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 $column_width = Catalyst::Utils::term_width() - 35 - 9;
84 my $paths = Text::SimpleTable->new(
85 [ 35, 'Path Spec' ], [ $column_width, 'Private' ],
88 my $has_unattached_actions;
89 my $unattached_actions = Text::SimpleTable->new(
90 [ 35, 'Private' ], [ $column_width, 'Missing parent' ],
93 ENDPOINT: foreach my $endpoint (
94 sort { $a->reverse cmp $b->reverse }
95 @{ $self->_endpoints }
97 my $args = $endpoint->attributes->{Args}->[0];
98 my @parts = (defined($args) ? (("*") x $args) : '...');
100 my $parent = "DUMMY";
101 my $curr = $endpoint;
103 if (my $cap = $curr->attributes->{CaptureArgs}) {
104 unshift(@parts, (("*") x $cap->[0]));
106 if (my $pp = $curr->attributes->{PartPath}) {
107 unshift(@parts, $pp->[0])
108 if (defined $pp->[0] && length $pp->[0]);
110 $parent = $curr->attributes->{Chained}->[0];
111 $curr = $self->_actions->{$parent};
112 unshift(@parents, $curr) if $curr;
114 if ($parent ne '/') {
115 $has_unattached_actions = 1;
116 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
120 foreach my $p (@parents) {
122 if (my $cap = $p->attributes->{CaptureArgs}) {
123 $name .= ' ('.$cap->[0].')';
125 unless ($p eq $parents[0]) {
126 $name = "-> ${name}";
128 push(@rows, [ '', $name ]);
130 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
131 $rows[0][0] = join('/', '', @parts) || '/';
132 $paths->row(@$_) for @rows;
135 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
136 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
137 if $has_unattached_actions;
140 =head2 $self->match( $c, $path )
142 Calls C<recurse_match> to see if a chain matches the C<$path>.
147 my ( $self, $c, $path ) = @_;
149 my $request = $c->request;
150 return 0 if @{$request->args};
152 my @parts = split('/', $path);
154 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
156 if ($parts && @$parts) {
157 for my $arg (@$parts) {
158 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
159 push @{$request->args}, $arg;
163 return 0 unless $chain;
165 my $action = Catalyst::ActionChain->from_chain($chain);
167 $request->action("/${action}");
168 $request->match("/${action}");
169 $request->captures($captures);
171 $c->namespace( $action->namespace );
176 =head2 $self->recurse_match( $c, $parent, \@path_parts )
178 Recursive search for a matching chain.
183 my ( $self, $c, $parent, $path_parts ) = @_;
184 my $children = $self->_children_of->{$parent};
185 return () unless $children;
188 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
190 # $b then $a to try longest part first
191 my @parts = @$path_parts;
192 if (length $try_part) { # test and strip PathPart
194 ($try_part eq join('/', # assemble equal number of parts
195 splice( # and strip them off @parts as well
196 @parts, 0, scalar(@{[split('/', $try_part)]})
197 ))); # @{[]} to avoid split to @_
199 my @try_actions = @{$children->{$try_part}};
200 TRY_ACTION: foreach my $action (@try_actions) {
201 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
203 # Short-circuit if not enough remaining parts
204 next TRY_ACTION unless @parts >= $capture_attr->[0];
207 my @parts = @parts; # localise
209 # strip CaptureArgs into list
210 push(@captures, splice(@parts, 0, $capture_attr->[0]));
212 # try the remaining parts against children of this action
213 my ($actions, $captures, $action_parts) = $self->recurse_match(
214 $c, '/'.$action->reverse, \@parts
216 # No best action currently
217 # OR The action has less parts
218 # OR The action has equal parts but less captured data (ergo more defined)
221 $#$action_parts < $#{$best_action->{parts}} ||
222 ($#$action_parts == $#{$best_action->{parts}} &&
223 $#$captures < $#{$best_action->{captures}}))){
225 actions => [ $action, @$actions ],
226 captures=> [ @captures, @$captures ],
227 parts => $action_parts
233 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
234 next TRY_ACTION unless $action->match($c);
237 # Default args is blank, not 0, since Args()
238 my $args_attr = $action->attributes->{Args}->[0];
239 $args_attr = '' unless defined $args_attr;
241 # No best action currently
242 # OR This one matches with fewer parts left than the current best action,
243 # And therefore is a better match
244 # OR No parts and this expects 0
245 # The current best action might also be Args(0),
246 # but we couldn't chose between then anyway so we'll take the last seen
249 @parts < @{$best_action->{parts}} ||
250 (!@parts && $args_attr eq 0)){
252 actions => [ $action ],
260 return @$best_action{qw/actions captures parts/} if $best_action;
264 =head2 $self->register( $c, $action )
266 Calls register_path for every Path attribute for the given $action.
271 my ( $self, $c, $action ) = @_;
273 my @chained_attr = @{ $action->attributes->{Chained} || [] };
275 return 0 unless @chained_attr;
277 if (@chained_attr > 1) {
278 Catalyst::Exception->throw(
279 "Multiple Chained attributes not supported registering ${action}"
282 my $chained_to = $chained_attr[0];
284 Catalyst::Exception->throw(
285 "Actions cannot chain to themselves registering /${action}"
286 ) if ($chained_to eq '/' . $action);
288 my $children = ($self->_children_of->{ $chained_to } ||= {});
290 my @path_part = @{ $action->attributes->{PathPart} || [] };
292 my $part = $action->name;
294 if (@path_part == 1 && defined $path_part[0]) {
295 $part = $path_part[0];
296 } elsif (@path_part > 1) {
297 Catalyst::Exception->throw(
298 "Multiple PathPart attributes not supported registering " . $action->reverse()
302 if ($part =~ m(^/)) {
303 Catalyst::Exception->throw(
304 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
308 $action->attributes->{PartPath} = [ $part ];
310 unshift(@{ $children->{$part} ||= [] }, $action);
312 $self->_actions->{'/'.$action->reverse} = $action;
314 if (exists $action->attributes->{Args}) {
315 my $args = $action->attributes->{Args}->[0];
316 if (defined($args) and not (
317 Scalar::Util::looks_like_number($args) and
320 require Data::Dumper;
321 local $Data::Dumper::Terse = 1;
322 local $Data::Dumper::Indent = 0;
323 $args = Data::Dumper::Dumper($args);
324 Catalyst::Exception->throw(
325 "Invalid Args($args) for action " . $action->reverse() .
326 " (use 'Args' or 'Args(<number>)'"
331 unless ($action->attributes->{CaptureArgs}) {
332 unshift(@{ $self->_endpoints }, $action);
338 =head2 $self->uri_for_action($action, $captures)
340 Get the URI part for the action, using C<$captures> to fill
346 my ( $self, $action, $captures ) = @_;
348 return undef unless ($action->attributes->{Chained}
349 && !$action->attributes->{CaptureArgs});
352 my @captures = @$captures;
353 my $parent = "DUMMY";
356 if (my $cap = $curr->attributes->{CaptureArgs}) {
357 return undef unless @captures >= $cap->[0]; # not enough captures
359 unshift(@parts, splice(@captures, -$cap->[0]));
362 if (my $pp = $curr->attributes->{PartPath}) {
363 unshift(@parts, $pp->[0])
364 if (defined($pp->[0]) && length($pp->[0]));
366 $parent = $curr->attributes->{Chained}->[0];
367 $curr = $self->_actions->{$parent};
370 return undef unless $parent eq '/'; # fail for dangling action
372 return undef if @captures; # fail for too many captures
374 return join('/', '', @parts);
378 =head2 $c->expand_action($action)
380 Return a list of actions that represents a chained action. See
381 L<Catalyst::Dispatcher> for more info. You probably want to
382 use the expand_action it provides rather than this directly.
387 my ($self, $action) = @_;
389 return unless $action->attributes && $action->attributes->{Chained};
396 my $parent = $curr->attributes->{Chained}->[0];
397 $curr = $self->_actions->{$parent};
400 return Catalyst::ActionChain->from_chain([reverse @chain]);
403 __PACKAGE__->meta->make_immutable;
409 The C<Chained> attribute allows you to chain public path parts together
410 by their private names. A chain part's path can be specified with
411 C<PathPart> and can be declared to expect an arbitrary number of
412 arguments. The endpoint of the chain specifies how many arguments it
413 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
414 C<:Args> without an integer would be unlimited. The path parts that
415 aren't endpoints are using C<CaptureArgs> to specify how many parameters
416 they expect to receive. As an example setup:
418 package MyApp::Controller::Greeting;
419 use base qw/ Catalyst::Controller /;
421 # this is the beginning of our chain
422 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
423 my ( $self, $c, $integer ) = @_;
424 $c->stash->{ message } = "Hello ";
425 $c->stash->{ arg_sum } = $integer;
428 # this is our endpoint, because it has no :CaptureArgs
429 sub world : PathPart('world') Chained('hello') Args(1) {
430 my ( $self, $c, $integer ) = @_;
431 $c->stash->{ message } .= "World!";
432 $c->stash->{ arg_sum } += $integer;
434 $c->response->body( join "<br/>\n" =>
435 $c->stash->{ message }, $c->stash->{ arg_sum } );
438 The debug output provides a separate table for chained actions, showing
439 the whole chain as it would match and the actions it contains. Here's an
440 example of the startup output with our actions above:
443 [debug] Loaded Path Part actions:
444 .-----------------------+------------------------------.
445 | Path Spec | Private |
446 +-----------------------+------------------------------+
447 | /hello/*/world/* | /greeting/hello (1) |
448 | | => /greeting/world |
449 '-----------------------+------------------------------'
452 As you can see, Catalyst only deals with chains as whole paths and
453 builds one for each endpoint, which are the actions with C<:Chained> but
454 without C<:CaptureArgs>.
456 Let's assume this application gets a request at the path
457 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
458 to the C<hello> action and pass the value C<23> as an argument to it
459 after the context. It does so because we have previously used
460 C<:CaptureArgs(1)> to declare that it has one path part after itself as
461 its argument. We told Catalyst that this is the beginning of the chain
462 by specifying C<:Chained('/')>. Also note that instead of saying
463 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
464 defaults to the name of the action.
466 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
467 action. This is the last action to be called: Catalyst knows this is an
468 endpoint because we did not specify a C<:CaptureArgs>
469 attribute. Nevertheless we specify that this action expects an argument,
470 but at this point we're using C<:Args(1)> to do that. We could also have
471 said C<:Args> or left it out altogether, which would mean this action
472 would get all arguments that are there. This action's C<:Chained>
473 attribute says C<hello> and tells Catalyst that the C<hello> action in
474 the current controller is its parent.
476 With this we have built a chain consisting of two public path parts.
477 C<hello> captures one part of the path as its argument, and also
478 specifies the path root as its parent. So this part is
479 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
480 argument. It sums up to the path part C<world/$arg>. This leads to a
481 complete chain of C</hello/$arg/world/$arg> which is matched against the
484 This example application would, if run and called by e.g.
485 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
486 value C<arg_sum> to "23". The C<world> action would then append "World!"
487 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
488 sake of simplicity no view is shown. Instead we just put the values of
489 the stash into our body. So the output would look like:
494 And our test server would have given us this debugging output for the
498 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
499 [debug] Path is "/greeting/world"
500 [debug] Arguments are "12"
501 [info] Request took 0.164113s (6.093/s)
502 .------------------------------------------+-----------.
504 +------------------------------------------+-----------+
505 | /greeting/hello | 0.000029s |
506 | /greeting/world | 0.000024s |
507 '------------------------------------------+-----------'
510 What would be common uses of this dispatch technique? It gives the
511 possibility to split up logic that contains steps that each depend on
512 each other. An example would be, for example, a wiki path like
513 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
516 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
517 my ( $self, $c, $page_name ) = @_;
518 # load the page named $page_name and put the object
522 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
523 my ( $self, $c, $revision_id ) = @_;
524 # use the page object in the stash to get at its
525 # revision with number $revision_id
528 sub view : PathPart Chained('rev') Args(0) {
529 my ( $self, $c ) = @_;
530 # display the revision in our stash. Another option
531 # would be to forward a compatible object to the action
532 # that displays the default wiki pages, unless we want
533 # a different interface here, for example restore
537 It would now be possible to add other endpoints, for example C<restore>
538 to restore this specific revision as the current state.
540 You don't have to put all the chained actions in one controller. The
541 specification of the parent through C<:Chained> also takes an absolute
542 action path as its argument. Just specify it with a leading C</>.
544 If you want, for example, to have actions for the public paths
545 C</foo/12/edit> and C</foo/12>, just specify two actions with
546 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
547 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
548 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
549 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
550 this debugging output:
553 [debug] Loaded Path Part actions:
554 .-----------------------+------------------------------.
555 | Path Spec | Private |
556 +-----------------------+------------------------------+
557 | /foo/* | /controller/foo_view |
558 | /foo/*/edit | /controller/foo_load (1) |
559 | | => /controller/edit |
560 '-----------------------+------------------------------'
563 Here's a more detailed specification of the attributes belonging to
572 Sets the name of this part of the chain. If it is specified without
573 arguments, it takes the name of the action as default. So basically
574 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
575 This can also contain slashes to bind to a deeper level. An action
576 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
577 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
578 effect as using C<:PathPart>, it would default to the action name.
582 Sets PathPart to the path_prefix of the current controller.
586 Has to be specified for every child in the chain. Possible values are
587 absolute and relative private action paths or a single slash C</> to
588 tell Catalyst that this is the root of a chain. The attribute
589 C<:Chained> without arguments also defaults to the C</> behavior.
590 Relative action paths may use C<../> to refer to actions in parent
593 Because you can specify an absolute path to the parent action, it
594 doesn't matter to Catalyst where that parent is located. So, if your
595 design requests it, you can redispatch a chain through any controller or
598 Another interesting possibility gives C<:Chained('.')>, which chains
599 itself to an action with the path of the current controller's namespace.
602 # in MyApp::Controller::Foo
603 sub bar : Chained CaptureArgs(1) { ... }
605 # in MyApp::Controller::Foo::Bar
606 sub baz : Chained('.') Args(1) { ... }
608 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
609 as the argument to Chained here chains the C<baz> action to an action
610 with the path of the current controller namespace, namely
611 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
612 chain comes out as the end product.
616 Chains an action to another action with the same name in the parent
617 controller. For Example:
619 # in MyApp::Controller::Foo
620 sub bar : Chained CaptureArgs(1) { ... }
622 # in MyApp::Controller::Foo::Moo
623 sub bar : ChainedParent Args(1) { ... }
625 This builds a chain like C</bar/*/bar/*>.
629 Must be specified for every part of the chain that is not an
630 endpoint. With this attribute Catalyst knows how many of the following
631 parts of the path (separated by C</>) this action wants to capture as
632 its arguments. If it doesn't expect any, just specify
633 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
634 after the context, but you can also find them as array references in
635 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
636 level of the action in the chain that captured the parts of the path.
638 An action that is part of a chain (that is, one that has a C<:Chained>
639 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
644 By default, endpoints receive the rest of the arguments in the path. You
645 can tell Catalyst through C<:Args> explicitly how many arguments your
646 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
647 also affects whether this chain is invoked on a request. A chain with an
648 endpoint specifying one argument will only match if exactly one argument
651 You can specify an exact number of arguments like C<:Args(3)>, including
652 C<0>. If you just say C<:Args> without any arguments, it is the same as
653 leaving it out altogether: The chain is matched regardless of the number
654 of path parts after the endpoint.
656 Just as with C<:CaptureArgs>, the arguments get passed to the action in
657 C<@_> after the context object. They can also be reached through
658 C<$c-E<gt>request-E<gt>arguments>.
662 =head2 Auto actions, dispatching and forwarding
664 Note that the list of C<auto> actions called depends on the private path
665 of the endpoint of the chain, not on the chained actions way. The
666 C<auto> actions will be run before the chain dispatching begins. In
667 every other aspect, C<auto> actions behave as documented.
669 The C<forward>ing to other actions does just what you would expect. But if
670 you C<detach> out of a chain, the rest of the chain will not get called
675 Catalyst Contributors, see Catalyst.pm
679 This library is free software. You can redistribute it and/or modify it under
680 the same terms as Perl itself.