1 package Catalyst::DispatchType::Chained;
4 use base qw/Catalyst::DispatchType/;
6 use Catalyst::ActionChain;
9 # please don't perltidy this. hairy code within.
13 Catalyst::DispatchType::Chained - Path Part DispatchType
17 # root action - captures one argument after it
18 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
19 my ( $self, $c, $foo_arg ) = @_;
23 # child action endpoint - takes one argument
24 sub bar : Chained('foo_setup') Args(1) {
25 my ( $self, $c, $bar_arg ) = @_;
35 =head2 $self->list($c)
37 Debug output for Path Part dispatch points
42 my ( $self, $c ) = @_;
44 return unless $self->{endpoints};
46 my $paths = Text::SimpleTable->new(
47 [ 35, 'Path Spec' ], [ 36, 'Private' ]
50 ENDPOINT: foreach my $endpoint (
51 sort { $a->reverse cmp $b->reverse }
52 @{ $self->{endpoints} }
54 my $args = $endpoint->attributes->{Args}->[0];
55 my @parts = (defined($args) ? (("*") x $args) : '...');
60 if (my $cap = $curr->attributes->{CaptureArgs}) {
61 unshift(@parts, (("*") x $cap->[0]));
63 if (my $pp = $curr->attributes->{PartPath}) {
64 unshift(@parts, $pp->[0])
65 if (defined $pp->[0] && length $pp->[0]);
67 $parent = $curr->attributes->{Chained}->[0];
68 $curr = $self->{actions}{$parent};
69 unshift(@parents, $curr) if $curr;
71 next ENDPOINT unless $parent eq '/'; # skip dangling action
73 foreach my $p (@parents) {
75 if (my $cap = $p->attributes->{CaptureArgs}) {
76 $name .= ' ('.$cap->[0].')';
78 unless ($p eq $parents[0]) {
81 push(@rows, [ '', $name ]);
83 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
84 $rows[0][0] = join('/', '', @parts);
85 $paths->row(@$_) for @rows;
88 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
91 =head2 $self->match( $c, $path )
93 Calls C<recurse_match> to see if a chain matches the C<$path>.
98 my ( $self, $c, $path ) = @_;
100 return 0 if @{$c->req->args};
102 my @parts = split('/', $path);
104 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
105 push @{$c->req->args}, @$parts if $parts && @$parts;
107 return 0 unless $chain;
109 my $action = Catalyst::ActionChain->from_chain($chain);
111 $c->req->action("/${action}");
112 $c->req->match("/${action}");
113 $c->req->captures($captures);
115 $c->namespace( $action->namespace );
120 =head2 $self->recurse_match( $c, $parent, \@path_parts )
122 Recursive search for a matching chain.
127 my ( $self, $c, $parent, $path_parts ) = @_;
128 my $children = $self->{children_of}{$parent};
129 return () unless $children;
132 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
134 # $b then $a to try longest part first
135 my @parts = @$path_parts;
136 if (length $try_part) { # test and strip PathPart
138 ($try_part eq join('/', # assemble equal number of parts
139 splice( # and strip them off @parts as well
140 @parts, 0, scalar(@{[split('/', $try_part)]})
141 ))); # @{[]} to avoid split to @_
143 my @try_actions = @{$children->{$try_part}};
144 TRY_ACTION: foreach my $action (@try_actions) {
145 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
147 # Short-circuit if not enough remaining parts
148 next TRY_ACTION unless @parts >= $capture_attr->[0];
151 my @parts = @parts; # localise
153 # strip CaptureArgs into list
154 push(@captures, splice(@parts, 0, $capture_attr->[0]));
156 # try the remaining parts against children of this action
157 my ($actions, $captures, $action_parts) = $self->recurse_match(
158 $c, '/'.$action->reverse, \@parts
160 # No best action currently
161 # OR The action has less parts
162 # OR The action has equal parts but less captured data (ergo more defined)
165 $#$action_parts < $#{$best_action->{parts}} ||
166 ($#$action_parts == $#{$best_action->{parts}} &&
167 $#$captures < $#{$best_action->{captures}}))){
169 actions => [ $action, @$actions ],
170 captures=> [ @captures, @$captures ],
171 parts => $action_parts
177 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
178 next TRY_ACTION unless $action->match($c);
180 my $args_attr = $action->attributes->{Args}->[0];
182 # No best action currently
183 # OR This one matches with fewer parts left than the current best action,
184 # And therefore is a better match
185 # OR No parts and this expects 0
186 # The current best action might also be Args(0),
187 # but we couldn't chose between then anyway so we'll take the last seen
190 @parts < @{$best_action->{parts}} ||
191 (!@parts && $args_attr eq 0)){
193 actions => [ $action ],
201 return @$best_action{qw/actions captures parts/} if $best_action;
205 =head2 $self->register( $c, $action )
207 Calls register_path for every Path attribute for the given $action.
212 my ( $self, $c, $action ) = @_;
214 my @chained_attr = @{ $action->attributes->{Chained} || [] };
216 return 0 unless @chained_attr;
218 if (@chained_attr > 1) {
219 Catalyst::Exception->throw(
220 "Multiple Chained attributes not supported registering ${action}"
224 my $children = ($self->{children_of}{ $chained_attr[0] } ||= {});
226 my @path_part = @{ $action->attributes->{PathPart} || [] };
228 my $part = $action->name;
230 if (@path_part == 1 && defined $path_part[0]) {
231 $part = $path_part[0];
232 } elsif (@path_part > 1) {
233 Catalyst::Exception->throw(
234 "Multiple PathPart attributes not supported registering ${action}"
238 if ($part =~ m(^/)) {
239 Catalyst::Exception->throw(
240 "Absolute parameters to PathPart not allowed registering ${action}"
244 $action->attributes->{PartPath} = [ $part ];
246 unshift(@{ $children->{$part} ||= [] }, $action);
248 ($self->{actions} ||= {})->{'/'.$action->reverse} = $action;
250 unless ($action->attributes->{CaptureArgs}) {
251 unshift(@{ $self->{endpoints} ||= [] }, $action);
257 =head2 $self->uri_for_action($action, $captures)
259 Get the URI part for the action, using C<$captures> to fill
265 my ( $self, $action, $captures ) = @_;
267 return undef unless ($action->attributes->{Chained}
268 && !$action->attributes->{CaptureArgs});
271 my @captures = @$captures;
272 my $parent = "DUMMY";
275 if (my $cap = $curr->attributes->{CaptureArgs}) {
276 return undef unless @captures >= $cap->[0]; # not enough captures
278 unshift(@parts, splice(@captures, -$cap->[0]));
281 if (my $pp = $curr->attributes->{PartPath}) {
282 unshift(@parts, $pp->[0])
283 if (defined($pp->[0]) && length($pp->[0]));
285 $parent = $curr->attributes->{Chained}->[0];
286 $curr = $self->{actions}{$parent};
289 return undef unless $parent eq '/'; # fail for dangling action
291 return undef if @captures; # fail for too many captures
293 return join('/', '', @parts);
297 =head2 $c->expand_action($action)
299 Return a list of actions that represents a chained action. See
300 L<Catalyst::Dispatcher> for more info. You probably want to
301 use the expand_action it provides rather than this directly.
306 my ($self, $action) = @_;
308 return unless $action->attributes && $action->attributes->{Chained};
315 my $parent = $curr->attributes->{Chained}->[0];
316 $curr = $self->{'actions'}{$parent};
319 return Catalyst::ActionChain->from_chain([reverse @chain]);
326 The C<Chained> attribute allows you to chain public path parts together
327 by their private names. A chain part's path can be specified with
328 C<PathPart> and can be declared to expect an arbitrary number of
329 arguments. The endpoint of the chain specifies how many arguments it
330 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
331 C<:Args> without an integer would be unlimited. The path parts that
332 aren't endpoints are using C<CaptureArgs> to specify how many parameters
333 they expect to receive. As an example setup:
335 package MyApp::Controller::Greeting;
336 use base qw/ Catalyst::Controller /;
338 # this is the beginning of our chain
339 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
340 my ( $self, $c, $integer ) = @_;
341 $c->stash->{ message } = "Hello ";
342 $c->stash->{ arg_sum } = $integer;
345 # this is our endpoint, because it has no :CaptureArgs
346 sub world : PathPart('world') Chained('hello') Args(1) {
347 my ( $self, $c, $integer ) = @_;
348 $c->stash->{ message } .= "World!";
349 $c->stash->{ arg_sum } += $integer;
351 $c->response->body( join "<br/>\n" =>
352 $c->stash->{ message }, $c->stash->{ arg_sum } );
355 The debug output provides a separate table for chained actions, showing
356 the whole chain as it would match and the actions it contains. Here's an
357 example of the startup output with our actions above:
360 [debug] Loaded Path Part actions:
361 .-----------------------+------------------------------.
362 | Path Spec | Private |
363 +-----------------------+------------------------------+
364 | /hello/*/world/* | /greeting/hello (1) |
365 | | => /greeting/world |
366 '-----------------------+------------------------------'
369 As you can see, Catalyst only deals with chains as whole paths and
370 builds one for each endpoint, which are the actions with C<:Chained> but
371 without C<:CaptureArgs>.
373 Let's assume this application gets a request at the path
374 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
375 to the C<hello> action and pass the value C<23> as an argument to it
376 after the context. It does so because we have previously used
377 C<:CaptureArgs(1)> to declare that it has one path part after itself as
378 its argument. We told Catalyst that this is the beginning of the chain
379 by specifying C<:Chained('/')>. Also note that instead of saying
380 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
381 defaults to the name of the action.
383 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
384 action. This is the last action to be called: Catalyst knows this is an
385 endpoint because we did not specify a C<:CaptureArgs>
386 attribute. Nevertheless we specify that this action expects an argument,
387 but at this point we're using C<:Args(1)> to do that. We could also have
388 said C<:Args> or left it out altogether, which would mean this action
389 would get all arguments that are there. This action's C<:Chained>
390 attribute says C<hello> and tells Catalyst that the C<hello> action in
391 the current controller is its parent.
393 With this we have built a chain consisting of two public path parts.
394 C<hello> captures one part of the path as its argument, and also
395 specifies the path root as its parent. So this part is
396 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
397 argument. It sums up to the path part C<world/$arg>. This leads to a
398 complete chain of C</hello/$arg/world/$arg> which is matched against the
401 This example application would, if run and called by e.g.
402 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
403 value C<arg_sum> to "23". The C<world> action would then append "World!"
404 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
405 sake of simplicity no view is shown. Instead we just put the values of
406 the stash into our body. So the output would look like:
411 And our test server would have given us this debugging output for the
415 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
416 [debug] Path is "/greeting/world"
417 [debug] Arguments are "12"
418 [info] Request took 0.164113s (6.093/s)
419 .------------------------------------------+-----------.
421 +------------------------------------------+-----------+
422 | /greeting/hello | 0.000029s |
423 | /greeting/world | 0.000024s |
424 '------------------------------------------+-----------'
427 What would be common uses of this dispatch technique? It gives the
428 possibility to split up logic that contains steps that each depend on
429 each other. An example would be, for example, a wiki path like
430 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
433 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
434 my ( $self, $c, $page_name ) = @_;
435 # load the page named $page_name and put the object
439 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
440 my ( $self, $c, $revision_id ) = @_;
441 # use the page object in the stash to get at its
442 # revision with number $revision_id
445 sub view : PathPart Chained('rev') Args(0) {
446 my ( $self, $c ) = @_;
447 # display the revision in our stash. Another option
448 # would be to forward a compatible object to the action
449 # that displays the default wiki pages, unless we want
450 # a different interface here, for example restore
454 It would now be possible to add other endpoints, for example C<restore>
455 to restore this specific revision as the current state.
457 You don't have to put all the chained actions in one controller. The
458 specification of the parent through C<:Chained> also takes an absolute
459 action path as its argument. Just specify it with a leading C</>.
461 If you want, for example, to have actions for the public paths
462 C</foo/12/edit> and C</foo/12>, just specify two actions with
463 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
464 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
465 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
466 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
467 this debugging output:
470 [debug] Loaded Path Part actions:
471 .-----------------------+------------------------------.
472 | Path Spec | Private |
473 +-----------------------+------------------------------+
474 | /foo/* | /controller/foo_view |
475 | /foo/*/edit | /controller/foo_load (1) |
476 | | => /controller/edit |
477 '-----------------------+------------------------------'
480 Here's a more detailed specification of the attributes belonging to
489 Sets the name of this part of the chain. If it is specified without
490 arguments, it takes the name of the action as default. So basically
491 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
492 This can also contain slashes to bind to a deeper level. An action
493 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
494 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
495 effect as using C<:PathPart>, it would default to the action name.
499 Sets PathPart to the path_prefix of the current controller.
503 Has to be specified for every child in the chain. Possible values are
504 absolute and relative private action paths or a single slash C</> to
505 tell Catalyst that this is the root of a chain. The attribute
506 C<:Chained> without arguments also defaults to the C</> behavior.
507 Relative action paths may use C<../> to refer to actions in parent
510 Because you can specify an absolute path to the parent action, it
511 doesn't matter to Catalyst where that parent is located. So, if your
512 design requests it, you can redispatch a chain through any controller or
515 Another interesting possibility gives C<:Chained('.')>, which chains
516 itself to an action with the path of the current controller's namespace.
519 # in MyApp::Controller::Foo
520 sub bar : Chained CaptureArgs(1) { ... }
522 # in MyApp::Controller::Foo::Bar
523 sub baz : Chained('.') Args(1) { ... }
525 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
526 as the argument to Chained here chains the C<baz> action to an action
527 with the path of the current controller namespace, namely
528 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
529 chain comes out as the end product.
533 Chains an action to another action with the same name in the parent
534 controller. For Example:
536 # in MyApp::Controller::Foo
537 sub bar : Chained CaptureArgs(1) { ... }
539 # in MyApp::Controller::Foo::Moo
540 sub bar : ChainedParent Args(1) { ... }
542 This builds a chain like C</bar/*/bar/*>.
546 Must be specified for every part of the chain that is not an
547 endpoint. With this attribute Catalyst knows how many of the following
548 parts of the path (separated by C</>) this action wants to capture as
549 its arguments. If it doesn't expect any, just specify
550 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
551 after the context, but you can also find them as array references in
552 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
553 level of the action in the chain that captured the parts of the path.
555 An action that is part of a chain (that is, one that has a C<:Chained>
556 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
561 By default, endpoints receive the rest of the arguments in the path. You
562 can tell Catalyst through C<:Args> explicitly how many arguments your
563 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
564 also affects whether this chain is invoked on a request. A chain with an
565 endpoint specifying one argument will only match if exactly one argument
568 You can specify an exact number of arguments like C<:Args(3)>, including
569 C<0>. If you just say C<:Args> without any arguments, it is the same as
570 leaving it out altogether: The chain is matched regardless of the number
571 of path parts after the endpoint.
573 Just as with C<:CaptureArgs>, the arguments get passed to the action in
574 C<@_> after the context object. They can also be reached through
575 C<$c-E<gt>request-E<gt>arguments>.
579 =head2 Auto actions, dispatching and forwarding
581 Note that the list of C<auto> actions called depends on the private path
582 of the endpoint of the chain, not on the chained actions way. The
583 C<auto> actions will be run before the chain dispatching begins. In
584 every other aspect, C<auto> actions behave as documented.
586 The C<forward>ing to other actions does just what you would expect. But if
587 you C<detach> out of a chain, the rest of the chain will not get called
592 Catalyst Contributors, see Catalyst.pm
596 This program is free software, you can redistribute it and/or modify it under
597 the same terms as Perl itself.