We told Catalyst that this is the beginning of the chain
501 by specifying C<:Chained('/')>. Also note that instead of saying
502 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
503 defaults to the name of the action.
505 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
506 action. This is the last action to be called: Catalyst knows this is an
507 endpoint because we did not specify a C<:CaptureArgs>
508 attribute. Nevertheless we specify that this action expects an argument,
509 but at this point we're using C<:Args(1)> to do that. We could also have
510 said C<:Args> or left it out altogether, which would mean this action
511 would get all arguments that are there. This action's C<:Chained>
512 attribute says C<hello> and tells Catalyst that the C<hello> action in
513 the current controller is its parent.
515 With this we have built a chain consisting of two public path parts.
516 C<hello> captures one part of the path as its argument, and also
517 specifies the path root as its parent. So this part is
518 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
519 argument. It sums up to the path part C<world/$arg>. This leads to a
520 complete chain of C</hello/$arg/world/$arg> which is matched against the
523 This example application would, if run and called by e.g.
524 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
525 value C<arg_sum> to "23". The C<world> action would then append "World!"
526 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
527 sake of simplicity no view is shown. Instead we just put the values of
528 the stash into our body. So the output would look like:
533 And our test server would have given us this debugging output for the
537 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
538 [debug] Path is "/greeting/world"
539 [debug] Arguments are "12"
540 [info] Request took 0.164113s (6.093/s)
541 .------------------------------------------+-----------.
543 +------------------------------------------+-----------+
544 | /greeting/hello | 0.000029s |
545 | /greeting/world | 0.000024s |
546 '------------------------------------------+-----------'
549 What would be common uses of this dispatch technique? It gives the
550 possibility to split up logic that contains steps that each depend on
551 each other. An example would be, for example, a wiki path like
552 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
555 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
556 my ( $self, $c, $page_name ) = @_;
557 # load the page named $page_name and put the object
561 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
562 my ( $self, $c, $revision_id ) = @_;
563 # use the page object in the stash to get at its
564 # revision with number $revision_id
567 sub view : PathPart Chained('rev') Args(0) {
568 my ( $self, $c ) = @_;
569 # display the revision in our stash. Another option
570 # would be to forward a compatible object to the action
571 # that displays the default wiki pages, unless we want
572 # a different interface here, for example restore
576 It would now be possible to add other endpoints, for example C<restore>
577 to restore this specific revision as the current state.
579 You don't have to put all the chained actions in one controller. The
580 specification of the parent through C<:Chained> also takes an absolute
581 action path as its argument. Just specify it with a leading C</>.
583 If you want, for example, to have actions for the public paths
584 C</foo/12/edit> and C</foo/12>, just specify two actions with
585 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
586 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
587 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
588 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
589 this debugging output:
592 [debug] Loaded Path Part actions:
593 .-----------------------+------------------------------.
594 | Path Spec | Private |
595 +-----------------------+------------------------------+
596 | /foo/* | /controller/foo_view |
597 | /foo/*/edit | /controller/foo_load (1) |
598 | | => /controller/edit |
599 '-----------------------+------------------------------'
602 Here's a more detailed specification of the attributes belonging to
611 Sets the name of this part of the chain. If it is specified without
612 arguments, it takes the name of the action as default. So basically
613 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
614 This can also contain slashes to bind to a deeper level. An action
615 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
616 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
617 effect as using C<:PathPart>, it would default to the action name.
621 Sets PathPart to the path_prefix of the current controller.
625 Has to be specified for every child in the chain. Possible values are
626 absolute and relative private action paths or a single slash C</> to
627 tell Catalyst that this is the root of a chain. The attribute
628 C<:Chained> without arguments also defaults to the C</> behavior.
629 Relative action paths may use C<../> to refer to actions in parent
632 Because you can specify an absolute path to the parent action, it
633 doesn't matter to Catalyst where that parent is located. So, if your
634 design requests it, you can redispatch a chain through any controller or
637 Another interesting possibility gives C<:Chained('.')>, which chains
638 itself to an action with the path of the current controller's namespace.
641 # in MyApp::Controller::Foo
642 sub bar : Chained CaptureArgs(1) { ... }
644 # in MyApp::Controller::Foo::Bar
645 sub baz : Chained('.') Args(1) { ... }
647 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
648 as the argument to Chained here chains the C<baz> action to an action
649 with the path of the current controller namespace, namely
650 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
651 chain comes out as the end product.
655 Chains an action to another action with the same name in the parent
656 controller. For Example:
658 # in MyApp::Controller::Foo
659 sub bar : Chained CaptureArgs(1) { ... }
661 # in MyApp::Controller::Foo::Moo
662 sub bar : ChainedParent Args(1) { ... }
664 This builds a chain like C</bar/*/bar/*>.
668 Must be specified for every part of the chain that is not an
669 endpoint. With this attribute Catalyst knows how many of the following
670 parts of the path (separated by C</>) this action wants to capture as
671 its arguments. If it doesn't expect any, just specify
672 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
673 after the context, but you can also find them as array references in
674 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
675 level of the action in the chain that captured the parts of the path.
677 An action that is part of a chain (that is, one that has a C<:Chained>
678 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
683 By default, endpoints receive the rest of the arguments in the path. You
684 can tell Catalyst through C<:Args> explicitly how many arguments your
685 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
686 also affects whether this chain is invoked on a request. A chain with an
687 endpoint specifying one argument will only match if exactly one argument
690 You can specify an exact number of arguments like C<:Args(3)>, including
691 C<0>. If you just say C<:Args> without any arguments, it is the same as
692 leaving it out altogether: The chain is matched regardless of the number
693 of path parts after the endpoint.
695 Just as with C<:CaptureArgs>, the arguments get passed to the action in
696 C<@_> after the context object. They can also be reached through
697 C<$c-E<gt>request-E<gt>arguments>.
701 =head2 Auto actions, dispatching and forwarding
703 Note that the list of C<auto> actions called depends on the private path
704 of the endpoint of the chain, not on the chained actions way. The
705 C<auto> actions will be run before the chain dispatching begins. In
706 every other aspect, C<auto> actions behave as documented.
708 The C<forward>ing to other actions does just what you would expect. i.e.
709 only the target action is run. The actions that that action is chained
711 If you C<detach> out of a chain, the rest of the chain will not get
712 called after the C<detach>.
714 =head2 match_captures
716 A method which can optionally be implemented by actions to
719 See L<Catalyst::Action> for further details.
723 Catalyst Contributors, see Catalyst.pm
727 This library is free software. You can redistribute it and/or modify it under
728 the same terms as Perl itself.