1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
33 # please don't perltidy this. hairy code within.
37 Catalyst::DispatchType::Chained - Path Part DispatchType
41 # root action - captures one argument after it
42 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
43 my ( $self, $c, $foo_arg ) = @_;
47 # child action endpoint - takes one argument
48 sub bar : Chained('foo_setup') Args(1) {
49 my ( $self, $c, $bar_arg ) = @_;
59 =head2 $self->list($c)
61 Debug output for Path Part dispatch points
66 my ( $self, $c ) = @_;
68 return unless $self->_endpoints;
70 my $paths = Text::SimpleTable->new(
71 [ 35, 'Path Spec' ], [ 36, 'Private' ]
74 my $has_unattached_actions;
75 my $unattached_actions = Text::SimpleTable->new(
76 [ 35, 'Private' ], [ 36, 'Missing parent' ],
79 ENDPOINT: foreach my $endpoint (
80 sort { $a->reverse cmp $b->reverse }
81 @{ $self->_endpoints }
83 my $args = $endpoint->attributes->{Args}->[0];
84 my @parts = (defined($args) ? (("*") x $args) : '...');
89 if (my $cap = $curr->attributes->{CaptureArgs}) {
90 unshift(@parts, (("*") x $cap->[0]));
92 if (my $pp = $curr->attributes->{PartPath}) {
93 unshift(@parts, $pp->[0])
94 if (defined $pp->[0] && length $pp->[0]);
96 $parent = $curr->attributes->{Chained}->[0];
97 $curr = $self->_actions->{$parent};
98 unshift(@parents, $curr) if $curr;
100 if ($parent ne '/') {
101 $has_unattached_actions = 1;
102 $unattached_actions->row('/'.$parents[0]->reverse, $parent);
106 foreach my $p (@parents) {
108 if (my $cap = $p->attributes->{CaptureArgs}) {
109 $name .= ' ('.$cap->[0].')';
111 unless ($p eq $parents[0]) {
112 $name = "-> ${name}";
114 push(@rows, [ '', $name ]);
116 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
117 $rows[0][0] = join('/', '', @parts);
118 $paths->row(@$_) for @rows;
121 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
122 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
123 if $has_unattached_actions;
126 =head2 $self->match( $c, $path )
128 Calls C<recurse_match> to see if a chain matches the C<$path>.
133 my ( $self, $c, $path ) = @_;
135 my $request = $c->request;
136 return 0 if @{$request->args};
138 my @parts = split('/', $path);
140 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
141 push @{$request->args}, @$parts if $parts && @$parts;
143 return 0 unless $chain;
145 my $action = Catalyst::ActionChain->from_chain($chain);
147 $request->action("/${action}");
148 $request->match("/${action}");
149 $request->captures($captures);
151 $c->namespace( $action->namespace );
156 =head2 $self->recurse_match( $c, $parent, \@path_parts )
158 Recursive search for a matching chain.
163 my ( $self, $c, $parent, $path_parts ) = @_;
164 my $children = $self->_children_of->{$parent};
165 return () unless $children;
168 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
170 # $b then $a to try longest part first
171 my @parts = @$path_parts;
172 if (length $try_part) { # test and strip PathPart
174 ($try_part eq join('/', # assemble equal number of parts
175 splice( # and strip them off @parts as well
176 @parts, 0, scalar(@{[split('/', $try_part)]})
177 ))); # @{[]} to avoid split to @_
179 my @try_actions = @{$children->{$try_part}};
180 TRY_ACTION: foreach my $action (@try_actions) {
181 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
183 # Short-circuit if not enough remaining parts
184 next TRY_ACTION unless @parts >= $capture_attr->[0];
187 my @parts = @parts; # localise
189 # strip CaptureArgs into list
190 push(@captures, splice(@parts, 0, $capture_attr->[0]));
192 # try the remaining parts against children of this action
193 my ($actions, $captures, $action_parts) = $self->recurse_match(
194 $c, '/'.$action->reverse, \@parts
196 # No best action currently
197 # OR The action has less parts
198 # OR The action has equal parts but less captured data (ergo more defined)
201 $#$action_parts < $#{$best_action->{parts}} ||
202 ($#$action_parts == $#{$best_action->{parts}} &&
203 $#$captures < $#{$best_action->{captures}}))){
205 actions => [ $action, @$actions ],
206 captures=> [ @captures, @$captures ],
207 parts => $action_parts
213 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
214 next TRY_ACTION unless $action->match($c);
216 my $args_attr = $action->attributes->{Args}->[0];
218 # No best action currently
219 # OR This one matches with fewer parts left than the current best action,
220 # And therefore is a better match
221 # OR No parts and this expects 0
222 # The current best action might also be Args(0),
223 # but we couldn't chose between then anyway so we'll take the last seen
226 @parts < @{$best_action->{parts}} ||
227 (!@parts && $args_attr eq 0)){
229 actions => [ $action ],
237 return @$best_action{qw/actions captures parts/} if $best_action;
241 =head2 $self->register( $c, $action )
243 Calls register_path for every Path attribute for the given $action.
248 my ( $self, $c, $action ) = @_;
250 my @chained_attr = @{ $action->attributes->{Chained} || [] };
252 return 0 unless @chained_attr;
254 if (@chained_attr > 1) {
255 Catalyst::Exception->throw(
256 "Multiple Chained attributes not supported registering ${action}"
260 my $children = ($self->_children_of->{ $chained_attr[0] } ||= {});
262 my @path_part = @{ $action->attributes->{PathPart} || [] };
264 my $part = $action->name;
266 if (@path_part == 1 && defined $path_part[0]) {
267 $part = $path_part[0];
268 } elsif (@path_part > 1) {
269 Catalyst::Exception->throw(
270 "Multiple PathPart attributes not supported registering " . $action->reverse()
274 if ($part =~ m(^/)) {
275 Catalyst::Exception->throw(
276 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
280 $action->attributes->{PartPath} = [ $part ];
282 unshift(@{ $children->{$part} ||= [] }, $action);
284 $self->_actions->{'/'.$action->reverse} = $action;
286 unless ($action->attributes->{CaptureArgs}) {
287 unshift(@{ $self->_endpoints }, $action);
293 =head2 $self->uri_for_action($action, $captures)
295 Get the URI part for the action, using C<$captures> to fill
301 my ( $self, $action, $captures ) = @_;
303 return undef unless ($action->attributes->{Chained}
304 && !$action->attributes->{CaptureArgs});
307 my @captures = @$captures;
308 my $parent = "DUMMY";
311 if (my $cap = $curr->attributes->{CaptureArgs}) {
312 return undef unless @captures >= $cap->[0]; # not enough captures
314 unshift(@parts, splice(@captures, -$cap->[0]));
317 if (my $pp = $curr->attributes->{PartPath}) {
318 unshift(@parts, $pp->[0])
319 if (defined($pp->[0]) && length($pp->[0]));
321 $parent = $curr->attributes->{Chained}->[0];
322 $curr = $self->_actions->{$parent};
325 return undef unless $parent eq '/'; # fail for dangling action
327 return undef if @captures; # fail for too many captures
329 return join('/', '', @parts);
333 =head2 $c->expand_action($action)
335 Return a list of actions that represents a chained action. See
336 L<Catalyst::Dispatcher> for more info. You probably want to
337 use the expand_action it provides rather than this directly.
342 my ($self, $action) = @_;
344 return unless $action->attributes && $action->attributes->{Chained};
351 my $parent = $curr->attributes->{Chained}->[0];
352 $curr = $self->_actions->{$parent};
355 return Catalyst::ActionChain->from_chain([reverse @chain]);
358 __PACKAGE__->meta->make_immutable;
364 The C<Chained> attribute allows you to chain public path parts together
365 by their private names. A chain part's path can be specified with
366 C<PathPart> and can be declared to expect an arbitrary number of
367 arguments. The endpoint of the chain specifies how many arguments it
368 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
369 C<:Args> without an integer would be unlimited. The path parts that
370 aren't endpoints are using C<CaptureArgs> to specify how many parameters
371 they expect to receive. As an example setup:
373 package MyApp::Controller::Greeting;
374 use base qw/ Catalyst::Controller /;
376 # this is the beginning of our chain
377 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
378 my ( $self, $c, $integer ) = @_;
379 $c->stash->{ message } = "Hello ";
380 $c->stash->{ arg_sum } = $integer;
383 # this is our endpoint, because it has no :CaptureArgs
384 sub world : PathPart('world') Chained('hello') Args(1) {
385 my ( $self, $c, $integer ) = @_;
386 $c->stash->{ message } .= "World!";
387 $c->stash->{ arg_sum } += $integer;
389 $c->response->body( join "<br/>\n" =>
390 $c->stash->{ message }, $c->stash->{ arg_sum } );
393 The debug output provides a separate table for chained actions, showing
394 the whole chain as it would match and the actions it contains. Here's an
395 example of the startup output with our actions above:
398 [debug] Loaded Path Part actions:
399 .-----------------------+------------------------------.
400 | Path Spec | Private |
401 +-----------------------+------------------------------+
402 | /hello/*/world/* | /greeting/hello (1) |
403 | | => /greeting/world |
404 '-----------------------+------------------------------'
407 As you can see, Catalyst only deals with chains as whole paths and
408 builds one for each endpoint, which are the actions with C<:Chained> but
409 without C<:CaptureArgs>.
411 Let's assume this application gets a request at the path
412 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
413 to the C<hello> action and pass the value C<23> as an argument to it
414 after the context. It does so because we have previously used
415 C<:CaptureArgs(1)> to declare that it has one path part after itself as
416 its argument. We told Catalyst that this is the beginning of the chain
417 by specifying C<:Chained('/')>. Also note that instead of saying
418 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
419 defaults to the name of the action.
421 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
422 action. This is the last action to be called: Catalyst knows this is an
423 endpoint because we did not specify a C<:CaptureArgs>
424 attribute. Nevertheless we specify that this action expects an argument,
425 but at this point we're using C<:Args(1)> to do that. We could also have
426 said C<:Args> or left it out altogether, which would mean this action
427 would get all arguments that are there. This action's C<:Chained>
428 attribute says C<hello> and tells Catalyst that the C<hello> action in
429 the current controller is its parent.
431 With this we have built a chain consisting of two public path parts.
432 C<hello> captures one part of the path as its argument, and also
433 specifies the path root as its parent. So this part is
434 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
435 argument. It sums up to the path part C<world/$arg>. This leads to a
436 complete chain of C</hello/$arg/world/$arg> which is matched against the
439 This example application would, if run and called by e.g.
440 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
441 value C<arg_sum> to "23". The C<world> action would then append "World!"
442 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
443 sake of simplicity no view is shown. Instead we just put the values of
444 the stash into our body. So the output would look like:
449 And our test server would have given us this debugging output for the
453 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
454 [debug] Path is "/greeting/world"
455 [debug] Arguments are "12"
456 [info] Request took 0.164113s (6.093/s)
457 .------------------------------------------+-----------.
459 +------------------------------------------+-----------+
460 | /greeting/hello | 0.000029s |
461 | /greeting/world | 0.000024s |
462 '------------------------------------------+-----------'
465 What would be common uses of this dispatch technique? It gives the
466 possibility to split up logic that contains steps that each depend on
467 each other. An example would be, for example, a wiki path like
468 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
471 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
472 my ( $self, $c, $page_name ) = @_;
473 # load the page named $page_name and put the object
477 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
478 my ( $self, $c, $revision_id ) = @_;
479 # use the page object in the stash to get at its
480 # revision with number $revision_id
483 sub view : PathPart Chained('rev') Args(0) {
484 my ( $self, $c ) = @_;
485 # display the revision in our stash. Another option
486 # would be to forward a compatible object to the action
487 # that displays the default wiki pages, unless we want
488 # a different interface here, for example restore
492 It would now be possible to add other endpoints, for example C<restore>
493 to restore this specific revision as the current state.
495 You don't have to put all the chained actions in one controller. The
496 specification of the parent through C<:Chained> also takes an absolute
497 action path as its argument. Just specify it with a leading C</>.
499 If you want, for example, to have actions for the public paths
500 C</foo/12/edit> and C</foo/12>, just specify two actions with
501 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
502 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
503 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
504 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
505 this debugging output:
508 [debug] Loaded Path Part actions:
509 .-----------------------+------------------------------.
510 | Path Spec | Private |
511 +-----------------------+------------------------------+
512 | /foo/* | /controller/foo_view |
513 | /foo/*/edit | /controller/foo_load (1) |
514 | | => /controller/edit |
515 '-----------------------+------------------------------'
518 Here's a more detailed specification of the attributes belonging to
527 Sets the name of this part of the chain. If it is specified without
528 arguments, it takes the name of the action as default. So basically
529 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
530 This can also contain slashes to bind to a deeper level. An action
531 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
532 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
533 effect as using C<:PathPart>, it would default to the action name.
537 Sets PathPart to the path_prefix of the current controller.
541 Has to be specified for every child in the chain. Possible values are
542 absolute and relative private action paths or a single slash C</> to
543 tell Catalyst that this is the root of a chain. The attribute
544 C<:Chained> without arguments also defaults to the C</> behavior.
545 Relative action paths may use C<../> to refer to actions in parent
548 Because you can specify an absolute path to the parent action, it
549 doesn't matter to Catalyst where that parent is located. So, if your
550 design requests it, you can redispatch a chain through any controller or
553 Another interesting possibility gives C<:Chained('.')>, which chains
554 itself to an action with the path of the current controller's namespace.
557 # in MyApp::Controller::Foo
558 sub bar : Chained CaptureArgs(1) { ... }
560 # in MyApp::Controller::Foo::Bar
561 sub baz : Chained('.') Args(1) { ... }
563 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
564 as the argument to Chained here chains the C<baz> action to an action
565 with the path of the current controller namespace, namely
566 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
567 chain comes out as the end product.
571 Chains an action to another action with the same name in the parent
572 controller. For Example:
574 # in MyApp::Controller::Foo
575 sub bar : Chained CaptureArgs(1) { ... }
577 # in MyApp::Controller::Foo::Moo
578 sub bar : ChainedParent Args(1) { ... }
580 This builds a chain like C</bar/*/bar/*>.
584 Must be specified for every part of the chain that is not an
585 endpoint. With this attribute Catalyst knows how many of the following
586 parts of the path (separated by C</>) this action wants to capture as
587 its arguments. If it doesn't expect any, just specify
588 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
589 after the context, but you can also find them as array references in
590 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
591 level of the action in the chain that captured the parts of the path.
593 An action that is part of a chain (that is, one that has a C<:Chained>
594 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
599 By default, endpoints receive the rest of the arguments in the path. You
600 can tell Catalyst through C<:Args> explicitly how many arguments your
601 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
602 also affects whether this chain is invoked on a request. A chain with an
603 endpoint specifying one argument will only match if exactly one argument
606 You can specify an exact number of arguments like C<:Args(3)>, including
607 C<0>. If you just say C<:Args> without any arguments, it is the same as
608 leaving it out altogether: The chain is matched regardless of the number
609 of path parts after the endpoint.
611 Just as with C<:CaptureArgs>, the arguments get passed to the action in
612 C<@_> after the context object. They can also be reached through
613 C<$c-E<gt>request-E<gt>arguments>.
617 =head2 Auto actions, dispatching and forwarding
619 Note that the list of C<auto> actions called depends on the private path
620 of the endpoint of the chain, not on the chained actions way. The
621 C<auto> actions will be run before the chain dispatching begins. In
622 every other aspect, C<auto> actions behave as documented.
624 The C<forward>ing to other actions does just what you would expect. But if
625 you C<detach> out of a chain, the rest of the chain will not get called
630 Catalyst Contributors, see Catalyst.pm
634 This program is free software, you can redistribute it and/or modify it under
635 the same terms as Perl itself.