1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
34 # please don't perltidy this. hairy code within.
38 Catalyst::DispatchType::Chained - Path Part DispatchType
42 Path part matching, allowing several actions to sequentially take care of processing a request:
44 # root action - captures one argument after it
45 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
46 my ( $self, $c, $foo_arg ) = @_;
50 # child action endpoint - takes one argument
51 sub bar : Chained('foo_setup') Args(1) {
52 my ( $self, $c, $bar_arg ) = @_;
58 Dispatch type managing default behaviour. For more information on
63 =item * L<Catalyst::Manual::Intro> for how they affect application authors
65 =item * L<Catalyst::DispatchType> for implementation information.
71 =head2 $self->list($c)
73 Debug output for Path Part dispatch points
78 my ( $self, $c ) = @_;
80 return unless $self->_endpoints;
82 my $column_width = Catalyst::Utils::term_width() - 35 - 9;
83 my $paths = Text::SimpleTable->new(
84 [ 35, 'Path Spec' ], [ $column_width, 'Private' ],
87 my $has_unattached_actions;
88 my $unattached_actions = Text::SimpleTable->new(
89 [ 35, 'Private' ], [ $column_width, 'Missing parent' ],
92 ENDPOINT: foreach my $endpoint (
93 sort { $a->reverse cmp $b->reverse }
94 @{ $self->_endpoints }
96 my $args = $endpoint->attributes->{Args}->[0];
97 my @parts = (defined($args) ? (("*") x $args) : '...');
100 my $curr = $endpoint;
102 if (my $cap = $curr->attributes->{CaptureArgs}) {
103 unshift(@parts, (("*") x $cap->[0]));
105 if (my $pp = $curr->attributes->{PartPath}) {
106 unshift(@parts, $pp->[0])
107 if (defined $pp->[0] && length $pp->[0]);
109 $parent = $curr->attributes->{Chained}->[0];
110 $curr = $self->_actions->{$parent};
111 unshift(@parents, $curr) if $curr;
113 if ($parent ne '/') {
114 $has_unattached_actions = 1;
115 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
119 foreach my $p (@parents) {
121 if (my $cap = $p->attributes->{CaptureArgs}) {
122 $name .= ' ('.$cap->[0].')';
124 unless ($p eq $parents[0]) {
125 $name = "-> ${name}";
127 push(@rows, [ '', $name ]);
129 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
130 $rows[0][0] = join('/', '', @parts) || '/';
131 $paths->row(@$_) for @rows;
134 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
135 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
136 if $has_unattached_actions;
139 =head2 $self->match( $c, $path )
141 Calls C<recurse_match> to see if a chain matches the C<$path>.
146 my ( $self, $c, $path ) = @_;
148 my $request = $c->request;
149 return 0 if @{$request->args};
151 my @parts = split('/', $path);
153 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
154 push @{$request->args}, @$parts if $parts && @$parts;
156 return 0 unless $chain;
158 my $action = Catalyst::ActionChain->from_chain($chain);
160 $request->action("/${action}");
161 $request->match("/${action}");
162 $request->captures($captures);
164 $c->namespace( $action->namespace );
169 =head2 $self->recurse_match( $c, $parent, \@path_parts )
171 Recursive search for a matching chain.
176 my ( $self, $c, $parent, $path_parts ) = @_;
177 my $children = $self->_children_of->{$parent};
178 return () unless $children;
181 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
183 # $b then $a to try longest part first
184 my @parts = @$path_parts;
185 if (length $try_part) { # test and strip PathPart
187 ($try_part eq join('/', # assemble equal number of parts
188 splice( # and strip them off @parts as well
189 @parts, 0, scalar(@{[split('/', $try_part)]})
190 ))); # @{[]} to avoid split to @_
192 my @try_actions = @{$children->{$try_part}};
193 TRY_ACTION: foreach my $action (@try_actions) {
194 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
196 # Short-circuit if not enough remaining parts
197 next TRY_ACTION unless @parts >= $capture_attr->[0];
200 my @parts = @parts; # localise
202 # strip CaptureArgs into list
203 push(@captures, splice(@parts, 0, $capture_attr->[0]));
205 # try the remaining parts against children of this action
206 my ($actions, $captures, $action_parts) = $self->recurse_match(
207 $c, '/'.$action->reverse, \@parts
209 # No best action currently
210 # OR The action has less parts
211 # OR The action has equal parts but less captured data (ergo more defined)
214 $#$action_parts < $#{$best_action->{parts}} ||
215 ($#$action_parts == $#{$best_action->{parts}} &&
216 $#$captures < $#{$best_action->{captures}}))){
218 actions => [ $action, @$actions ],
219 captures=> [ @captures, @$captures ],
220 parts => $action_parts
226 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
227 next TRY_ACTION unless $action->match($c);
229 my $args_attr = $action->attributes->{Args}->[0];
231 # No best action currently
232 # OR This one matches with fewer parts left than the current best action,
233 # And therefore is a better match
234 # OR No parts and this expects 0
235 # The current best action might also be Args(0),
236 # but we couldn't chose between then anyway so we'll take the last seen
239 @parts < @{$best_action->{parts}} ||
240 (!@parts && $args_attr eq 0)){
242 actions => [ $action ],
250 return @$best_action{qw/actions captures parts/} if $best_action;
254 =head2 $self->register( $c, $action )
256 Calls register_path for every Path attribute for the given $action.
261 my ( $self, $c, $action ) = @_;
263 my @chained_attr = @{ $action->attributes->{Chained} || [] };
265 return 0 unless @chained_attr;
267 if (@chained_attr > 1) {
268 Catalyst::Exception->throw(
269 "Multiple Chained attributes not supported registering ${action}"
272 my $chained_to = $chained_attr[0];
274 Catalyst::Exception->throw(
275 "Actions cannot chain to themselves registering /${action}"
276 ) if ($chained_to eq '/' . $action);
278 my $children = ($self->_children_of->{ $chained_to } ||= {});
280 my @path_part = @{ $action->attributes->{PathPart} || [] };
282 my $part = $action->name;
284 if (@path_part == 1 && defined $path_part[0]) {
285 $part = $path_part[0];
286 } elsif (@path_part > 1) {
287 Catalyst::Exception->throw(
288 "Multiple PathPart attributes not supported registering " . $action->reverse()
292 if ($part =~ m(^/)) {
293 Catalyst::Exception->throw(
294 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
298 $action->attributes->{PartPath} = [ $part ];
300 unshift(@{ $children->{$part} ||= [] }, $action);
302 $self->_actions->{'/'.$action->reverse} = $action;
304 unless ($action->attributes->{CaptureArgs}) {
305 unshift(@{ $self->_endpoints }, $action);
311 =head2 $self->uri_for_action($action, $captures)
313 Get the URI part for the action, using C<$captures> to fill
319 my ( $self, $action, $captures ) = @_;
321 return undef unless ($action->attributes->{Chained}
322 && !$action->attributes->{CaptureArgs});
325 my @captures = @$captures;
326 my $parent = "DUMMY";
329 if (my $cap = $curr->attributes->{CaptureArgs}) {
330 return undef unless @captures >= $cap->[0]; # not enough captures
333 map { s/([^A-Za-z0-9\-_.!~*'()])/$URI::Escape::escapes{$1}/go; $_; }
334 splice(@captures, -$cap->[0]));
337 if (my $pp = $curr->attributes->{PartPath}) {
338 unshift(@parts, $pp->[0])
339 if (defined($pp->[0]) && length($pp->[0]));
341 $parent = $curr->attributes->{Chained}->[0];
342 $curr = $self->_actions->{$parent};
345 return undef unless $parent eq '/'; # fail for dangling action
347 return undef if @captures; # fail for too many captures
349 return join('/', '', @parts);
353 =head2 $c->expand_action($action)
355 Return a list of actions that represents a chained action. See
356 L<Catalyst::Dispatcher> for more info. You probably want to
357 use the expand_action it provides rather than this directly.
362 my ($self, $action) = @_;
364 return unless $action->attributes && $action->attributes->{Chained};
371 my $parent = $curr->attributes->{Chained}->[0];
372 $curr = $self->_actions->{$parent};
375 return Catalyst::ActionChain->from_chain([reverse @chain]);
378 __PACKAGE__->meta->make_immutable;
384 The C<Chained> attribute allows you to chain public path parts together
385 by their private names. A chain part's path can be specified with
386 C<PathPart> and can be declared to expect an arbitrary number of
387 arguments. The endpoint of the chain specifies how many arguments it
388 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
389 C<:Args> without an integer would be unlimited. The path parts that
390 aren't endpoints are using C<CaptureArgs> to specify how many parameters
391 they expect to receive. As an example setup:
393 package MyApp::Controller::Greeting;
394 use base qw/ Catalyst::Controller /;
396 # this is the beginning of our chain
397 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
398 my ( $self, $c, $integer ) = @_;
399 $c->stash->{ message } = "Hello ";
400 $c->stash->{ arg_sum } = $integer;
403 # this is our endpoint, because it has no :CaptureArgs
404 sub world : PathPart('world') Chained('hello') Args(1) {
405 my ( $self, $c, $integer ) = @_;
406 $c->stash->{ message } .= "World!";
407 $c->stash->{ arg_sum } += $integer;
409 $c->response->body( join "<br/>\n" =>
410 $c->stash->{ message }, $c->stash->{ arg_sum } );
413 The debug output provides a separate table for chained actions, showing
414 the whole chain as it would match and the actions it contains. Here's an
415 example of the startup output with our actions above:
418 [debug] Loaded Path Part actions:
419 .-----------------------+------------------------------.
420 | Path Spec | Private |
421 +-----------------------+------------------------------+
422 | /hello/*/world/* | /greeting/hello (1) |
423 | | => /greeting/world |
424 '-----------------------+------------------------------'
427 As you can see, Catalyst only deals with chains as whole paths and
428 builds one for each endpoint, which are the actions with C<:Chained> but
429 without C<:CaptureArgs>.
431 Let's assume this application gets a request at the path
432 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
433 to the C<hello> action and pass the value C<23> as an argument to it
434 after the context. It does so because we have previously used
435 C<:CaptureArgs(1)> to declare that it has one path part after itself as
436 its argument. We told Catalyst that this is the beginning of the chain
437 by specifying C<:Chained('/')>. Also note that instead of saying
438 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
439 defaults to the name of the action.
441 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
442 action. This is the last action to be called: Catalyst knows this is an
443 endpoint because we did not specify a C<:CaptureArgs>
444 attribute. Nevertheless we specify that this action expects an argument,
445 but at this point we're using C<:Args(1)> to do that. We could also have
446 said C<:Args> or left it out altogether, which would mean this action
447 would get all arguments that are there. This action's C<:Chained>
448 attribute says C<hello> and tells Catalyst that the C<hello> action in
449 the current controller is its parent.
451 With this we have built a chain consisting of two public path parts.
452 C<hello> captures one part of the path as its argument, and also
453 specifies the path root as its parent. So this part is
454 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
455 argument. It sums up to the path part C<world/$arg>. This leads to a
456 complete chain of C</hello/$arg/world/$arg> which is matched against the
459 This example application would, if run and called by e.g.
460 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
461 value C<arg_sum> to "23". The C<world> action would then append "World!"
462 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
463 sake of simplicity no view is shown. Instead we just put the values of
464 the stash into our body. So the output would look like:
469 And our test server would have given us this debugging output for the
473 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
474 [debug] Path is "/greeting/world"
475 [debug] Arguments are "12"
476 [info] Request took 0.164113s (6.093/s)
477 .------------------------------------------+-----------.
479 +------------------------------------------+-----------+
480 | /greeting/hello | 0.000029s |
481 | /greeting/world | 0.000024s |
482 '------------------------------------------+-----------'
485 What would be common uses of this dispatch technique? It gives the
486 possibility to split up logic that contains steps that each depend on
487 each other. An example would be, for example, a wiki path like
488 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
491 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
492 my ( $self, $c, $page_name ) = @_;
493 # load the page named $page_name and put the object
497 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
498 my ( $self, $c, $revision_id ) = @_;
499 # use the page object in the stash to get at its
500 # revision with number $revision_id
503 sub view : PathPart Chained('rev') Args(0) {
504 my ( $self, $c ) = @_;
505 # display the revision in our stash. Another option
506 # would be to forward a compatible object to the action
507 # that displays the default wiki pages, unless we want
508 # a different interface here, for example restore
512 It would now be possible to add other endpoints, for example C<restore>
513 to restore this specific revision as the current state.
515 You don't have to put all the chained actions in one controller. The
516 specification of the parent through C<:Chained> also takes an absolute
517 action path as its argument. Just specify it with a leading C</>.
519 If you want, for example, to have actions for the public paths
520 C</foo/12/edit> and C</foo/12>, just specify two actions with
521 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
522 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
523 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
524 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
525 this debugging output:
528 [debug] Loaded Path Part actions:
529 .-----------------------+------------------------------.
530 | Path Spec | Private |
531 +-----------------------+------------------------------+
532 | /foo/* | /controller/foo_view |
533 | /foo/*/edit | /controller/foo_load (1) |
534 | | => /controller/edit |
535 '-----------------------+------------------------------'
538 Here's a more detailed specification of the attributes belonging to
547 Sets the name of this part of the chain. If it is specified without
548 arguments, it takes the name of the action as default. So basically
549 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
550 This can also contain slashes to bind to a deeper level. An action
551 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
552 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
553 effect as using C<:PathPart>, it would default to the action name.
557 Sets PathPart to the path_prefix of the current controller.
561 Has to be specified for every child in the chain. Possible values are
562 absolute and relative private action paths or a single slash C</> to
563 tell Catalyst that this is the root of a chain. The attribute
564 C<:Chained> without arguments also defaults to the C</> behavior.
565 Relative action paths may use C<../> to refer to actions in parent
568 Because you can specify an absolute path to the parent action, it
569 doesn't matter to Catalyst where that parent is located. So, if your
570 design requests it, you can redispatch a chain through any controller or
573 Another interesting possibility gives C<:Chained('.')>, which chains
574 itself to an action with the path of the current controller's namespace.
577 # in MyApp::Controller::Foo
578 sub bar : Chained CaptureArgs(1) { ... }
580 # in MyApp::Controller::Foo::Bar
581 sub baz : Chained('.') Args(1) { ... }
583 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
584 as the argument to Chained here chains the C<baz> action to an action
585 with the path of the current controller namespace, namely
586 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
587 chain comes out as the end product.
591 Chains an action to another action with the same name in the parent
592 controller. For Example:
594 # in MyApp::Controller::Foo
595 sub bar : Chained CaptureArgs(1) { ... }
597 # in MyApp::Controller::Foo::Moo
598 sub bar : ChainedParent Args(1) { ... }
600 This builds a chain like C</bar/*/bar/*>.
604 Must be specified for every part of the chain that is not an
605 endpoint. With this attribute Catalyst knows how many of the following
606 parts of the path (separated by C</>) this action wants to capture as
607 its arguments. If it doesn't expect any, just specify
608 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
609 after the context, but you can also find them as array references in
610 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
611 level of the action in the chain that captured the parts of the path.
613 An action that is part of a chain (that is, one that has a C<:Chained>
614 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
619 By default, endpoints receive the rest of the arguments in the path. You
620 can tell Catalyst through C<:Args> explicitly how many arguments your
621 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
622 also affects whether this chain is invoked on a request. A chain with an
623 endpoint specifying one argument will only match if exactly one argument
626 You can specify an exact number of arguments like C<:Args(3)>, including
627 C<0>. If you just say C<:Args> without any arguments, it is the same as
628 leaving it out altogether: The chain is matched regardless of the number
629 of path parts after the endpoint.
631 Just as with C<:CaptureArgs>, the arguments get passed to the action in
632 C<@_> after the context object. They can also be reached through
633 C<$c-E<gt>request-E<gt>arguments>.
637 =head2 Auto actions, dispatching and forwarding
639 Note that the list of C<auto> actions called depends on the private path
640 of the endpoint of the chain, not on the chained actions way. The
641 C<auto> actions will be run before the chain dispatching begins. In
642 every other aspect, C<auto> actions behave as documented.
644 The C<forward>ing to other actions does just what you would expect. But if
645 you C<detach> out of a chain, the rest of the chain will not get called
650 Catalyst Contributors, see Catalyst.pm
654 This program is free software, you can redistribute it and/or modify it under
655 the same terms as Perl itself.