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 = $capture_attr->[0] || 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, $capture_count));
250 # check if the action may fit, depending on a given test by the app
251 if ($action->can('match_captures')) { 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 /\//, $action->attributes->{PathPart}->[0];
282 # No best action currently
283 # OR This one matches with fewer parts left than the current best action,
284 # And therefore is a better match
285 # OR No parts and this expects 0
286 # The current best action might also be Args(0),
287 # but we couldn't chose between then anyway so we'll take the last seen
291 @parts < @{$best_action->{parts}} ||
294 defined($args_attr) &&
297 ( exists($best_action->{args_attr}) && defined($best_action->{args_attr}) ? ($best_action->{args_attr} ne 0) : 1 )
302 actions => [ $action ],
305 args_attr => $args_attr,
306 n_pathparts => scalar(@pathparts),
312 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
316 =head2 $self->register( $c, $action )
318 Calls register_path for every Path attribute for the given $action.
322 sub _check_args_attr {
323 my ( $self, $action, $name ) = @_;
325 return unless exists $action->attributes->{$name};
327 if (@{$action->attributes->{$name}} > 1) {
328 Catalyst::Exception->throw(
329 "Multiple $name attributes not supported registering " . $action->reverse()
332 my $args = $action->attributes->{$name}->[0];
333 if (defined($args) and not (
334 Scalar::Util::looks_like_number($args) and
335 int($args) == $args and $args >= 0
337 require Data::Dumper;
338 local $Data::Dumper::Terse = 1;
339 local $Data::Dumper::Indent = 0;
340 $args = Data::Dumper::Dumper($args);
341 Catalyst::Exception->throw(
342 "Invalid $name($args) for action " . $action->reverse() .
343 " (use '$name' or '$name(<number>)')"
349 my ( $self, $c, $action ) = @_;
351 my @chained_attr = @{ $action->attributes->{Chained} || [] };
353 return 0 unless @chained_attr;
355 if (@chained_attr > 1) {
356 Catalyst::Exception->throw(
357 "Multiple Chained attributes not supported registering ${action}"
360 my $chained_to = $chained_attr[0];
362 Catalyst::Exception->throw(
363 "Actions cannot chain to themselves registering /${action}"
364 ) if ($chained_to eq '/' . $action);
366 my $children = ($self->_children_of->{ $chained_to } ||= {});
368 my @path_part = @{ $action->attributes->{PathPart} || [] };
370 my $part = $action->name;
372 if (@path_part == 1 && defined $path_part[0]) {
373 $part = $path_part[0];
374 } elsif (@path_part > 1) {
375 Catalyst::Exception->throw(
376 "Multiple PathPart attributes not supported registering " . $action->reverse()
380 if ($part =~ m(^/)) {
381 Catalyst::Exception->throw(
382 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
386 my $encoded_part = URI->new($part)->canonical;
387 $encoded_part =~ s{(?<=[^/])/+\z}{};
389 $action->attributes->{PathPart} = [ $encoded_part ];
391 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
393 $self->_actions->{'/'.$action->reverse} = $action;
395 foreach my $name (qw(Args CaptureArgs)) {
396 $self->_check_args_attr($action, $name);
399 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
400 Catalyst::Exception->throw(
401 "Combining Args and CaptureArgs attributes not supported registering " .
406 unless ($action->attributes->{CaptureArgs}) {
407 unshift(@{ $self->_endpoints }, $action);
413 =head2 $self->uri_for_action($action, $captures)
415 Get the URI part for the action, using C<$captures> to fill
421 my ( $self, $action, $captures ) = @_;
423 return undef unless ($action->attributes->{Chained}
424 && !$action->attributes->{CaptureArgs});
427 my @captures = @$captures;
428 my $parent = "DUMMY";
431 if (my $cap = $curr->attributes->{CaptureArgs}) {
432 return undef unless @captures >= ($cap->[0]||0); # not enough captures
434 unshift(@parts, splice(@captures, -$cap->[0]));
437 if (my $pp = $curr->attributes->{PathPart}) {
438 unshift(@parts, $pp->[0])
439 if (defined($pp->[0]) && length($pp->[0]));
441 $parent = $curr->attributes->{Chained}->[0];
442 $curr = $self->_actions->{$parent};
445 return undef unless $parent eq '/'; # fail for dangling action
447 return undef if @captures; # fail for too many captures
449 return join('/', '', @parts);
453 =head2 $c->expand_action($action)
455 Return a list of actions that represents a chained action. See
456 L<Catalyst::Dispatcher> for more info. You probably want to
457 use the expand_action it provides rather than this directly.
462 my ($self, $action) = @_;
464 return unless $action->attributes && $action->attributes->{Chained};
471 my $parent = $curr->attributes->{Chained}->[0];
472 $curr = $self->_actions->{$parent};
475 return Catalyst::ActionChain->from_chain([reverse @chain]);
478 __PACKAGE__->meta->make_immutable;
485 The C<Chained> attribute allows you to chain public path parts together
486 by their private names. A chain part's path can be specified with
487 C<PathPart> and can be declared to expect an arbitrary number of
488 arguments. The endpoint of the chain specifies how many arguments it
489 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
490 C<:Args> without an integer would be unlimited. The path parts that
491 aren't endpoints are using C<CaptureArgs> to specify how many parameters
492 they expect to receive. As an example setup:
494 package MyApp::Controller::Greeting;
495 use base qw/ Catalyst::Controller /;
497 # this is the beginning of our chain
498 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
499 my ( $self, $c, $integer ) = @_;
500 $c->stash->{ message } = "Hello ";
501 $c->stash->{ arg_sum } = $integer;
504 # this is our endpoint, because it has no :CaptureArgs
505 sub world : PathPart('world') Chained('hello') Args(1) {
506 my ( $self, $c, $integer ) = @_;
507 $c->stash->{ message } .= "World!";
508 $c->stash->{ arg_sum } += $integer;
510 $c->response->body( join "<br/>\n" =>
511 $c->stash->{ message }, $c->stash->{ arg_sum } );
514 The debug output provides a separate table for chained actions, showing
515 the whole chain as it would match and the actions it contains. Here's an
516 example of the startup output with our actions above:
519 [debug] Loaded Path Part actions:
520 .-----------------------+------------------------------.
521 | Path Spec | Private |
522 +-----------------------+------------------------------+
523 | /hello/*/world/* | /greeting/hello (1) |
524 | | => /greeting/world |
525 '-----------------------+------------------------------'
528 As you can see, Catalyst only deals with chains as whole paths and
529 builds one for each endpoint, which are the actions with C<:Chained> but
530 without C<:CaptureArgs>.
532 Let's assume this application gets a request at the path
533 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
534 to the C<hello> action and pass the value C<23> as an argument to it
535 after the context. It does so because we have previously used
536 C<:CaptureArgs(1)> to declare that it has one path part after itself as
537 its argument. We told Catalyst that this is the beginning of the chain
538 by specifying C<:Chained('/')>. Also note that instead of saying
539 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
540 defaults to the name of the action.
542 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
543 action. This is the last action to be called: Catalyst knows this is an
544 endpoint because we did not specify a C<:CaptureArgs>
545 attribute. Nevertheless we specify that this action expects an argument,
546 but at this point we're using C<:Args(1)> to do that. We could also have
547 said C<:Args> or left it out altogether, which would mean this action
548 would get all arguments that are there. This action's C<:Chained>
549 attribute says C<hello> and tells Catalyst that the C<hello> action in
550 the current controller is its parent.
552 With this we have built a chain consisting of two public path parts.
553 C<hello> captures one part of the path as its argument, and also
554 specifies the path root as its parent. So this part is
555 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
556 argument. It sums up to the path part C<world/$arg>. This leads to a
557 complete chain of C</hello/$arg/world/$arg> which is matched against the
560 This example application would, if run and called by e.g.
561 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
562 value C<arg_sum> to "23". The C<world> action would then append "World!"
563 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
564 sake of simplicity no view is shown. Instead we just put the values of
565 the stash into our body. So the output would look like:
570 And our test server would have given us this debugging output for the
574 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
575 [debug] Path is "/greeting/world"
576 [debug] Arguments are "12"
577 [info] Request took 0.164113s (6.093/s)
578 .------------------------------------------+-----------.
580 +------------------------------------------+-----------+
581 | /greeting/hello | 0.000029s |
582 | /greeting/world | 0.000024s |
583 '------------------------------------------+-----------'
586 What would be common uses of this dispatch technique? It gives the
587 possibility to split up logic that contains steps that each depend on
588 each other. An example would be, for example, a wiki path like
589 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
592 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
593 my ( $self, $c, $page_name ) = @_;
594 # load the page named $page_name and put the object
598 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
599 my ( $self, $c, $revision_id ) = @_;
600 # use the page object in the stash to get at its
601 # revision with number $revision_id
604 sub view : PathPart Chained('rev') Args(0) {
605 my ( $self, $c ) = @_;
606 # display the revision in our stash. Another option
607 # would be to forward a compatible object to the action
608 # that displays the default wiki pages, unless we want
609 # a different interface here, for example restore
613 It would now be possible to add other endpoints, for example C<restore>
614 to restore this specific revision as the current state.
616 You don't have to put all the chained actions in one controller. The
617 specification of the parent through C<:Chained> also takes an absolute
618 action path as its argument. Just specify it with a leading C</>.
620 If you want, for example, to have actions for the public paths
621 C</foo/12/edit> and C</foo/12>, just specify two actions with
622 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
623 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
624 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
625 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
626 this debugging output:
629 [debug] Loaded Path Part actions:
630 .-----------------------+------------------------------.
631 | Path Spec | Private |
632 +-----------------------+------------------------------+
633 | /foo/* | /controller/foo_view |
634 | /foo/*/edit | /controller/foo_load (1) |
635 | | => /controller/edit |
636 '-----------------------+------------------------------'
639 Here's a more detailed specification of the attributes belonging to
648 Sets the name of this part of the chain. If it is specified without
649 arguments, it takes the name of the action as default. So basically
650 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
651 This can also contain slashes to bind to a deeper level. An action
652 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
653 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
654 effect as using C<:PathPart>, it would default to the action name.
658 Sets PathPart to the path_prefix of the current controller.
662 Has to be specified for every child in the chain. Possible values are
663 absolute and relative private action paths or a single slash C</> to
664 tell Catalyst that this is the root of a chain. The attribute
665 C<:Chained> without arguments also defaults to the C</> behavior.
666 Relative action paths may use C<../> to refer to actions in parent
669 Because you can specify an absolute path to the parent action, it
670 doesn't matter to Catalyst where that parent is located. So, if your
671 design requests it, you can redispatch a chain through any controller or
674 Another interesting possibility gives C<:Chained('.')>, which chains
675 itself to an action with the path of the current controller's namespace.
678 # in MyApp::Controller::Foo
679 sub bar : Chained CaptureArgs(1) { ... }
681 # in MyApp::Controller::Foo::Bar
682 sub baz : Chained('.') Args(1) { ... }
684 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
685 as the argument to Chained here chains the C<baz> action to an action
686 with the path of the current controller namespace, namely
687 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
688 chain comes out as the end product.
692 Chains an action to another action with the same name in the parent
693 controller. For Example:
695 # in MyApp::Controller::Foo
696 sub bar : Chained CaptureArgs(1) { ... }
698 # in MyApp::Controller::Foo::Moo
699 sub bar : ChainedParent Args(1) { ... }
701 This builds a chain like C</bar/*/bar/*>.
705 Must be specified for every part of the chain that is not an
706 endpoint. With this attribute Catalyst knows how many of the following
707 parts of the path (separated by C</>) this action wants to capture as
708 its arguments. If it doesn't expect any, just specify
709 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
710 after the context, but you can also find them as array references in
711 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
712 level of the action in the chain that captured the parts of the path.
714 An action that is part of a chain (that is, one that has a C<:Chained>
715 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
720 By default, endpoints receive the rest of the arguments in the path. You
721 can tell Catalyst through C<:Args> explicitly how many arguments your
722 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
723 also affects whether this chain is invoked on a request. A chain with an
724 endpoint specifying one argument will only match if exactly one argument
727 You can specify an exact number of arguments like C<:Args(3)>, including
728 C<0>. If you just say C<:Args> without any arguments, it is the same as
729 leaving it out altogether: The chain is matched regardless of the number
730 of path parts after the endpoint.
732 Just as with C<:CaptureArgs>, the arguments get passed to the action in
733 C<@_> after the context object. They can also be reached through
734 C<$c-E<gt>request-E<gt>arguments>.
738 =head2 Auto actions, dispatching and forwarding
740 Note that the list of C<auto> actions called depends on the private path
741 of the endpoint of the chain, not on the chained actions way. The
742 C<auto> actions will be run before the chain dispatching begins. In
743 every other aspect, C<auto> actions behave as documented.
745 The C<forward>ing to other actions does just what you would expect. i.e.
746 only the target action is run. The actions that that action is chained
748 If you C<detach> out of a chain, the rest of the chain will not get
749 called after the C<detach>.
751 =head2 match_captures
753 A method which can optionally be implemented by actions to
756 See L<Catalyst::Action> for further details.
760 Catalyst Contributors, see Catalyst.pm
764 This library is free software. You can redistribute it and/or modify it under
765 the same terms as Perl itself.