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 $extra = $self->_list_extra_http_methods($endpoint);
104 my $curr = $endpoint;
106 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
107 unshift(@parts, (("*") x $cap));
109 if (my $pp = $curr->attributes->{PathPart}) {
110 unshift(@parts, $pp->[0])
111 if (defined $pp->[0] && length $pp->[0]);
113 $parent = $curr->attributes->{Chained}->[0];
114 $curr = $self->_actions->{$parent};
115 unshift(@parents, $curr) if $curr;
117 if ($parent ne '/') {
118 $has_unattached_actions = 1;
119 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
123 foreach my $p (@parents) {
126 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
127 $name = "${extra} ${name}";
129 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
130 $name .= ' ('.$cap.')';
132 unless ($p eq $parents[0]) {
133 $name = "-> ${name}";
135 push(@rows, [ '', $name ]);
137 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : '')."/${endpoint}" ]);
138 $rows[0][0] = join('/', '', @parts) || '/';
139 $paths->row(@$_) for @rows;
142 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
143 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
144 if $has_unattached_actions;
147 sub _list_extra_http_methods {
148 my ( $self, $action ) = @_;
149 return unless defined $action->list_extra_info->{HTTP_METHODS};
150 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
153 =head2 $self->match( $c, $path )
155 Calls C<recurse_match> to see if a chain matches the C<$path>.
160 my ( $self, $c, $path ) = @_;
162 my $request = $c->request;
163 return 0 if @{$request->args};
165 my @parts = split('/', $path);
167 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
169 if ($parts && @$parts) {
170 for my $arg (@$parts) {
171 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
172 push @{$request->args}, $arg;
176 return 0 unless $chain;
178 my $action = Catalyst::ActionChain->from_chain($chain);
180 $request->action("/${action}");
181 $request->match("/${action}");
182 $request->captures($captures);
184 $c->namespace( $action->namespace );
189 =head2 $self->recurse_match( $c, $parent, \@path_parts )
191 Recursive search for a matching chain.
196 my ( $self, $c, $parent, $path_parts ) = @_;
197 my $children = $self->_children_of->{$parent};
198 return () unless $children;
201 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
203 # $b then $a to try longest part first
204 my @parts = @$path_parts;
205 if (length $try_part) { # test and strip PathPart
207 ($try_part eq join('/', # assemble equal number of parts
208 splice( # and strip them off @parts as well
209 @parts, 0, scalar(@{[split('/', $try_part)]})
210 ))); # @{[]} to avoid split to @_
212 my @try_actions = @{$children->{$try_part}};
213 TRY_ACTION: foreach my $action (@try_actions) {
214 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
215 my $capture_count = $capture_attr->[0] || 0;
217 # Short-circuit if not enough remaining parts
218 next TRY_ACTION unless @parts >= $capture_count;
221 my @parts = @parts; # localise
223 # strip CaptureArgs into list
224 push(@captures, splice(@parts, 0, $capture_count));
226 # check if the action may fit, depending on a given test by the app
227 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
229 # try the remaining parts against children of this action
230 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
231 $c, '/'.$action->reverse, \@parts
233 # No best action currently
234 # OR The action has less parts
235 # OR The action has equal parts but less captured data (ergo more defined)
238 $#$action_parts < $#{$best_action->{parts}} ||
239 ($#$action_parts == $#{$best_action->{parts}} &&
240 $#$captures < $#{$best_action->{captures}} &&
241 $n_pathparts > $best_action->{n_pathparts}))) {
242 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
244 actions => [ $action, @$actions ],
245 captures=> [ @captures, @$captures ],
246 parts => $action_parts,
247 n_pathparts => scalar(@pathparts) + $n_pathparts,
253 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
254 next TRY_ACTION unless $action->match($c);
256 my $args_attr = $action->attributes->{Args}->[0];
257 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
258 # No best action currently
259 # OR This one matches with fewer parts left than the current best action,
260 # And therefore is a better match
261 # OR No parts and this expects 0
262 # The current best action might also be Args(0),
263 # but we couldn't chose between then anyway so we'll take the last seen
266 @parts < @{$best_action->{parts}} ||
267 (!@parts && defined($args_attr) && $args_attr eq "0")){
269 actions => [ $action ],
272 n_pathparts => scalar(@pathparts),
278 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
282 =head2 $self->register( $c, $action )
284 Calls register_path for every Path attribute for the given $action.
288 sub _check_args_attr {
289 my ( $self, $action, $name ) = @_;
291 return unless exists $action->attributes->{$name};
293 if (@{$action->attributes->{$name}} > 1) {
294 Catalyst::Exception->throw(
295 "Multiple $name attributes not supported registering " . $action->reverse()
298 my $args = $action->attributes->{$name}->[0];
299 if (defined($args) and not (
300 Scalar::Util::looks_like_number($args) and
303 require Data::Dumper;
304 local $Data::Dumper::Terse = 1;
305 local $Data::Dumper::Indent = 0;
306 $args = Data::Dumper::Dumper($args);
307 Catalyst::Exception->throw(
308 "Invalid $name($args) for action " . $action->reverse() .
309 " (use '$name' or '$name(<number>)')"
315 my ( $self, $c, $action ) = @_;
317 my @chained_attr = @{ $action->attributes->{Chained} || [] };
319 return 0 unless @chained_attr;
321 if (@chained_attr > 1) {
322 Catalyst::Exception->throw(
323 "Multiple Chained attributes not supported registering ${action}"
326 my $chained_to = $chained_attr[0];
328 Catalyst::Exception->throw(
329 "Actions cannot chain to themselves registering /${action}"
330 ) if ($chained_to eq '/' . $action);
332 my $children = ($self->_children_of->{ $chained_to } ||= {});
334 my @path_part = @{ $action->attributes->{PathPart} || [] };
336 my $part = $action->name;
338 if (@path_part == 1 && defined $path_part[0]) {
339 $part = $path_part[0];
340 } elsif (@path_part > 1) {
341 Catalyst::Exception->throw(
342 "Multiple PathPart attributes not supported registering " . $action->reverse()
346 if ($part =~ m(^/)) {
347 Catalyst::Exception->throw(
348 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
352 $action->attributes->{PathPart} = [ $part ];
354 unshift(@{ $children->{$part} ||= [] }, $action);
356 $self->_actions->{'/'.$action->reverse} = $action;
358 foreach my $name (qw(Args CaptureArgs)) {
359 $self->_check_args_attr($action, $name);
362 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
363 Catalyst::Exception->throw(
364 "Combining Args and CaptureArgs not allowed registering " . $action->reverse()
368 unless ($action->attributes->{CaptureArgs}) {
369 unshift(@{ $self->_endpoints }, $action);
375 =head2 $self->uri_for_action($action, $captures)
377 Get the URI part for the action, using C<$captures> to fill
383 my ( $self, $action, $captures ) = @_;
385 return undef unless ($action->attributes->{Chained}
386 && !$action->attributes->{CaptureArgs});
389 my @captures = @$captures;
390 my $parent = "DUMMY";
393 if (my $cap = $curr->attributes->{CaptureArgs}) {
394 return undef unless @captures >= ($cap->[0]||0); # not enough captures
396 unshift(@parts, splice(@captures, -$cap->[0]));
399 if (my $pp = $curr->attributes->{PathPart}) {
400 unshift(@parts, $pp->[0])
401 if (defined($pp->[0]) && length($pp->[0]));
403 $parent = $curr->attributes->{Chained}->[0];
404 $curr = $self->_actions->{$parent};
407 return undef unless $parent eq '/'; # fail for dangling action
409 return undef if @captures; # fail for too many captures
411 return join('/', '', @parts);
415 =head2 $c->expand_action($action)
417 Return a list of actions that represents a chained action. See
418 L<Catalyst::Dispatcher> for more info. You probably want to
419 use the expand_action it provides rather than this directly.
424 my ($self, $action) = @_;
426 return unless $action->attributes && $action->attributes->{Chained};
433 my $parent = $curr->attributes->{Chained}->[0];
434 $curr = $self->_actions->{$parent};
437 return Catalyst::ActionChain->from_chain([reverse @chain]);
440 __PACKAGE__->meta->make_immutable;
447 The C<Chained> attribute allows you to chain public path parts together
448 by their private names. A chain part's path can be specified with
449 C<PathPart> and can be declared to expect an arbitrary number of
450 arguments. The endpoint of the chain specifies how many arguments it
451 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
452 C<:Args> without an integer would be unlimited. The path parts that
453 aren't endpoints are using C<CaptureArgs> to specify how many parameters
454 they expect to receive. As an example setup:
456 package MyApp::Controller::Greeting;
457 use base qw/ Catalyst::Controller /;
459 # this is the beginning of our chain
460 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
461 my ( $self, $c, $integer ) = @_;
462 $c->stash->{ message } = "Hello ";
463 $c->stash->{ arg_sum } = $integer;
466 # this is our endpoint, because it has no :CaptureArgs
467 sub world : PathPart('world') Chained('hello') Args(1) {
468 my ( $self, $c, $integer ) = @_;
469 $c->stash->{ message } .= "World!";
470 $c->stash->{ arg_sum } += $integer;
472 $c->response->body( join "<br/>\n" =>
473 $c->stash->{ message }, $c->stash->{ arg_sum } );
476 The debug output provides a separate table for chained actions, showing
477 the whole chain as it would match and the actions it contains. Here's an
478 example of the startup output with our actions above:
481 [debug] Loaded Path Part actions:
482 .-----------------------+------------------------------.
483 | Path Spec | Private |
484 +-----------------------+------------------------------+
485 | /hello/*/world/* | /greeting/hello (1) |
486 | | => /greeting/world |
487 '-----------------------+------------------------------'
490 As you can see, Catalyst only deals with chains as whole paths and
491 builds one for each endpoint, which are the actions with C<:Chained> but
492 without C<:CaptureArgs>.
494 Let's assume this application gets a request at the path
495 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
496 to the C<hello> action and pass the value C<23> as an argument to it
497 after the context. It does so because we have previously used
498 C<:CaptureArgs(1)> to declare that it has one path part after itself as
499 its argument. We told Catalyst that this is the beginning of the chain
500 by specifying C<:Chained('/')>. Also note that instead of saying
501 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
502 defaults to the name of the action.
504 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
505 action. This is the last action to be called: Catalyst knows this is an
506 endpoint because we did not specify a C<:CaptureArgs>
507 attribute. Nevertheless we specify that this action expects an argument,
508 but at this point we're using C<:Args(1)> to do that. We could also have
509 said C<:Args> or left it out altogether, which would mean this action
510 would get all arguments that are there. This action's C<:Chained>
511 attribute says C<hello> and tells Catalyst that the C<hello> action in
512 the current controller is its parent.
514 With this we have built a chain consisting of two public path parts.
515 C<hello> captures one part of the path as its argument, and also
516 specifies the path root as its parent. So this part is
517 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
518 argument. It sums up to the path part C<world/$arg>. This leads to a
519 complete chain of C</hello/$arg/world/$arg> which is matched against the
522 This example application would, if run and called by e.g.
523 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
524 value C<arg_sum> to "23". The C<world> action would then append "World!"
525 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
526 sake of simplicity no view is shown. Instead we just put the values of
527 the stash into our body. So the output would look like:
532 And our test server would have given us this debugging output for the
536 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
537 [debug] Path is "/greeting/world"
538 [debug] Arguments are "12"
539 [info] Request took 0.164113s (6.093/s)
540 .------------------------------------------+-----------.
542 +------------------------------------------+-----------+
543 | /greeting/hello | 0.000029s |
544 | /greeting/world | 0.000024s |
545 '------------------------------------------+-----------'
548 What would be common uses of this dispatch technique? It gives the
549 possibility to split up logic that contains steps that each depend on
550 each other. An example would be, for example, a wiki path like
551 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
554 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
555 my ( $self, $c, $page_name ) = @_;
556 # load the page named $page_name and put the object
560 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
561 my ( $self, $c, $revision_id ) = @_;
562 # use the page object in the stash to get at its
563 # revision with number $revision_id
566 sub view : PathPart Chained('rev') Args(0) {
567 my ( $self, $c ) = @_;
568 # display the revision in our stash. Another option
569 # would be to forward a compatible object to the action
570 # that displays the default wiki pages, unless we want
571 # a different interface here, for example restore
575 It would now be possible to add other endpoints, for example C<restore>
576 to restore this specific revision as the current state.
578 You don't have to put all the chained actions in one controller. The
579 specification of the parent through C<:Chained> also takes an absolute
580 action path as its argument. Just specify it with a leading C</>.
582 If you want, for example, to have actions for the public paths
583 C</foo/12/edit> and C</foo/12>, just specify two actions with
584 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
585 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
586 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
587 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
588 this debugging output:
591 [debug] Loaded Path Part actions:
592 .-----------------------+------------------------------.
593 | Path Spec | Private |
594 +-----------------------+------------------------------+
595 | /foo/* | /controller/foo_view |
596 | /foo/*/edit | /controller/foo_load (1) |
597 | | => /controller/edit |
598 '-----------------------+------------------------------'
601 Here's a more detailed specification of the attributes belonging to
610 Sets the name of this part of the chain. If it is specified without
611 arguments, it takes the name of the action as default. So basically
612 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
613 This can also contain slashes to bind to a deeper level. An action
614 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
615 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
616 effect as using C<:PathPart>, it would default to the action name.
620 Sets PathPart to the path_prefix of the current controller.
624 Has to be specified for every child in the chain. Possible values are
625 absolute and relative private action paths or a single slash C</> to
626 tell Catalyst that this is the root of a chain. The attribute
627 C<:Chained> without arguments also defaults to the C</> behavior.
628 Relative action paths may use C<../> to refer to actions in parent
631 Because you can specify an absolute path to the parent action, it
632 doesn't matter to Catalyst where that parent is located. So, if your
633 design requests it, you can redispatch a chain through any controller or
636 Another interesting possibility gives C<:Chained('.')>, which chains
637 itself to an action with the path of the current controller's namespace.
640 # in MyApp::Controller::Foo
641 sub bar : Chained CaptureArgs(1) { ... }
643 # in MyApp::Controller::Foo::Bar
644 sub baz : Chained('.') Args(1) { ... }
646 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
647 as the argument to Chained here chains the C<baz> action to an action
648 with the path of the current controller namespace, namely
649 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
650 chain comes out as the end product.
654 Chains an action to another action with the same name in the parent
655 controller. For Example:
657 # in MyApp::Controller::Foo
658 sub bar : Chained CaptureArgs(1) { ... }
660 # in MyApp::Controller::Foo::Moo
661 sub bar : ChainedParent Args(1) { ... }
663 This builds a chain like C</bar/*/bar/*>.
667 Must be specified for every part of the chain that is not an
668 endpoint. With this attribute Catalyst knows how many of the following
669 parts of the path (separated by C</>) this action wants to capture as
670 its arguments. If it doesn't expect any, just specify
671 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
672 after the context, but you can also find them as array references in
673 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
674 level of the action in the chain that captured the parts of the path.
676 An action that is part of a chain (that is, one that has a C<:Chained>
677 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
682 By default, endpoints receive the rest of the arguments in the path. You
683 can tell Catalyst through C<:Args> explicitly how many arguments your
684 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
685 also affects whether this chain is invoked on a request. A chain with an
686 endpoint specifying one argument will only match if exactly one argument
689 You can specify an exact number of arguments like C<:Args(3)>, including
690 C<0>. If you just say C<:Args> without any arguments, it is the same as
691 leaving it out altogether: The chain is matched regardless of the number
692 of path parts after the endpoint.
694 Just as with C<:CaptureArgs>, the arguments get passed to the action in
695 C<@_> after the context object. They can also be reached through
696 C<$c-E<gt>request-E<gt>arguments>.
700 =head2 Auto actions, dispatching and forwarding
702 Note that the list of C<auto> actions called depends on the private path
703 of the endpoint of the chain, not on the chained actions way. The
704 C<auto> actions will be run before the chain dispatching begins. In
705 every other aspect, C<auto> actions behave as documented.
707 The C<forward>ing to other actions does just what you would expect. i.e.
708 only the target action is run. The actions that that action is chained
710 If you C<detach> out of a chain, the rest of the chain will not get
711 called after the C<detach>.
713 =head2 match_captures
715 A method which can optionally be implemented by actions to
718 See L<Catalyst::Action> for further details.
722 Catalyst Contributors, see Catalyst.pm
726 This library is free software. You can redistribute it and/or modify it under
727 the same terms as Perl itself.