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}) {
217 # Short-circuit if not enough remaining parts
218 next TRY_ACTION unless @parts >= $capture_attr->[0];
221 my @parts = @parts; # localise
223 # strip CaptureArgs into list
224 push(@captures, splice(@parts, 0, $capture_attr->[0]));
226 # check if the action may fit, depending on a given test by the app
227 if ($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.
289 my ( $self, $c, $action ) = @_;
291 my @chained_attr = @{ $action->attributes->{Chained} || [] };
293 return 0 unless @chained_attr;
295 if (@chained_attr > 1) {
296 Catalyst::Exception->throw(
297 "Multiple Chained attributes not supported registering ${action}"
300 my $chained_to = $chained_attr[0];
302 Catalyst::Exception->throw(
303 "Actions cannot chain to themselves registering /${action}"
304 ) if ($chained_to eq '/' . $action);
306 my $children = ($self->_children_of->{ $chained_to } ||= {});
308 my @path_part = @{ $action->attributes->{PathPart} || [] };
310 my $part = $action->name;
312 if (@path_part == 1 && defined $path_part[0]) {
313 $part = $path_part[0];
314 } elsif (@path_part > 1) {
315 Catalyst::Exception->throw(
316 "Multiple PathPart attributes not supported registering " . $action->reverse()
320 if ($part =~ m(^/)) {
321 Catalyst::Exception->throw(
322 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
326 $action->attributes->{PathPart} = [ $part ];
328 unshift(@{ $children->{$part} ||= [] }, $action);
330 $self->_actions->{'/'.$action->reverse} = $action;
332 if (exists $action->attributes->{Args}) {
333 my $args = $action->attributes->{Args}->[0];
334 if (defined($args) and not (
335 Scalar::Util::looks_like_number($args) and
338 require Data::Dumper;
339 local $Data::Dumper::Terse = 1;
340 local $Data::Dumper::Indent = 0;
341 $args = Data::Dumper::Dumper($args);
342 Catalyst::Exception->throw(
343 "Invalid Args($args) for action " . $action->reverse() .
344 " (use 'Args' or 'Args(<number>)'"
349 unless ($action->attributes->{CaptureArgs}) {
350 unshift(@{ $self->_endpoints }, $action);
356 =head2 $self->uri_for_action($action, $captures)
358 Get the URI part for the action, using C<$captures> to fill
364 my ( $self, $action, $captures ) = @_;
366 return undef unless ($action->attributes->{Chained}
367 && !$action->attributes->{CaptureArgs});
370 my @captures = @$captures;
371 my $parent = "DUMMY";
374 if (my $cap = $curr->attributes->{CaptureArgs}) {
375 return undef unless @captures >= ($cap->[0]||0); # not enough captures
377 unshift(@parts, splice(@captures, -$cap->[0]));
380 if (my $pp = $curr->attributes->{PathPart}) {
381 unshift(@parts, $pp->[0])
382 if (defined($pp->[0]) && length($pp->[0]));
384 $parent = $curr->attributes->{Chained}->[0];
385 $curr = $self->_actions->{$parent};
388 return undef unless $parent eq '/'; # fail for dangling action
390 return undef if @captures; # fail for too many captures
392 return join('/', '', @parts);
396 =head2 $c->expand_action($action)
398 Return a list of actions that represents a chained action. See
399 L<Catalyst::Dispatcher> for more info. You probably want to
400 use the expand_action it provides rather than this directly.
405 my ($self, $action) = @_;
407 return unless $action->attributes && $action->attributes->{Chained};
414 my $parent = $curr->attributes->{Chained}->[0];
415 $curr = $self->_actions->{$parent};
418 return Catalyst::ActionChain->from_chain([reverse @chain]);
421 __PACKAGE__->meta->make_immutable;
428 The C<Chained> attribute allows you to chain public path parts together
429 by their private names. A chain part's path can be specified with
430 C<PathPart> and can be declared to expect an arbitrary number of
431 arguments. The endpoint of the chain specifies how many arguments it
432 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
433 C<:Args> without an integer would be unlimited. The path parts that
434 aren't endpoints are using C<CaptureArgs> to specify how many parameters
435 they expect to receive. As an example setup:
437 package MyApp::Controller::Greeting;
438 use base qw/ Catalyst::Controller /;
440 # this is the beginning of our chain
441 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
442 my ( $self, $c, $integer ) = @_;
443 $c->stash->{ message } = "Hello ";
444 $c->stash->{ arg_sum } = $integer;
447 # this is our endpoint, because it has no :CaptureArgs
448 sub world : PathPart('world') Chained('hello') Args(1) {
449 my ( $self, $c, $integer ) = @_;
450 $c->stash->{ message } .= "World!";
451 $c->stash->{ arg_sum } += $integer;
453 $c->response->body( join "<br/>\n" =>
454 $c->stash->{ message }, $c->stash->{ arg_sum } );
457 The debug output provides a separate table for chained actions, showing
458 the whole chain as it would match and the actions it contains. Here's an
459 example of the startup output with our actions above:
462 [debug] Loaded Path Part actions:
463 .-----------------------+------------------------------.
464 | Path Spec | Private |
465 +-----------------------+------------------------------+
466 | /hello/*/world/* | /greeting/hello (1) |
467 | | => /greeting/world |
468 '-----------------------+------------------------------'
471 As you can see, Catalyst only deals with chains as whole paths and
472 builds one for each endpoint, which are the actions with C<:Chained> but
473 without C<:CaptureArgs>.
475 Let's assume this application gets a request at the path
476 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
477 to the C<hello> action and pass the value C<23> as an argument to it
478 after the context. It does so because we have previously used
479 C<:CaptureArgs(1)> to declare that it has one path part after itself as
480 its argument. We told Catalyst that this is the beginning of the chain
481 by specifying C<:Chained('/')>. Also note that instead of saying
482 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
483 defaults to the name of the action.
485 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
486 action. This is the last action to be called: Catalyst knows this is an
487 endpoint because we did not specify a C<:CaptureArgs>
488 attribute. Nevertheless we specify that this action expects an argument,
489 but at this point we're using C<:Args(1)> to do that. We could also have
490 said C<:Args> or left it out altogether, which would mean this action
491 would get all arguments that are there. This action's C<:Chained>
492 attribute says C<hello> and tells Catalyst that the C<hello> action in
493 the current controller is its parent.
495 With this we have built a chain consisting of two public path parts.
496 C<hello> captures one part of the path as its argument, and also
497 specifies the path root as its parent. So this part is
498 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
499 argument. It sums up to the path part C<world/$arg>. This leads to a
500 complete chain of C</hello/$arg/world/$arg> which is matched against the
503 This example application would, if run and called by e.g.
504 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
505 value C<arg_sum> to "23". The C<world> action would then append "World!"
506 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
507 sake of simplicity no view is shown. Instead we just put the values of
508 the stash into our body. So the output would look like:
513 And our test server would have given us this debugging output for the
517 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
518 [debug] Path is "/greeting/world"
519 [debug] Arguments are "12"
520 [info] Request took 0.164113s (6.093/s)
521 .------------------------------------------+-----------.
523 +------------------------------------------+-----------+
524 | /greeting/hello | 0.000029s |
525 | /greeting/world | 0.000024s |
526 '------------------------------------------+-----------'
529 What would be common uses of this dispatch technique? It gives the
530 possibility to split up logic that contains steps that each depend on
531 each other. An example would be, for example, a wiki path like
532 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
535 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
536 my ( $self, $c, $page_name ) = @_;
537 # load the page named $page_name and put the object
541 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
542 my ( $self, $c, $revision_id ) = @_;
543 # use the page object in the stash to get at its
544 # revision with number $revision_id
547 sub view : PathPart Chained('rev') Args(0) {
548 my ( $self, $c ) = @_;
549 # display the revision in our stash. Another option
550 # would be to forward a compatible object to the action
551 # that displays the default wiki pages, unless we want
552 # a different interface here, for example restore
556 It would now be possible to add other endpoints, for example C<restore>
557 to restore this specific revision as the current state.
559 You don't have to put all the chained actions in one controller. The
560 specification of the parent through C<:Chained> also takes an absolute
561 action path as its argument. Just specify it with a leading C</>.
563 If you want, for example, to have actions for the public paths
564 C</foo/12/edit> and C</foo/12>, just specify two actions with
565 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
566 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
567 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
568 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
569 this debugging output:
572 [debug] Loaded Path Part actions:
573 .-----------------------+------------------------------.
574 | Path Spec | Private |
575 +-----------------------+------------------------------+
576 | /foo/* | /controller/foo_view |
577 | /foo/*/edit | /controller/foo_load (1) |
578 | | => /controller/edit |
579 '-----------------------+------------------------------'
582 Here's a more detailed specification of the attributes belonging to
591 Sets the name of this part of the chain. If it is specified without
592 arguments, it takes the name of the action as default. So basically
593 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
594 This can also contain slashes to bind to a deeper level. An action
595 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
596 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
597 effect as using C<:PathPart>, it would default to the action name.
601 Sets PathPart to the path_prefix of the current controller.
605 Has to be specified for every child in the chain. Possible values are
606 absolute and relative private action paths or a single slash C</> to
607 tell Catalyst that this is the root of a chain. The attribute
608 C<:Chained> without arguments also defaults to the C</> behavior.
609 Relative action paths may use C<../> to refer to actions in parent
612 Because you can specify an absolute path to the parent action, it
613 doesn't matter to Catalyst where that parent is located. So, if your
614 design requests it, you can redispatch a chain through any controller or
617 Another interesting possibility gives C<:Chained('.')>, which chains
618 itself to an action with the path of the current controller's namespace.
621 # in MyApp::Controller::Foo
622 sub bar : Chained CaptureArgs(1) { ... }
624 # in MyApp::Controller::Foo::Bar
625 sub baz : Chained('.') Args(1) { ... }
627 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
628 as the argument to Chained here chains the C<baz> action to an action
629 with the path of the current controller namespace, namely
630 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
631 chain comes out as the end product.
635 Chains an action to another action with the same name in the parent
636 controller. For Example:
638 # in MyApp::Controller::Foo
639 sub bar : Chained CaptureArgs(1) { ... }
641 # in MyApp::Controller::Foo::Moo
642 sub bar : ChainedParent Args(1) { ... }
644 This builds a chain like C</bar/*/bar/*>.
648 Must be specified for every part of the chain that is not an
649 endpoint. With this attribute Catalyst knows how many of the following
650 parts of the path (separated by C</>) this action wants to capture as
651 its arguments. If it doesn't expect any, just specify
652 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
653 after the context, but you can also find them as array references in
654 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
655 level of the action in the chain that captured the parts of the path.
657 An action that is part of a chain (that is, one that has a C<:Chained>
658 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
663 By default, endpoints receive the rest of the arguments in the path. You
664 can tell Catalyst through C<:Args> explicitly how many arguments your
665 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
666 also affects whether this chain is invoked on a request. A chain with an
667 endpoint specifying one argument will only match if exactly one argument
670 You can specify an exact number of arguments like C<:Args(3)>, including
671 C<0>. If you just say C<:Args> without any arguments, it is the same as
672 leaving it out altogether: The chain is matched regardless of the number
673 of path parts after the endpoint.
675 Just as with C<:CaptureArgs>, the arguments get passed to the action in
676 C<@_> after the context object. They can also be reached through
677 C<$c-E<gt>request-E<gt>arguments>.
681 =head2 Auto actions, dispatching and forwarding
683 Note that the list of C<auto> actions called depends on the private path
684 of the endpoint of the chain, not on the chained actions way. The
685 C<auto> actions will be run before the chain dispatching begins. In
686 every other aspect, C<auto> actions behave as documented.
688 The C<forward>ing to other actions does just what you would expect. ie
689 only the target action is run. The actions that that action is chained
691 If you C<detach> out of a chain, the rest of the chain will not get
692 called after the C<detach>.
694 =head2 match_captures
696 A method which can optionally be implemented by actions to
699 See L<Catalyst::Action> for further details.
703 Catalyst Contributors, see Catalyst.pm
707 This library is free software. You can redistribute it and/or modify it under
708 the same terms as Perl itself.