1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
34 # please don't perltidy this. hairy code within.
38 Catalyst::DispatchType::Chained - Path Part DispatchType
42 # root action - captures one argument after it
43 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
44 my ( $self, $c, $foo_arg ) = @_;
48 # child action endpoint - takes one argument
49 sub bar : Chained('foo_setup') Args(1) {
50 my ( $self, $c, $bar_arg ) = @_;
60 =head2 $self->list($c)
62 Debug output for Path Part dispatch points
67 my ( $self, $c ) = @_;
69 return unless $self->_endpoints;
71 my $column_width = Catalyst::Utils::term_width() - 35 - 9;
72 my $paths = Text::SimpleTable->new(
73 [ 35, 'Path Spec' ], [ $column_width, 'Private' ],
76 my $has_unattached_actions;
77 my $unattached_actions = Text::SimpleTable->new(
78 [ 35, 'Private' ], [ 36, 'Missing parent' ],
81 ENDPOINT: foreach my $endpoint (
82 sort { $a->reverse cmp $b->reverse }
83 @{ $self->_endpoints }
85 my $args = $endpoint->attributes->{Args}->[0];
86 my @parts = (defined($args) ? (("*") x $args) : '...');
91 if (my $cap = $curr->attributes->{CaptureArgs}) {
92 unshift(@parts, (("*") x $cap->[0]));
94 if (my $pp = $curr->attributes->{PartPath}) {
95 unshift(@parts, $pp->[0])
96 if (defined $pp->[0] && length $pp->[0]);
98 $parent = $curr->attributes->{Chained}->[0];
99 $curr = $self->_actions->{$parent};
100 unshift(@parents, $curr) if $curr;
102 if ($parent ne '/') {
103 $has_unattached_actions = 1;
104 $unattached_actions->row('/'.$parents[0]->reverse, $parent);
108 foreach my $p (@parents) {
110 if (my $cap = $p->attributes->{CaptureArgs}) {
111 $name .= ' ('.$cap->[0].')';
113 unless ($p eq $parents[0]) {
114 $name = "-> ${name}";
116 push(@rows, [ '', $name ]);
118 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
119 $rows[0][0] = join('/', '', @parts);
120 $paths->row(@$_) for @rows;
123 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
124 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
125 if $has_unattached_actions;
128 =head2 $self->match( $c, $path )
130 Calls C<recurse_match> to see if a chain matches the C<$path>.
135 my ( $self, $c, $path ) = @_;
137 my $request = $c->request;
138 return 0 if @{$request->args};
140 my @parts = split('/', $path);
142 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
143 push @{$request->args}, @$parts if $parts && @$parts;
145 return 0 unless $chain;
147 my $action = Catalyst::ActionChain->from_chain($chain);
149 $request->action("/${action}");
150 $request->match("/${action}");
151 $request->captures($captures);
153 $c->namespace( $action->namespace );
158 =head2 $self->recurse_match( $c, $parent, \@path_parts )
160 Recursive search for a matching chain.
165 my ( $self, $c, $parent, $path_parts ) = @_;
166 my $children = $self->_children_of->{$parent};
167 return () unless $children;
170 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
172 # $b then $a to try longest part first
173 my @parts = @$path_parts;
174 if (length $try_part) { # test and strip PathPart
176 ($try_part eq join('/', # assemble equal number of parts
177 splice( # and strip them off @parts as well
178 @parts, 0, scalar(@{[split('/', $try_part)]})
179 ))); # @{[]} to avoid split to @_
181 my @try_actions = @{$children->{$try_part}};
182 TRY_ACTION: foreach my $action (@try_actions) {
183 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
185 # Short-circuit if not enough remaining parts
186 next TRY_ACTION unless @parts >= $capture_attr->[0];
189 my @parts = @parts; # localise
191 # strip CaptureArgs into list
192 push(@captures, splice(@parts, 0, $capture_attr->[0]));
194 # try the remaining parts against children of this action
195 my ($actions, $captures, $action_parts) = $self->recurse_match(
196 $c, '/'.$action->reverse, \@parts
198 # No best action currently
199 # OR The action has less parts
200 # OR The action has equal parts but less captured data (ergo more defined)
203 $#$action_parts < $#{$best_action->{parts}} ||
204 ($#$action_parts == $#{$best_action->{parts}} &&
205 $#$captures < $#{$best_action->{captures}}))){
207 actions => [ $action, @$actions ],
208 captures=> [ @captures, @$captures ],
209 parts => $action_parts
215 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
216 next TRY_ACTION unless $action->match($c);
218 my $args_attr = $action->attributes->{Args}->[0];
220 # No best action currently
221 # OR This one matches with fewer parts left than the current best action,
222 # And therefore is a better match
223 # OR No parts and this expects 0
224 # The current best action might also be Args(0),
225 # but we couldn't chose between then anyway so we'll take the last seen
228 @parts < @{$best_action->{parts}} ||
229 (!@parts && $args_attr eq 0)){
231 actions => [ $action ],
239 return @$best_action{qw/actions captures parts/} if $best_action;
243 =head2 $self->register( $c, $action )
245 Calls register_path for every Path attribute for the given $action.
250 my ( $self, $c, $action ) = @_;
252 my @chained_attr = @{ $action->attributes->{Chained} || [] };
254 return 0 unless @chained_attr;
256 if (@chained_attr > 1) {
257 Catalyst::Exception->throw(
258 "Multiple Chained attributes not supported registering ${action}"
262 my $children = ($self->_children_of->{ $chained_attr[0] } ||= {});
264 my @path_part = @{ $action->attributes->{PathPart} || [] };
266 my $part = $action->name;
268 if (@path_part == 1 && defined $path_part[0]) {
269 $part = $path_part[0];
270 } elsif (@path_part > 1) {
271 Catalyst::Exception->throw(
272 "Multiple PathPart attributes not supported registering " . $action->reverse()
276 if ($part =~ m(^/)) {
277 Catalyst::Exception->throw(
278 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
282 $action->attributes->{PartPath} = [ $part ];
284 unshift(@{ $children->{$part} ||= [] }, $action);
286 $self->_actions->{'/'.$action->reverse} = $action;
288 unless ($action->attributes->{CaptureArgs}) {
289 unshift(@{ $self->_endpoints }, $action);
295 =head2 $self->uri_for_action($action, $captures)
297 Get the URI part for the action, using C<$captures> to fill
303 my ( $self, $action, $captures ) = @_;
305 return undef unless ($action->attributes->{Chained}
306 && !$action->attributes->{CaptureArgs});
309 my @captures = @$captures;
310 my $parent = "DUMMY";
313 if (my $cap = $curr->attributes->{CaptureArgs}) {
314 return undef unless @captures >= $cap->[0]; # not enough captures
316 unshift(@parts, splice(@captures, -$cap->[0]));
319 if (my $pp = $curr->attributes->{PartPath}) {
320 unshift(@parts, $pp->[0])
321 if (defined($pp->[0]) && length($pp->[0]));
323 $parent = $curr->attributes->{Chained}->[0];
324 $curr = $self->_actions->{$parent};
327 return undef unless $parent eq '/'; # fail for dangling action
329 return undef if @captures; # fail for too many captures
331 return join('/', '', @parts);
335 =head2 $c->expand_action($action)
337 Return a list of actions that represents a chained action. See
338 L<Catalyst::Dispatcher> for more info. You probably want to
339 use the expand_action it provides rather than this directly.
344 my ($self, $action) = @_;
346 return unless $action->attributes && $action->attributes->{Chained};
353 my $parent = $curr->attributes->{Chained}->[0];
354 $curr = $self->_actions->{$parent};
357 return Catalyst::ActionChain->from_chain([reverse @chain]);
360 __PACKAGE__->meta->make_immutable;
366 The C<Chained> attribute allows you to chain public path parts together
367 by their private names. A chain part's path can be specified with
368 C<PathPart> and can be declared to expect an arbitrary number of
369 arguments. The endpoint of the chain specifies how many arguments it
370 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
371 C<:Args> without an integer would be unlimited. The path parts that
372 aren't endpoints are using C<CaptureArgs> to specify how many parameters
373 they expect to receive. As an example setup:
375 package MyApp::Controller::Greeting;
376 use base qw/ Catalyst::Controller /;
378 # this is the beginning of our chain
379 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
380 my ( $self, $c, $integer ) = @_;
381 $c->stash->{ message } = "Hello ";
382 $c->stash->{ arg_sum } = $integer;
385 # this is our endpoint, because it has no :CaptureArgs
386 sub world : PathPart('world') Chained('hello') Args(1) {
387 my ( $self, $c, $integer ) = @_;
388 $c->stash->{ message } .= "World!";
389 $c->stash->{ arg_sum } += $integer;
391 $c->response->body( join "<br/>\n" =>
392 $c->stash->{ message }, $c->stash->{ arg_sum } );
395 The debug output provides a separate table for chained actions, showing
396 the whole chain as it would match and the actions it contains. Here's an
397 example of the startup output with our actions above:
400 [debug] Loaded Path Part actions:
401 .-----------------------+------------------------------.
402 | Path Spec | Private |
403 +-----------------------+------------------------------+
404 | /hello/*/world/* | /greeting/hello (1) |
405 | | => /greeting/world |
406 '-----------------------+------------------------------'
409 As you can see, Catalyst only deals with chains as whole paths and
410 builds one for each endpoint, which are the actions with C<:Chained> but
411 without C<:CaptureArgs>.
413 Let's assume this application gets a request at the path
414 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
415 to the C<hello> action and pass the value C<23> as an argument to it
416 after the context. It does so because we have previously used
417 C<:CaptureArgs(1)> to declare that it has one path part after itself as
418 its argument. We told Catalyst that this is the beginning of the chain
419 by specifying C<:Chained('/')>. Also note that instead of saying
420 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
421 defaults to the name of the action.
423 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
424 action. This is the last action to be called: Catalyst knows this is an
425 endpoint because we did not specify a C<:CaptureArgs>
426 attribute. Nevertheless we specify that this action expects an argument,
427 but at this point we're using C<:Args(1)> to do that. We could also have
428 said C<:Args> or left it out altogether, which would mean this action
429 would get all arguments that are there. This action's C<:Chained>
430 attribute says C<hello> and tells Catalyst that the C<hello> action in
431 the current controller is its parent.
433 With this we have built a chain consisting of two public path parts.
434 C<hello> captures one part of the path as its argument, and also
435 specifies the path root as its parent. So this part is
436 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
437 argument. It sums up to the path part C<world/$arg>. This leads to a
438 complete chain of C</hello/$arg/world/$arg> which is matched against the
441 This example application would, if run and called by e.g.
442 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
443 value C<arg_sum> to "23". The C<world> action would then append "World!"
444 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
445 sake of simplicity no view is shown. Instead we just put the values of
446 the stash into our body. So the output would look like:
451 And our test server would have given us this debugging output for the
455 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
456 [debug] Path is "/greeting/world"
457 [debug] Arguments are "12"
458 [info] Request took 0.164113s (6.093/s)
459 .------------------------------------------+-----------.
461 +------------------------------------------+-----------+
462 | /greeting/hello | 0.000029s |
463 | /greeting/world | 0.000024s |
464 '------------------------------------------+-----------'
467 What would be common uses of this dispatch technique? It gives the
468 possibility to split up logic that contains steps that each depend on
469 each other. An example would be, for example, a wiki path like
470 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
473 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
474 my ( $self, $c, $page_name ) = @_;
475 # load the page named $page_name and put the object
479 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
480 my ( $self, $c, $revision_id ) = @_;
481 # use the page object in the stash to get at its
482 # revision with number $revision_id
485 sub view : PathPart Chained('rev') Args(0) {
486 my ( $self, $c ) = @_;
487 # display the revision in our stash. Another option
488 # would be to forward a compatible object to the action
489 # that displays the default wiki pages, unless we want
490 # a different interface here, for example restore
494 It would now be possible to add other endpoints, for example C<restore>
495 to restore this specific revision as the current state.
497 You don't have to put all the chained actions in one controller. The
498 specification of the parent through C<:Chained> also takes an absolute
499 action path as its argument. Just specify it with a leading C</>.
501 If you want, for example, to have actions for the public paths
502 C</foo/12/edit> and C</foo/12>, just specify two actions with
503 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
504 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
505 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
506 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
507 this debugging output:
510 [debug] Loaded Path Part actions:
511 .-----------------------+------------------------------.
512 | Path Spec | Private |
513 +-----------------------+------------------------------+
514 | /foo/* | /controller/foo_view |
515 | /foo/*/edit | /controller/foo_load (1) |
516 | | => /controller/edit |
517 '-----------------------+------------------------------'
520 Here's a more detailed specification of the attributes belonging to
529 Sets the name of this part of the chain. If it is specified without
530 arguments, it takes the name of the action as default. So basically
531 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
532 This can also contain slashes to bind to a deeper level. An action
533 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
534 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
535 effect as using C<:PathPart>, it would default to the action name.
539 Sets PathPart to the path_prefix of the current controller.
543 Has to be specified for every child in the chain. Possible values are
544 absolute and relative private action paths or a single slash C</> to
545 tell Catalyst that this is the root of a chain. The attribute
546 C<:Chained> without arguments also defaults to the C</> behavior.
547 Relative action paths may use C<../> to refer to actions in parent
550 Because you can specify an absolute path to the parent action, it
551 doesn't matter to Catalyst where that parent is located. So, if your
552 design requests it, you can redispatch a chain through any controller or
555 Another interesting possibility gives C<:Chained('.')>, which chains
556 itself to an action with the path of the current controller's namespace.
559 # in MyApp::Controller::Foo
560 sub bar : Chained CaptureArgs(1) { ... }
562 # in MyApp::Controller::Foo::Bar
563 sub baz : Chained('.') Args(1) { ... }
565 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
566 as the argument to Chained here chains the C<baz> action to an action
567 with the path of the current controller namespace, namely
568 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
569 chain comes out as the end product.
573 Chains an action to another action with the same name in the parent
574 controller. For Example:
576 # in MyApp::Controller::Foo
577 sub bar : Chained CaptureArgs(1) { ... }
579 # in MyApp::Controller::Foo::Moo
580 sub bar : ChainedParent Args(1) { ... }
582 This builds a chain like C</bar/*/bar/*>.
586 Must be specified for every part of the chain that is not an
587 endpoint. With this attribute Catalyst knows how many of the following
588 parts of the path (separated by C</>) this action wants to capture as
589 its arguments. If it doesn't expect any, just specify
590 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
591 after the context, but you can also find them as array references in
592 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
593 level of the action in the chain that captured the parts of the path.
595 An action that is part of a chain (that is, one that has a C<:Chained>
596 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
601 By default, endpoints receive the rest of the arguments in the path. You
602 can tell Catalyst through C<:Args> explicitly how many arguments your
603 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
604 also affects whether this chain is invoked on a request. A chain with an
605 endpoint specifying one argument will only match if exactly one argument
608 You can specify an exact number of arguments like C<:Args(3)>, including
609 C<0>. If you just say C<:Args> without any arguments, it is the same as
610 leaving it out altogether: The chain is matched regardless of the number
611 of path parts after the endpoint.
613 Just as with C<:CaptureArgs>, the arguments get passed to the action in
614 C<@_> after the context object. They can also be reached through
615 C<$c-E<gt>request-E<gt>arguments>.
619 =head2 Auto actions, dispatching and forwarding
621 Note that the list of C<auto> actions called depends on the private path
622 of the endpoint of the chain, not on the chained actions way. The
623 C<auto> actions will be run before the chain dispatching begins. In
624 every other aspect, C<auto> actions behave as documented.
626 The C<forward>ing to other actions does just what you would expect. But if
627 you C<detach> out of a chain, the rest of the chain will not get called
632 Catalyst Contributors, see Catalyst.pm
636 This program is free software, you can redistribute it and/or modify it under
637 the same terms as Perl itself.