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 = $endpoint->attributes->{Args}->[0];
100 my @parts = (defined($args) ? (("*") x $args) : '...');
102 my $parent = "DUMMY";
103 my $curr = $endpoint;
105 if (my $cap = $curr->attributes->{CaptureArgs}) {
106 unshift(@parts, (("*") x $cap->[0]));
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 (my $cap = $p->attributes->{CaptureArgs}) {
125 $name .= ' ('.$cap->[0].')';
127 unless ($p eq $parents[0]) {
128 $name = "-> ${name}";
130 push(@rows, [ '', $name ]);
132 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
133 $rows[0][0] = join('/', '', @parts) || '/';
134 $paths->row(@$_) for @rows;
137 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
138 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
139 if $has_unattached_actions;
142 =head2 $self->match( $c, $path )
144 Calls C<recurse_match> to see if a chain matches the C<$path>.
149 my ( $self, $c, $path ) = @_;
151 my $request = $c->request;
152 return 0 if @{$request->args};
154 my @parts = split('/', $path);
156 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
158 if ($parts && @$parts) {
159 for my $arg (@$parts) {
160 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
161 push @{$request->args}, $arg;
165 return 0 unless $chain;
167 my $action = Catalyst::ActionChain->from_chain($chain);
169 $request->action("/${action}");
170 $request->match("/${action}");
171 $request->captures($captures);
173 $c->namespace( $action->namespace );
178 =head2 $self->recurse_match( $c, $parent, \@path_parts )
180 Recursive search for a matching chain.
185 my ( $self, $c, $parent, $path_parts ) = @_;
186 my $children = $self->_children_of->{$parent};
187 return () unless $children;
190 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
192 # $b then $a to try longest part first
193 my @parts = @$path_parts;
194 if (length $try_part) { # test and strip PathPart
196 ($try_part eq join('/', # assemble equal number of parts
197 splice( # and strip them off @parts as well
198 @parts, 0, scalar(@{[split('/', $try_part)]})
199 ))); # @{[]} to avoid split to @_
201 my @try_actions = @{$children->{$try_part}};
202 TRY_ACTION: foreach my $action (@try_actions) {
203 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
206 # Short-circuit if not enough remaining parts
207 next TRY_ACTION unless @parts >= $capture_attr->[0];
210 my @parts = @parts; # localise
212 # strip CaptureArgs into list
213 push(@captures, splice(@parts, 0, $capture_attr->[0]));
215 # check if the action may fit, depending on a given test by the app
216 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
218 # try the remaining parts against children of this action
219 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
220 $c, '/'.$action->reverse, \@parts
222 # No best action currently
223 # OR The action has less parts
224 # OR The action has equal parts but less captured data (ergo more defined)
227 $#$action_parts < $#{$best_action->{parts}} ||
228 ($#$action_parts == $#{$best_action->{parts}} &&
229 $#$captures < $#{$best_action->{captures}} &&
230 $n_pathparts > $best_action->{n_pathparts}))) {
231 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
233 actions => [ $action, @$actions ],
234 captures=> [ @captures, @$captures ],
235 parts => $action_parts,
236 n_pathparts => scalar(@pathparts) + $n_pathparts,
242 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
243 next TRY_ACTION unless $action->match($c);
245 my $args_attr = $action->attributes->{Args}->[0];
246 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
247 # No best action currently
248 # OR This one matches with fewer parts left than the current best action,
249 # And therefore is a better match
250 # OR No parts and this expects 0
251 # The current best action might also be Args(0),
252 # but we couldn't chose between then anyway so we'll take the last seen
255 @parts < @{$best_action->{parts}} ||
256 (!@parts && defined($args_attr) && $args_attr eq "0")){
258 actions => [ $action ],
261 n_pathparts => scalar(@pathparts),
267 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
271 =head2 $self->register( $c, $action )
273 Calls register_path for every Path attribute for the given $action.
278 my ( $self, $c, $action ) = @_;
280 my @chained_attr = @{ $action->attributes->{Chained} || [] };
282 return 0 unless @chained_attr;
284 if (@chained_attr > 1) {
285 Catalyst::Exception->throw(
286 "Multiple Chained attributes not supported registering ${action}"
289 my $chained_to = $chained_attr[0];
291 Catalyst::Exception->throw(
292 "Actions cannot chain to themselves registering /${action}"
293 ) if ($chained_to eq '/' . $action);
295 my $children = ($self->_children_of->{ $chained_to } ||= {});
297 my @path_part = @{ $action->attributes->{PathPart} || [] };
299 my $part = $action->name;
301 if (@path_part == 1 && defined $path_part[0]) {
302 $part = $path_part[0];
303 } elsif (@path_part > 1) {
304 Catalyst::Exception->throw(
305 "Multiple PathPart attributes not supported registering " . $action->reverse()
309 if ($part =~ m(^/)) {
310 Catalyst::Exception->throw(
311 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
315 $action->attributes->{PathPart} = [ $part ];
317 unshift(@{ $children->{$part} ||= [] }, $action);
319 $self->_actions->{'/'.$action->reverse} = $action;
321 if (exists $action->attributes->{Args}) {
322 my $args = $action->attributes->{Args}->[0];
323 if (defined($args) and not (
324 Scalar::Util::looks_like_number($args) and
327 require Data::Dumper;
328 local $Data::Dumper::Terse = 1;
329 local $Data::Dumper::Indent = 0;
330 $args = Data::Dumper::Dumper($args);
331 Catalyst::Exception->throw(
332 "Invalid Args($args) for action " . $action->reverse() .
333 " (use 'Args' or 'Args(<number>)'"
338 unless ($action->attributes->{CaptureArgs}) {
339 unshift(@{ $self->_endpoints }, $action);
345 =head2 $self->uri_for_action($action, $captures)
347 Get the URI part for the action, using C<$captures> to fill
353 my ( $self, $action, $captures ) = @_;
355 return undef unless ($action->attributes->{Chained}
356 && !$action->attributes->{CaptureArgs});
359 my @captures = @$captures;
360 my $parent = "DUMMY";
363 if (my $cap = $curr->attributes->{CaptureArgs}) {
364 return undef unless @captures >= ($cap->[0]||0); # not enough captures
366 unshift(@parts, splice(@captures, -$cap->[0]));
369 if (my $pp = $curr->attributes->{PathPart}) {
370 unshift(@parts, $pp->[0])
371 if (defined($pp->[0]) && length($pp->[0]));
373 $parent = $curr->attributes->{Chained}->[0];
374 $curr = $self->_actions->{$parent};
377 return undef unless $parent eq '/'; # fail for dangling action
379 return undef if @captures; # fail for too many captures
381 return join('/', '', @parts);
385 =head2 $c->expand_action($action)
387 Return a list of actions that represents a chained action. See
388 L<Catalyst::Dispatcher> for more info. You probably want to
389 use the expand_action it provides rather than this directly.
394 my ($self, $action) = @_;
396 return unless $action->attributes && $action->attributes->{Chained};
403 my $parent = $curr->attributes->{Chained}->[0];
404 $curr = $self->_actions->{$parent};
407 return Catalyst::ActionChain->from_chain([reverse @chain]);
410 __PACKAGE__->meta->make_immutable;
417 The C<Chained> attribute allows you to chain public path parts together
418 by their private names. A chain part's path can be specified with
419 C<PathPart> and can be declared to expect an arbitrary number of
420 arguments. The endpoint of the chain specifies how many arguments it
421 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
422 C<:Args> without an integer would be unlimited. The path parts that
423 aren't endpoints are using C<CaptureArgs> to specify how many parameters
424 they expect to receive. As an example setup:
426 package MyApp::Controller::Greeting;
427 use base qw/ Catalyst::Controller /;
429 # this is the beginning of our chain
430 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
431 my ( $self, $c, $integer ) = @_;
432 $c->stash->{ message } = "Hello ";
433 $c->stash->{ arg_sum } = $integer;
436 # this is our endpoint, because it has no :CaptureArgs
437 sub world : PathPart('world') Chained('hello') Args(1) {
438 my ( $self, $c, $integer ) = @_;
439 $c->stash->{ message } .= "World!";
440 $c->stash->{ arg_sum } += $integer;
442 $c->response->body( join "<br/>\n" =>
443 $c->stash->{ message }, $c->stash->{ arg_sum } );
446 The debug output provides a separate table for chained actions, showing
447 the whole chain as it would match and the actions it contains. Here's an
448 example of the startup output with our actions above:
451 [debug] Loaded Path Part actions:
452 .-----------------------+------------------------------.
453 | Path Spec | Private |
454 +-----------------------+------------------------------+
455 | /hello/*/world/* | /greeting/hello (1) |
456 | | => /greeting/world |
457 '-----------------------+------------------------------'
460 As you can see, Catalyst only deals with chains as whole paths and
461 builds one for each endpoint, which are the actions with C<:Chained> but
462 without C<:CaptureArgs>.
464 Let's assume this application gets a request at the path
465 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
466 to the C<hello> action and pass the value C<23> as an argument to it
467 after the context. It does so because we have previously used
468 C<:CaptureArgs(1)> to declare that it has one path part after itself as
469 its argument. We told Catalyst that this is the beginning of the chain
470 by specifying C<:Chained('/')>. Also note that instead of saying
471 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
472 defaults to the name of the action.
474 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
475 action. This is the last action to be called: Catalyst knows this is an
476 endpoint because we did not specify a C<:CaptureArgs>
477 attribute. Nevertheless we specify that this action expects an argument,
478 but at this point we're using C<:Args(1)> to do that. We could also have
479 said C<:Args> or left it out altogether, which would mean this action
480 would get all arguments that are there. This action's C<:Chained>
481 attribute says C<hello> and tells Catalyst that the C<hello> action in
482 the current controller is its parent.
484 With this we have built a chain consisting of two public path parts.
485 C<hello> captures one part of the path as its argument, and also
486 specifies the path root as its parent. So this part is
487 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
488 argument. It sums up to the path part C<world/$arg>. This leads to a
489 complete chain of C</hello/$arg/world/$arg> which is matched against the
492 This example application would, if run and called by e.g.
493 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
494 value C<arg_sum> to "23". The C<world> action would then append "World!"
495 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
496 sake of simplicity no view is shown. Instead we just put the values of
497 the stash into our body. So the output would look like:
502 And our test server would have given us this debugging output for the
506 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
507 [debug] Path is "/greeting/world"
508 [debug] Arguments are "12"
509 [info] Request took 0.164113s (6.093/s)
510 .------------------------------------------+-----------.
512 +------------------------------------------+-----------+
513 | /greeting/hello | 0.000029s |
514 | /greeting/world | 0.000024s |
515 '------------------------------------------+-----------'
518 What would be common uses of this dispatch technique? It gives the
519 possibility to split up logic that contains steps that each depend on
520 each other. An example would be, for example, a wiki path like
521 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
524 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
525 my ( $self, $c, $page_name ) = @_;
526 # load the page named $page_name and put the object
530 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
531 my ( $self, $c, $revision_id ) = @_;
532 # use the page object in the stash to get at its
533 # revision with number $revision_id
536 sub view : PathPart Chained('rev') Args(0) {
537 my ( $self, $c ) = @_;
538 # display the revision in our stash. Another option
539 # would be to forward a compatible object to the action
540 # that displays the default wiki pages, unless we want
541 # a different interface here, for example restore
545 It would now be possible to add other endpoints, for example C<restore>
546 to restore this specific revision as the current state.
548 You don't have to put all the chained actions in one controller. The
549 specification of the parent through C<:Chained> also takes an absolute
550 action path as its argument. Just specify it with a leading C</>.
552 If you want, for example, to have actions for the public paths
553 C</foo/12/edit> and C</foo/12>, just specify two actions with
554 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
555 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
556 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
557 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
558 this debugging output:
561 [debug] Loaded Path Part actions:
562 .-----------------------+------------------------------.
563 | Path Spec | Private |
564 +-----------------------+------------------------------+
565 | /foo/* | /controller/foo_view |
566 | /foo/*/edit | /controller/foo_load (1) |
567 | | => /controller/edit |
568 '-----------------------+------------------------------'
571 Here's a more detailed specification of the attributes belonging to
580 Sets the name of this part of the chain. If it is specified without
581 arguments, it takes the name of the action as default. So basically
582 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
583 This can also contain slashes to bind to a deeper level. An action
584 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
585 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
586 effect as using C<:PathPart>, it would default to the action name.
590 Sets PathPart to the path_prefix of the current controller.
594 Has to be specified for every child in the chain. Possible values are
595 absolute and relative private action paths or a single slash C</> to
596 tell Catalyst that this is the root of a chain. The attribute
597 C<:Chained> without arguments also defaults to the C</> behavior.
598 Relative action paths may use C<../> to refer to actions in parent
601 Because you can specify an absolute path to the parent action, it
602 doesn't matter to Catalyst where that parent is located. So, if your
603 design requests it, you can redispatch a chain through any controller or
606 Another interesting possibility gives C<:Chained('.')>, which chains
607 itself to an action with the path of the current controller's namespace.
610 # in MyApp::Controller::Foo
611 sub bar : Chained CaptureArgs(1) { ... }
613 # in MyApp::Controller::Foo::Bar
614 sub baz : Chained('.') Args(1) { ... }
616 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
617 as the argument to Chained here chains the C<baz> action to an action
618 with the path of the current controller namespace, namely
619 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
620 chain comes out as the end product.
624 Chains an action to another action with the same name in the parent
625 controller. For Example:
627 # in MyApp::Controller::Foo
628 sub bar : Chained CaptureArgs(1) { ... }
630 # in MyApp::Controller::Foo::Moo
631 sub bar : ChainedParent Args(1) { ... }
633 This builds a chain like C</bar/*/bar/*>.
637 Must be specified for every part of the chain that is not an
638 endpoint. With this attribute Catalyst knows how many of the following
639 parts of the path (separated by C</>) this action wants to capture as
640 its arguments. If it doesn't expect any, just specify
641 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
642 after the context, but you can also find them as array references in
643 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
644 level of the action in the chain that captured the parts of the path.
646 An action that is part of a chain (that is, one that has a C<:Chained>
647 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
652 By default, endpoints receive the rest of the arguments in the path. You
653 can tell Catalyst through C<:Args> explicitly how many arguments your
654 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
655 also affects whether this chain is invoked on a request. A chain with an
656 endpoint specifying one argument will only match if exactly one argument
659 You can specify an exact number of arguments like C<:Args(3)>, including
660 C<0>. If you just say C<:Args> without any arguments, it is the same as
661 leaving it out altogether: The chain is matched regardless of the number
662 of path parts after the endpoint.
664 Just as with C<:CaptureArgs>, the arguments get passed to the action in
665 C<@_> after the context object. They can also be reached through
666 C<$c-E<gt>request-E<gt>arguments>.
670 =head2 Auto actions, dispatching and forwarding
672 Note that the list of C<auto> actions called depends on the private path
673 of the endpoint of the chain, not on the chained actions way. The
674 C<auto> actions will be run before the chain dispatching begins. In
675 every other aspect, C<auto> actions behave as documented.
677 The C<forward>ing to other actions does just what you would expect. But if
678 you C<detach> out of a chain, the rest of the chain will not get called
681 =head2 match_captures
683 A method which can optionally be implemented by actions to
686 See L<Catalyst::Action> for further details.
690 Catalyst Contributors, see Catalyst.pm
694 This library is free software. You can redistribute it and/or modify it under
695 the same terms as Perl itself.