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 $column_width = Catalyst::Utils::term_width() - 35 - 9;
84 my $paths = Text::SimpleTable->new(
85 [ 35, 'Path Spec' ], [ $column_width, 'Private' ],
88 my $has_unattached_actions;
89 my $unattached_actions = Text::SimpleTable->new(
90 [ 35, 'Private' ], [ $column_width, 'Missing parent' ],
93 ENDPOINT: foreach my $endpoint (
94 sort { $a->reverse cmp $b->reverse }
95 @{ $self->_endpoints }
97 my $args = $endpoint->attributes->{Args}->[0];
98 my @parts = (defined($args) ? (("*") x $args) : '...');
100 my $parent = "DUMMY";
101 my $curr = $endpoint;
103 if (my $cap = $curr->attributes->{CaptureArgs}) {
104 unshift(@parts, (("*") x $cap->[0]));
106 if (my $pp = $curr->attributes->{PartPath}) {
107 unshift(@parts, $pp->[0])
108 if (defined $pp->[0] && length $pp->[0]);
110 $parent = $curr->attributes->{Chained}->[0];
111 $curr = $self->_actions->{$parent};
112 unshift(@parents, $curr) if $curr;
114 if ($parent ne '/') {
115 $has_unattached_actions = 1;
116 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
120 foreach my $p (@parents) {
122 if (my $cap = $p->attributes->{CaptureArgs}) {
123 $name .= ' ('.$cap->[0].')';
125 unless ($p eq $parents[0]) {
126 $name = "-> ${name}";
128 push(@rows, [ '', $name ]);
130 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
131 $rows[0][0] = join('/', '', @parts) || '/';
132 $paths->row(@$_) for @rows;
135 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
136 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
137 if $has_unattached_actions;
140 =head2 $self->match( $c, $path )
142 Calls C<recurse_match> to see if a chain matches the C<$path>.
147 my ( $self, $c, $path ) = @_;
149 my $request = $c->request;
150 return 0 if @{$request->args};
152 my @parts = split('/', $path);
154 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
156 if ($parts && @$parts) {
157 for my $arg (@$parts) {
158 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
159 push @{$request->args}, $arg;
163 return 0 unless $chain;
165 my $action = Catalyst::ActionChain->from_chain($chain);
167 $request->action("/${action}");
168 $request->match("/${action}");
169 $request->captures($captures);
171 $c->namespace( $action->namespace );
176 =head2 $self->recurse_match( $c, $parent, \@path_parts )
178 Recursive search for a matching chain.
183 my ( $self, $c, $parent, $path_parts ) = @_;
184 my $children = $self->_children_of->{$parent};
185 return () unless $children;
188 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
190 # $b then $a to try longest part first
191 my @parts = @$path_parts;
192 if (length $try_part) { # test and strip PathPart
194 ($try_part eq join('/', # assemble equal number of parts
195 splice( # and strip them off @parts as well
196 @parts, 0, scalar(@{[split('/', $try_part)]})
197 ))); # @{[]} to avoid split to @_
199 my @try_actions = @{$children->{$try_part}};
200 TRY_ACTION: foreach my $action (@try_actions) {
201 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
203 # Short-circuit if not enough remaining parts
204 next TRY_ACTION unless @parts >= $capture_attr->[0];
207 my @parts = @parts; # localise
209 # strip CaptureArgs into list
210 push(@captures, splice(@parts, 0, $capture_attr->[0]));
212 # try the remaining parts against children of this action
213 my ($actions, $captures, $action_parts) = $self->recurse_match(
214 $c, '/'.$action->reverse, \@parts
216 # No best action currently
217 # OR The action has less parts
218 # OR The action has equal parts but less captured data (ergo more defined)
221 $#$action_parts < $#{$best_action->{parts}} ||
222 ($#$action_parts == $#{$best_action->{parts}} &&
223 $#$captures < $#{$best_action->{captures}}))){
225 actions => [ $action, @$actions ],
226 captures=> [ @captures, @$captures ],
227 parts => $action_parts
233 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
234 next TRY_ACTION unless $action->match($c);
236 my $args_attr = $action->attributes->{Args}->[0];
238 # No best action currently
239 # OR This one matches with fewer parts left than the current best action,
240 # And therefore is a better match
241 # OR No parts and this expects 0
242 # The current best action might also be Args(0),
243 # but we couldn't chose between then anyway so we'll take the last seen
246 @parts < @{$best_action->{parts}} ||
247 (!@parts && $args_attr eq 0)){
249 actions => [ $action ],
257 return @$best_action{qw/actions captures parts/} if $best_action;
261 =head2 $self->register( $c, $action )
263 Calls register_path for every Path attribute for the given $action.
268 my ( $self, $c, $action ) = @_;
270 my @chained_attr = @{ $action->attributes->{Chained} || [] };
272 return 0 unless @chained_attr;
274 if (@chained_attr > 1) {
275 Catalyst::Exception->throw(
276 "Multiple Chained attributes not supported registering ${action}"
279 my $chained_to = $chained_attr[0];
281 Catalyst::Exception->throw(
282 "Actions cannot chain to themselves registering /${action}"
283 ) if ($chained_to eq '/' . $action);
285 my $children = ($self->_children_of->{ $chained_to } ||= {});
287 my @path_part = @{ $action->attributes->{PathPart} || [] };
289 my $part = $action->name;
291 if (@path_part == 1 && defined $path_part[0]) {
292 $part = $path_part[0];
293 } elsif (@path_part > 1) {
294 Catalyst::Exception->throw(
295 "Multiple PathPart attributes not supported registering " . $action->reverse()
299 if ($part =~ m(^/)) {
300 Catalyst::Exception->throw(
301 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
305 $action->attributes->{PartPath} = [ $part ];
307 unshift(@{ $children->{$part} ||= [] }, $action);
309 $self->_actions->{'/'.$action->reverse} = $action;
311 if (exists $action->attributes->{Args}) {
312 my $args = $action->attributes->{Args}->[0];
313 if (defined($args) and not (
314 Scalar::Util::looks_like_number($args) and
317 require Data::Dumper;
318 local $Data::Dumper::Terse = 1;
319 local $Data::Dumper::Indent = 0;
320 $args = Data::Dumper::Dumper($args);
321 Catalyst::Exception->throw(
322 "Invalid Args($args) for action " . $action->reverse() .
323 " (use 'Args' or 'Args(<number>)'"
328 unless ($action->attributes->{CaptureArgs}) {
329 unshift(@{ $self->_endpoints }, $action);
335 =head2 $self->uri_for_action($action, $captures)
337 Get the URI part for the action, using C<$captures> to fill
343 my ( $self, $action, $captures ) = @_;
345 return undef unless ($action->attributes->{Chained}
346 && !$action->attributes->{CaptureArgs});
349 my @captures = @$captures;
350 my $parent = "DUMMY";
353 if (my $cap = $curr->attributes->{CaptureArgs}) {
354 return undef unless @captures >= $cap->[0]; # not enough captures
356 unshift(@parts, splice(@captures, -$cap->[0]));
359 if (my $pp = $curr->attributes->{PartPath}) {
360 unshift(@parts, $pp->[0])
361 if (defined($pp->[0]) && length($pp->[0]));
363 $parent = $curr->attributes->{Chained}->[0];
364 $curr = $self->_actions->{$parent};
367 return undef unless $parent eq '/'; # fail for dangling action
369 return undef if @captures; # fail for too many captures
371 return join('/', '', @parts);
375 =head2 $c->expand_action($action)
377 Return a list of actions that represents a chained action. See
378 L<Catalyst::Dispatcher> for more info. You probably want to
379 use the expand_action it provides rather than this directly.
384 my ($self, $action) = @_;
386 return unless $action->attributes && $action->attributes->{Chained};
393 my $parent = $curr->attributes->{Chained}->[0];
394 $curr = $self->_actions->{$parent};
397 return Catalyst::ActionChain->from_chain([reverse @chain]);
400 __PACKAGE__->meta->make_immutable;
406 The C<Chained> attribute allows you to chain public path parts together
407 by their private names. A chain part's path can be specified with
408 C<PathPart> and can be declared to expect an arbitrary number of
409 arguments. The endpoint of the chain specifies how many arguments it
410 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
411 C<:Args> without an integer would be unlimited. The path parts that
412 aren't endpoints are using C<CaptureArgs> to specify how many parameters
413 they expect to receive. As an example setup:
415 package MyApp::Controller::Greeting;
416 use base qw/ Catalyst::Controller /;
418 # this is the beginning of our chain
419 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
420 my ( $self, $c, $integer ) = @_;
421 $c->stash->{ message } = "Hello ";
422 $c->stash->{ arg_sum } = $integer;
425 # this is our endpoint, because it has no :CaptureArgs
426 sub world : PathPart('world') Chained('hello') Args(1) {
427 my ( $self, $c, $integer ) = @_;
428 $c->stash->{ message } .= "World!";
429 $c->stash->{ arg_sum } += $integer;
431 $c->response->body( join "<br/>\n" =>
432 $c->stash->{ message }, $c->stash->{ arg_sum } );
435 The debug output provides a separate table for chained actions, showing
436 the whole chain as it would match and the actions it contains. Here's an
437 example of the startup output with our actions above:
440 [debug] Loaded Path Part actions:
441 .-----------------------+------------------------------.
442 | Path Spec | Private |
443 +-----------------------+------------------------------+
444 | /hello/*/world/* | /greeting/hello (1) |
445 | | => /greeting/world |
446 '-----------------------+------------------------------'
449 As you can see, Catalyst only deals with chains as whole paths and
450 builds one for each endpoint, which are the actions with C<:Chained> but
451 without C<:CaptureArgs>.
453 Let's assume this application gets a request at the path
454 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
455 to the C<hello> action and pass the value C<23> as an argument to it
456 after the context. It does so because we have previously used
457 C<:CaptureArgs(1)> to declare that it has one path part after itself as
458 its argument. We told Catalyst that this is the beginning of the chain
459 by specifying C<:Chained('/')>. Also note that instead of saying
460 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
461 defaults to the name of the action.
463 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
464 action. This is the last action to be called: Catalyst knows this is an
465 endpoint because we did not specify a C<:CaptureArgs>
466 attribute. Nevertheless we specify that this action expects an argument,
467 but at this point we're using C<:Args(1)> to do that. We could also have
468 said C<:Args> or left it out altogether, which would mean this action
469 would get all arguments that are there. This action's C<:Chained>
470 attribute says C<hello> and tells Catalyst that the C<hello> action in
471 the current controller is its parent.
473 With this we have built a chain consisting of two public path parts.
474 C<hello> captures one part of the path as its argument, and also
475 specifies the path root as its parent. So this part is
476 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
477 argument. It sums up to the path part C<world/$arg>. This leads to a
478 complete chain of C</hello/$arg/world/$arg> which is matched against the
481 This example application would, if run and called by e.g.
482 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
483 value C<arg_sum> to "23". The C<world> action would then append "World!"
484 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
485 sake of simplicity no view is shown. Instead we just put the values of
486 the stash into our body. So the output would look like:
491 And our test server would have given us this debugging output for the
495 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
496 [debug] Path is "/greeting/world"
497 [debug] Arguments are "12"
498 [info] Request took 0.164113s (6.093/s)
499 .------------------------------------------+-----------.
501 +------------------------------------------+-----------+
502 | /greeting/hello | 0.000029s |
503 | /greeting/world | 0.000024s |
504 '------------------------------------------+-----------'
507 What would be common uses of this dispatch technique? It gives the
508 possibility to split up logic that contains steps that each depend on
509 each other. An example would be, for example, a wiki path like
510 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
513 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
514 my ( $self, $c, $page_name ) = @_;
515 # load the page named $page_name and put the object
519 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
520 my ( $self, $c, $revision_id ) = @_;
521 # use the page object in the stash to get at its
522 # revision with number $revision_id
525 sub view : PathPart Chained('rev') Args(0) {
526 my ( $self, $c ) = @_;
527 # display the revision in our stash. Another option
528 # would be to forward a compatible object to the action
529 # that displays the default wiki pages, unless we want
530 # a different interface here, for example restore
534 It would now be possible to add other endpoints, for example C<restore>
535 to restore this specific revision as the current state.
537 You don't have to put all the chained actions in one controller. The
538 specification of the parent through C<:Chained> also takes an absolute
539 action path as its argument. Just specify it with a leading C</>.
541 If you want, for example, to have actions for the public paths
542 C</foo/12/edit> and C</foo/12>, just specify two actions with
543 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
544 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
545 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
546 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
547 this debugging output:
550 [debug] Loaded Path Part actions:
551 .-----------------------+------------------------------.
552 | Path Spec | Private |
553 +-----------------------+------------------------------+
554 | /foo/* | /controller/foo_view |
555 | /foo/*/edit | /controller/foo_load (1) |
556 | | => /controller/edit |
557 '-----------------------+------------------------------'
560 Here's a more detailed specification of the attributes belonging to
569 Sets the name of this part of the chain. If it is specified without
570 arguments, it takes the name of the action as default. So basically
571 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
572 This can also contain slashes to bind to a deeper level. An action
573 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
574 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
575 effect as using C<:PathPart>, it would default to the action name.
579 Sets PathPart to the path_prefix of the current controller.
583 Has to be specified for every child in the chain. Possible values are
584 absolute and relative private action paths or a single slash C</> to
585 tell Catalyst that this is the root of a chain. The attribute
586 C<:Chained> without arguments also defaults to the C</> behavior.
587 Relative action paths may use C<../> to refer to actions in parent
590 Because you can specify an absolute path to the parent action, it
591 doesn't matter to Catalyst where that parent is located. So, if your
592 design requests it, you can redispatch a chain through any controller or
595 Another interesting possibility gives C<:Chained('.')>, which chains
596 itself to an action with the path of the current controller's namespace.
599 # in MyApp::Controller::Foo
600 sub bar : Chained CaptureArgs(1) { ... }
602 # in MyApp::Controller::Foo::Bar
603 sub baz : Chained('.') Args(1) { ... }
605 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
606 as the argument to Chained here chains the C<baz> action to an action
607 with the path of the current controller namespace, namely
608 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
609 chain comes out as the end product.
613 Chains an action to another action with the same name in the parent
614 controller. For Example:
616 # in MyApp::Controller::Foo
617 sub bar : Chained CaptureArgs(1) { ... }
619 # in MyApp::Controller::Foo::Moo
620 sub bar : ChainedParent Args(1) { ... }
622 This builds a chain like C</bar/*/bar/*>.
626 Must be specified for every part of the chain that is not an
627 endpoint. With this attribute Catalyst knows how many of the following
628 parts of the path (separated by C</>) this action wants to capture as
629 its arguments. If it doesn't expect any, just specify
630 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
631 after the context, but you can also find them as array references in
632 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
633 level of the action in the chain that captured the parts of the path.
635 An action that is part of a chain (that is, one that has a C<:Chained>
636 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
641 By default, endpoints receive the rest of the arguments in the path. You
642 can tell Catalyst through C<:Args> explicitly how many arguments your
643 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
644 also affects whether this chain is invoked on a request. A chain with an
645 endpoint specifying one argument will only match if exactly one argument
648 You can specify an exact number of arguments like C<:Args(3)>, including
649 C<0>. If you just say C<:Args> without any arguments, it is the same as
650 leaving it out altogether: The chain is matched regardless of the number
651 of path parts after the endpoint.
653 Just as with C<:CaptureArgs>, the arguments get passed to the action in
654 C<@_> after the context object. They can also be reached through
655 C<$c-E<gt>request-E<gt>arguments>.
659 =head2 Auto actions, dispatching and forwarding
661 Note that the list of C<auto> actions called depends on the private path
662 of the endpoint of the chain, not on the chained actions way. The
663 C<auto> actions will be run before the chain dispatching begins. In
664 every other aspect, C<auto> actions behave as documented.
666 The C<forward>ing to other actions does just what you would expect. But if
667 you C<detach> out of a chain, the rest of the chain will not get called
672 Catalyst Contributors, see Catalyst.pm
676 This library is free software. You can redistribute it and/or modify it under
677 the same terms as Perl itself.