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 = $endpoint->attributes->{Args}->[0];
100 my @parts = (defined($args) ? (("*") x $args) : '...');
102 my $parent = "DUMMY";
103 my $curr = $endpoint;
105 if (my $cap = $curr->attributes->{CaptureArgs}) {
106 unshift(@parts, (("*") x $cap->[0]));
108 if (my $pp = $curr->attributes->{PartPath}) {
109 unshift(@parts, $pp->[0])
110 if (defined $pp->[0] && length $pp->[0]);
112 $parent = $curr->attributes->{Chained}->[0];
113 $curr = $self->_actions->{$parent};
114 unshift(@parents, $curr) if $curr;
116 if ($parent ne '/') {
117 $has_unattached_actions = 1;
118 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
122 foreach my $p (@parents) {
124 if (my $cap = $p->attributes->{CaptureArgs}) {
125 $name .= ' ('.$cap->[0].')';
127 unless ($p eq $parents[0]) {
128 $name = "-> ${name}";
130 push(@rows, [ '', $name ]);
132 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
133 $rows[0][0] = join('/', '', @parts) || '/';
134 $paths->row(@$_) for @rows;
137 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
138 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
139 if $has_unattached_actions;
142 =head2 $self->match( $c, $path )
144 Calls C<recurse_match> to see if a chain matches the C<$path>.
149 my ( $self, $c, $path ) = @_;
151 my $request = $c->request;
152 return 0 if @{$request->args};
154 my @parts = split('/', $path);
156 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
158 if ($parts && @$parts) {
159 for my $arg (@$parts) {
160 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
161 push @{$request->args}, $arg;
165 return 0 unless $chain;
167 my $action = Catalyst::ActionChain->from_chain($chain);
169 $request->action("/${action}");
170 $request->match("/${action}");
171 $request->captures($captures);
173 $c->namespace( $action->namespace );
178 =head2 $self->recurse_match( $c, $parent, \@path_parts )
180 Recursive search for a matching chain.
185 my ( $self, $c, $parent, $path_parts ) = @_;
186 my $children = $self->_children_of->{$parent};
187 return () unless $children;
190 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
192 # $b then $a to try longest part first
193 my @parts = @$path_parts;
194 if (length $try_part) { # test and strip PathPart
196 ($try_part eq join('/', # assemble equal number of parts
197 splice( # and strip them off @parts as well
198 @parts, 0, scalar(@{[split('/', $try_part)]})
199 ))); # @{[]} to avoid split to @_
201 my @try_actions = @{$children->{$try_part}};
202 TRY_ACTION: foreach my $action (@try_actions) {
203 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
205 # Short-circuit if not enough remaining parts
206 next TRY_ACTION unless @parts >= $capture_attr->[0];
209 my @parts = @parts; # localise
211 # strip CaptureArgs into list
212 push(@captures, splice(@parts, 0, $capture_attr->[0]));
214 # try the remaining parts against children of this action
215 my ($actions, $captures, $action_parts) = $self->recurse_match(
216 $c, '/'.$action->reverse, \@parts
218 # No best action currently
219 # OR The action has less parts
220 # OR The action has equal parts but less captured data (ergo more defined)
223 $#$action_parts < $#{$best_action->{parts}} ||
224 ($#$action_parts == $#{$best_action->{parts}} &&
225 $#$captures < $#{$best_action->{captures}}))){
227 actions => [ $action, @$actions ],
228 captures=> [ @captures, @$captures ],
229 parts => $action_parts
235 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
236 next TRY_ACTION unless $action->match($c);
239 # Default args is blank, not 0, since Args()
240 my $args_attr = $action->attributes->{Args}->[0];
241 $args_attr = '' unless defined $args_attr;
243 # No best action currently
244 # OR This one matches with fewer parts left than the current best action,
245 # And therefore is a better match
246 # OR No parts and this expects 0
247 # The current best action might also be Args(0),
248 # but we couldn't chose between then anyway so we'll take the last seen
251 @parts < @{$best_action->{parts}} ||
252 (!@parts && $args_attr eq 0)){
254 actions => [ $action ],
262 return @$best_action{qw/actions captures parts/} if $best_action;
266 =head2 $self->register( $c, $action )
268 Calls register_path for every Path attribute for the given $action.
273 my ( $self, $c, $action ) = @_;
275 my @chained_attr = @{ $action->attributes->{Chained} || [] };
277 return 0 unless @chained_attr;
279 if (@chained_attr > 1) {
280 Catalyst::Exception->throw(
281 "Multiple Chained attributes not supported registering ${action}"
284 my $chained_to = $chained_attr[0];
286 Catalyst::Exception->throw(
287 "Actions cannot chain to themselves registering /${action}"
288 ) if ($chained_to eq '/' . $action);
290 my $children = ($self->_children_of->{ $chained_to } ||= {});
292 my @path_part = @{ $action->attributes->{PathPart} || [] };
294 my $part = $action->name;
296 if (@path_part == 1 && defined $path_part[0]) {
297 $part = $path_part[0];
298 } elsif (@path_part > 1) {
299 Catalyst::Exception->throw(
300 "Multiple PathPart attributes not supported registering " . $action->reverse()
304 if ($part =~ m(^/)) {
305 Catalyst::Exception->throw(
306 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
310 $action->attributes->{PartPath} = [ $part ];
312 unshift(@{ $children->{$part} ||= [] }, $action);
314 $self->_actions->{'/'.$action->reverse} = $action;
316 if (exists $action->attributes->{Args}) {
317 my $args = $action->attributes->{Args}->[0];
318 if (defined($args) and not (
319 Scalar::Util::looks_like_number($args) and
322 require Data::Dumper;
323 local $Data::Dumper::Terse = 1;
324 local $Data::Dumper::Indent = 0;
325 $args = Data::Dumper::Dumper($args);
326 Catalyst::Exception->throw(
327 "Invalid Args($args) for action " . $action->reverse() .
328 " (use 'Args' or 'Args(<number>)'"
333 unless ($action->attributes->{CaptureArgs}) {
334 unshift(@{ $self->_endpoints }, $action);
340 =head2 $self->uri_for_action($action, $captures)
342 Get the URI part for the action, using C<$captures> to fill
348 my ( $self, $action, $captures ) = @_;
350 return undef unless ($action->attributes->{Chained}
351 && !$action->attributes->{CaptureArgs});
354 my @captures = @$captures;
355 my $parent = "DUMMY";
358 if (my $cap = $curr->attributes->{CaptureArgs}) {
359 return undef unless @captures >= $cap->[0]; # not enough captures
361 unshift(@parts, splice(@captures, -$cap->[0]));
364 if (my $pp = $curr->attributes->{PartPath}) {
365 unshift(@parts, $pp->[0])
366 if (defined($pp->[0]) && length($pp->[0]));
368 $parent = $curr->attributes->{Chained}->[0];
369 $curr = $self->_actions->{$parent};
372 return undef unless $parent eq '/'; # fail for dangling action
374 return undef if @captures; # fail for too many captures
376 return join('/', '', @parts);
380 =head2 $c->expand_action($action)
382 Return a list of actions that represents a chained action. See
383 L<Catalyst::Dispatcher> for more info. You probably want to
384 use the expand_action it provides rather than this directly.
389 my ($self, $action) = @_;
391 return unless $action->attributes && $action->attributes->{Chained};
398 my $parent = $curr->attributes->{Chained}->[0];
399 $curr = $self->_actions->{$parent};
402 return Catalyst::ActionChain->from_chain([reverse @chain]);
405 __PACKAGE__->meta->make_immutable;
411 The C<Chained> attribute allows you to chain public path parts together
412 by their private names. A chain part's path can be specified with
413 C<PathPart> and can be declared to expect an arbitrary number of
414 arguments. The endpoint of the chain specifies how many arguments it
415 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
416 C<:Args> without an integer would be unlimited. The path parts that
417 aren't endpoints are using C<CaptureArgs> to specify how many parameters
418 they expect to receive. As an example setup:
420 package MyApp::Controller::Greeting;
421 use base qw/ Catalyst::Controller /;
423 # this is the beginning of our chain
424 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
425 my ( $self, $c, $integer ) = @_;
426 $c->stash->{ message } = "Hello ";
427 $c->stash->{ arg_sum } = $integer;
430 # this is our endpoint, because it has no :CaptureArgs
431 sub world : PathPart('world') Chained('hello') Args(1) {
432 my ( $self, $c, $integer ) = @_;
433 $c->stash->{ message } .= "World!";
434 $c->stash->{ arg_sum } += $integer;
436 $c->response->body( join "<br/>\n" =>
437 $c->stash->{ message }, $c->stash->{ arg_sum } );
440 The debug output provides a separate table for chained actions, showing
441 the whole chain as it would match and the actions it contains. Here's an
442 example of the startup output with our actions above:
445 [debug] Loaded Path Part actions:
446 .-----------------------+------------------------------.
447 | Path Spec | Private |
448 +-----------------------+------------------------------+
449 | /hello/*/world/* | /greeting/hello (1) |
450 | | => /greeting/world |
451 '-----------------------+------------------------------'
454 As you can see, Catalyst only deals with chains as whole paths and
455 builds one for each endpoint, which are the actions with C<:Chained> but
456 without C<:CaptureArgs>.
458 Let's assume this application gets a request at the path
459 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
460 to the C<hello> action and pass the value C<23> as an argument to it
461 after the context. It does so because we have previously used
462 C<:CaptureArgs(1)> to declare that it has one path part after itself as
463 its argument. We told Catalyst that this is the beginning of the chain
464 by specifying C<:Chained('/')>. Also note that instead of saying
465 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
466 defaults to the name of the action.
468 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
469 action. This is the last action to be called: Catalyst knows this is an
470 endpoint because we did not specify a C<:CaptureArgs>
471 attribute. Nevertheless we specify that this action expects an argument,
472 but at this point we're using C<:Args(1)> to do that. We could also have
473 said C<:Args> or left it out altogether, which would mean this action
474 would get all arguments that are there. This action's C<:Chained>
475 attribute says C<hello> and tells Catalyst that the C<hello> action in
476 the current controller is its parent.
478 With this we have built a chain consisting of two public path parts.
479 C<hello> captures one part of the path as its argument, and also
480 specifies the path root as its parent. So this part is
481 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
482 argument. It sums up to the path part C<world/$arg>. This leads to a
483 complete chain of C</hello/$arg/world/$arg> which is matched against the
486 This example application would, if run and called by e.g.
487 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
488 value C<arg_sum> to "23". The C<world> action would then append "World!"
489 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
490 sake of simplicity no view is shown. Instead we just put the values of
491 the stash into our body. So the output would look like:
496 And our test server would have given us this debugging output for the
500 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
501 [debug] Path is "/greeting/world"
502 [debug] Arguments are "12"
503 [info] Request took 0.164113s (6.093/s)
504 .------------------------------------------+-----------.
506 +------------------------------------------+-----------+
507 | /greeting/hello | 0.000029s |
508 | /greeting/world | 0.000024s |
509 '------------------------------------------+-----------'
512 What would be common uses of this dispatch technique? It gives the
513 possibility to split up logic that contains steps that each depend on
514 each other. An example would be, for example, a wiki path like
515 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
518 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
519 my ( $self, $c, $page_name ) = @_;
520 # load the page named $page_name and put the object
524 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
525 my ( $self, $c, $revision_id ) = @_;
526 # use the page object in the stash to get at its
527 # revision with number $revision_id
530 sub view : PathPart Chained('rev') Args(0) {
531 my ( $self, $c ) = @_;
532 # display the revision in our stash. Another option
533 # would be to forward a compatible object to the action
534 # that displays the default wiki pages, unless we want
535 # a different interface here, for example restore
539 It would now be possible to add other endpoints, for example C<restore>
540 to restore this specific revision as the current state.
542 You don't have to put all the chained actions in one controller. The
543 specification of the parent through C<:Chained> also takes an absolute
544 action path as its argument. Just specify it with a leading C</>.
546 If you want, for example, to have actions for the public paths
547 C</foo/12/edit> and C</foo/12>, just specify two actions with
548 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
549 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
550 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
551 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
552 this debugging output:
555 [debug] Loaded Path Part actions:
556 .-----------------------+------------------------------.
557 | Path Spec | Private |
558 +-----------------------+------------------------------+
559 | /foo/* | /controller/foo_view |
560 | /foo/*/edit | /controller/foo_load (1) |
561 | | => /controller/edit |
562 '-----------------------+------------------------------'
565 Here's a more detailed specification of the attributes belonging to
574 Sets the name of this part of the chain. If it is specified without
575 arguments, it takes the name of the action as default. So basically
576 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
577 This can also contain slashes to bind to a deeper level. An action
578 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
579 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
580 effect as using C<:PathPart>, it would default to the action name.
584 Sets PathPart to the path_prefix of the current controller.
588 Has to be specified for every child in the chain. Possible values are
589 absolute and relative private action paths or a single slash C</> to
590 tell Catalyst that this is the root of a chain. The attribute
591 C<:Chained> without arguments also defaults to the C</> behavior.
592 Relative action paths may use C<../> to refer to actions in parent
595 Because you can specify an absolute path to the parent action, it
596 doesn't matter to Catalyst where that parent is located. So, if your
597 design requests it, you can redispatch a chain through any controller or
600 Another interesting possibility gives C<:Chained('.')>, which chains
601 itself to an action with the path of the current controller's namespace.
604 # in MyApp::Controller::Foo
605 sub bar : Chained CaptureArgs(1) { ... }
607 # in MyApp::Controller::Foo::Bar
608 sub baz : Chained('.') Args(1) { ... }
610 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
611 as the argument to Chained here chains the C<baz> action to an action
612 with the path of the current controller namespace, namely
613 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
614 chain comes out as the end product.
618 Chains an action to another action with the same name in the parent
619 controller. For Example:
621 # in MyApp::Controller::Foo
622 sub bar : Chained CaptureArgs(1) { ... }
624 # in MyApp::Controller::Foo::Moo
625 sub bar : ChainedParent Args(1) { ... }
627 This builds a chain like C</bar/*/bar/*>.
631 Must be specified for every part of the chain that is not an
632 endpoint. With this attribute Catalyst knows how many of the following
633 parts of the path (separated by C</>) this action wants to capture as
634 its arguments. If it doesn't expect any, just specify
635 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
636 after the context, but you can also find them as array references in
637 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
638 level of the action in the chain that captured the parts of the path.
640 An action that is part of a chain (that is, one that has a C<:Chained>
641 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
646 By default, endpoints receive the rest of the arguments in the path. You
647 can tell Catalyst through C<:Args> explicitly how many arguments your
648 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
649 also affects whether this chain is invoked on a request. A chain with an
650 endpoint specifying one argument will only match if exactly one argument
653 You can specify an exact number of arguments like C<:Args(3)>, including
654 C<0>. If you just say C<:Args> without any arguments, it is the same as
655 leaving it out altogether: The chain is matched regardless of the number
656 of path parts after the endpoint.
658 Just as with C<:CaptureArgs>, the arguments get passed to the action in
659 C<@_> after the context object. They can also be reached through
660 C<$c-E<gt>request-E<gt>arguments>.
664 =head2 Auto actions, dispatching and forwarding
666 Note that the list of C<auto> actions called depends on the private path
667 of the endpoint of the chain, not on the chained actions way. The
668 C<auto> actions will be run before the chain dispatching begins. In
669 every other aspect, C<auto> actions behave as documented.
671 The C<forward>ing to other actions does just what you would expect. But if
672 you C<detach> out of a chain, the rest of the chain will not get called
677 Catalyst Contributors, see Catalyst.pm
681 This library is free software. You can redistribute it and/or modify it under
682 the same terms as Perl itself.