1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
11 use Encode 2.21 'decode_utf8';
36 # please don't perltidy this. hairy code within.
40 Catalyst::DispatchType::Chained - Path Part DispatchType
44 Path part matching, allowing several actions to sequentially take care of processing a request:
46 # root action - captures one argument after it
47 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
48 my ( $self, $c, $foo_arg ) = @_;
52 # child action endpoint - takes one argument
53 sub bar : Chained('foo_setup') Args(1) {
54 my ( $self, $c, $bar_arg ) = @_;
60 Dispatch type managing default behaviour. For more information on
65 =item * L<Catalyst::Manual::Intro> for how they affect application authors
67 =item * L<Catalyst::DispatchType> for implementation information.
73 =head2 $self->list($c)
75 Debug output for Path Part dispatch points
80 my ( $self, $c ) = @_;
82 return unless $self->_endpoints;
84 my $avail_width = Catalyst::Utils::term_width() - 9;
85 my $col1_width = ($avail_width * .50) < 35 ? 35 : int($avail_width * .50);
86 my $col2_width = $avail_width - $col1_width;
87 my $paths = Text::SimpleTable->new(
88 [ $col1_width, 'Path Spec' ], [ $col2_width, 'Private' ],
91 my $has_unattached_actions;
92 my $unattached_actions = Text::SimpleTable->new(
93 [ $col1_width, 'Private' ], [ $col2_width, 'Missing parent' ],
96 ENDPOINT: foreach my $endpoint (
97 sort { $a->reverse cmp $b->reverse }
98 @{ $self->_endpoints }
100 my $args = $endpoint->list_extra_info->{Args};
101 my @parts = (defined($args) ? (("*") x $args) : '...');
103 my $parent = "DUMMY";
104 my $extra = $self->_list_extra_http_methods($endpoint);
105 my $consumes = $self->_list_extra_consumes($endpoint);
106 my $scheme = $self->_list_extra_scheme($endpoint);
107 my $curr = $endpoint;
109 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
110 unshift(@parts, (("*") x $cap));
112 if (my $pp = $curr->attributes->{PathPart}) {
113 unshift(@parts, $pp->[0])
114 if (defined $pp->[0] && length $pp->[0]);
116 $parent = $curr->attributes->{Chained}->[0];
117 $curr = $self->_actions->{$parent};
118 unshift(@parents, $curr) if $curr;
120 if ($parent ne '/') {
121 $has_unattached_actions = 1;
122 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
126 foreach my $p (@parents) {
129 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
130 $name = "${extra} ${name}";
132 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
133 $name .= ' ('.$cap.')';
135 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
138 if (defined(my $s = $p->list_extra_info->{Scheme})) {
142 unless ($p eq $parents[0]) {
143 $name = "-> ${name}";
145 push(@rows, [ '', $name ]);
147 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : ''). ($scheme ? "$scheme: ":'')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
148 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
149 $rows[0][0] = join('/', '', @display_parts) || '/';
150 $paths->row(@$_) for @rows;
153 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
154 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
155 if $has_unattached_actions;
158 sub _list_extra_http_methods {
159 my ( $self, $action ) = @_;
160 return unless defined $action->list_extra_info->{HTTP_METHODS};
161 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
165 sub _list_extra_consumes {
166 my ( $self, $action ) = @_;
167 return unless defined $action->list_extra_info->{CONSUMES};
168 return join(', ', @{$action->list_extra_info->{CONSUMES}});
171 sub _list_extra_scheme {
172 my ( $self, $action ) = @_;
173 return unless defined $action->list_extra_info->{Scheme};
174 return uc $action->list_extra_info->{Scheme};
177 =head2 $self->match( $c, $path )
179 Calls C<recurse_match> to see if a chain matches the C<$path>.
184 my ( $self, $c, $path ) = @_;
186 my $request = $c->request;
187 return 0 if @{$request->args};
189 my @parts = split('/', $path);
191 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
193 if ($parts && @$parts) {
194 for my $arg (@$parts) {
195 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
196 push @{$request->args}, $arg;
200 return 0 unless $chain;
202 my $action = Catalyst::ActionChain->from_chain($chain);
204 $request->action("/${action}");
205 $request->match("/${action}");
206 $request->captures($captures);
208 $c->namespace( $action->namespace );
213 =head2 $self->recurse_match( $c, $parent, \@path_parts )
215 Recursive search for a matching chain.
220 my ( $self, $c, $parent, $path_parts ) = @_;
221 my $children = $self->_children_of->{$parent};
222 return () unless $children;
225 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
227 # $b then $a to try longest part first
228 my @parts = @$path_parts;
229 if (length $try_part) { # test and strip PathPart
231 ($try_part eq join('/', # assemble equal number of parts
232 splice( # and strip them off @parts as well
233 @parts, 0, scalar(@{[split('/', $try_part)]})
234 ))); # @{[]} to avoid split to @_
236 my @try_actions = @{$children->{$try_part}};
237 TRY_ACTION: foreach my $action (@try_actions) {
238 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
239 my $capture_count = $action->number_of_captures|| 0;
241 # Short-circuit if not enough remaining parts
242 next TRY_ACTION unless @parts >= $capture_count;
245 my @parts = @parts; # localise
247 # strip CaptureArgs into list
248 push(@captures, splice(@parts, 0, $capture_count));
250 # check if the action may fit, depending on a given test by the app
251 next TRY_ACTION unless $action->match_captures($c, \@captures);
253 # try the remaining parts against children of this action
254 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
255 $c, '/'.$action->reverse, \@parts
257 # No best action currently
258 # OR The action has less parts
259 # OR The action has equal parts but less captured data (ergo more defined)
262 $#$action_parts < $#{$best_action->{parts}} ||
263 ($#$action_parts == $#{$best_action->{parts}} &&
264 $#$captures < $#{$best_action->{captures}} &&
265 $n_pathparts > $best_action->{n_pathparts}))) {
266 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
268 actions => [ $action, @$actions ],
269 captures=> [ @captures, @$captures ],
270 parts => $action_parts,
271 n_pathparts => scalar(@pathparts) + $n_pathparts,
277 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
278 next TRY_ACTION unless $action->match($c);
280 my $args_attr = $action->attributes->{Args}->[0];
281 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
282 # No best action currently
283 # OR This one matches with fewer parts left than the current best action,
284 # And therefore is a better match
285 # OR No parts and this expects 0
286 # The current best action might also be Args(0),
287 # but we couldn't chose between then anyway so we'll take the last seen
290 @parts < @{$best_action->{parts}} ||
291 (!@parts && defined($args_attr) && $args_attr eq "0")){
293 actions => [ $action ],
296 n_pathparts => scalar(@pathparts),
302 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
306 =head2 $self->register( $c, $action )
308 Calls register_path for every Path attribute for the given $action.
313 my ( $self, $c, $action ) = @_;
315 my @chained_attr = @{ $action->attributes->{Chained} || [] };
317 return 0 unless @chained_attr;
319 if (@chained_attr > 1) {
320 Catalyst::Exception->throw(
321 "Multiple Chained attributes not supported registering ${action}"
324 my $chained_to = $chained_attr[0];
326 Catalyst::Exception->throw(
327 "Actions cannot chain to themselves registering /${action}"
328 ) if ($chained_to eq '/' . $action);
330 my $children = ($self->_children_of->{ $chained_to } ||= {});
332 my @path_part = @{ $action->attributes->{PathPart} || [] };
334 my $part = $action->name;
336 if (@path_part == 1 && defined $path_part[0]) {
337 $part = $path_part[0];
338 } elsif (@path_part > 1) {
339 Catalyst::Exception->throw(
340 "Multiple PathPart attributes not supported registering " . $action->reverse()
344 if ($part =~ m(^/)) {
345 Catalyst::Exception->throw(
346 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
350 my $encoded_part = URI->new($part)->canonical;
351 $encoded_part =~ s{(?<=[^/])/+\z}{};
353 $action->attributes->{PathPart} = [ $encoded_part ];
355 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
357 $self->_actions->{'/'.$action->reverse} = $action;
359 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
360 Catalyst::Exception->throw(
361 "Combining Args and CaptureArgs attributes not supported registering " .
366 unless ($action->attributes->{CaptureArgs}) {
367 unshift(@{ $self->_endpoints }, $action);
373 =head2 $self->uri_for_action($action, $captures)
375 Get the URI part for the action, using C<$captures> to fill
381 my ( $self, $action, $captures ) = @_;
383 return undef unless ($action->attributes->{Chained}
384 && !$action->attributes->{CaptureArgs});
387 my @captures = @$captures;
388 my $parent = "DUMMY";
391 if (my $cap = $curr->attributes->{CaptureArgs}) {
392 return undef unless @captures >= ($cap->[0]||0); # not enough captures
394 unshift(@parts, splice(@captures, -$cap->[0]));
397 if (my $pp = $curr->attributes->{PathPart}) {
398 unshift(@parts, $pp->[0])
399 if (defined($pp->[0]) && length($pp->[0]));
401 $parent = $curr->attributes->{Chained}->[0];
402 $curr = $self->_actions->{$parent};
405 return undef unless $parent eq '/'; # fail for dangling action
407 return undef if @captures; # fail for too many captures
409 return join('/', '', @parts);
413 =head2 $c->expand_action($action)
415 Return a list of actions that represents a chained action. See
416 L<Catalyst::Dispatcher> for more info. You probably want to
417 use the expand_action it provides rather than this directly.
422 my ($self, $action) = @_;
424 return unless $action->attributes && $action->attributes->{Chained};
431 my $parent = $curr->attributes->{Chained}->[0];
432 $curr = $self->_actions->{$parent};
435 return Catalyst::ActionChain->from_chain([reverse @chain]);
438 __PACKAGE__->meta->make_immutable;
445 The C<Chained> attribute allows you to chain public path parts together
446 by their private names. A chain part's path can be specified with
447 C<PathPart> and can be declared to expect an arbitrary number of
448 arguments. The endpoint of the chain specifies how many arguments it
449 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
450 C<:Args> without an integer would be unlimited. The path parts that
451 aren't endpoints are using C<CaptureArgs> to specify how many parameters
452 they expect to receive. As an example setup:
454 package MyApp::Controller::Greeting;
455 use base qw/ Catalyst::Controller /;
457 # this is the beginning of our chain
458 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
459 my ( $self, $c, $integer ) = @_;
460 $c->stash->{ message } = "Hello ";
461 $c->stash->{ arg_sum } = $integer;
464 # this is our endpoint, because it has no :CaptureArgs
465 sub world : PathPart('world') Chained('hello') Args(1) {
466 my ( $self, $c, $integer ) = @_;
467 $c->stash->{ message } .= "World!";
468 $c->stash->{ arg_sum } += $integer;
470 $c->response->body( join "<br/>\n" =>
471 $c->stash->{ message }, $c->stash->{ arg_sum } );
474 The debug output provides a separate table for chained actions, showing
475 the whole chain as it would match and the actions it contains. Here's an
476 example of the startup output with our actions above:
479 [debug] Loaded Path Part actions:
480 .-----------------------+------------------------------.
481 | Path Spec | Private |
482 +-----------------------+------------------------------+
483 | /hello/*/world/* | /greeting/hello (1) |
484 | | => /greeting/world |
485 '-----------------------+------------------------------'
488 As you can see, Catalyst only deals with chains as whole paths and
489 builds one for each endpoint, which are the actions with C<:Chained> but
490 without C<:CaptureArgs>.
492 Let's assume this application gets a request at the path
493 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
494 to the C<hello> action and pass the value C<23> as an argument to it
495 after the context. It does so because we have previously used
496 C<:CaptureArgs(1)> to declare that it has one path part after itself as
497 its argument. We told Catalyst that this is the beginning of the chain
498 by specifying C<:Chained('/')>. Also note that instead of saying
499 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
500 defaults to the name of the action.
502 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
503 action. This is the last action to be called: Catalyst knows this is an
504 endpoint because we did not specify a C<:CaptureArgs>
505 attribute. Nevertheless we specify that this action expects an argument,
506 but at this point we're using C<:Args(1)> to do that. We could also have
507 said C<:Args> or left it out altogether, which would mean this action
508 would get all arguments that are there. This action's C<:Chained>
509 attribute says C<hello> and tells Catalyst that the C<hello> action in
510 the current controller is its parent.
512 With this we have built a chain consisting of two public path parts.
513 C<hello> captures one part of the path as its argument, and also
514 specifies the path root as its parent. So this part is
515 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
516 argument. It sums up to the path part C<world/$arg>. This leads to a
517 complete chain of C</hello/$arg/world/$arg> which is matched against the
520 This example application would, if run and called by e.g.
521 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
522 value C<arg_sum> to "23". The C<world> action would then append "World!"
523 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
524 sake of simplicity no view is shown. Instead we just put the values of
525 the stash into our body. So the output would look like:
530 And our test server would have given us this debugging output for the
534 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
535 [debug] Path is "/greeting/world"
536 [debug] Arguments are "12"
537 [info] Request took 0.164113s (6.093/s)
538 .------------------------------------------+-----------.
540 +------------------------------------------+-----------+
541 | /greeting/hello | 0.000029s |
542 | /greeting/world | 0.000024s |
543 '------------------------------------------+-----------'
546 What would be common uses of this dispatch technique? It gives the
547 possibility to split up logic that contains steps that each depend on
548 each other. An example would be, for example, a wiki path like
549 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
552 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
553 my ( $self, $c, $page_name ) = @_;
554 # load the page named $page_name and put the object
558 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
559 my ( $self, $c, $revision_id ) = @_;
560 # use the page object in the stash to get at its
561 # revision with number $revision_id
564 sub view : PathPart Chained('rev') Args(0) {
565 my ( $self, $c ) = @_;
566 # display the revision in our stash. Another option
567 # would be to forward a compatible object to the action
568 # that displays the default wiki pages, unless we want
569 # a different interface here, for example restore
573 It would now be possible to add other endpoints, for example C<restore>
574 to restore this specific revision as the current state.
576 You don't have to put all the chained actions in one controller. The
577 specification of the parent through C<:Chained> also takes an absolute
578 action path as its argument. Just specify it with a leading C</>.
580 If you want, for example, to have actions for the public paths
581 C</foo/12/edit> and C</foo/12>, just specify two actions with
582 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
583 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
584 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
585 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
586 this debugging output:
589 [debug] Loaded Path Part actions:
590 .-----------------------+------------------------------.
591 | Path Spec | Private |
592 +-----------------------+------------------------------+
593 | /foo/* | /controller/foo_view |
594 | /foo/*/edit | /controller/foo_load (1) |
595 | | => /controller/edit |
596 '-----------------------+------------------------------'
599 Here's a more detailed specification of the attributes belonging to
608 Sets the name of this part of the chain. If it is specified without
609 arguments, it takes the name of the action as default. So basically
610 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
611 This can also contain slashes to bind to a deeper level. An action
612 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
613 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
614 effect as using C<:PathPart>, it would default to the action name.
618 Sets PathPart to the path_prefix of the current controller.
622 Has to be specified for every child in the chain. Possible values are
623 absolute and relative private action paths or a single slash C</> to
624 tell Catalyst that this is the root of a chain. The attribute
625 C<:Chained> without arguments also defaults to the C</> behavior.
626 Relative action paths may use C<../> to refer to actions in parent
629 Because you can specify an absolute path to the parent action, it
630 doesn't matter to Catalyst where that parent is located. So, if your
631 design requests it, you can redispatch a chain through any controller or
634 Another interesting possibility gives C<:Chained('.')>, which chains
635 itself to an action with the path of the current controller's namespace.
638 # in MyApp::Controller::Foo
639 sub bar : Chained CaptureArgs(1) { ... }
641 # in MyApp::Controller::Foo::Bar
642 sub baz : Chained('.') Args(1) { ... }
644 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
645 as the argument to Chained here chains the C<baz> action to an action
646 with the path of the current controller namespace, namely
647 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
648 chain comes out as the end product.
652 Chains an action to another action with the same name in the parent
653 controller. For Example:
655 # in MyApp::Controller::Foo
656 sub bar : Chained CaptureArgs(1) { ... }
658 # in MyApp::Controller::Foo::Moo
659 sub bar : ChainedParent Args(1) { ... }
661 This builds a chain like C</bar/*/bar/*>.
665 Must be specified for every part of the chain that is not an
666 endpoint. With this attribute Catalyst knows how many of the following
667 parts of the path (separated by C</>) this action wants to capture as
668 its arguments. If it doesn't expect any, just specify
669 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
670 after the context, but you can also find them as array references in
671 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
672 level of the action in the chain that captured the parts of the path.
674 An action that is part of a chain (that is, one that has a C<:Chained>
675 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
678 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
679 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
680 named constraint such as CaptureArgs(Int,Str) would require two args with
681 the first being a Integer and the second a string. You may declare your own
682 custom type constraints and import them into the controller namespace:
684 package MyApp::Controller::Root;
687 use MooseX::MethodAttributes;
688 use MyApp::Types qw/Int/;
690 extends 'Catalyst::Controller';
692 sub chain_base :Chained(/) CaptureArgs(1) { }
694 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
696 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
698 See L<Catalyst::RouteMatching> for more.
702 By default, endpoints receive the rest of the arguments in the path. You
703 can tell Catalyst through C<:Args> explicitly how many arguments your
704 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
705 also affects whether this chain is invoked on a request. A chain with an
706 endpoint specifying one argument will only match if exactly one argument
709 You can specify an exact number of arguments like C<:Args(3)>, including
710 C<0>. If you just say C<:Args> without any arguments, it is the same as
711 leaving it out altogether: The chain is matched regardless of the number
712 of path parts after the endpoint.
714 Just as with C<:CaptureArgs>, the arguments get passed to the action in
715 C<@_> after the context object. They can also be reached through
716 C<$c-E<gt>request-E<gt>arguments>.
720 =head2 Auto actions, dispatching and forwarding
722 Note that the list of C<auto> actions called depends on the private path
723 of the endpoint of the chain, not on the chained actions way. The
724 C<auto> actions will be run before the chain dispatching begins. In
725 every other aspect, C<auto> actions behave as documented.
727 The C<forward>ing to other actions does just what you would expect. i.e.
728 only the target action is run. The actions that that action is chained
730 If you C<detach> out of a chain, the rest of the chain will not get
731 called after the C<detach>.
733 =head2 match_captures
735 A method which can optionally be implemented by actions to
738 See L<Catalyst::Action> for further details.
742 Catalyst Contributors, see Catalyst.pm
746 This library is free software. You can redistribute it and/or modify it under
747 the same terms as Perl itself.