1 package Catalyst::DispatchType::Chained;
5 extends 'Catalyst::DispatchType';
8 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 $paths = Text::SimpleTable->new(
72 [ 35, 'Path Spec' ], [ 36, 'Private' ]
75 ENDPOINT: foreach my $endpoint (
76 sort { $a->reverse cmp $b->reverse }
77 @{ $self->_endpoints }
79 my $args = $endpoint->attributes->{Args}->[0];
80 my @parts = (defined($args) ? (("*") x $args) : '...');
85 if (my $cap = $curr->attributes->{CaptureArgs}) {
86 unshift(@parts, (("*") x $cap->[0]));
88 if (my $pp = $curr->attributes->{PartPath}) {
89 unshift(@parts, $pp->[0])
90 if (defined $pp->[0] && length $pp->[0]);
92 $parent = $curr->attributes->{Chained}->[0];
93 $curr = $self->_actions->{$parent};
94 unshift(@parents, $curr) if $curr;
96 next ENDPOINT unless $parent eq '/'; # skip dangling action
98 foreach my $p (@parents) {
100 if (my $cap = $p->attributes->{CaptureArgs}) {
101 $name .= ' ('.$cap->[0].')';
103 unless ($p eq $parents[0]) {
104 $name = "-> ${name}";
106 push(@rows, [ '', $name ]);
108 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
109 $rows[0][0] = join('/', '', @parts);
110 $paths->row(@$_) for @rows;
113 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
116 =head2 $self->match( $c, $path )
118 Calls C<recurse_match> to see if a chain matches the C<$path>.
123 my ( $self, $c, $path ) = @_;
125 my $request = $c->request;
126 return 0 if @{$request->args};
128 my @parts = split('/', $path);
130 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
131 push @{$request->args}, @$parts if $parts && @$parts;
133 return 0 unless $chain;
135 my $action = Catalyst::ActionChain->from_chain($chain);
137 $request->action("/${action}");
138 $request->match("/${action}");
139 $request->captures($captures);
141 $c->namespace( $action->namespace );
146 =head2 $self->recurse_match( $c, $parent, \@path_parts )
148 Recursive search for a matching chain.
153 my ( $self, $c, $parent, $path_parts ) = @_;
154 my $children = $self->_children_of->{$parent};
155 return () unless $children;
158 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
160 # $b then $a to try longest part first
161 my @parts = @$path_parts;
162 if (length $try_part) { # test and strip PathPart
164 ($try_part eq join('/', # assemble equal number of parts
165 splice( # and strip them off @parts as well
166 @parts, 0, scalar(@{[split('/', $try_part)]})
167 ))); # @{[]} to avoid split to @_
169 my @try_actions = @{$children->{$try_part}};
170 TRY_ACTION: foreach my $action (@try_actions) {
171 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
173 # Short-circuit if not enough remaining parts
174 next TRY_ACTION unless @parts >= $capture_attr->[0];
177 my @parts = @parts; # localise
179 # strip CaptureArgs into list
180 push(@captures, splice(@parts, 0, $capture_attr->[0]));
182 # try the remaining parts against children of this action
183 my ($actions, $captures, $action_parts) = $self->recurse_match(
184 $c, '/'.$action->reverse, \@parts
186 if ($actions && (!$best_action || $#$action_parts < $#{$best_action->{parts}})){
188 actions => [ $action, @$actions ],
189 captures=> [ @captures, @$captures ],
190 parts => $action_parts
196 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
197 next TRY_ACTION unless $action->match($c);
199 my $args_attr = $action->attributes->{Args}->[0];
201 # No best action currently
202 # OR This one matches with fewer parts left than the current best action,
203 # And therefore is a better match
204 # OR No parts and this expects 0
205 # The current best action might also be Args(0),
206 # but we couldn't chose between then anyway so we'll take the last seen
209 @parts < @{$best_action->{parts}} ||
210 (!@parts && $args_attr eq 0)){
212 actions => [ $action ],
220 return @$best_action{qw/actions captures parts/} if $best_action;
224 =head2 $self->register( $c, $action )
226 Calls register_path for every Path attribute for the given $action.
231 my ( $self, $c, $action ) = @_;
233 my @chained_attr = @{ $action->attributes->{Chained} || [] };
235 return 0 unless @chained_attr;
237 if (@chained_attr > 2) {
238 Catalyst::Exception->throw(
239 "Multiple Chained attributes not supported registering ${action}"
243 my $parent = $chained_attr[0];
245 if (defined($parent) && length($parent)) {
246 if ($parent eq '.') {
247 $parent = '/'.$action->namespace;
248 } elsif ($parent !~ m/^\//) {
249 if ($action->namespace) {
250 $parent = '/'.join('/', $action->namespace, $parent);
252 $parent = '/'.$parent; # special case namespace '' (root)
259 $action->attributes->{Chained} = [ $parent ];
261 my $children = ($self->_children_of->{$parent} ||= {});
263 my @path_part = @{ $action->attributes->{PathPart} || [] };
265 my $part = $action->name;
267 if (@path_part == 1 && defined $path_part[0]) {
268 $part = $path_part[0];
269 } elsif (@path_part > 1) {
270 Catalyst::Exception->throw(
271 "Multiple PathPart attributes not supported registering " . $action->reverse()
275 if ($part =~ m(^/)) {
276 Catalyst::Exception->throw(
277 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
281 $action->attributes->{PartPath} = [ $part ];
283 unshift(@{ $children->{$part} ||= [] }, $action);
285 $self->_actions->{'/'.$action->reverse} = $action;
287 unless ($action->attributes->{CaptureArgs}) {
288 unshift(@{ $self->_endpoints }, $action);
294 =head2 $self->uri_for_action($action, $captures)
296 Get the URI part for the action, using C<$captures> to fill
302 my ( $self, $action, $captures ) = @_;
304 return undef unless ($action->attributes->{Chained}
305 && !$action->attributes->{CaptureArgs});
308 my @captures = @$captures;
309 my $parent = "DUMMY";
312 if (my $cap = $curr->attributes->{CaptureArgs}) {
313 return undef unless @captures >= $cap->[0]; # not enough captures
315 unshift(@parts, splice(@captures, -$cap->[0]));
318 if (my $pp = $curr->attributes->{PartPath}) {
319 unshift(@parts, $pp->[0])
320 if (defined($pp->[0]) && length($pp->[0]));
322 $parent = $curr->attributes->{Chained}->[0];
323 $curr = $self->_actions->{$parent};
326 return undef unless $parent eq '/'; # fail for dangling action
328 return undef if @captures; # fail for too many captures
330 return join('/', '', @parts);
334 __PACKAGE__->meta->make_immutable;
340 The C<Chained> attribute allows you to chain public path parts together
341 by their private names. A chain part's path can be specified with
342 C<PathPart> and can be declared to expect an arbitrary number of
343 arguments. The endpoint of the chain specifies how many arguments it
344 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
345 C<:Args> without an integer would be unlimited. The path parts that
346 aren't endpoints are using C<CaptureArgs> to specify how many parameters
347 they expect to receive. As an example setup:
349 package MyApp::Controller::Greeting;
350 use base qw/ Catalyst::Controller /;
352 # this is the beginning of our chain
353 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
354 my ( $self, $c, $integer ) = @_;
355 $c->stash->{ message } = "Hello ";
356 $c->stash->{ arg_sum } = $integer;
359 # this is our endpoint, because it has no :CaptureArgs
360 sub world : PathPart('world') Chained('hello') Args(1) {
361 my ( $self, $c, $integer ) = @_;
362 $c->stash->{ message } .= "World!";
363 $c->stash->{ arg_sum } += $integer;
365 $c->response->body( join "<br/>\n" =>
366 $c->stash->{ message }, $c->stash->{ arg_sum } );
369 The debug output provides a separate table for chained actions, showing
370 the whole chain as it would match and the actions it contains. Here's an
371 example of the startup output with our actions above:
374 [debug] Loaded Path Part actions:
375 .-----------------------+------------------------------.
376 | Path Spec | Private |
377 +-----------------------+------------------------------+
378 | /hello/*/world/* | /greeting/hello (1) |
379 | | => /greeting/world |
380 '-----------------------+------------------------------'
383 As you can see, Catalyst only deals with chains as whole paths and
384 builds one for each endpoint, which are the actions with C<:Chained> but
385 without C<:CaptureArgs>.
387 Let's assume this application gets a request at the path
388 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
389 to the C<hello> action and pass the value C<23> as an argument to it
390 after the context. It does so because we have previously used
391 C<:CaptureArgs(1)> to declare that it has one path part after itself as
392 its argument. We told Catalyst that this is the beginning of the chain
393 by specifying C<:Chained('/')>. Also note that instead of saying
394 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
395 defaults to the name of the action.
397 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
398 action. This is the last action to be called: Catalyst knows this is an
399 endpoint because we did not specify a C<:CaptureArgs>
400 attribute. Nevertheless we specify that this action expects an argument,
401 but at this point we're using C<:Args(1)> to do that. We could also have
402 said C<:Args> or left it out altogether, which would mean this action
403 would get all arguments that are there. This action's C<:Chained>
404 attribute says C<hello> and tells Catalyst that the C<hello> action in
405 the current controller is its parent.
407 With this we have built a chain consisting of two public path parts.
408 C<hello> captures one part of the path as its argument, and also
409 specifies the path root as its parent. So this part is
410 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
411 argument. It sums up to the path part C<world/$arg>. This leads to a
412 complete chain of C</hello/$arg/world/$arg> which is matched against the
415 This example application would, if run and called by e.g.
416 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
417 value C<arg_sum> to "23". The C<world> action would then append "World!"
418 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
419 sake of simplicity no view is shown. Instead we just put the values of
420 the stash into our body. So the output would look like:
425 And our test server would have given us this debugging output for the
429 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
430 [debug] Path is "/greeting/world"
431 [debug] Arguments are "12"
432 [info] Request took 0.164113s (6.093/s)
433 .------------------------------------------+-----------.
435 +------------------------------------------+-----------+
436 | /greeting/hello | 0.000029s |
437 | /greeting/world | 0.000024s |
438 '------------------------------------------+-----------'
441 What would be common uses of this dispatch technique? It gives the
442 possibility to split up logic that contains steps that each depend on
443 each other. An example would be, for example, a wiki path like
444 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
447 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
448 my ( $self, $c, $page_name ) = @_;
449 # load the page named $page_name and put the object
453 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
454 my ( $self, $c, $revision_id ) = @_;
455 # use the page object in the stash to get at its
456 # revision with number $revision_id
459 sub view : PathPart Chained('rev') Args(0) {
460 my ( $self, $c ) = @_;
461 # display the revision in our stash. Another option
462 # would be to forward a compatible object to the action
463 # that displays the default wiki pages, unless we want
464 # a different interface here, for example restore
468 It would now be possible to add other endpoints, for example C<restore>
469 to restore this specific revision as the current state.
471 You don't have to put all the chained actions in one controller. The
472 specification of the parent through C<:Chained> also takes an absolute
473 action path as its argument. Just specify it with a leading C</>.
475 If you want, for example, to have actions for the public paths
476 C</foo/12/edit> and C</foo/12>, just specify two actions with
477 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
478 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
479 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
480 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
481 this debugging output:
484 [debug] Loaded Path Part actions:
485 .-----------------------+------------------------------.
486 | Path Spec | Private |
487 +-----------------------+------------------------------+
488 | /foo/* | /controller/foo_view |
489 | /foo/*/edit | /controller/foo_load (1) |
490 | | => /controller/edit |
491 '-----------------------+------------------------------'
494 Here's a more detailed specification of the attributes belonging to
503 Sets the name of this part of the chain. If it is specified without
504 arguments, it takes the name of the action as default. So basically
505 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
506 This can also contain slashes to bind to a deeper level. An action
507 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
508 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
509 effect as using C<:PathPart>, it would default to the action name.
513 Has to be specified for every child in the chain. Possible values are
514 absolute and relative private action paths, with the relatives pointing
515 to the current controller, or a single slash C</> to tell Catalyst that
516 this is the root of a chain. The attribute C<:Chained> without arguments
517 also defaults to the C</> behavior.
519 Because you can specify an absolute path to the parent action, it
520 doesn't matter to Catalyst where that parent is located. So, if your
521 design requests it, you can redispatch a chain through any controller or
524 Another interesting possibility gives C<:Chained('.')>, which chains
525 itself to an action with the path of the current controller's namespace.
528 # in MyApp::Controller::Foo
529 sub bar : Chained CaptureArgs(1) { ... }
531 # in MyApp::Controller::Foo::Bar
532 sub baz : Chained('.') Args(1) { ... }
534 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
535 as the argument to Chained here chains the C<baz> action to an action
536 with the path of the current controller namespace, namely
537 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
538 chain comes out as the end product.
542 Must be specified for every part of the chain that is not an
543 endpoint. With this attribute Catalyst knows how many of the following
544 parts of the path (separated by C</>) this action wants to capture as
545 its arguments. If it doesn't expect any, just specify
546 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
547 after the context, but you can also find them as array references in
548 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
549 level of the action in the chain that captured the parts of the path.
551 An action that is part of a chain (that is, one that has a C<:Chained>
552 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
557 By default, endpoints receive the rest of the arguments in the path. You
558 can tell Catalyst through C<:Args> explicitly how many arguments your
559 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
560 also affects whether this chain is invoked on a request. A chain with an
561 endpoint specifying one argument will only match if exactly one argument
564 You can specify an exact number of arguments like C<:Args(3)>, including
565 C<0>. If you just say C<:Args> without any arguments, it is the same as
566 leaving it out altogether: The chain is matched regardless of the number
567 of path parts after the endpoint.
569 Just as with C<:CaptureArgs>, the arguments get passed to the action in
570 C<@_> after the context object. They can also be reached through
571 C<$c-E<gt>request-E<gt>arguments>.
575 =head2 Auto actions, dispatching and forwarding
577 Note that the list of C<auto> actions called depends on the private path
578 of the endpoint of the chain, not on the chained actions way. The
579 C<auto> actions will be run before the chain dispatching begins. In
580 every other aspect, C<auto> actions behave as documented.
582 The C<forward>ing to other actions does just what you would expect. But if
583 you C<detach> out of a chain, the rest of the chain will not get called
588 Matt S Trout <mst@shadowcatsystems.co.uk>
592 This program is free software, you can redistribute it and/or modify it under
593 the same terms as Perl itself.