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->{PartPath}) {
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}) {
205 # Short-circuit if not enough remaining parts
206 next TRY_ACTION unless @parts >= $capture_attr->[0];
209 my @parts = @parts; # localise
211 # strip CaptureArgs into list
212 push(@captures, splice(@parts, 0, $capture_attr->[0]));
214 # try the remaining parts against children of this action
215 my ($actions, $captures, $action_parts) = $self->recurse_match(
216 $c, '/'.$action->reverse, \@parts
218 # No best action currently
219 # OR The action has less parts
220 # OR The action has equal parts but less captured data (ergo more defined)
223 $#$action_parts < $#{$best_action->{parts}} ||
224 ($#$action_parts == $#{$best_action->{parts}} &&
225 $#$captures < $#{$best_action->{captures}}))){
227 actions => [ $action, @$actions ],
228 captures=> [ @captures, @$captures ],
229 parts => $action_parts
235 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
236 next TRY_ACTION unless $action->match($c);
239 # Default args is blank, not 0, since Args()
240 my $args_attr = $action->attributes->{Args}->[0] || '';
242 # No best action currently
243 # OR This one matches with fewer parts left than the current best action,
244 # And therefore is a better match
245 # OR No parts and this expects 0
246 # The current best action might also be Args(0),
247 # but we couldn't chose between then anyway so we'll take the last seen
250 @parts < @{$best_action->{parts}} ||
251 (!@parts && $args_attr eq 0)){
253 actions => [ $action ],
261 return @$best_action{qw/actions captures parts/} if $best_action;
265 =head2 $self->register( $c, $action )
267 Calls register_path for every Path attribute for the given $action.
272 my ( $self, $c, $action ) = @_;
274 my @chained_attr = @{ $action->attributes->{Chained} || [] };
276 return 0 unless @chained_attr;
278 if (@chained_attr > 1) {
279 Catalyst::Exception->throw(
280 "Multiple Chained attributes not supported registering ${action}"
283 my $chained_to = $chained_attr[0];
285 Catalyst::Exception->throw(
286 "Actions cannot chain to themselves registering /${action}"
287 ) if ($chained_to eq '/' . $action);
289 my $children = ($self->_children_of->{ $chained_to } ||= {});
291 my @path_part = @{ $action->attributes->{PathPart} || [] };
293 my $part = $action->name;
295 if (@path_part == 1 && defined $path_part[0]) {
296 $part = $path_part[0];
297 } elsif (@path_part > 1) {
298 Catalyst::Exception->throw(
299 "Multiple PathPart attributes not supported registering " . $action->reverse()
303 if ($part =~ m(^/)) {
304 Catalyst::Exception->throw(
305 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
309 $action->attributes->{PartPath} = [ $part ];
311 unshift(@{ $children->{$part} ||= [] }, $action);
313 $self->_actions->{'/'.$action->reverse} = $action;
315 if (exists $action->attributes->{Args}) {
316 my $args = $action->attributes->{Args}->[0];
317 if (defined($args) and not (
318 Scalar::Util::looks_like_number($args) and
321 require Data::Dumper;
322 local $Data::Dumper::Terse = 1;
323 local $Data::Dumper::Indent = 0;
324 $args = Data::Dumper::Dumper($args);
325 Catalyst::Exception->throw(
326 "Invalid Args($args) for action " . $action->reverse() .
327 " (use 'Args' or 'Args(<number>)'"
332 unless ($action->attributes->{CaptureArgs}) {
333 unshift(@{ $self->_endpoints }, $action);
339 =head2 $self->uri_for_action($action, $captures)
341 Get the URI part for the action, using C<$captures> to fill
347 my ( $self, $action, $captures ) = @_;
349 return undef unless ($action->attributes->{Chained}
350 && !$action->attributes->{CaptureArgs});
353 my @captures = @$captures;
354 my $parent = "DUMMY";
357 if (my $cap = $curr->attributes->{CaptureArgs}) {
358 return undef unless @captures >= $cap->[0]; # not enough captures
360 unshift(@parts, splice(@captures, -$cap->[0]));
363 if (my $pp = $curr->attributes->{PartPath}) {
364 unshift(@parts, $pp->[0])
365 if (defined($pp->[0]) && length($pp->[0]));
367 $parent = $curr->attributes->{Chained}->[0];
368 $curr = $self->_actions->{$parent};
371 return undef unless $parent eq '/'; # fail for dangling action
373 return undef if @captures; # fail for too many captures
375 return join('/', '', @parts);
379 =head2 $c->expand_action($action)
381 Return a list of actions that represents a chained action. See
382 L<Catalyst::Dispatcher> for more info. You probably want to
383 use the expand_action it provides rather than this directly.
388 my ($self, $action) = @_;
390 return unless $action->attributes && $action->attributes->{Chained};
397 my $parent = $curr->attributes->{Chained}->[0];
398 $curr = $self->_actions->{$parent};
401 return Catalyst::ActionChain->from_chain([reverse @chain]);
404 __PACKAGE__->meta->make_immutable;
410 The C<Chained> attribute allows you to chain public path parts together
411 by their private names. A chain part's path can be specified with
412 C<PathPart> and can be declared to expect an arbitrary number of
413 arguments. The endpoint of the chain specifies how many arguments it
414 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
415 C<:Args> without an integer would be unlimited. The path parts that
416 aren't endpoints are using C<CaptureArgs> to specify how many parameters
417 they expect to receive. As an example setup:
419 package MyApp::Controller::Greeting;
420 use base qw/ Catalyst::Controller /;
422 # this is the beginning of our chain
423 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
424 my ( $self, $c, $integer ) = @_;
425 $c->stash->{ message } = "Hello ";
426 $c->stash->{ arg_sum } = $integer;
429 # this is our endpoint, because it has no :CaptureArgs
430 sub world : PathPart('world') Chained('hello') Args(1) {
431 my ( $self, $c, $integer ) = @_;
432 $c->stash->{ message } .= "World!";
433 $c->stash->{ arg_sum } += $integer;
435 $c->response->body( join "<br/>\n" =>
436 $c->stash->{ message }, $c->stash->{ arg_sum } );
439 The debug output provides a separate table for chained actions, showing
440 the whole chain as it would match and the actions it contains. Here's an
441 example of the startup output with our actions above:
444 [debug] Loaded Path Part actions:
445 .-----------------------+------------------------------.
446 | Path Spec | Private |
447 +-----------------------+------------------------------+
448 | /hello/*/world/* | /greeting/hello (1) |
449 | | => /greeting/world |
450 '-----------------------+------------------------------'
453 As you can see, Catalyst only deals with chains as whole paths and
454 builds one for each endpoint, which are the actions with C<:Chained> but
455 without C<:CaptureArgs>.
457 Let's assume this application gets a request at the path
458 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
459 to the C<hello> action and pass the value C<23> as an argument to it
460 after the context. It does so because we have previously used
461 C<:CaptureArgs(1)> to declare that it has one path part after itself as
462 its argument. We told Catalyst that this is the beginning of the chain
463 by specifying C<:Chained('/')>. Also note that instead of saying
464 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
465 defaults to the name of the action.
467 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
468 action. This is the last action to be called: Catalyst knows this is an
469 endpoint because we did not specify a C<:CaptureArgs>
470 attribute. Nevertheless we specify that this action expects an argument,
471 but at this point we're using C<:Args(1)> to do that. We could also have
472 said C<:Args> or left it out altogether, which would mean this action
473 would get all arguments that are there. This action's C<:Chained>
474 attribute says C<hello> and tells Catalyst that the C<hello> action in
475 the current controller is its parent.
477 With this we have built a chain consisting of two public path parts.
478 C<hello> captures one part of the path as its argument, and also
479 specifies the path root as its parent. So this part is
480 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
481 argument. It sums up to the path part C<world/$arg>. This leads to a
482 complete chain of C</hello/$arg/world/$arg> which is matched against the
485 This example application would, if run and called by e.g.
486 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
487 value C<arg_sum> to "23". The C<world> action would then append "World!"
488 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
489 sake of simplicity no view is shown. Instead we just put the values of
490 the stash into our body. So the output would look like:
495 And our test server would have given us this debugging output for the
499 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
500 [debug] Path is "/greeting/world"
501 [debug] Arguments are "12"
502 [info] Request took 0.164113s (6.093/s)
503 .------------------------------------------+-----------.
505 +------------------------------------------+-----------+
506 | /greeting/hello | 0.000029s |
507 | /greeting/world | 0.000024s |
508 '------------------------------------------+-----------'
511 What would be common uses of this dispatch technique? It gives the
512 possibility to split up logic that contains steps that each depend on
513 each other. An example would be, for example, a wiki path like
514 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
517 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
518 my ( $self, $c, $page_name ) = @_;
519 # load the page named $page_name and put the object
523 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
524 my ( $self, $c, $revision_id ) = @_;
525 # use the page object in the stash to get at its
526 # revision with number $revision_id
529 sub view : PathPart Chained('rev') Args(0) {
530 my ( $self, $c ) = @_;
531 # display the revision in our stash. Another option
532 # would be to forward a compatible object to the action
533 # that displays the default wiki pages, unless we want
534 # a different interface here, for example restore
538 It would now be possible to add other endpoints, for example C<restore>
539 to restore this specific revision as the current state.
541 You don't have to put all the chained actions in one controller. The
542 specification of the parent through C<:Chained> also takes an absolute
543 action path as its argument. Just specify it with a leading C</>.
545 If you want, for example, to have actions for the public paths
546 C</foo/12/edit> and C</foo/12>, just specify two actions with
547 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
548 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
549 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
550 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
551 this debugging output:
554 [debug] Loaded Path Part actions:
555 .-----------------------+------------------------------.
556 | Path Spec | Private |
557 +-----------------------+------------------------------+
558 | /foo/* | /controller/foo_view |
559 | /foo/*/edit | /controller/foo_load (1) |
560 | | => /controller/edit |
561 '-----------------------+------------------------------'
564 Here's a more detailed specification of the attributes belonging to
573 Sets the name of this part of the chain. If it is specified without
574 arguments, it takes the name of the action as default. So basically
575 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
576 This can also contain slashes to bind to a deeper level. An action
577 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
578 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
579 effect as using C<:PathPart>, it would default to the action name.
583 Sets PathPart to the path_prefix of the current controller.
587 Has to be specified for every child in the chain. Possible values are
588 absolute and relative private action paths or a single slash C</> to
589 tell Catalyst that this is the root of a chain. The attribute
590 C<:Chained> without arguments also defaults to the C</> behavior.
591 Relative action paths may use C<../> to refer to actions in parent
594 Because you can specify an absolute path to the parent action, it
595 doesn't matter to Catalyst where that parent is located. So, if your
596 design requests it, you can redispatch a chain through any controller or
599 Another interesting possibility gives C<:Chained('.')>, which chains
600 itself to an action with the path of the current controller's namespace.
603 # in MyApp::Controller::Foo
604 sub bar : Chained CaptureArgs(1) { ... }
606 # in MyApp::Controller::Foo::Bar
607 sub baz : Chained('.') Args(1) { ... }
609 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
610 as the argument to Chained here chains the C<baz> action to an action
611 with the path of the current controller namespace, namely
612 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
613 chain comes out as the end product.
617 Chains an action to another action with the same name in the parent
618 controller. For Example:
620 # in MyApp::Controller::Foo
621 sub bar : Chained CaptureArgs(1) { ... }
623 # in MyApp::Controller::Foo::Moo
624 sub bar : ChainedParent Args(1) { ... }
626 This builds a chain like C</bar/*/bar/*>.
630 Must be specified for every part of the chain that is not an
631 endpoint. With this attribute Catalyst knows how many of the following
632 parts of the path (separated by C</>) this action wants to capture as
633 its arguments. If it doesn't expect any, just specify
634 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
635 after the context, but you can also find them as array references in
636 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
637 level of the action in the chain that captured the parts of the path.
639 An action that is part of a chain (that is, one that has a C<:Chained>
640 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
645 By default, endpoints receive the rest of the arguments in the path. You
646 can tell Catalyst through C<:Args> explicitly how many arguments your
647 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
648 also affects whether this chain is invoked on a request. A chain with an
649 endpoint specifying one argument will only match if exactly one argument
652 You can specify an exact number of arguments like C<:Args(3)>, including
653 C<0>. If you just say C<:Args> without any arguments, it is the same as
654 leaving it out altogether: The chain is matched regardless of the number
655 of path parts after the endpoint.
657 Just as with C<:CaptureArgs>, the arguments get passed to the action in
658 C<@_> after the context object. They can also be reached through
659 C<$c-E<gt>request-E<gt>arguments>.
663 =head2 Auto actions, dispatching and forwarding
665 Note that the list of C<auto> actions called depends on the private path
666 of the endpoint of the chain, not on the chained actions way. The
667 C<auto> actions will be run before the chain dispatching begins. In
668 every other aspect, C<auto> actions behave as documented.
670 The C<forward>ing to other actions does just what you would expect. But if
671 you C<detach> out of a chain, the rest of the chain will not get called
676 Catalyst Contributors, see Catalyst.pm
680 This library is free software. You can redistribute it and/or modify it under
681 the same terms as Perl itself.