1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
35 # please don't perltidy this. hairy code within.
39 Catalyst::DispatchType::Chained - Path Part DispatchType
43 Path part matching, allowing several actions to sequentially take care of processing a request:
45 # root action - captures one argument after it
46 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
47 my ( $self, $c, $foo_arg ) = @_;
51 # child action endpoint - takes one argument
52 sub bar : Chained('foo_setup') Args(1) {
53 my ( $self, $c, $bar_arg ) = @_;
59 Dispatch type managing default behaviour. For more information on
64 =item * L<Catalyst::Manual::Intro> for how they affect application authors
66 =item * L<Catalyst::DispatchType> for implementation information.
72 =head2 $self->list($c)
74 Debug output for Path Part dispatch points
79 my ( $self, $c ) = @_;
81 return unless $self->_endpoints;
83 my $avail_width = Catalyst::Utils::term_width() - 9;
84 my $col1_width = ($avail_width * .50) < 35 ? 35 : int($avail_width * .50);
85 my $col2_width = $avail_width - $col1_width;
86 my $paths = Text::SimpleTable->new(
87 [ $col1_width, 'Path Spec' ], [ $col2_width, 'Private' ],
90 my $has_unattached_actions;
91 my $unattached_actions = Text::SimpleTable->new(
92 [ $col1_width, 'Private' ], [ $col2_width, 'Missing parent' ],
95 ENDPOINT: foreach my $endpoint (
96 sort { $a->reverse cmp $b->reverse }
97 @{ $self->_endpoints }
99 my $args = $endpoint->list_extra_info->{Args};
100 my @parts = (defined($args) ? (("*") x $args) : '...');
102 my $parent = "DUMMY";
103 my $curr = $endpoint;
105 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
106 unshift(@parts, (("*") x $cap));
108 if (my $pp = $curr->attributes->{PathPart}) {
109 unshift(@parts, $pp->[0])
110 if (defined $pp->[0] && length $pp->[0]);
112 $parent = $curr->attributes->{Chained}->[0];
113 $curr = $self->_actions->{$parent};
114 unshift(@parents, $curr) if $curr;
116 if ($parent ne '/') {
117 $has_unattached_actions = 1;
118 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
122 foreach my $p (@parents) {
124 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
125 $name .= ' ('.$cap.')';
127 unless ($p eq $parents[0]) {
128 $name = "-> ${name}";
130 if (defined(my $extra = $p->list_extra_info->{HTTP_METHODS})) {
131 $name .= ' ('.join(', ', @$extra).')';
133 push(@rows, [ '', $name ]);
135 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
136 $rows[0][0] = join('/', '', @parts) || '/';
137 $paths->row(@$_) for @rows;
140 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
141 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
142 if $has_unattached_actions;
145 =head2 $self->match( $c, $path )
147 Calls C<recurse_match> to see if a chain matches the C<$path>.
152 my ( $self, $c, $path ) = @_;
154 my $request = $c->request;
155 return 0 if @{$request->args};
157 my @parts = split('/', $path);
159 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
161 if ($parts && @$parts) {
162 for my $arg (@$parts) {
163 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
164 push @{$request->args}, $arg;
168 return 0 unless $chain;
170 my $action = Catalyst::ActionChain->from_chain($chain);
172 $request->action("/${action}");
173 $request->match("/${action}");
174 $request->captures($captures);
176 $c->namespace( $action->namespace );
181 =head2 $self->recurse_match( $c, $parent, \@path_parts )
183 Recursive search for a matching chain.
188 my ( $self, $c, $parent, $path_parts ) = @_;
189 my $children = $self->_children_of->{$parent};
190 return () unless $children;
193 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
195 # $b then $a to try longest part first
196 my @parts = @$path_parts;
197 if (length $try_part) { # test and strip PathPart
199 ($try_part eq join('/', # assemble equal number of parts
200 splice( # and strip them off @parts as well
201 @parts, 0, scalar(@{[split('/', $try_part)]})
202 ))); # @{[]} to avoid split to @_
204 my @try_actions = @{$children->{$try_part}};
205 TRY_ACTION: foreach my $action (@try_actions) {
206 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
209 # Short-circuit if not enough remaining parts
210 next TRY_ACTION unless @parts >= $capture_attr->[0];
213 my @parts = @parts; # localise
215 # strip CaptureArgs into list
216 push(@captures, splice(@parts, 0, $capture_attr->[0]));
218 # check if the action may fit, depending on a given test by the app
219 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
221 # try the remaining parts against children of this action
222 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
223 $c, '/'.$action->reverse, \@parts
225 # No best action currently
226 # OR The action has less parts
227 # OR The action has equal parts but less captured data (ergo more defined)
230 $#$action_parts < $#{$best_action->{parts}} ||
231 ($#$action_parts == $#{$best_action->{parts}} &&
232 $#$captures < $#{$best_action->{captures}} &&
233 $n_pathparts > $best_action->{n_pathparts}))) {
234 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
236 actions => [ $action, @$actions ],
237 captures=> [ @captures, @$captures ],
238 parts => $action_parts,
239 n_pathparts => scalar(@pathparts) + $n_pathparts,
245 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
246 next TRY_ACTION unless $action->match($c);
248 my $args_attr = $action->attributes->{Args}->[0];
249 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
250 # No best action currently
251 # OR This one matches with fewer parts left than the current best action,
252 # And therefore is a better match
253 # OR No parts and this expects 0
254 # The current best action might also be Args(0),
255 # but we couldn't chose between then anyway so we'll take the last seen
258 @parts < @{$best_action->{parts}} ||
259 (!@parts && defined($args_attr) && $args_attr eq "0")){
261 actions => [ $action ],
264 n_pathparts => scalar(@pathparts),
270 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
274 =head2 $self->register( $c, $action )
276 Calls register_path for every Path attribute for the given $action.
281 my ( $self, $c, $action ) = @_;
283 my @chained_attr = @{ $action->attributes->{Chained} || [] };
285 return 0 unless @chained_attr;
287 if (@chained_attr > 1) {
288 Catalyst::Exception->throw(
289 "Multiple Chained attributes not supported registering ${action}"
292 my $chained_to = $chained_attr[0];
294 Catalyst::Exception->throw(
295 "Actions cannot chain to themselves registering /${action}"
296 ) if ($chained_to eq '/' . $action);
298 my $children = ($self->_children_of->{ $chained_to } ||= {});
300 my @path_part = @{ $action->attributes->{PathPart} || [] };
302 my $part = $action->name;
304 if (@path_part == 1 && defined $path_part[0]) {
305 $part = $path_part[0];
306 } elsif (@path_part > 1) {
307 Catalyst::Exception->throw(
308 "Multiple PathPart attributes not supported registering " . $action->reverse()
312 if ($part =~ m(^/)) {
313 Catalyst::Exception->throw(
314 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
318 $action->attributes->{PathPart} = [ $part ];
320 unshift(@{ $children->{$part} ||= [] }, $action);
322 $self->_actions->{'/'.$action->reverse} = $action;
324 if (exists $action->attributes->{Args}) {
325 my $args = $action->attributes->{Args}->[0];
326 if (defined($args) and not (
327 Scalar::Util::looks_like_number($args) and
330 require Data::Dumper;
331 local $Data::Dumper::Terse = 1;
332 local $Data::Dumper::Indent = 0;
333 $args = Data::Dumper::Dumper($args);
334 Catalyst::Exception->throw(
335 "Invalid Args($args) for action " . $action->reverse() .
336 " (use 'Args' or 'Args(<number>)'"
341 unless ($action->attributes->{CaptureArgs}) {
342 unshift(@{ $self->_endpoints }, $action);
348 =head2 $self->uri_for_action($action, $captures)
350 Get the URI part for the action, using C<$captures> to fill
356 my ( $self, $action, $captures ) = @_;
358 return undef unless ($action->attributes->{Chained}
359 && !$action->attributes->{CaptureArgs});
362 my @captures = @$captures;
363 my $parent = "DUMMY";
366 if (my $cap = $curr->attributes->{CaptureArgs}) {
367 return undef unless @captures >= ($cap->[0]||0); # not enough captures
369 unshift(@parts, splice(@captures, -$cap->[0]));
372 if (my $pp = $curr->attributes->{PathPart}) {
373 unshift(@parts, $pp->[0])
374 if (defined($pp->[0]) && length($pp->[0]));
376 $parent = $curr->attributes->{Chained}->[0];
377 $curr = $self->_actions->{$parent};
380 return undef unless $parent eq '/'; # fail for dangling action
382 return undef if @captures; # fail for too many captures
384 return join('/', '', @parts);
388 =head2 $c->expand_action($action)
390 Return a list of actions that represents a chained action. See
391 L<Catalyst::Dispatcher> for more info. You probably want to
392 use the expand_action it provides rather than this directly.
397 my ($self, $action) = @_;
399 return unless $action->attributes && $action->attributes->{Chained};
406 my $parent = $curr->attributes->{Chained}->[0];
407 $curr = $self->_actions->{$parent};
410 return Catalyst::ActionChain->from_chain([reverse @chain]);
413 __PACKAGE__->meta->make_immutable;
420 The C<Chained> attribute allows you to chain public path parts together
421 by their private names. A chain part's path can be specified with
422 C<PathPart> and can be declared to expect an arbitrary number of
423 arguments. The endpoint of the chain specifies how many arguments it
424 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
425 C<:Args> without an integer would be unlimited. The path parts that
426 aren't endpoints are using C<CaptureArgs> to specify how many parameters
427 they expect to receive. As an example setup:
429 package MyApp::Controller::Greeting;
430 use base qw/ Catalyst::Controller /;
432 # this is the beginning of our chain
433 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
434 my ( $self, $c, $integer ) = @_;
435 $c->stash->{ message } = "Hello ";
436 $c->stash->{ arg_sum } = $integer;
439 # this is our endpoint, because it has no :CaptureArgs
440 sub world : PathPart('world') Chained('hello') Args(1) {
441 my ( $self, $c, $integer ) = @_;
442 $c->stash->{ message } .= "World!";
443 $c->stash->{ arg_sum } += $integer;
445 $c->response->body( join "<br/>\n" =>
446 $c->stash->{ message }, $c->stash->{ arg_sum } );
449 The debug output provides a separate table for chained actions, showing
450 the whole chain as it would match and the actions it contains. Here's an
451 example of the startup output with our actions above:
454 [debug] Loaded Path Part actions:
455 .-----------------------+------------------------------.
456 | Path Spec | Private |
457 +-----------------------+------------------------------+
458 | /hello/*/world/* | /greeting/hello (1) |
459 | | => /greeting/world |
460 '-----------------------+------------------------------'
463 As you can see, Catalyst only deals with chains as whole paths and
464 builds one for each endpoint, which are the actions with C<:Chained> but
465 without C<:CaptureArgs>.
467 Let's assume this application gets a request at the path
468 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
469 to the C<hello> action and pass the value C<23> as an argument to it
470 after the context. It does so because we have previously used
471 C<:CaptureArgs(1)> to declare that it has one path part after itself as
472 its argument. We told Catalyst that this is the beginning of the chain
473 by specifying C<:Chained('/')>. Also note that instead of saying
474 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
475 defaults to the name of the action.
477 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
478 action. This is the last action to be called: Catalyst knows this is an
479 endpoint because we did not specify a C<:CaptureArgs>
480 attribute. Nevertheless we specify that this action expects an argument,
481 but at this point we're using C<:Args(1)> to do that. We could also have
482 said C<:Args> or left it out altogether, which would mean this action
483 would get all arguments that are there. This action's C<:Chained>
484 attribute says C<hello> and tells Catalyst that the C<hello> action in
485 the current controller is its parent.
487 With this we have built a chain consisting of two public path parts.
488 C<hello> captures one part of the path as its argument, and also
489 specifies the path root as its parent. So this part is
490 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
491 argument. It sums up to the path part C<world/$arg>. This leads to a
492 complete chain of C</hello/$arg/world/$arg> which is matched against the
495 This example application would, if run and called by e.g.
496 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
497 value C<arg_sum> to "23". The C<world> action would then append "World!"
498 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
499 sake of simplicity no view is shown. Instead we just put the values of
500 the stash into our body. So the output would look like:
505 And our test server would have given us this debugging output for the
509 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
510 [debug] Path is "/greeting/world"
511 [debug] Arguments are "12"
512 [info] Request took 0.164113s (6.093/s)
513 .------------------------------------------+-----------.
515 +------------------------------------------+-----------+
516 | /greeting/hello | 0.000029s |
517 | /greeting/world | 0.000024s |
518 '------------------------------------------+-----------'
521 What would be common uses of this dispatch technique? It gives the
522 possibility to split up logic that contains steps that each depend on
523 each other. An example would be, for example, a wiki path like
524 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
527 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
528 my ( $self, $c, $page_name ) = @_;
529 # load the page named $page_name and put the object
533 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
534 my ( $self, $c, $revision_id ) = @_;
535 # use the page object in the stash to get at its
536 # revision with number $revision_id
539 sub view : PathPart Chained('rev') Args(0) {
540 my ( $self, $c ) = @_;
541 # display the revision in our stash. Another option
542 # would be to forward a compatible object to the action
543 # that displays the default wiki pages, unless we want
544 # a different interface here, for example restore
548 It would now be possible to add other endpoints, for example C<restore>
549 to restore this specific revision as the current state.
551 You don't have to put all the chained actions in one controller. The
552 specification of the parent through C<:Chained> also takes an absolute
553 action path as its argument. Just specify it with a leading C</>.
555 If you want, for example, to have actions for the public paths
556 C</foo/12/edit> and C</foo/12>, just specify two actions with
557 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
558 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
559 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
560 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
561 this debugging output:
564 [debug] Loaded Path Part actions:
565 .-----------------------+------------------------------.
566 | Path Spec | Private |
567 +-----------------------+------------------------------+
568 | /foo/* | /controller/foo_view |
569 | /foo/*/edit | /controller/foo_load (1) |
570 | | => /controller/edit |
571 '-----------------------+------------------------------'
574 Here's a more detailed specification of the attributes belonging to
583 Sets the name of this part of the chain. If it is specified without
584 arguments, it takes the name of the action as default. So basically
585 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
586 This can also contain slashes to bind to a deeper level. An action
587 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
588 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
589 effect as using C<:PathPart>, it would default to the action name.
593 Sets PathPart to the path_prefix of the current controller.
597 Has to be specified for every child in the chain. Possible values are
598 absolute and relative private action paths or a single slash C</> to
599 tell Catalyst that this is the root of a chain. The attribute
600 C<:Chained> without arguments also defaults to the C</> behavior.
601 Relative action paths may use C<../> to refer to actions in parent
604 Because you can specify an absolute path to the parent action, it
605 doesn't matter to Catalyst where that parent is located. So, if your
606 design requests it, you can redispatch a chain through any controller or
609 Another interesting possibility gives C<:Chained('.')>, which chains
610 itself to an action with the path of the current controller's namespace.
613 # in MyApp::Controller::Foo
614 sub bar : Chained CaptureArgs(1) { ... }
616 # in MyApp::Controller::Foo::Bar
617 sub baz : Chained('.') Args(1) { ... }
619 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
620 as the argument to Chained here chains the C<baz> action to an action
621 with the path of the current controller namespace, namely
622 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
623 chain comes out as the end product.
627 Chains an action to another action with the same name in the parent
628 controller. For Example:
630 # in MyApp::Controller::Foo
631 sub bar : Chained CaptureArgs(1) { ... }
633 # in MyApp::Controller::Foo::Moo
634 sub bar : ChainedParent Args(1) { ... }
636 This builds a chain like C</bar/*/bar/*>.
640 Must be specified for every part of the chain that is not an
641 endpoint. With this attribute Catalyst knows how many of the following
642 parts of the path (separated by C</>) this action wants to capture as
643 its arguments. If it doesn't expect any, just specify
644 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
645 after the context, but you can also find them as array references in
646 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
647 level of the action in the chain that captured the parts of the path.
649 An action that is part of a chain (that is, one that has a C<:Chained>
650 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
655 By default, endpoints receive the rest of the arguments in the path. You
656 can tell Catalyst through C<:Args> explicitly how many arguments your
657 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
658 also affects whether this chain is invoked on a request. A chain with an
659 endpoint specifying one argument will only match if exactly one argument
662 You can specify an exact number of arguments like C<:Args(3)>, including
663 C<0>. If you just say C<:Args> without any arguments, it is the same as
664 leaving it out altogether: The chain is matched regardless of the number
665 of path parts after the endpoint.
667 Just as with C<:CaptureArgs>, the arguments get passed to the action in
668 C<@_> after the context object. They can also be reached through
669 C<$c-E<gt>request-E<gt>arguments>.
673 =head2 Auto actions, dispatching and forwarding
675 Note that the list of C<auto> actions called depends on the private path
676 of the endpoint of the chain, not on the chained actions way. The
677 C<auto> actions will be run before the chain dispatching begins. In
678 every other aspect, C<auto> actions behave as documented.
680 The C<forward>ing to other actions does just what you would expect. But if
681 you C<detach> out of a chain, the rest of the chain will not get called
684 =head2 match_captures
686 A method which can optionally be implemented by actions to
689 See L<Catalyst::Action> for further details.
693 Catalyst Contributors, see Catalyst.pm
697 This library is free software. You can redistribute it and/or modify it under
698 the same terms as Perl itself.