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 $parent = "DUMMY";
390 # If this is an action chain get the last action in the chain
391 if($curr->can('chain') ) {
392 $curr = ${$curr->chain}[-1];
395 if (my $cap = $curr->number_of_captures) {
396 return undef unless @captures >= $cap; # not enough captures
398 unshift(@parts, splice(@captures, -$cap));
401 if (my $pp = $curr->attributes->{PathPart}) {
402 unshift(@parts, $pp->[0])
403 if (defined($pp->[0]) && length($pp->[0]));
405 $parent = $curr->attributes->{Chained}->[0];
406 $curr = $self->_actions->{$parent};
409 return undef unless $parent eq '/'; # fail for dangling action
411 return undef if @captures; # fail for too many captures
413 return join('/', '', @parts);
417 =head2 $c->expand_action($action)
419 Return a list of actions that represents a chained action. See
420 L<Catalyst::Dispatcher> for more info. You probably want to
421 use the expand_action it provides rather than this directly.
426 my ($self, $action) = @_;
428 return unless $action->attributes && $action->attributes->{Chained};
435 my $parent = $curr->attributes->{Chained}->[0];
436 $curr = $self->_actions->{$parent};
439 return Catalyst::ActionChain->from_chain([reverse @chain]);
442 __PACKAGE__->meta->make_immutable;
449 The C<Chained> attribute allows you to chain public path parts together
450 by their private names. A chain part's path can be specified with
451 C<PathPart> and can be declared to expect an arbitrary number of
452 arguments. The endpoint of the chain specifies how many arguments it
453 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
454 C<:Args> without an integer would be unlimited. The path parts that
455 aren't endpoints are using C<CaptureArgs> to specify how many parameters
456 they expect to receive. As an example setup:
458 package MyApp::Controller::Greeting;
459 use base qw/ Catalyst::Controller /;
461 # this is the beginning of our chain
462 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
463 my ( $self, $c, $integer ) = @_;
464 $c->stash->{ message } = "Hello ";
465 $c->stash->{ arg_sum } = $integer;
468 # this is our endpoint, because it has no :CaptureArgs
469 sub world : PathPart('world') Chained('hello') Args(1) {
470 my ( $self, $c, $integer ) = @_;
471 $c->stash->{ message } .= "World!";
472 $c->stash->{ arg_sum } += $integer;
474 $c->response->body( join "<br/>\n" =>
475 $c->stash->{ message }, $c->stash->{ arg_sum } );
478 The debug output provides a separate table for chained actions, showing
479 the whole chain as it would match and the actions it contains. Here's an
480 example of the startup output with our actions above:
483 [debug] Loaded Path Part actions:
484 .-----------------------+------------------------------.
485 | Path Spec | Private |
486 +-----------------------+------------------------------+
487 | /hello/*/world/* | /greeting/hello (1) |
488 | | => /greeting/world |
489 '-----------------------+------------------------------'
492 As you can see, Catalyst only deals with chains as whole paths and
493 builds one for each endpoint, which are the actions with C<:Chained> but
494 without C<:CaptureArgs>.
496 Let's assume this application gets a request at the path
497 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
498 to the C<hello> action and pass the value C<23> as an argument to it
499 after the context. It does so because we have previously used
500 C<:CaptureArgs(1)> to declare that it has one path part after itself as
501 its argument. We told Catalyst that this is the beginning of the chain
502 by specifying C<:Chained('/')>. Also note that instead of saying
503 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
504 defaults to the name of the action.
506 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
507 action. This is the last action to be called: Catalyst knows this is an
508 endpoint because we did not specify a C<:CaptureArgs>
509 attribute. Nevertheless we specify that this action expects an argument,
510 but at this point we're using C<:Args(1)> to do that. We could also have
511 said C<:Args> or left it out altogether, which would mean this action
512 would get all arguments that are there. This action's C<:Chained>
513 attribute says C<hello> and tells Catalyst that the C<hello> action in
514 the current controller is its parent.
516 With this we have built a chain consisting of two public path parts.
517 C<hello> captures one part of the path as its argument, and also
518 specifies the path root as its parent. So this part is
519 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
520 argument. It sums up to the path part C<world/$arg>. This leads to a
521 complete chain of C</hello/$arg/world/$arg> which is matched against the
524 This example application would, if run and called by e.g.
525 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
526 value C<arg_sum> to "23". The C<world> action would then append "World!"
527 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
528 sake of simplicity no view is shown. Instead we just put the values of
529 the stash into our body. So the output would look like:
534 And our test server would have given us this debugging output for the
538 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
539 [debug] Path is "/greeting/world"
540 [debug] Arguments are "12"
541 [info] Request took 0.164113s (6.093/s)
542 .------------------------------------------+-----------.
544 +------------------------------------------+-----------+
545 | /greeting/hello | 0.000029s |
546 | /greeting/world | 0.000024s |
547 '------------------------------------------+-----------'
550 What would be common uses of this dispatch technique? It gives the
551 possibility to split up logic that contains steps that each depend on
552 each other. An example would be, for example, a wiki path like
553 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
556 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
557 my ( $self, $c, $page_name ) = @_;
558 # load the page named $page_name and put the object
562 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
563 my ( $self, $c, $revision_id ) = @_;
564 # use the page object in the stash to get at its
565 # revision with number $revision_id
568 sub view : PathPart Chained('rev') Args(0) {
569 my ( $self, $c ) = @_;
570 # display the revision in our stash. Another option
571 # would be to forward a compatible object to the action
572 # that displays the default wiki pages, unless we want
573 # a different interface here, for example restore
577 It would now be possible to add other endpoints, for example C<restore>
578 to restore this specific revision as the current state.
580 You don't have to put all the chained actions in one controller. The
581 specification of the parent through C<:Chained> also takes an absolute
582 action path as its argument. Just specify it with a leading C</>.
584 If you want, for example, to have actions for the public paths
585 C</foo/12/edit> and C</foo/12>, just specify two actions with
586 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
587 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
588 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
589 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
590 this debugging output:
593 [debug] Loaded Path Part actions:
594 .-----------------------+------------------------------.
595 | Path Spec | Private |
596 +-----------------------+------------------------------+
597 | /foo/* | /controller/foo_view |
598 | /foo/*/edit | /controller/foo_load (1) |
599 | | => /controller/edit |
600 '-----------------------+------------------------------'
603 Here's a more detailed specification of the attributes belonging to
612 Sets the name of this part of the chain. If it is specified without
613 arguments, it takes the name of the action as default. So basically
614 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
615 This can also contain slashes to bind to a deeper level. An action
616 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
617 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
618 effect as using C<:PathPart>, it would default to the action name.
622 Sets PathPart to the path_prefix of the current controller.
626 Has to be specified for every child in the chain. Possible values are
627 absolute and relative private action paths or a single slash C</> to
628 tell Catalyst that this is the root of a chain. The attribute
629 C<:Chained> without arguments also defaults to the C</> behavior.
630 Relative action paths may use C<../> to refer to actions in parent
633 Because you can specify an absolute path to the parent action, it
634 doesn't matter to Catalyst where that parent is located. So, if your
635 design requests it, you can redispatch a chain through any controller or
638 Another interesting possibility gives C<:Chained('.')>, which chains
639 itself to an action with the path of the current controller's namespace.
642 # in MyApp::Controller::Foo
643 sub bar : Chained CaptureArgs(1) { ... }
645 # in MyApp::Controller::Foo::Bar
646 sub baz : Chained('.') Args(1) { ... }
648 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
649 as the argument to Chained here chains the C<baz> action to an action
650 with the path of the current controller namespace, namely
651 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
652 chain comes out as the end product.
656 Chains an action to another action with the same name in the parent
657 controller. For Example:
659 # in MyApp::Controller::Foo
660 sub bar : Chained CaptureArgs(1) { ... }
662 # in MyApp::Controller::Foo::Moo
663 sub bar : ChainedParent Args(1) { ... }
665 This builds a chain like C</bar/*/bar/*>.
669 Must be specified for every part of the chain that is not an
670 endpoint. With this attribute Catalyst knows how many of the following
671 parts of the path (separated by C</>) this action wants to capture as
672 its arguments. If it doesn't expect any, just specify
673 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
674 after the context, but you can also find them as array references in
675 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
676 level of the action in the chain that captured the parts of the path.
678 An action that is part of a chain (that is, one that has a C<:Chained>
679 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
682 Allowed values for CaptureArgs is a single integer (CaptureArgs(2), meaning two
683 allowed) or you can declare a L<Moose>, L<MooseX::Types> or L<Type::Tiny>
684 named constraint such as CaptureArgs(Int,Str) would require two args with
685 the first being a Integer and the second a string. You may declare your own
686 custom type constraints and import them into the controller namespace:
688 package MyApp::Controller::Root;
691 use MooseX::MethodAttributes;
692 use MyApp::Types qw/Int/;
694 extends 'Catalyst::Controller';
696 sub chain_base :Chained(/) CaptureArgs(1) { }
698 sub any_priority_chain :Chained(chain_base) PathPart('') Args(1) { }
700 sub int_priority_chain :Chained(chain_base) PathPart('') Args(Int) { }
702 See L<Catalyst::RouteMatching> for more.
706 By default, endpoints receive the rest of the arguments in the path. You
707 can tell Catalyst through C<:Args> explicitly how many arguments your
708 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
709 also affects whether this chain is invoked on a request. A chain with an
710 endpoint specifying one argument will only match if exactly one argument
713 You can specify an exact number of arguments like C<:Args(3)>, including
714 C<0>. If you just say C<:Args> without any arguments, it is the same as
715 leaving it out altogether: The chain is matched regardless of the number
716 of path parts after the endpoint.
718 Just as with C<:CaptureArgs>, the arguments get passed to the action in
719 C<@_> after the context object. They can also be reached through
720 C<$c-E<gt>request-E<gt>arguments>.
724 =head2 Auto actions, dispatching and forwarding
726 Note that the list of C<auto> actions called depends on the private path
727 of the endpoint of the chain, not on the chained actions way. The
728 C<auto> actions will be run before the chain dispatching begins. In
729 every other aspect, C<auto> actions behave as documented.
731 The C<forward>ing to other actions does just what you would expect. i.e.
732 only the target action is run. The actions that that action is chained
734 If you C<detach> out of a chain, the rest of the chain will not get
735 called after the C<detach>.
737 =head2 match_captures
739 A method which can optionally be implemented by actions to
742 See L<Catalyst::Action> for further details.
746 Catalyst Contributors, see Catalyst.pm
750 This library is free software. You can redistribute it and/or modify it under
751 the same terms as Perl itself.