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 $consumes = $self->_list_extra_consumes($endpoint);
105 my $curr = $endpoint;
107 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
108 unshift(@parts, (("*") x $cap));
110 if (my $pp = $curr->attributes->{PathPart}) {
111 unshift(@parts, $pp->[0])
112 if (defined $pp->[0] && length $pp->[0]);
114 $parent = $curr->attributes->{Chained}->[0];
115 $curr = $self->_actions->{$parent};
116 unshift(@parents, $curr) if $curr;
118 if ($parent ne '/') {
119 $has_unattached_actions = 1;
120 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
124 foreach my $p (@parents) {
127 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
128 $name = "${extra} ${name}";
130 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
131 $name .= ' ('.$cap.')';
133 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
137 unless ($p eq $parents[0]) {
138 $name = "-> ${name}";
140 push(@rows, [ '', $name ]);
142 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : '')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
143 $rows[0][0] = join('/', '', @parts) || '/';
144 $paths->row(@$_) for @rows;
147 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
148 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
149 if $has_unattached_actions;
152 sub _list_extra_http_methods {
153 my ( $self, $action ) = @_;
154 return unless defined $action->list_extra_info->{HTTP_METHODS};
155 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
159 sub _list_extra_consumes {
160 my ( $self, $action ) = @_;
161 return unless defined $action->list_extra_info->{CONSUMES};
162 return join(', ', @{$action->list_extra_info->{CONSUMES}});
166 =head2 $self->match( $c, $path )
168 Calls C<recurse_match> to see if a chain matches the C<$path>.
173 my ( $self, $c, $path ) = @_;
175 my $request = $c->request;
176 return 0 if @{$request->args};
178 my @parts = split('/', $path);
180 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
182 if ($parts && @$parts) {
183 for my $arg (@$parts) {
184 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
185 push @{$request->args}, $arg;
189 return 0 unless $chain;
191 my $action = Catalyst::ActionChain->from_chain($chain);
193 $request->action("/${action}");
194 $request->match("/${action}");
195 $request->captures($captures);
197 $c->namespace( $action->namespace );
202 =head2 $self->recurse_match( $c, $parent, \@path_parts )
204 Recursive search for a matching chain.
209 my ( $self, $c, $parent, $path_parts ) = @_;
210 my $children = $self->_children_of->{$parent};
211 return () unless $children;
214 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
216 # $b then $a to try longest part first
217 my @parts = @$path_parts;
218 if (length $try_part) { # test and strip PathPart
220 ($try_part eq join('/', # assemble equal number of parts
221 splice( # and strip them off @parts as well
222 @parts, 0, scalar(@{[split('/', $try_part)]})
223 ))); # @{[]} to avoid split to @_
225 my @try_actions = @{$children->{$try_part}};
226 TRY_ACTION: foreach my $action (@try_actions) {
227 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
228 my $capture_count = $capture_attr->[0] || 0;
230 # Short-circuit if not enough remaining parts
231 next TRY_ACTION unless @parts >= $capture_count;
234 my @parts = @parts; # localise
236 # strip CaptureArgs into list
237 push(@captures, splice(@parts, 0, $capture_count));
239 # check if the action may fit, depending on a given test by the app
240 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
242 # try the remaining parts against children of this action
243 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
244 $c, '/'.$action->reverse, \@parts
246 # No best action currently
247 # OR The action has less parts
248 # OR The action has equal parts but less captured data (ergo more defined)
251 $#$action_parts < $#{$best_action->{parts}} ||
252 ($#$action_parts == $#{$best_action->{parts}} &&
253 $#$captures < $#{$best_action->{captures}} &&
254 $n_pathparts > $best_action->{n_pathparts}))) {
255 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
257 actions => [ $action, @$actions ],
258 captures=> [ @captures, @$captures ],
259 parts => $action_parts,
260 n_pathparts => scalar(@pathparts) + $n_pathparts,
266 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
267 next TRY_ACTION unless $action->match($c);
269 my $args_attr = $action->attributes->{Args}->[0];
270 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
271 # No best action currently
272 # OR This one matches with fewer parts left than the current best action,
273 # And therefore is a better match
274 # OR No parts and this expects 0
275 # The current best action might also be Args(0),
276 # but we couldn't chose between then anyway so we'll take the last seen
279 @parts < @{$best_action->{parts}} ||
280 (!@parts && defined($args_attr) && $args_attr eq "0")){
282 actions => [ $action ],
285 n_pathparts => scalar(@pathparts),
291 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
295 =head2 $self->register( $c, $action )
297 Calls register_path for every Path attribute for the given $action.
301 sub _check_args_attr {
302 my ( $self, $action, $name ) = @_;
304 return unless exists $action->attributes->{$name};
306 if (@{$action->attributes->{$name}} > 1) {
307 Catalyst::Exception->throw(
308 "Multiple $name attributes not supported registering " . $action->reverse()
311 my $args = $action->attributes->{$name}->[0];
312 if (defined($args) and not (
313 Scalar::Util::looks_like_number($args) and
314 int($args) == $args and $args >= 0
316 require Data::Dumper;
317 local $Data::Dumper::Terse = 1;
318 local $Data::Dumper::Indent = 0;
319 $args = Data::Dumper::Dumper($args);
320 Catalyst::Exception->throw(
321 "Invalid $name($args) for action " . $action->reverse() .
322 " (use '$name' or '$name(<number>)')"
328 my ( $self, $c, $action ) = @_;
330 my @chained_attr = @{ $action->attributes->{Chained} || [] };
332 return 0 unless @chained_attr;
334 if (@chained_attr > 1) {
335 Catalyst::Exception->throw(
336 "Multiple Chained attributes not supported registering ${action}"
339 my $chained_to = $chained_attr[0];
341 Catalyst::Exception->throw(
342 "Actions cannot chain to themselves registering /${action}"
343 ) if ($chained_to eq '/' . $action);
345 my $children = ($self->_children_of->{ $chained_to } ||= {});
347 my @path_part = @{ $action->attributes->{PathPart} || [] };
349 my $part = $action->name;
351 if (@path_part == 1 && defined $path_part[0]) {
352 $part = $path_part[0];
353 } elsif (@path_part > 1) {
354 Catalyst::Exception->throw(
355 "Multiple PathPart attributes not supported registering " . $action->reverse()
359 if ($part =~ m(^/)) {
360 Catalyst::Exception->throw(
361 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
365 $action->attributes->{PathPart} = [ $part ];
367 unshift(@{ $children->{$part} ||= [] }, $action);
369 $self->_actions->{'/'.$action->reverse} = $action;
371 foreach my $name (qw(Args CaptureArgs)) {
372 $self->_check_args_attr($action, $name);
375 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
376 Catalyst::Exception->throw(
377 "Combining Args and CaptureArgs attributes not supported registering " .
382 unless ($action->attributes->{CaptureArgs}) {
383 unshift(@{ $self->_endpoints }, $action);
389 =head2 $self->uri_for_action($action, $captures)
391 Get the URI part for the action, using C<$captures> to fill
397 my ( $self, $action, $captures ) = @_;
399 return undef unless ($action->attributes->{Chained}
400 && !$action->attributes->{CaptureArgs});
403 my @captures = @$captures;
404 my $parent = "DUMMY";
407 if (my $cap = $curr->attributes->{CaptureArgs}) {
408 return undef unless @captures >= ($cap->[0]||0); # not enough captures
410 unshift(@parts, splice(@captures, -$cap->[0]));
413 if (my $pp = $curr->attributes->{PathPart}) {
414 unshift(@parts, $pp->[0])
415 if (defined($pp->[0]) && length($pp->[0]));
417 $parent = $curr->attributes->{Chained}->[0];
418 $curr = $self->_actions->{$parent};
421 return undef unless $parent eq '/'; # fail for dangling action
423 return undef if @captures; # fail for too many captures
425 return join('/', '', @parts);
429 =head2 $c->expand_action($action)
431 Return a list of actions that represents a chained action. See
432 L<Catalyst::Dispatcher> for more info. You probably want to
433 use the expand_action it provides rather than this directly.
438 my ($self, $action) = @_;
440 return unless $action->attributes && $action->attributes->{Chained};
447 my $parent = $curr->attributes->{Chained}->[0];
448 $curr = $self->_actions->{$parent};
451 return Catalyst::ActionChain->from_chain([reverse @chain]);
454 __PACKAGE__->meta->make_immutable;
461 The C<Chained> attribute allows you to chain public path parts together
462 by their private names. A chain part's path can be specified with
463 C<PathPart> and can be declared to expect an arbitrary number of
464 arguments. The endpoint of the chain specifies how many arguments it
465 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
466 C<:Args> without an integer would be unlimited. The path parts that
467 aren't endpoints are using C<CaptureArgs> to specify how many parameters
468 they expect to receive. As an example setup:
470 package MyApp::Controller::Greeting;
471 use base qw/ Catalyst::Controller /;
473 # this is the beginning of our chain
474 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
475 my ( $self, $c, $integer ) = @_;
476 $c->stash->{ message } = "Hello ";
477 $c->stash->{ arg_sum } = $integer;
480 # this is our endpoint, because it has no :CaptureArgs
481 sub world : PathPart('world') Chained('hello') Args(1) {
482 my ( $self, $c, $integer ) = @_;
483 $c->stash->{ message } .= "World!";
484 $c->stash->{ arg_sum } += $integer;
486 $c->response->body( join "<br/>\n" =>
487 $c->stash->{ message }, $c->stash->{ arg_sum } );
490 The debug output provides a separate table for chained actions, showing
491 the whole chain as it would match and the actions it contains. Here's an
492 example of the startup output with our actions above:
495 [debug] Loaded Path Part actions:
496 .-----------------------+------------------------------.
497 | Path Spec | Private |
498 +-----------------------+------------------------------+
499 | /hello/*/world/* | /greeting/hello (1) |
500 | | => /greeting/world |
501 '-----------------------+------------------------------'
504 As you can see, Catalyst only deals with chains as whole paths and
505 builds one for each endpoint, which are the actions with C<:Chained> but
506 without C<:CaptureArgs>.
508 Let's assume this application gets a request at the path
509 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
510 to the C<hello> action and pass the value C<23> as an argument to it
511 after the context. It does so because we have previously used
512 C<:CaptureArgs(1)> to declare that it has one path part after itself as
513 its argument. We told Catalyst that this is the beginning of the chain
514 by specifying C<:Chained('/')>. Also note that instead of saying
515 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
516 defaults to the name of the action.
518 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
519 action. This is the last action to be called: Catalyst knows this is an
520 endpoint because we did not specify a C<:CaptureArgs>
521 attribute. Nevertheless we specify that this action expects an argument,
522 but at this point we're using C<:Args(1)> to do that. We could also have
523 said C<:Args> or left it out altogether, which would mean this action
524 would get all arguments that are there. This action's C<:Chained>
525 attribute says C<hello> and tells Catalyst that the C<hello> action in
526 the current controller is its parent.
528 With this we have built a chain consisting of two public path parts.
529 C<hello> captures one part of the path as its argument, and also
530 specifies the path root as its parent. So this part is
531 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
532 argument. It sums up to the path part C<world/$arg>. This leads to a
533 complete chain of C</hello/$arg/world/$arg> which is matched against the
536 This example application would, if run and called by e.g.
537 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
538 value C<arg_sum> to "23". The C<world> action would then append "World!"
539 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
540 sake of simplicity no view is shown. Instead we just put the values of
541 the stash into our body. So the output would look like:
546 And our test server would have given us this debugging output for the
550 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
551 [debug] Path is "/greeting/world"
552 [debug] Arguments are "12"
553 [info] Request took 0.164113s (6.093/s)
554 .------------------------------------------+-----------.
556 +------------------------------------------+-----------+
557 | /greeting/hello | 0.000029s |
558 | /greeting/world | 0.000024s |
559 '------------------------------------------+-----------'
562 What would be common uses of this dispatch technique? It gives the
563 possibility to split up logic that contains steps that each depend on
564 each other. An example would be, for example, a wiki path like
565 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
568 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
569 my ( $self, $c, $page_name ) = @_;
570 # load the page named $page_name and put the object
574 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
575 my ( $self, $c, $revision_id ) = @_;
576 # use the page object in the stash to get at its
577 # revision with number $revision_id
580 sub view : PathPart Chained('rev') Args(0) {
581 my ( $self, $c ) = @_;
582 # display the revision in our stash. Another option
583 # would be to forward a compatible object to the action
584 # that displays the default wiki pages, unless we want
585 # a different interface here, for example restore
589 It would now be possible to add other endpoints, for example C<restore>
590 to restore this specific revision as the current state.
592 You don't have to put all the chained actions in one controller. The
593 specification of the parent through C<:Chained> also takes an absolute
594 action path as its argument. Just specify it with a leading C</>.
596 If you want, for example, to have actions for the public paths
597 C</foo/12/edit> and C</foo/12>, just specify two actions with
598 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
599 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
600 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
601 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
602 this debugging output:
605 [debug] Loaded Path Part actions:
606 .-----------------------+------------------------------.
607 | Path Spec | Private |
608 +-----------------------+------------------------------+
609 | /foo/* | /controller/foo_view |
610 | /foo/*/edit | /controller/foo_load (1) |
611 | | => /controller/edit |
612 '-----------------------+------------------------------'
615 Here's a more detailed specification of the attributes belonging to
624 Sets the name of this part of the chain. If it is specified without
625 arguments, it takes the name of the action as default. So basically
626 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
627 This can also contain slashes to bind to a deeper level. An action
628 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
629 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
630 effect as using C<:PathPart>, it would default to the action name.
634 Sets PathPart to the path_prefix of the current controller.
638 Has to be specified for every child in the chain. Possible values are
639 absolute and relative private action paths or a single slash C</> to
640 tell Catalyst that this is the root of a chain. The attribute
641 C<:Chained> without arguments also defaults to the C</> behavior.
642 Relative action paths may use C<../> to refer to actions in parent
645 Because you can specify an absolute path to the parent action, it
646 doesn't matter to Catalyst where that parent is located. So, if your
647 design requests it, you can redispatch a chain through any controller or
650 Another interesting possibility gives C<:Chained('.')>, which chains
651 itself to an action with the path of the current controller's namespace.
654 # in MyApp::Controller::Foo
655 sub bar : Chained CaptureArgs(1) { ... }
657 # in MyApp::Controller::Foo::Bar
658 sub baz : Chained('.') Args(1) { ... }
660 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
661 as the argument to Chained here chains the C<baz> action to an action
662 with the path of the current controller namespace, namely
663 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
664 chain comes out as the end product.
668 Chains an action to another action with the same name in the parent
669 controller. For Example:
671 # in MyApp::Controller::Foo
672 sub bar : Chained CaptureArgs(1) { ... }
674 # in MyApp::Controller::Foo::Moo
675 sub bar : ChainedParent Args(1) { ... }
677 This builds a chain like C</bar/*/bar/*>.
681 Must be specified for every part of the chain that is not an
682 endpoint. With this attribute Catalyst knows how many of the following
683 parts of the path (separated by C</>) this action wants to capture as
684 its arguments. If it doesn't expect any, just specify
685 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
686 after the context, but you can also find them as array references in
687 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
688 level of the action in the chain that captured the parts of the path.
690 An action that is part of a chain (that is, one that has a C<:Chained>
691 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
696 By default, endpoints receive the rest of the arguments in the path. You
697 can tell Catalyst through C<:Args> explicitly how many arguments your
698 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
699 also affects whether this chain is invoked on a request. A chain with an
700 endpoint specifying one argument will only match if exactly one argument
703 You can specify an exact number of arguments like C<:Args(3)>, including
704 C<0>. If you just say C<:Args> without any arguments, it is the same as
705 leaving it out altogether: The chain is matched regardless of the number
706 of path parts after the endpoint.
708 Just as with C<:CaptureArgs>, the arguments get passed to the action in
709 C<@_> after the context object. They can also be reached through
710 C<$c-E<gt>request-E<gt>arguments>.
714 =head2 Auto actions, dispatching and forwarding
716 Note that the list of C<auto> actions called depends on the private path
717 of the endpoint of the chain, not on the chained actions way. The
718 C<auto> actions will be run before the chain dispatching begins. In
719 every other aspect, C<auto> actions behave as documented.
721 The C<forward>ing to other actions does just what you would expect. i.e.
722 only the target action is run. The actions that that action is chained
724 If you C<detach> out of a chain, the rest of the chain will not get
725 called after the C<detach>.
727 =head2 match_captures
729 A method which can optionally be implemented by actions to
732 See L<Catalyst::Action> for further details.
736 Catalyst Contributors, see Catalyst.pm
740 This library is free software. You can redistribute it and/or modify it under
741 the same terms as Perl itself.