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);
155 if ($parts && @$parts) {
156 for my $arg (@$parts) {
157 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
158 push @{$request->args}, $arg;
162 return 0 unless $chain;
164 my $action = Catalyst::ActionChain->from_chain($chain);
166 $request->action("/${action}");
167 $request->match("/${action}");
168 $request->captures($captures);
170 $c->namespace( $action->namespace );
175 =head2 $self->recurse_match( $c, $parent, \@path_parts )
177 Recursive search for a matching chain.
182 my ( $self, $c, $parent, $path_parts ) = @_;
183 my $children = $self->_children_of->{$parent};
184 return () unless $children;
187 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
189 # $b then $a to try longest part first
190 my @parts = @$path_parts;
191 if (length $try_part) { # test and strip PathPart
193 ($try_part eq join('/', # assemble equal number of parts
194 splice( # and strip them off @parts as well
195 @parts, 0, scalar(@{[split('/', $try_part)]})
196 ))); # @{[]} to avoid split to @_
198 my @try_actions = @{$children->{$try_part}};
199 TRY_ACTION: foreach my $action (@try_actions) {
200 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
202 # Short-circuit if not enough remaining parts
203 next TRY_ACTION unless @parts >= $capture_attr->[0];
206 my @parts = @parts; # localise
208 # strip CaptureArgs into list
209 push(@captures, splice(@parts, 0, $capture_attr->[0]));
211 # try the remaining parts against children of this action
212 my ($actions, $captures, $action_parts) = $self->recurse_match(
213 $c, '/'.$action->reverse, \@parts
215 # No best action currently
216 # OR The action has less parts
217 # OR The action has equal parts but less captured data (ergo more defined)
220 $#$action_parts < $#{$best_action->{parts}} ||
221 ($#$action_parts == $#{$best_action->{parts}} &&
222 $#$captures < $#{$best_action->{captures}}))){
224 actions => [ $action, @$actions ],
225 captures=> [ @captures, @$captures ],
226 parts => $action_parts
232 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
233 next TRY_ACTION unless $action->match($c);
235 my $args_attr = $action->attributes->{Args}->[0];
237 # No best action currently
238 # OR This one matches with fewer parts left than the current best action,
239 # And therefore is a better match
240 # OR No parts and this expects 0
241 # The current best action might also be Args(0),
242 # but we couldn't chose between then anyway so we'll take the last seen
245 @parts < @{$best_action->{parts}} ||
246 (!@parts && $args_attr eq 0)){
248 actions => [ $action ],
256 return @$best_action{qw/actions captures parts/} if $best_action;
260 =head2 $self->register( $c, $action )
262 Calls register_path for every Path attribute for the given $action.
267 my ( $self, $c, $action ) = @_;
269 my @chained_attr = @{ $action->attributes->{Chained} || [] };
271 return 0 unless @chained_attr;
273 if (@chained_attr > 1) {
274 Catalyst::Exception->throw(
275 "Multiple Chained attributes not supported registering ${action}"
278 my $chained_to = $chained_attr[0];
280 Catalyst::Exception->throw(
281 "Actions cannot chain to themselves registering /${action}"
282 ) if ($chained_to eq '/' . $action);
284 my $children = ($self->_children_of->{ $chained_to } ||= {});
286 my @path_part = @{ $action->attributes->{PathPart} || [] };
288 my $part = $action->name;
290 if (@path_part == 1 && defined $path_part[0]) {
291 $part = $path_part[0];
292 } elsif (@path_part > 1) {
293 Catalyst::Exception->throw(
294 "Multiple PathPart attributes not supported registering " . $action->reverse()
298 if ($part =~ m(^/)) {
299 Catalyst::Exception->throw(
300 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
304 $action->attributes->{PartPath} = [ $part ];
306 unshift(@{ $children->{$part} ||= [] }, $action);
308 $self->_actions->{'/'.$action->reverse} = $action;
310 unless ($action->attributes->{CaptureArgs}) {
311 unshift(@{ $self->_endpoints }, $action);
317 =head2 $self->uri_for_action($action, $captures)
319 Get the URI part for the action, using C<$captures> to fill
325 my ( $self, $action, $captures ) = @_;
327 return undef unless ($action->attributes->{Chained}
328 && !$action->attributes->{CaptureArgs});
331 my @captures = @$captures;
332 my $parent = "DUMMY";
335 if (my $cap = $curr->attributes->{CaptureArgs}) {
336 return undef unless @captures >= $cap->[0]; # not enough captures
339 map { s/([^A-Za-z0-9\-_.!~*'()])/$URI::Escape::escapes{$1}/go; $_; }
340 splice(@captures, -$cap->[0]));
343 if (my $pp = $curr->attributes->{PartPath}) {
344 unshift(@parts, $pp->[0])
345 if (defined($pp->[0]) && length($pp->[0]));
347 $parent = $curr->attributes->{Chained}->[0];
348 $curr = $self->_actions->{$parent};
351 return undef unless $parent eq '/'; # fail for dangling action
353 return undef if @captures; # fail for too many captures
355 return join('/', '', @parts);
359 =head2 $c->expand_action($action)
361 Return a list of actions that represents a chained action. See
362 L<Catalyst::Dispatcher> for more info. You probably want to
363 use the expand_action it provides rather than this directly.
368 my ($self, $action) = @_;
370 return unless $action->attributes && $action->attributes->{Chained};
377 my $parent = $curr->attributes->{Chained}->[0];
378 $curr = $self->_actions->{$parent};
381 return Catalyst::ActionChain->from_chain([reverse @chain]);
384 __PACKAGE__->meta->make_immutable;
390 The C<Chained> attribute allows you to chain public path parts together
391 by their private names. A chain part's path can be specified with
392 C<PathPart> and can be declared to expect an arbitrary number of
393 arguments. The endpoint of the chain specifies how many arguments it
394 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
395 C<:Args> without an integer would be unlimited. The path parts that
396 aren't endpoints are using C<CaptureArgs> to specify how many parameters
397 they expect to receive. As an example setup:
399 package MyApp::Controller::Greeting;
400 use base qw/ Catalyst::Controller /;
402 # this is the beginning of our chain
403 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
404 my ( $self, $c, $integer ) = @_;
405 $c->stash->{ message } = "Hello ";
406 $c->stash->{ arg_sum } = $integer;
409 # this is our endpoint, because it has no :CaptureArgs
410 sub world : PathPart('world') Chained('hello') Args(1) {
411 my ( $self, $c, $integer ) = @_;
412 $c->stash->{ message } .= "World!";
413 $c->stash->{ arg_sum } += $integer;
415 $c->response->body( join "<br/>\n" =>
416 $c->stash->{ message }, $c->stash->{ arg_sum } );
419 The debug output provides a separate table for chained actions, showing
420 the whole chain as it would match and the actions it contains. Here's an
421 example of the startup output with our actions above:
424 [debug] Loaded Path Part actions:
425 .-----------------------+------------------------------.
426 | Path Spec | Private |
427 +-----------------------+------------------------------+
428 | /hello/*/world/* | /greeting/hello (1) |
429 | | => /greeting/world |
430 '-----------------------+------------------------------'
433 As you can see, Catalyst only deals with chains as whole paths and
434 builds one for each endpoint, which are the actions with C<:Chained> but
435 without C<:CaptureArgs>.
437 Let's assume this application gets a request at the path
438 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
439 to the C<hello> action and pass the value C<23> as an argument to it
440 after the context. It does so because we have previously used
441 C<:CaptureArgs(1)> to declare that it has one path part after itself as
442 its argument. We told Catalyst that this is the beginning of the chain
443 by specifying C<:Chained('/')>. Also note that instead of saying
444 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
445 defaults to the name of the action.
447 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
448 action. This is the last action to be called: Catalyst knows this is an
449 endpoint because we did not specify a C<:CaptureArgs>
450 attribute. Nevertheless we specify that this action expects an argument,
451 but at this point we're using C<:Args(1)> to do that. We could also have
452 said C<:Args> or left it out altogether, which would mean this action
453 would get all arguments that are there. This action's C<:Chained>
454 attribute says C<hello> and tells Catalyst that the C<hello> action in
455 the current controller is its parent.
457 With this we have built a chain consisting of two public path parts.
458 C<hello> captures one part of the path as its argument, and also
459 specifies the path root as its parent. So this part is
460 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
461 argument. It sums up to the path part C<world/$arg>. This leads to a
462 complete chain of C</hello/$arg/world/$arg> which is matched against the
465 This example application would, if run and called by e.g.
466 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
467 value C<arg_sum> to "23". The C<world> action would then append "World!"
468 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
469 sake of simplicity no view is shown. Instead we just put the values of
470 the stash into our body. So the output would look like:
475 And our test server would have given us this debugging output for the
479 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
480 [debug] Path is "/greeting/world"
481 [debug] Arguments are "12"
482 [info] Request took 0.164113s (6.093/s)
483 .------------------------------------------+-----------.
485 +------------------------------------------+-----------+
486 | /greeting/hello | 0.000029s |
487 | /greeting/world | 0.000024s |
488 '------------------------------------------+-----------'
491 What would be common uses of this dispatch technique? It gives the
492 possibility to split up logic that contains steps that each depend on
493 each other. An example would be, for example, a wiki path like
494 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
497 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
498 my ( $self, $c, $page_name ) = @_;
499 # load the page named $page_name and put the object
503 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
504 my ( $self, $c, $revision_id ) = @_;
505 # use the page object in the stash to get at its
506 # revision with number $revision_id
509 sub view : PathPart Chained('rev') Args(0) {
510 my ( $self, $c ) = @_;
511 # display the revision in our stash. Another option
512 # would be to forward a compatible object to the action
513 # that displays the default wiki pages, unless we want
514 # a different interface here, for example restore
518 It would now be possible to add other endpoints, for example C<restore>
519 to restore this specific revision as the current state.
521 You don't have to put all the chained actions in one controller. The
522 specification of the parent through C<:Chained> also takes an absolute
523 action path as its argument. Just specify it with a leading C</>.
525 If you want, for example, to have actions for the public paths
526 C</foo/12/edit> and C</foo/12>, just specify two actions with
527 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
528 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
529 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
530 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
531 this debugging output:
534 [debug] Loaded Path Part actions:
535 .-----------------------+------------------------------.
536 | Path Spec | Private |
537 +-----------------------+------------------------------+
538 | /foo/* | /controller/foo_view |
539 | /foo/*/edit | /controller/foo_load (1) |
540 | | => /controller/edit |
541 '-----------------------+------------------------------'
544 Here's a more detailed specification of the attributes belonging to
553 Sets the name of this part of the chain. If it is specified without
554 arguments, it takes the name of the action as default. So basically
555 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
556 This can also contain slashes to bind to a deeper level. An action
557 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
558 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
559 effect as using C<:PathPart>, it would default to the action name.
563 Sets PathPart to the path_prefix of the current controller.
567 Has to be specified for every child in the chain. Possible values are
568 absolute and relative private action paths or a single slash C</> to
569 tell Catalyst that this is the root of a chain. The attribute
570 C<:Chained> without arguments also defaults to the C</> behavior.
571 Relative action paths may use C<../> to refer to actions in parent
574 Because you can specify an absolute path to the parent action, it
575 doesn't matter to Catalyst where that parent is located. So, if your
576 design requests it, you can redispatch a chain through any controller or
579 Another interesting possibility gives C<:Chained('.')>, which chains
580 itself to an action with the path of the current controller's namespace.
583 # in MyApp::Controller::Foo
584 sub bar : Chained CaptureArgs(1) { ... }
586 # in MyApp::Controller::Foo::Bar
587 sub baz : Chained('.') Args(1) { ... }
589 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
590 as the argument to Chained here chains the C<baz> action to an action
591 with the path of the current controller namespace, namely
592 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
593 chain comes out as the end product.
597 Chains an action to another action with the same name in the parent
598 controller. For Example:
600 # in MyApp::Controller::Foo
601 sub bar : Chained CaptureArgs(1) { ... }
603 # in MyApp::Controller::Foo::Moo
604 sub bar : ChainedParent Args(1) { ... }
606 This builds a chain like C</bar/*/bar/*>.
610 Must be specified for every part of the chain that is not an
611 endpoint. With this attribute Catalyst knows how many of the following
612 parts of the path (separated by C</>) this action wants to capture as
613 its arguments. If it doesn't expect any, just specify
614 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
615 after the context, but you can also find them as array references in
616 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
617 level of the action in the chain that captured the parts of the path.
619 An action that is part of a chain (that is, one that has a C<:Chained>
620 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
625 By default, endpoints receive the rest of the arguments in the path. You
626 can tell Catalyst through C<:Args> explicitly how many arguments your
627 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
628 also affects whether this chain is invoked on a request. A chain with an
629 endpoint specifying one argument will only match if exactly one argument
632 You can specify an exact number of arguments like C<:Args(3)>, including
633 C<0>. If you just say C<:Args> without any arguments, it is the same as
634 leaving it out altogether: The chain is matched regardless of the number
635 of path parts after the endpoint.
637 Just as with C<:CaptureArgs>, the arguments get passed to the action in
638 C<@_> after the context object. They can also be reached through
639 C<$c-E<gt>request-E<gt>arguments>.
643 =head2 Auto actions, dispatching and forwarding
645 Note that the list of C<auto> actions called depends on the private path
646 of the endpoint of the chain, not on the chained actions way. The
647 C<auto> actions will be run before the chain dispatching begins. In
648 every other aspect, C<auto> actions behave as documented.
650 The C<forward>ing to other actions does just what you would expect. But if
651 you C<detach> out of a chain, the rest of the chain will not get called
656 Catalyst Contributors, see Catalyst.pm
660 This program is free software, you can redistribute it and/or modify it under
661 the same terms as Perl itself.