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 ENDPOINT: foreach my $endpoint (
75 sort { $a->reverse cmp $b->reverse }
76 @{ $self->_endpoints }
78 my $args = $endpoint->attributes->{Args}->[0];
79 my @parts = (defined($args) ? (("*") x $args) : '...');
84 if (my $cap = $curr->attributes->{CaptureArgs}) {
85 unshift(@parts, (("*") x $cap->[0]));
87 if (my $pp = $curr->attributes->{PartPath}) {
88 unshift(@parts, $pp->[0])
89 if (defined $pp->[0] && length $pp->[0]);
91 $parent = $curr->attributes->{Chained}->[0];
92 $curr = $self->_actions->{$parent};
93 unshift(@parents, $curr) if $curr;
95 next ENDPOINT unless $parent eq '/'; # skip dangling action
97 foreach my $p (@parents) {
99 if (my $cap = $p->attributes->{CaptureArgs}) {
100 $name .= ' ('.$cap->[0].')';
102 unless ($p eq $parents[0]) {
103 $name = "-> ${name}";
105 push(@rows, [ '', $name ]);
107 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
108 $rows[0][0] = join('/', '', @parts);
109 $paths->row(@$_) for @rows;
112 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
115 =head2 $self->match( $c, $path )
117 Calls C<recurse_match> to see if a chain matches the C<$path>.
122 my ( $self, $c, $path ) = @_;
124 my $request = $c->request;
125 return 0 if @{$request->args};
127 my @parts = split('/', $path);
129 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
130 push @{$request->args}, @$parts if $parts && @$parts;
132 return 0 unless $chain;
134 my $action = Catalyst::ActionChain->from_chain($chain);
136 $request->action("/${action}");
137 $request->match("/${action}");
138 $request->captures($captures);
140 $c->namespace( $action->namespace );
145 =head2 $self->recurse_match( $c, $parent, \@path_parts )
147 Recursive search for a matching chain.
152 my ( $self, $c, $parent, $path_parts ) = @_;
153 my $children = $self->_children_of->{$parent};
154 return () unless $children;
157 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
159 # $b then $a to try longest part first
160 my @parts = @$path_parts;
161 if (length $try_part) { # test and strip PathPart
163 ($try_part eq join('/', # assemble equal number of parts
164 splice( # and strip them off @parts as well
165 @parts, 0, scalar(@{[split('/', $try_part)]})
166 ))); # @{[]} to avoid split to @_
168 my @try_actions = @{$children->{$try_part}};
169 TRY_ACTION: foreach my $action (@try_actions) {
170 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
172 # Short-circuit if not enough remaining parts
173 next TRY_ACTION unless @parts >= $capture_attr->[0];
176 my @parts = @parts; # localise
178 # strip CaptureArgs into list
179 push(@captures, splice(@parts, 0, $capture_attr->[0]));
181 # try the remaining parts against children of this action
182 my ($actions, $captures, $action_parts) = $self->recurse_match(
183 $c, '/'.$action->reverse, \@parts
185 # No best action currently
186 # OR The action has less parts
187 # OR The action has equal parts but less captured data (ergo more defined)
190 $#$action_parts < $#{$best_action->{parts}} ||
191 ($#$action_parts == $#{$best_action->{parts}} &&
192 $#$captures < $#{$best_action->{captures}}))){
194 actions => [ $action, @$actions ],
195 captures=> [ @captures, @$captures ],
196 parts => $action_parts
202 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
203 next TRY_ACTION unless $action->match($c);
205 my $args_attr = $action->attributes->{Args}->[0];
207 # No best action currently
208 # OR This one matches with fewer parts left than the current best action,
209 # And therefore is a better match
210 # OR No parts and this expects 0
211 # The current best action might also be Args(0),
212 # but we couldn't chose between then anyway so we'll take the last seen
215 @parts < @{$best_action->{parts}} ||
216 (!@parts && $args_attr eq 0)){
218 actions => [ $action ],
226 return @$best_action{qw/actions captures parts/} if $best_action;
230 =head2 $self->register( $c, $action )
232 Calls register_path for every Path attribute for the given $action.
237 my ( $self, $c, $action ) = @_;
239 my @chained_attr = @{ $action->attributes->{Chained} || [] };
241 return 0 unless @chained_attr;
243 if (@chained_attr > 1) {
244 Catalyst::Exception->throw(
245 "Multiple Chained attributes not supported registering ${action}"
249 my $children = ($self->_children_of->{ $chained_attr[0] } ||= {});
251 my @path_part = @{ $action->attributes->{PathPart} || [] };
253 my $part = $action->name;
255 if (@path_part == 1 && defined $path_part[0]) {
256 $part = $path_part[0];
257 } elsif (@path_part > 1) {
258 Catalyst::Exception->throw(
259 "Multiple PathPart attributes not supported registering " . $action->reverse()
263 if ($part =~ m(^/)) {
264 Catalyst::Exception->throw(
265 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
269 $action->attributes->{PartPath} = [ $part ];
271 unshift(@{ $children->{$part} ||= [] }, $action);
273 $self->_actions->{'/'.$action->reverse} = $action;
275 unless ($action->attributes->{CaptureArgs}) {
276 unshift(@{ $self->_endpoints }, $action);
282 =head2 $self->uri_for_action($action, $captures)
284 Get the URI part for the action, using C<$captures> to fill
290 my ( $self, $action, $captures ) = @_;
292 return undef unless ($action->attributes->{Chained}
293 && !$action->attributes->{CaptureArgs});
296 my @captures = @$captures;
297 my $parent = "DUMMY";
300 if (my $cap = $curr->attributes->{CaptureArgs}) {
301 return undef unless @captures >= $cap->[0]; # not enough captures
303 unshift(@parts, splice(@captures, -$cap->[0]));
306 if (my $pp = $curr->attributes->{PartPath}) {
307 unshift(@parts, $pp->[0])
308 if (defined($pp->[0]) && length($pp->[0]));
310 $parent = $curr->attributes->{Chained}->[0];
311 $curr = $self->_actions->{$parent};
314 return undef unless $parent eq '/'; # fail for dangling action
316 return undef if @captures; # fail for too many captures
318 return join('/', '', @parts);
322 __PACKAGE__->meta->make_immutable;
328 The C<Chained> attribute allows you to chain public path parts together
329 by their private names. A chain part's path can be specified with
330 C<PathPart> and can be declared to expect an arbitrary number of
331 arguments. The endpoint of the chain specifies how many arguments it
332 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
333 C<:Args> without an integer would be unlimited. The path parts that
334 aren't endpoints are using C<CaptureArgs> to specify how many parameters
335 they expect to receive. As an example setup:
337 package MyApp::Controller::Greeting;
338 use base qw/ Catalyst::Controller /;
340 # this is the beginning of our chain
341 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
342 my ( $self, $c, $integer ) = @_;
343 $c->stash->{ message } = "Hello ";
344 $c->stash->{ arg_sum } = $integer;
347 # this is our endpoint, because it has no :CaptureArgs
348 sub world : PathPart('world') Chained('hello') Args(1) {
349 my ( $self, $c, $integer ) = @_;
350 $c->stash->{ message } .= "World!";
351 $c->stash->{ arg_sum } += $integer;
353 $c->response->body( join "<br/>\n" =>
354 $c->stash->{ message }, $c->stash->{ arg_sum } );
357 The debug output provides a separate table for chained actions, showing
358 the whole chain as it would match and the actions it contains. Here's an
359 example of the startup output with our actions above:
362 [debug] Loaded Path Part actions:
363 .-----------------------+------------------------------.
364 | Path Spec | Private |
365 +-----------------------+------------------------------+
366 | /hello/*/world/* | /greeting/hello (1) |
367 | | => /greeting/world |
368 '-----------------------+------------------------------'
371 As you can see, Catalyst only deals with chains as whole paths and
372 builds one for each endpoint, which are the actions with C<:Chained> but
373 without C<:CaptureArgs>.
375 Let's assume this application gets a request at the path
376 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
377 to the C<hello> action and pass the value C<23> as an argument to it
378 after the context. It does so because we have previously used
379 C<:CaptureArgs(1)> to declare that it has one path part after itself as
380 its argument. We told Catalyst that this is the beginning of the chain
381 by specifying C<:Chained('/')>. Also note that instead of saying
382 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
383 defaults to the name of the action.
385 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
386 action. This is the last action to be called: Catalyst knows this is an
387 endpoint because we did not specify a C<:CaptureArgs>
388 attribute. Nevertheless we specify that this action expects an argument,
389 but at this point we're using C<:Args(1)> to do that. We could also have
390 said C<:Args> or left it out altogether, which would mean this action
391 would get all arguments that are there. This action's C<:Chained>
392 attribute says C<hello> and tells Catalyst that the C<hello> action in
393 the current controller is its parent.
395 With this we have built a chain consisting of two public path parts.
396 C<hello> captures one part of the path as its argument, and also
397 specifies the path root as its parent. So this part is
398 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
399 argument. It sums up to the path part C<world/$arg>. This leads to a
400 complete chain of C</hello/$arg/world/$arg> which is matched against the
403 This example application would, if run and called by e.g.
404 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
405 value C<arg_sum> to "23". The C<world> action would then append "World!"
406 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
407 sake of simplicity no view is shown. Instead we just put the values of
408 the stash into our body. So the output would look like:
413 And our test server would have given us this debugging output for the
417 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
418 [debug] Path is "/greeting/world"
419 [debug] Arguments are "12"
420 [info] Request took 0.164113s (6.093/s)
421 .------------------------------------------+-----------.
423 +------------------------------------------+-----------+
424 | /greeting/hello | 0.000029s |
425 | /greeting/world | 0.000024s |
426 '------------------------------------------+-----------'
429 What would be common uses of this dispatch technique? It gives the
430 possibility to split up logic that contains steps that each depend on
431 each other. An example would be, for example, a wiki path like
432 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
435 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
436 my ( $self, $c, $page_name ) = @_;
437 # load the page named $page_name and put the object
441 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
442 my ( $self, $c, $revision_id ) = @_;
443 # use the page object in the stash to get at its
444 # revision with number $revision_id
447 sub view : PathPart Chained('rev') Args(0) {
448 my ( $self, $c ) = @_;
449 # display the revision in our stash. Another option
450 # would be to forward a compatible object to the action
451 # that displays the default wiki pages, unless we want
452 # a different interface here, for example restore
456 It would now be possible to add other endpoints, for example C<restore>
457 to restore this specific revision as the current state.
459 You don't have to put all the chained actions in one controller. The
460 specification of the parent through C<:Chained> also takes an absolute
461 action path as its argument. Just specify it with a leading C</>.
463 If you want, for example, to have actions for the public paths
464 C</foo/12/edit> and C</foo/12>, just specify two actions with
465 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
466 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
467 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
468 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
469 this debugging output:
472 [debug] Loaded Path Part actions:
473 .-----------------------+------------------------------.
474 | Path Spec | Private |
475 +-----------------------+------------------------------+
476 | /foo/* | /controller/foo_view |
477 | /foo/*/edit | /controller/foo_load (1) |
478 | | => /controller/edit |
479 '-----------------------+------------------------------'
482 Here's a more detailed specification of the attributes belonging to
491 Sets the name of this part of the chain. If it is specified without
492 arguments, it takes the name of the action as default. So basically
493 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
494 This can also contain slashes to bind to a deeper level. An action
495 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
496 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
497 effect as using C<:PathPart>, it would default to the action name.
501 Sets PathPart to the path_prefix of the current controller.
505 Has to be specified for every child in the chain. Possible values are
506 absolute and relative private action paths or a single slash C</> to
507 tell Catalyst that this is the root of a chain. The attribute
508 C<:Chained> without arguments also defaults to the C</> behavior.
509 Relative action paths may use C<../> to refer to actions in parent
512 Because you can specify an absolute path to the parent action, it
513 doesn't matter to Catalyst where that parent is located. So, if your
514 design requests it, you can redispatch a chain through any controller or
517 Another interesting possibility gives C<:Chained('.')>, which chains
518 itself to an action with the path of the current controller's namespace.
521 # in MyApp::Controller::Foo
522 sub bar : Chained CaptureArgs(1) { ... }
524 # in MyApp::Controller::Foo::Bar
525 sub baz : Chained('.') Args(1) { ... }
527 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
528 as the argument to Chained here chains the C<baz> action to an action
529 with the path of the current controller namespace, namely
530 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
531 chain comes out as the end product.
535 Chains an action to another action with the same name in the parent
536 controller. For Example:
538 # in MyApp::Controller::Foo
539 sub bar : Chained CaptureArgs(1) { ... }
541 # in MyApp::Controller::Foo::Moo
542 sub bar : ChainedParent Args(1) { ... }
544 This builds a chain like C</bar/*/bar/*>.
548 Must be specified for every part of the chain that is not an
549 endpoint. With this attribute Catalyst knows how many of the following
550 parts of the path (separated by C</>) this action wants to capture as
551 its arguments. If it doesn't expect any, just specify
552 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
553 after the context, but you can also find them as array references in
554 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
555 level of the action in the chain that captured the parts of the path.
557 An action that is part of a chain (that is, one that has a C<:Chained>
558 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
563 By default, endpoints receive the rest of the arguments in the path. You
564 can tell Catalyst through C<:Args> explicitly how many arguments your
565 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
566 also affects whether this chain is invoked on a request. A chain with an
567 endpoint specifying one argument will only match if exactly one argument
570 You can specify an exact number of arguments like C<:Args(3)>, including
571 C<0>. If you just say C<:Args> without any arguments, it is the same as
572 leaving it out altogether: The chain is matched regardless of the number
573 of path parts after the endpoint.
575 Just as with C<:CaptureArgs>, the arguments get passed to the action in
576 C<@_> after the context object. They can also be reached through
577 C<$c-E<gt>request-E<gt>arguments>.
581 =head2 Auto actions, dispatching and forwarding
583 Note that the list of C<auto> actions called depends on the private path
584 of the endpoint of the chain, not on the chained actions way. The
585 C<auto> actions will be run before the chain dispatching begins. In
586 every other aspect, C<auto> actions behave as documented.
588 The C<forward>ing to other actions does just what you would expect. But if
589 you C<detach> out of a chain, the rest of the chain will not get called
594 Catalyst Contributors, see Catalyst.pm
598 This program is free software, you can redistribute it and/or modify it under
599 the same terms as Perl itself.