1 package Catalyst::DispatchType::Chained;
6 extends 'Catalyst::DispatchType';
9 use Catalyst::ActionChain;
35 # please don't perltidy this. hairy code within.
39 Catalyst::DispatchType::Chained - Path Part DispatchType
43 # root action - captures one argument after it
44 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
45 my ( $self, $c, $foo_arg ) = @_;
49 # child action endpoint - takes one argument
50 sub bar : Chained('foo_setup') Args(1) {
51 my ( $self, $c, $bar_arg ) = @_;
61 =head2 $self->list($c)
63 Debug output for Path Part dispatch points
68 my ( $self, $c ) = @_;
70 return unless $self->_endpoints;
72 my $paths = Text::SimpleTable->new(
73 [ 35, 'Path Spec' ], [ 36, 'Private' ]
76 ENDPOINT: foreach my $endpoint (
77 sort { $a->reverse cmp $b->reverse }
78 @{ $self->_endpoints }
80 my $args = $endpoint->attributes->{Args}->[0];
81 my @parts = (defined($args) ? (("*") x $args) : '...');
86 if (my $cap = $curr->attributes->{CaptureArgs}) {
87 unshift(@parts, (("*") x $cap->[0]));
89 if (my $pp = $curr->attributes->{PartPath}) {
90 unshift(@parts, $pp->[0])
91 if (defined $pp->[0] && length $pp->[0]);
93 $parent = $curr->attributes->{Chained}->[0];
94 $curr = $self->_actions->{$parent};
95 unshift(@parents, $curr) if $curr;
97 next ENDPOINT unless $parent eq '/'; # skip dangling action
99 foreach my $p (@parents) {
101 if (my $cap = $p->attributes->{CaptureArgs}) {
102 $name .= ' ('.$cap->[0].')';
104 unless ($p eq $parents[0]) {
105 $name = "-> ${name}";
107 push(@rows, [ '', $name ]);
109 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
110 $rows[0][0] = join('/', '', @parts);
111 $paths->row(@$_) for @rows;
114 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
117 =head2 $self->match( $c, $path )
119 Calls C<recurse_match> to see if a chain matches the C<$path>.
124 my ( $self, $c, $path ) = @_;
126 my $request = $c->request;
127 return 0 if @{$request->args};
129 my @parts = split('/', $path);
131 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
132 push @{$request->args}, @$parts if $parts && @$parts;
134 return 0 unless $chain;
136 my $action = Catalyst::ActionChain->from_chain($chain);
138 $request->action("/${action}");
139 $request->match("/${action}");
140 $request->captures($captures);
142 $c->namespace( $action->namespace );
147 =head2 $self->recurse_match( $c, $parent, \@path_parts )
149 Recursive search for a matching chain.
154 my ( $self, $c, $parent, $path_parts ) = @_;
155 my $children = $self->_children_of->{$parent};
156 return () unless $children;
159 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
161 # $b then $a to try longest part first
162 my @parts = @$path_parts;
163 if (length $try_part) { # test and strip PathPart
165 ($try_part eq join('/', # assemble equal number of parts
166 splice( # and strip them off @parts as well
167 @parts, 0, scalar(@{[split('/', $try_part)]})
168 ))); # @{[]} to avoid split to @_
170 my @try_actions = @{$children->{$try_part}};
171 TRY_ACTION: foreach my $action (@try_actions) {
172 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
174 # Short-circuit if not enough remaining parts
175 next TRY_ACTION unless @parts >= $capture_attr->[0];
178 my @parts = @parts; # localise
180 # strip CaptureArgs into list
181 push(@captures, splice(@parts, 0, $capture_attr->[0]));
183 # try the remaining parts against children of this action
184 my ($actions, $captures, $action_parts) = $self->recurse_match(
185 $c, '/'.$action->reverse, \@parts
187 if ($actions && (!$best_action || $#$action_parts < $#{$best_action->{parts}})){
189 actions => [ $action, @$actions ],
190 captures=> [ @captures, @$captures ],
191 parts => $action_parts
197 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
198 next TRY_ACTION unless $action->match($c);
200 my $args_attr = $action->attributes->{Args}->[0];
202 # No best action currently
203 # OR This one matches with fewer parts left than the current best action,
204 # And therefore is a better match
205 # OR No parts and this expects 0
206 # The current best action might also be Args(0),
207 # but we couldn't chose between then anyway so we'll take the last seen
210 @parts < @{$best_action->{parts}} ||
211 (!@parts && $args_attr eq 0)){
213 actions => [ $action ],
221 return @$best_action{qw/actions captures parts/} if $best_action;
225 =head2 $self->register( $c, $action )
227 Calls register_path for every Path attribute for the given $action.
232 my ( $self, $c, $action ) = @_;
234 my @chained_attr = @{ $action->attributes->{Chained} || [] };
236 return 0 unless @chained_attr;
238 if (@chained_attr > 2) {
239 Catalyst::Exception->throw(
240 "Multiple Chained attributes not supported registering ${action}"
244 my $parent = $chained_attr[0];
246 if (defined($parent) && length($parent)) {
247 if ($parent eq '.') {
248 $parent = '/'.$action->namespace;
249 } elsif ($parent !~ m/^\//) {
250 if ($action->namespace) {
251 $parent = '/'.join('/', $action->namespace, $parent);
253 $parent = '/'.$parent; # special case namespace '' (root)
260 $action->attributes->{Chained} = [ $parent ];
262 my $children = ($self->_children_of->{$parent} ||= {});
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 __PACKAGE__->meta->make_immutable;
341 The C<Chained> attribute allows you to chain public path parts together
342 by their private names. A chain part's path can be specified with
343 C<PathPart> and can be declared to expect an arbitrary number of
344 arguments. The endpoint of the chain specifies how many arguments it
345 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
346 C<:Args> without an integer would be unlimited. The path parts that
347 aren't endpoints are using C<CaptureArgs> to specify how many parameters
348 they expect to receive. As an example setup:
350 package MyApp::Controller::Greeting;
351 use base qw/ Catalyst::Controller /;
353 # this is the beginning of our chain
354 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
355 my ( $self, $c, $integer ) = @_;
356 $c->stash->{ message } = "Hello ";
357 $c->stash->{ arg_sum } = $integer;
360 # this is our endpoint, because it has no :CaptureArgs
361 sub world : PathPart('world') Chained('hello') Args(1) {
362 my ( $self, $c, $integer ) = @_;
363 $c->stash->{ message } .= "World!";
364 $c->stash->{ arg_sum } += $integer;
366 $c->response->body( join "<br/>\n" =>
367 $c->stash->{ message }, $c->stash->{ arg_sum } );
370 The debug output provides a separate table for chained actions, showing
371 the whole chain as it would match and the actions it contains. Here's an
372 example of the startup output with our actions above:
375 [debug] Loaded Path Part actions:
376 .-----------------------+------------------------------.
377 | Path Spec | Private |
378 +-----------------------+------------------------------+
379 | /hello/*/world/* | /greeting/hello (1) |
380 | | => /greeting/world |
381 '-----------------------+------------------------------'
384 As you can see, Catalyst only deals with chains as whole paths and
385 builds one for each endpoint, which are the actions with C<:Chained> but
386 without C<:CaptureArgs>.
388 Let's assume this application gets a request at the path
389 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
390 to the C<hello> action and pass the value C<23> as an argument to it
391 after the context. It does so because we have previously used
392 C<:CaptureArgs(1)> to declare that it has one path part after itself as
393 its argument. We told Catalyst that this is the beginning of the chain
394 by specifying C<:Chained('/')>. Also note that instead of saying
395 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
396 defaults to the name of the action.
398 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
399 action. This is the last action to be called: Catalyst knows this is an
400 endpoint because we did not specify a C<:CaptureArgs>
401 attribute. Nevertheless we specify that this action expects an argument,
402 but at this point we're using C<:Args(1)> to do that. We could also have
403 said C<:Args> or left it out altogether, which would mean this action
404 would get all arguments that are there. This action's C<:Chained>
405 attribute says C<hello> and tells Catalyst that the C<hello> action in
406 the current controller is its parent.
408 With this we have built a chain consisting of two public path parts.
409 C<hello> captures one part of the path as its argument, and also
410 specifies the path root as its parent. So this part is
411 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
412 argument. It sums up to the path part C<world/$arg>. This leads to a
413 complete chain of C</hello/$arg/world/$arg> which is matched against the
416 This example application would, if run and called by e.g.
417 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
418 value C<arg_sum> to "23". The C<world> action would then append "World!"
419 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
420 sake of simplicity no view is shown. Instead we just put the values of
421 the stash into our body. So the output would look like:
426 And our test server would have given us this debugging output for the
430 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
431 [debug] Path is "/greeting/world"
432 [debug] Arguments are "12"
433 [info] Request took 0.164113s (6.093/s)
434 .------------------------------------------+-----------.
436 +------------------------------------------+-----------+
437 | /greeting/hello | 0.000029s |
438 | /greeting/world | 0.000024s |
439 '------------------------------------------+-----------'
442 What would be common uses of this dispatch technique? It gives the
443 possibility to split up logic that contains steps that each depend on
444 each other. An example would be, for example, a wiki path like
445 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
448 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
449 my ( $self, $c, $page_name ) = @_;
450 # load the page named $page_name and put the object
454 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
455 my ( $self, $c, $revision_id ) = @_;
456 # use the page object in the stash to get at its
457 # revision with number $revision_id
460 sub view : PathPart Chained('rev') Args(0) {
461 my ( $self, $c ) = @_;
462 # display the revision in our stash. Another option
463 # would be to forward a compatible object to the action
464 # that displays the default wiki pages, unless we want
465 # a different interface here, for example restore
469 It would now be possible to add other endpoints, for example C<restore>
470 to restore this specific revision as the current state.
472 You don't have to put all the chained actions in one controller. The
473 specification of the parent through C<:Chained> also takes an absolute
474 action path as its argument. Just specify it with a leading C</>.
476 If you want, for example, to have actions for the public paths
477 C</foo/12/edit> and C</foo/12>, just specify two actions with
478 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
479 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
480 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
481 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
482 this debugging output:
485 [debug] Loaded Path Part actions:
486 .-----------------------+------------------------------.
487 | Path Spec | Private |
488 +-----------------------+------------------------------+
489 | /foo/* | /controller/foo_view |
490 | /foo/*/edit | /controller/foo_load (1) |
491 | | => /controller/edit |
492 '-----------------------+------------------------------'
495 Here's a more detailed specification of the attributes belonging to
504 Sets the name of this part of the chain. If it is specified without
505 arguments, it takes the name of the action as default. So basically
506 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
507 This can also contain slashes to bind to a deeper level. An action
508 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
509 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
510 effect as using C<:PathPart>, it would default to the action name.
514 Has to be specified for every child in the chain. Possible values are
515 absolute and relative private action paths, with the relatives pointing
516 to the current controller, or a single slash C</> to tell Catalyst that
517 this is the root of a chain. The attribute C<:Chained> without arguments
518 also defaults to the C</> behavior.
520 Because you can specify an absolute path to the parent action, it
521 doesn't matter to Catalyst where that parent is located. So, if your
522 design requests it, you can redispatch a chain through any controller or
525 Another interesting possibility gives C<:Chained('.')>, which chains
526 itself to an action with the path of the current controller's namespace.
529 # in MyApp::Controller::Foo
530 sub bar : Chained CaptureArgs(1) { ... }
532 # in MyApp::Controller::Foo::Bar
533 sub baz : Chained('.') Args(1) { ... }
535 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
536 as the argument to Chained here chains the C<baz> action to an action
537 with the path of the current controller namespace, namely
538 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
539 chain comes out as the end product.
543 Must be specified for every part of the chain that is not an
544 endpoint. With this attribute Catalyst knows how many of the following
545 parts of the path (separated by C</>) this action wants to capture as
546 its arguments. If it doesn't expect any, just specify
547 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
548 after the context, but you can also find them as array references in
549 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
550 level of the action in the chain that captured the parts of the path.
552 An action that is part of a chain (that is, one that has a C<:Chained>
553 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
558 By default, endpoints receive the rest of the arguments in the path. You
559 can tell Catalyst through C<:Args> explicitly how many arguments your
560 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
561 also affects whether this chain is invoked on a request. A chain with an
562 endpoint specifying one argument will only match if exactly one argument
565 You can specify an exact number of arguments like C<:Args(3)>, including
566 C<0>. If you just say C<:Args> without any arguments, it is the same as
567 leaving it out altogether: The chain is matched regardless of the number
568 of path parts after the endpoint.
570 Just as with C<:CaptureArgs>, the arguments get passed to the action in
571 C<@_> after the context object. They can also be reached through
572 C<$c-E<gt>request-E<gt>arguments>.
576 =head2 Auto actions, dispatching and forwarding
578 Note that the list of C<auto> actions called depends on the private path
579 of the endpoint of the chain, not on the chained actions way. The
580 C<auto> actions will be run before the chain dispatching begins. In
581 every other aspect, C<auto> actions behave as documented.
583 The C<forward>ing to other actions does just what you would expect. But if
584 you C<detach> out of a chain, the rest of the chain will not get called
589 Matt S Trout <mst@shadowcatsystems.co.uk>
593 This program is free software, you can redistribute it and/or modify it under
594 the same terms as Perl itself.