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 = $endpoint->attributes->{Args}->[0];
100 my @parts = (defined($args) ? (("*") x $args) : '...');
102 my $parent = "DUMMY";
103 my $curr = $endpoint;
105 if (my $cap = $curr->attributes->{CaptureArgs}) {
106 unshift(@parts, (("*") x $cap->[0]));
108 if (my $pp = $curr->attributes->{PartPath}) {
109 unshift(@parts, $pp->[0])
110 if (defined $pp->[0] && length $pp->[0]);
112 $parent = $curr->attributes->{Chained}->[0];
113 $curr = $self->_actions->{$parent};
114 unshift(@parents, $curr) if $curr;
116 if ($parent ne '/') {
117 $has_unattached_actions = 1;
118 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
122 foreach my $p (@parents) {
124 if (my $cap = $p->attributes->{CaptureArgs}) {
125 $name .= ' ('.$cap->[0].')';
127 unless ($p eq $parents[0]) {
128 $name = "-> ${name}";
130 push(@rows, [ '', $name ]);
132 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
133 $rows[0][0] = join('/', '', @parts) || '/';
134 $paths->row(@$_) for @rows;
137 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
138 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
139 if $has_unattached_actions;
142 =head2 $self->match( $c, $path )
144 Calls C<recurse_match> to see if a chain matches the C<$path>.
149 my ( $self, $c, $path ) = @_;
151 my $request = $c->request;
152 return 0 if @{$request->args};
154 my @parts = split('/', $path);
156 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
158 if ($parts && @$parts) {
159 for my $arg (@$parts) {
160 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
161 push @{$request->args}, $arg;
165 return 0 unless $chain;
167 my $action = Catalyst::ActionChain->from_chain($chain);
169 $request->action("/${action}");
170 $request->match("/${action}");
171 $request->captures($captures);
173 $c->namespace( $action->namespace );
178 =head2 $self->recurse_match( $c, $parent, \@path_parts )
180 Recursive search for a matching chain.
185 my ( $self, $c, $parent, $path_parts ) = @_;
186 my $children = $self->_children_of->{$parent};
187 return () unless $children;
190 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
192 # $b then $a to try longest part first
193 my @parts = @$path_parts;
194 if (length $try_part) { # test and strip PathPart
196 ($try_part eq join('/', # assemble equal number of parts
197 splice( # and strip them off @parts as well
198 @parts, 0, scalar(@{[split('/', $try_part)]})
199 ))); # @{[]} to avoid split to @_
201 my @try_actions = @{$children->{$try_part}};
202 TRY_ACTION: foreach my $action (@try_actions) {
203 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
205 # Short-circuit if not enough remaining parts
206 next TRY_ACTION unless @parts >= $capture_attr->[0];
209 my @parts = @parts; # localise
211 # strip CaptureArgs into list
212 push(@captures, splice(@parts, 0, $capture_attr->[0]));
214 # try the remaining parts against children of this action
215 my ($actions, $captures, $action_parts) = $self->recurse_match(
216 $c, '/'.$action->reverse, \@parts
218 # No best action currently
219 # OR The action has less parts
220 # OR The action has equal parts but less captured data (ergo more defined)
223 $#$action_parts < $#{$best_action->{parts}} ||
224 ($#$action_parts == $#{$best_action->{parts}} &&
225 $#$captures < $#{$best_action->{captures}}))){
227 actions => [ $action, @$actions ],
228 captures=> [ @captures, @$captures ],
229 parts => $action_parts
235 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
236 next TRY_ACTION unless $action->match($c);
238 my $args_attr = $action->attributes->{Args}->[0];
240 # No best action currently
241 # OR This one matches with fewer parts left than the current best action,
242 # And therefore is a better match
243 # OR No parts and this expects 0
244 # The current best action might also be Args(0),
245 # but we couldn't chose between then anyway so we'll take the last seen
248 @parts < @{$best_action->{parts}} ||
249 (!@parts && $args_attr eq 0)){
251 actions => [ $action ],
259 return @$best_action{qw/actions captures parts/} if $best_action;
263 =head2 $self->register( $c, $action )
265 Calls register_path for every Path attribute for the given $action.
270 my ( $self, $c, $action ) = @_;
272 my @chained_attr = @{ $action->attributes->{Chained} || [] };
274 return 0 unless @chained_attr;
276 if (@chained_attr > 1) {
277 Catalyst::Exception->throw(
278 "Multiple Chained attributes not supported registering ${action}"
281 my $chained_to = $chained_attr[0];
283 Catalyst::Exception->throw(
284 "Actions cannot chain to themselves registering /${action}"
285 ) if ($chained_to eq '/' . $action);
287 my $children = ($self->_children_of->{ $chained_to } ||= {});
289 my @path_part = @{ $action->attributes->{PathPart} || [] };
291 my $part = $action->name;
293 if (@path_part == 1 && defined $path_part[0]) {
294 $part = $path_part[0];
295 } elsif (@path_part > 1) {
296 Catalyst::Exception->throw(
297 "Multiple PathPart attributes not supported registering " . $action->reverse()
301 if ($part =~ m(^/)) {
302 Catalyst::Exception->throw(
303 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
307 $action->attributes->{PartPath} = [ $part ];
309 unshift(@{ $children->{$part} ||= [] }, $action);
311 $self->_actions->{'/'.$action->reverse} = $action;
313 if (exists $action->attributes->{Args}) {
314 my $args = $action->attributes->{Args}->[0];
315 if (defined($args) and not (
316 Scalar::Util::looks_like_number($args) and
319 require Data::Dumper;
320 local $Data::Dumper::Terse = 1;
321 local $Data::Dumper::Indent = 0;
322 $args = Data::Dumper::Dumper($args);
323 Catalyst::Exception->throw(
324 "Invalid Args($args) for action " . $action->reverse() .
325 " (use 'Args' or 'Args(<number>)'"
330 unless ($action->attributes->{CaptureArgs}) {
331 unshift(@{ $self->_endpoints }, $action);
337 =head2 $self->uri_for_action($action, $captures)
339 Get the URI part for the action, using C<$captures> to fill
345 my ( $self, $action, $captures ) = @_;
347 return undef unless ($action->attributes->{Chained}
348 && !$action->attributes->{CaptureArgs});
351 my @captures = @$captures;
352 my $parent = "DUMMY";
355 if (my $cap = $curr->attributes->{CaptureArgs}) {
356 return undef unless @captures >= $cap->[0]; # not enough captures
358 unshift(@parts, splice(@captures, -$cap->[0]));
361 if (my $pp = $curr->attributes->{PartPath}) {
362 unshift(@parts, $pp->[0])
363 if (defined($pp->[0]) && length($pp->[0]));
365 $parent = $curr->attributes->{Chained}->[0];
366 $curr = $self->_actions->{$parent};
369 return undef unless $parent eq '/'; # fail for dangling action
371 return undef if @captures; # fail for too many captures
373 return join('/', '', @parts);
377 =head2 $c->expand_action($action)
379 Return a list of actions that represents a chained action. See
380 L<Catalyst::Dispatcher> for more info. You probably want to
381 use the expand_action it provides rather than this directly.
386 my ($self, $action) = @_;
388 return unless $action->attributes && $action->attributes->{Chained};
395 my $parent = $curr->attributes->{Chained}->[0];
396 $curr = $self->_actions->{$parent};
399 return Catalyst::ActionChain->from_chain([reverse @chain]);
402 =head2 $self->splice_captures_from( $c, $action, $args )
404 Calculates the number of capture args for the given action,
405 splices off the front of the supplied args, and pushes them back
406 on the args list wrapped in an array ref
410 sub splice_captures_from {
411 my ($self, $c, $action, $args) = @_; my $attrs = $action->attributes;
413 return 0 unless ($attrs->{Chained});
415 if ($attrs->{CaptureArgs}) {
416 $c->log->debug( 'Action '.$action->reverse.' is a midpoint' )
422 my @chain = @{ $self->expand_action( $action )->chain }; pop @chain;
424 # Now start from the root of the chain, populate captures
425 for my $num_caps (map { $_->attributes->{CaptureArgs}->[0] } @chain) {
426 if ($num_caps > scalar @{ $args }) {
427 $c->log->debug( 'Action '.$action->reverse.' insufficient args' )
432 push @captures, splice @{ $args }, 0, $num_caps;
435 if (defined $args->[ $attrs->{Args}->[0] ]) {
436 $c->log->debug( 'Action '.$action->reverse.' too many args' )
440 unshift @{ $args }, \@captures if (defined $captures[0]);
445 __PACKAGE__->meta->make_immutable;
451 The C<Chained> attribute allows you to chain public path parts together
452 by their private names. A chain part's path can be specified with
453 C<PathPart> and can be declared to expect an arbitrary number of
454 arguments. The endpoint of the chain specifies how many arguments it
455 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
456 C<:Args> without an integer would be unlimited. The path parts that
457 aren't endpoints are using C<CaptureArgs> to specify how many parameters
458 they expect to receive. As an example setup:
460 package MyApp::Controller::Greeting;
461 use base qw/ Catalyst::Controller /;
463 # this is the beginning of our chain
464 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
465 my ( $self, $c, $integer ) = @_;
466 $c->stash->{ message } = "Hello ";
467 $c->stash->{ arg_sum } = $integer;
470 # this is our endpoint, because it has no :CaptureArgs
471 sub world : PathPart('world') Chained('hello') Args(1) {
472 my ( $self, $c, $integer ) = @_;
473 $c->stash->{ message } .= "World!";
474 $c->stash->{ arg_sum } += $integer;
476 $c->response->body( join "<br/>\n" =>
477 $c->stash->{ message }, $c->stash->{ arg_sum } );
480 The debug output provides a separate table for chained actions, showing
481 the whole chain as it would match and the actions it contains. Here's an
482 example of the startup output with our actions above:
485 [debug] Loaded Path Part actions:
486 .-----------------------+------------------------------.
487 | Path Spec | Private |
488 +-----------------------+------------------------------+
489 | /hello/*/world/* | /greeting/hello (1) |
490 | | => /greeting/world |
491 '-----------------------+------------------------------'
494 As you can see, Catalyst only deals with chains as whole paths and
495 builds one for each endpoint, which are the actions with C<:Chained> but
496 without C<:CaptureArgs>.
498 Let's assume this application gets a request at the path
499 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
500 to the C<hello> action and pass the value C<23> as an argument to it
501 after the context. It does so because we have previously used
502 C<:CaptureArgs(1)> to declare that it has one path part after itself as
503 its argument. We told Catalyst that this is the beginning of the chain
504 by specifying C<:Chained('/')>. Also note that instead of saying
505 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
506 defaults to the name of the action.
508 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
509 action. This is the last action to be called: Catalyst knows this is an
510 endpoint because we did not specify a C<:CaptureArgs>
511 attribute. Nevertheless we specify that this action expects an argument,
512 but at this point we're using C<:Args(1)> to do that. We could also have
513 said C<:Args> or left it out altogether, which would mean this action
514 would get all arguments that are there. This action's C<:Chained>
515 attribute says C<hello> and tells Catalyst that the C<hello> action in
516 the current controller is its parent.
518 With this we have built a chain consisting of two public path parts.
519 C<hello> captures one part of the path as its argument, and also
520 specifies the path root as its parent. So this part is
521 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
522 argument. It sums up to the path part C<world/$arg>. This leads to a
523 complete chain of C</hello/$arg/world/$arg> which is matched against the
526 This example application would, if run and called by e.g.
527 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
528 value C<arg_sum> to "23". The C<world> action would then append "World!"
529 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
530 sake of simplicity no view is shown. Instead we just put the values of
531 the stash into our body. So the output would look like:
536 And our test server would have given us this debugging output for the
540 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
541 [debug] Path is "/greeting/world"
542 [debug] Arguments are "12"
543 [info] Request took 0.164113s (6.093/s)
544 .------------------------------------------+-----------.
546 +------------------------------------------+-----------+
547 | /greeting/hello | 0.000029s |
548 | /greeting/world | 0.000024s |
549 '------------------------------------------+-----------'
552 What would be common uses of this dispatch technique? It gives the
553 possibility to split up logic that contains steps that each depend on
554 each other. An example would be, for example, a wiki path like
555 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
558 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
559 my ( $self, $c, $page_name ) = @_;
560 # load the page named $page_name and put the object
564 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
565 my ( $self, $c, $revision_id ) = @_;
566 # use the page object in the stash to get at its
567 # revision with number $revision_id
570 sub view : PathPart Chained('rev') Args(0) {
571 my ( $self, $c ) = @_;
572 # display the revision in our stash. Another option
573 # would be to forward a compatible object to the action
574 # that displays the default wiki pages, unless we want
575 # a different interface here, for example restore
579 It would now be possible to add other endpoints, for example C<restore>
580 to restore this specific revision as the current state.
582 You don't have to put all the chained actions in one controller. The
583 specification of the parent through C<:Chained> also takes an absolute
584 action path as its argument. Just specify it with a leading C</>.
586 If you want, for example, to have actions for the public paths
587 C</foo/12/edit> and C</foo/12>, just specify two actions with
588 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
589 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
590 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
591 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
592 this debugging output:
595 [debug] Loaded Path Part actions:
596 .-----------------------+------------------------------.
597 | Path Spec | Private |
598 +-----------------------+------------------------------+
599 | /foo/* | /controller/foo_view |
600 | /foo/*/edit | /controller/foo_load (1) |
601 | | => /controller/edit |
602 '-----------------------+------------------------------'
605 Here's a more detailed specification of the attributes belonging to
614 Sets the name of this part of the chain. If it is specified without
615 arguments, it takes the name of the action as default. So basically
616 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
617 This can also contain slashes to bind to a deeper level. An action
618 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
619 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
620 effect as using C<:PathPart>, it would default to the action name.
624 Sets PathPart to the path_prefix of the current controller.
628 Has to be specified for every child in the chain. Possible values are
629 absolute and relative private action paths or a single slash C</> to
630 tell Catalyst that this is the root of a chain. The attribute
631 C<:Chained> without arguments also defaults to the C</> behavior.
632 Relative action paths may use C<../> to refer to actions in parent
635 Because you can specify an absolute path to the parent action, it
636 doesn't matter to Catalyst where that parent is located. So, if your
637 design requests it, you can redispatch a chain through any controller or
640 Another interesting possibility gives C<:Chained('.')>, which chains
641 itself to an action with the path of the current controller's namespace.
644 # in MyApp::Controller::Foo
645 sub bar : Chained CaptureArgs(1) { ... }
647 # in MyApp::Controller::Foo::Bar
648 sub baz : Chained('.') Args(1) { ... }
650 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
651 as the argument to Chained here chains the C<baz> action to an action
652 with the path of the current controller namespace, namely
653 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
654 chain comes out as the end product.
658 Chains an action to another action with the same name in the parent
659 controller. For Example:
661 # in MyApp::Controller::Foo
662 sub bar : Chained CaptureArgs(1) { ... }
664 # in MyApp::Controller::Foo::Moo
665 sub bar : ChainedParent Args(1) { ... }
667 This builds a chain like C</bar/*/bar/*>.
671 Must be specified for every part of the chain that is not an
672 endpoint. With this attribute Catalyst knows how many of the following
673 parts of the path (separated by C</>) this action wants to capture as
674 its arguments. If it doesn't expect any, just specify
675 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
676 after the context, but you can also find them as array references in
677 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
678 level of the action in the chain that captured the parts of the path.
680 An action that is part of a chain (that is, one that has a C<:Chained>
681 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
686 By default, endpoints receive the rest of the arguments in the path. You
687 can tell Catalyst through C<:Args> explicitly how many arguments your
688 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
689 also affects whether this chain is invoked on a request. A chain with an
690 endpoint specifying one argument will only match if exactly one argument
693 You can specify an exact number of arguments like C<:Args(3)>, including
694 C<0>. If you just say C<:Args> without any arguments, it is the same as
695 leaving it out altogether: The chain is matched regardless of the number
696 of path parts after the endpoint.
698 Just as with C<:CaptureArgs>, the arguments get passed to the action in
699 C<@_> after the context object. They can also be reached through
700 C<$c-E<gt>request-E<gt>arguments>.
704 =head2 Auto actions, dispatching and forwarding
706 Note that the list of C<auto> actions called depends on the private path
707 of the endpoint of the chain, not on the chained actions way. The
708 C<auto> actions will be run before the chain dispatching begins. In
709 every other aspect, C<auto> actions behave as documented.
711 The C<forward>ing to other actions does just what you would expect. But if
712 you C<detach> out of a chain, the rest of the chain will not get called
717 Catalyst Contributors, see Catalyst.pm
721 This library is free software. You can redistribute it and/or modify it under
722 the same terms as Perl itself.