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 $parent eq '/'; # fail for dangling action
327 return undef if @captures; # fail for too many captures
329 return join('/', '', @parts);
334 my ($self, $action) = @_;
336 return unless $action->attributes && $action->attributes->{Chained};
343 my $parent = $curr->attributes->{Chained}->[0];
344 $curr = $self->_actions->{$parent};
347 return Catalyst::ActionChain->from_chain([reverse @chain]);
350 __PACKAGE__->meta->make_immutable;
356 The C<Chained> attribute allows you to chain public path parts together
357 by their private names. A chain part's path can be specified with
358 C<PathPart> and can be declared to expect an arbitrary number of
359 arguments. The endpoint of the chain specifies how many arguments it
360 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
361 C<:Args> without an integer would be unlimited. The path parts that
362 aren't endpoints are using C<CaptureArgs> to specify how many parameters
363 they expect to receive. As an example setup:
365 package MyApp::Controller::Greeting;
366 use base qw/ Catalyst::Controller /;
368 # this is the beginning of our chain
369 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
370 my ( $self, $c, $integer ) = @_;
371 $c->stash->{ message } = "Hello ";
372 $c->stash->{ arg_sum } = $integer;
375 # this is our endpoint, because it has no :CaptureArgs
376 sub world : PathPart('world') Chained('hello') Args(1) {
377 my ( $self, $c, $integer ) = @_;
378 $c->stash->{ message } .= "World!";
379 $c->stash->{ arg_sum } += $integer;
381 $c->response->body( join "<br/>\n" =>
382 $c->stash->{ message }, $c->stash->{ arg_sum } );
385 The debug output provides a separate table for chained actions, showing
386 the whole chain as it would match and the actions it contains. Here's an
387 example of the startup output with our actions above:
390 [debug] Loaded Path Part actions:
391 .-----------------------+------------------------------.
392 | Path Spec | Private |
393 +-----------------------+------------------------------+
394 | /hello/*/world/* | /greeting/hello (1) |
395 | | => /greeting/world |
396 '-----------------------+------------------------------'
399 As you can see, Catalyst only deals with chains as whole paths and
400 builds one for each endpoint, which are the actions with C<:Chained> but
401 without C<:CaptureArgs>.
403 Let's assume this application gets a request at the path
404 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
405 to the C<hello> action and pass the value C<23> as an argument to it
406 after the context. It does so because we have previously used
407 C<:CaptureArgs(1)> to declare that it has one path part after itself as
408 its argument. We told Catalyst that this is the beginning of the chain
409 by specifying C<:Chained('/')>. Also note that instead of saying
410 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
411 defaults to the name of the action.
413 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
414 action. This is the last action to be called: Catalyst knows this is an
415 endpoint because we did not specify a C<:CaptureArgs>
416 attribute. Nevertheless we specify that this action expects an argument,
417 but at this point we're using C<:Args(1)> to do that. We could also have
418 said C<:Args> or left it out altogether, which would mean this action
419 would get all arguments that are there. This action's C<:Chained>
420 attribute says C<hello> and tells Catalyst that the C<hello> action in
421 the current controller is its parent.
423 With this we have built a chain consisting of two public path parts.
424 C<hello> captures one part of the path as its argument, and also
425 specifies the path root as its parent. So this part is
426 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
427 argument. It sums up to the path part C<world/$arg>. This leads to a
428 complete chain of C</hello/$arg/world/$arg> which is matched against the
431 This example application would, if run and called by e.g.
432 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
433 value C<arg_sum> to "23". The C<world> action would then append "World!"
434 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
435 sake of simplicity no view is shown. Instead we just put the values of
436 the stash into our body. So the output would look like:
441 And our test server would have given us this debugging output for the
445 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
446 [debug] Path is "/greeting/world"
447 [debug] Arguments are "12"
448 [info] Request took 0.164113s (6.093/s)
449 .------------------------------------------+-----------.
451 +------------------------------------------+-----------+
452 | /greeting/hello | 0.000029s |
453 | /greeting/world | 0.000024s |
454 '------------------------------------------+-----------'
457 What would be common uses of this dispatch technique? It gives the
458 possibility to split up logic that contains steps that each depend on
459 each other. An example would be, for example, a wiki path like
460 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
463 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
464 my ( $self, $c, $page_name ) = @_;
465 # load the page named $page_name and put the object
469 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
470 my ( $self, $c, $revision_id ) = @_;
471 # use the page object in the stash to get at its
472 # revision with number $revision_id
475 sub view : PathPart Chained('rev') Args(0) {
476 my ( $self, $c ) = @_;
477 # display the revision in our stash. Another option
478 # would be to forward a compatible object to the action
479 # that displays the default wiki pages, unless we want
480 # a different interface here, for example restore
484 It would now be possible to add other endpoints, for example C<restore>
485 to restore this specific revision as the current state.
487 You don't have to put all the chained actions in one controller. The
488 specification of the parent through C<:Chained> also takes an absolute
489 action path as its argument. Just specify it with a leading C</>.
491 If you want, for example, to have actions for the public paths
492 C</foo/12/edit> and C</foo/12>, just specify two actions with
493 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
494 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
495 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
496 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
497 this debugging output:
500 [debug] Loaded Path Part actions:
501 .-----------------------+------------------------------.
502 | Path Spec | Private |
503 +-----------------------+------------------------------+
504 | /foo/* | /controller/foo_view |
505 | /foo/*/edit | /controller/foo_load (1) |
506 | | => /controller/edit |
507 '-----------------------+------------------------------'
510 Here's a more detailed specification of the attributes belonging to
519 Sets the name of this part of the chain. If it is specified without
520 arguments, it takes the name of the action as default. So basically
521 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
522 This can also contain slashes to bind to a deeper level. An action
523 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
524 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
525 effect as using C<:PathPart>, it would default to the action name.
529 Sets PathPart to the path_prefix of the current controller.
533 Has to be specified for every child in the chain. Possible values are
534 absolute and relative private action paths or a single slash C</> to
535 tell Catalyst that this is the root of a chain. The attribute
536 C<:Chained> without arguments also defaults to the C</> behavior.
537 Relative action paths may use C<../> to refer to actions in parent
540 Because you can specify an absolute path to the parent action, it
541 doesn't matter to Catalyst where that parent is located. So, if your
542 design requests it, you can redispatch a chain through any controller or
545 Another interesting possibility gives C<:Chained('.')>, which chains
546 itself to an action with the path of the current controller's namespace.
549 # in MyApp::Controller::Foo
550 sub bar : Chained CaptureArgs(1) { ... }
552 # in MyApp::Controller::Foo::Bar
553 sub baz : Chained('.') Args(1) { ... }
555 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
556 as the argument to Chained here chains the C<baz> action to an action
557 with the path of the current controller namespace, namely
558 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
559 chain comes out as the end product.
563 Chains an action to another action with the same name in the parent
564 controller. For Example:
566 # in MyApp::Controller::Foo
567 sub bar : Chained CaptureArgs(1) { ... }
569 # in MyApp::Controller::Foo::Moo
570 sub bar : ChainedParent Args(1) { ... }
572 This builds a chain like C</bar/*/bar/*>.
576 Must be specified for every part of the chain that is not an
577 endpoint. With this attribute Catalyst knows how many of the following
578 parts of the path (separated by C</>) this action wants to capture as
579 its arguments. If it doesn't expect any, just specify
580 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
581 after the context, but you can also find them as array references in
582 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
583 level of the action in the chain that captured the parts of the path.
585 An action that is part of a chain (that is, one that has a C<:Chained>
586 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
591 By default, endpoints receive the rest of the arguments in the path. You
592 can tell Catalyst through C<:Args> explicitly how many arguments your
593 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
594 also affects whether this chain is invoked on a request. A chain with an
595 endpoint specifying one argument will only match if exactly one argument
598 You can specify an exact number of arguments like C<:Args(3)>, including
599 C<0>. If you just say C<:Args> without any arguments, it is the same as
600 leaving it out altogether: The chain is matched regardless of the number
601 of path parts after the endpoint.
603 Just as with C<:CaptureArgs>, the arguments get passed to the action in
604 C<@_> after the context object. They can also be reached through
605 C<$c-E<gt>request-E<gt>arguments>.
609 =head2 Auto actions, dispatching and forwarding
611 Note that the list of C<auto> actions called depends on the private path
612 of the endpoint of the chain, not on the chained actions way. The
613 C<auto> actions will be run before the chain dispatching begins. In
614 every other aspect, C<auto> actions behave as documented.
616 The C<forward>ing to other actions does just what you would expect. But if
617 you C<detach> out of a chain, the rest of the chain will not get called
622 Catalyst Contributors, see Catalyst.pm
626 This program is free software, you can redistribute it and/or modify it under
627 the same terms as Perl itself.