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);
236 my $args_attr = $action->attributes->{Args}->[0];
238 # No best action currently
239 # OR This one matches with fewer parts left than the current best action,
240 # And therefore is a better match
241 # OR No parts and this expects 0
242 # The current best action might also be Args(0),
243 # but we couldn't chose between then anyway so we'll take the last seen
246 @parts < @{$best_action->{parts}} ||
247 (!@parts && $args_attr eq 0)){
249 actions => [ $action ],
257 return @$best_action{qw/actions captures parts/} if $best_action;
261 =head2 $self->register( $c, $action )
263 Calls register_path for every Path attribute for the given $action.
268 my ( $self, $c, $action ) = @_;
270 my @chained_attr = @{ $action->attributes->{Chained} || [] };
272 return 0 unless @chained_attr;
274 if (@chained_attr > 1) {
275 Catalyst::Exception->throw(
276 "Multiple Chained attributes not supported registering ${action}"
279 my $chained_to = $chained_attr[0];
281 Catalyst::Exception->throw(
282 "Actions cannot chain to themselves registering /${action}"
283 ) if ($chained_to eq '/' . $action);
285 my $children = ($self->_children_of->{ $chained_to } ||= {});
287 my @path_part = @{ $action->attributes->{PathPart} || [] };
289 my $part = $action->name;
291 if (@path_part == 1 && defined $path_part[0]) {
292 $part = $path_part[0];
293 } elsif (@path_part > 1) {
294 Catalyst::Exception->throw(
295 "Multiple PathPart attributes not supported registering " . $action->reverse()
299 if ($part =~ m(^/)) {
300 Catalyst::Exception->throw(
301 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
305 $action->attributes->{PartPath} = [ $part ];
307 unshift(@{ $children->{$part} ||= [] }, $action);
309 $self->_actions->{'/'.$action->reverse} = $action;
311 if (exists $action->attributes->{Args}) {
312 my $args = $action->attributes->{Args}->[0];
313 if (defined($args) and not (
314 Scalar::Util::looks_like_number($args) and
317 require Data::Dumper;
318 local $Data::Dumper::Terse = 1;
319 local $Data::Dumper::Indent = 0;
320 $args = Data::Dumper::Dumper($args);
321 Catalyst::Exception->throw(
322 "Invalid Args($args) for action " . $action->reverse() .
323 " (use 'Args' or 'Args(<number>)'"
328 unless ($action->attributes->{CaptureArgs}) {
329 unshift(@{ $self->_endpoints }, $action);
335 =head2 $self->uri_for_action($action, $captures)
337 Get the URI part for the action, using C<$captures> to fill
343 my ( $self, $action, $captures ) = @_;
345 return undef unless ($action->attributes->{Chained}
346 && !$action->attributes->{CaptureArgs});
349 my @captures = @$captures;
350 my $parent = "DUMMY";
353 if (my $cap = $curr->attributes->{CaptureArgs}) {
354 return undef unless @captures >= $cap->[0]; # not enough captures
357 map { s/([^A-Za-z0-9\-_.!~*'()])/$URI::Escape::escapes{$1}/go; $_; }
358 splice(@captures, -$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 __PACKAGE__->meta->make_immutable;
408 The C<Chained> attribute allows you to chain public path parts together
409 by their private names. A chain part's path can be specified with
410 C<PathPart> and can be declared to expect an arbitrary number of
411 arguments. The endpoint of the chain specifies how many arguments it
412 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
413 C<:Args> without an integer would be unlimited. The path parts that
414 aren't endpoints are using C<CaptureArgs> to specify how many parameters
415 they expect to receive. As an example setup:
417 package MyApp::Controller::Greeting;
418 use base qw/ Catalyst::Controller /;
420 # this is the beginning of our chain
421 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
422 my ( $self, $c, $integer ) = @_;
423 $c->stash->{ message } = "Hello ";
424 $c->stash->{ arg_sum } = $integer;
427 # this is our endpoint, because it has no :CaptureArgs
428 sub world : PathPart('world') Chained('hello') Args(1) {
429 my ( $self, $c, $integer ) = @_;
430 $c->stash->{ message } .= "World!";
431 $c->stash->{ arg_sum } += $integer;
433 $c->response->body( join "<br/>\n" =>
434 $c->stash->{ message }, $c->stash->{ arg_sum } );
437 The debug output provides a separate table for chained actions, showing
438 the whole chain as it would match and the actions it contains. Here's an
439 example of the startup output with our actions above:
442 [debug] Loaded Path Part actions:
443 .-----------------------+------------------------------.
444 | Path Spec | Private |
445 +-----------------------+------------------------------+
446 | /hello/*/world/* | /greeting/hello (1) |
447 | | => /greeting/world |
448 '-----------------------+------------------------------'
451 As you can see, Catalyst only deals with chains as whole paths and
452 builds one for each endpoint, which are the actions with C<:Chained> but
453 without C<:CaptureArgs>.
455 Let's assume this application gets a request at the path
456 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
457 to the C<hello> action and pass the value C<23> as an argument to it
458 after the context. It does so because we have previously used
459 C<:CaptureArgs(1)> to declare that it has one path part after itself as
460 its argument. We told Catalyst that this is the beginning of the chain
461 by specifying C<:Chained('/')>. Also note that instead of saying
462 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
463 defaults to the name of the action.
465 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
466 action. This is the last action to be called: Catalyst knows this is an
467 endpoint because we did not specify a C<:CaptureArgs>
468 attribute. Nevertheless we specify that this action expects an argument,
469 but at this point we're using C<:Args(1)> to do that. We could also have
470 said C<:Args> or left it out altogether, which would mean this action
471 would get all arguments that are there. This action's C<:Chained>
472 attribute says C<hello> and tells Catalyst that the C<hello> action in
473 the current controller is its parent.
475 With this we have built a chain consisting of two public path parts.
476 C<hello> captures one part of the path as its argument, and also
477 specifies the path root as its parent. So this part is
478 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
479 argument. It sums up to the path part C<world/$arg>. This leads to a
480 complete chain of C</hello/$arg/world/$arg> which is matched against the
483 This example application would, if run and called by e.g.
484 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
485 value C<arg_sum> to "23". The C<world> action would then append "World!"
486 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
487 sake of simplicity no view is shown. Instead we just put the values of
488 the stash into our body. So the output would look like:
493 And our test server would have given us this debugging output for the
497 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
498 [debug] Path is "/greeting/world"
499 [debug] Arguments are "12"
500 [info] Request took 0.164113s (6.093/s)
501 .------------------------------------------+-----------.
503 +------------------------------------------+-----------+
504 | /greeting/hello | 0.000029s |
505 | /greeting/world | 0.000024s |
506 '------------------------------------------+-----------'
509 What would be common uses of this dispatch technique? It gives the
510 possibility to split up logic that contains steps that each depend on
511 each other. An example would be, for example, a wiki path like
512 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
515 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
516 my ( $self, $c, $page_name ) = @_;
517 # load the page named $page_name and put the object
521 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
522 my ( $self, $c, $revision_id ) = @_;
523 # use the page object in the stash to get at its
524 # revision with number $revision_id
527 sub view : PathPart Chained('rev') Args(0) {
528 my ( $self, $c ) = @_;
529 # display the revision in our stash. Another option
530 # would be to forward a compatible object to the action
531 # that displays the default wiki pages, unless we want
532 # a different interface here, for example restore
536 It would now be possible to add other endpoints, for example C<restore>
537 to restore this specific revision as the current state.
539 You don't have to put all the chained actions in one controller. The
540 specification of the parent through C<:Chained> also takes an absolute
541 action path as its argument. Just specify it with a leading C</>.
543 If you want, for example, to have actions for the public paths
544 C</foo/12/edit> and C</foo/12>, just specify two actions with
545 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
546 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
547 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
548 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
549 this debugging output:
552 [debug] Loaded Path Part actions:
553 .-----------------------+------------------------------.
554 | Path Spec | Private |
555 +-----------------------+------------------------------+
556 | /foo/* | /controller/foo_view |
557 | /foo/*/edit | /controller/foo_load (1) |
558 | | => /controller/edit |
559 '-----------------------+------------------------------'
562 Here's a more detailed specification of the attributes belonging to
571 Sets the name of this part of the chain. If it is specified without
572 arguments, it takes the name of the action as default. So basically
573 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
574 This can also contain slashes to bind to a deeper level. An action
575 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
576 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
577 effect as using C<:PathPart>, it would default to the action name.
581 Sets PathPart to the path_prefix of the current controller.
585 Has to be specified for every child in the chain. Possible values are
586 absolute and relative private action paths or a single slash C</> to
587 tell Catalyst that this is the root of a chain. The attribute
588 C<:Chained> without arguments also defaults to the C</> behavior.
589 Relative action paths may use C<../> to refer to actions in parent
592 Because you can specify an absolute path to the parent action, it
593 doesn't matter to Catalyst where that parent is located. So, if your
594 design requests it, you can redispatch a chain through any controller or
597 Another interesting possibility gives C<:Chained('.')>, which chains
598 itself to an action with the path of the current controller's namespace.
601 # in MyApp::Controller::Foo
602 sub bar : Chained CaptureArgs(1) { ... }
604 # in MyApp::Controller::Foo::Bar
605 sub baz : Chained('.') Args(1) { ... }
607 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
608 as the argument to Chained here chains the C<baz> action to an action
609 with the path of the current controller namespace, namely
610 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
611 chain comes out as the end product.
615 Chains an action to another action with the same name in the parent
616 controller. For Example:
618 # in MyApp::Controller::Foo
619 sub bar : Chained CaptureArgs(1) { ... }
621 # in MyApp::Controller::Foo::Moo
622 sub bar : ChainedParent Args(1) { ... }
624 This builds a chain like C</bar/*/bar/*>.
628 Must be specified for every part of the chain that is not an
629 endpoint. With this attribute Catalyst knows how many of the following
630 parts of the path (separated by C</>) this action wants to capture as
631 its arguments. If it doesn't expect any, just specify
632 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
633 after the context, but you can also find them as array references in
634 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
635 level of the action in the chain that captured the parts of the path.
637 An action that is part of a chain (that is, one that has a C<:Chained>
638 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
643 By default, endpoints receive the rest of the arguments in the path. You
644 can tell Catalyst through C<:Args> explicitly how many arguments your
645 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
646 also affects whether this chain is invoked on a request. A chain with an
647 endpoint specifying one argument will only match if exactly one argument
650 You can specify an exact number of arguments like C<:Args(3)>, including
651 C<0>. If you just say C<:Args> without any arguments, it is the same as
652 leaving it out altogether: The chain is matched regardless of the number
653 of path parts after the endpoint.
655 Just as with C<:CaptureArgs>, the arguments get passed to the action in
656 C<@_> after the context object. They can also be reached through
657 C<$c-E<gt>request-E<gt>arguments>.
661 =head2 Auto actions, dispatching and forwarding
663 Note that the list of C<auto> actions called depends on the private path
664 of the endpoint of the chain, not on the chained actions way. The
665 C<auto> actions will be run before the chain dispatching begins. In
666 every other aspect, C<auto> actions behave as documented.
668 The C<forward>ing to other actions does just what you would expect. But if
669 you C<detach> out of a chain, the rest of the chain will not get called
674 Catalyst Contributors, see Catalyst.pm
678 This library is free software. You can redistribute it and/or modify it under
679 the same terms as Perl itself.