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->{PathPart}) {
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]||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, $n_pathparts) = $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}} &&
226 $n_pathparts > $best_action->{n_pathparts}))) {
227 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
229 actions => [ $action, @$actions ],
230 captures=> [ @captures, @$captures ],
231 parts => $action_parts,
232 n_pathparts => scalar(@pathparts) + $n_pathparts,
238 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
239 next TRY_ACTION unless $action->match($c);
241 my $args_attr = $action->attributes->{Args}->[0];
242 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
243 # No best action currently
244 # OR This one matches with fewer parts left than the current best action,
245 # And therefore is a better match
246 # OR No parts and this expects 0
247 # The current best action might also be Args(0),
248 # but we couldn't chose between then anyway so we'll take the last seen
251 @parts < @{$best_action->{parts}} ||
252 (!@parts && $args_attr eq 0)){
254 actions => [ $action ],
257 n_pathparts => scalar(@pathparts),
263 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
267 =head2 $self->register( $c, $action )
269 Calls register_path for every Path attribute for the given $action.
274 my ( $self, $c, $action ) = @_;
276 my @chained_attr = @{ $action->attributes->{Chained} || [] };
278 return 0 unless @chained_attr;
280 if (@chained_attr > 1) {
281 Catalyst::Exception->throw(
282 "Multiple Chained attributes not supported registering ${action}"
285 my $chained_to = $chained_attr[0];
287 Catalyst::Exception->throw(
288 "Actions cannot chain to themselves registering /${action}"
289 ) if ($chained_to eq '/' . $action);
291 my $children = ($self->_children_of->{ $chained_to } ||= {});
293 my @path_part = @{ $action->attributes->{PathPart} || [] };
295 my $part = $action->name;
297 if (@path_part == 1 && defined $path_part[0]) {
298 $part = $path_part[0];
299 } elsif (@path_part > 1) {
300 Catalyst::Exception->throw(
301 "Multiple PathPart attributes not supported registering " . $action->reverse()
305 if ($part =~ m(^/)) {
306 Catalyst::Exception->throw(
307 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
311 $action->attributes->{PathPart} = [ $part ];
313 unshift(@{ $children->{$part} ||= [] }, $action);
315 $self->_actions->{'/'.$action->reverse} = $action;
317 if (exists $action->attributes->{Args}) {
318 my $args = $action->attributes->{Args}->[0];
319 if (defined($args) and not (
320 Scalar::Util::looks_like_number($args) and
323 require Data::Dumper;
324 local $Data::Dumper::Terse = 1;
325 local $Data::Dumper::Indent = 0;
326 $args = Data::Dumper::Dumper($args);
327 Catalyst::Exception->throw(
328 "Invalid Args($args) for action " . $action->reverse() .
329 " (use 'Args' or 'Args(<number>)'"
334 unless ($action->attributes->{CaptureArgs}) {
335 unshift(@{ $self->_endpoints }, $action);
341 =head2 $self->uri_for_action($action, $captures)
343 Get the URI part for the action, using C<$captures> to fill
349 my ( $self, $action, $captures ) = @_;
351 return undef unless ($action->attributes->{Chained}
352 && !$action->attributes->{CaptureArgs});
355 my @captures = @$captures;
356 my $parent = "DUMMY";
359 if (my $cap = $curr->attributes->{CaptureArgs}) {
360 return undef unless @captures >= $cap->[0]; # not enough captures
362 unshift(@parts, splice(@captures, -$cap->[0]));
365 if (my $pp = $curr->attributes->{PathPart}) {
366 unshift(@parts, $pp->[0])
367 if (defined($pp->[0]) && length($pp->[0]));
369 $parent = $curr->attributes->{Chained}->[0];
370 $curr = $self->_actions->{$parent};
373 return undef unless $parent eq '/'; # fail for dangling action
375 return undef if @captures; # fail for too many captures
377 return join('/', '', @parts);
381 =head2 $c->expand_action($action)
383 Return a list of actions that represents a chained action. See
384 L<Catalyst::Dispatcher> for more info. You probably want to
385 use the expand_action it provides rather than this directly.
390 my ($self, $action) = @_;
392 return unless $action->attributes && $action->attributes->{Chained};
399 my $parent = $curr->attributes->{Chained}->[0];
400 $curr = $self->_actions->{$parent};
403 return Catalyst::ActionChain->from_chain([reverse @chain]);
406 __PACKAGE__->meta->make_immutable;
412 The C<Chained> attribute allows you to chain public path parts together
413 by their private names. A chain part's path can be specified with
414 C<PathPart> and can be declared to expect an arbitrary number of
415 arguments. The endpoint of the chain specifies how many arguments it
416 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
417 C<:Args> without an integer would be unlimited. The path parts that
418 aren't endpoints are using C<CaptureArgs> to specify how many parameters
419 they expect to receive. As an example setup:
421 package MyApp::Controller::Greeting;
422 use base qw/ Catalyst::Controller /;
424 # this is the beginning of our chain
425 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
426 my ( $self, $c, $integer ) = @_;
427 $c->stash->{ message } = "Hello ";
428 $c->stash->{ arg_sum } = $integer;
431 # this is our endpoint, because it has no :CaptureArgs
432 sub world : PathPart('world') Chained('hello') Args(1) {
433 my ( $self, $c, $integer ) = @_;
434 $c->stash->{ message } .= "World!";
435 $c->stash->{ arg_sum } += $integer;
437 $c->response->body( join "<br/>\n" =>
438 $c->stash->{ message }, $c->stash->{ arg_sum } );
441 The debug output provides a separate table for chained actions, showing
442 the whole chain as it would match and the actions it contains. Here's an
443 example of the startup output with our actions above:
446 [debug] Loaded Path Part actions:
447 .-----------------------+------------------------------.
448 | Path Spec | Private |
449 +-----------------------+------------------------------+
450 | /hello/*/world/* | /greeting/hello (1) |
451 | | => /greeting/world |
452 '-----------------------+------------------------------'
455 As you can see, Catalyst only deals with chains as whole paths and
456 builds one for each endpoint, which are the actions with C<:Chained> but
457 without C<:CaptureArgs>.
459 Let's assume this application gets a request at the path
460 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
461 to the C<hello> action and pass the value C<23> as an argument to it
462 after the context. It does so because we have previously used
463 C<:CaptureArgs(1)> to declare that it has one path part after itself as
464 its argument. We told Catalyst that this is the beginning of the chain
465 by specifying C<:Chained('/')>. Also note that instead of saying
466 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
467 defaults to the name of the action.
469 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
470 action. This is the last action to be called: Catalyst knows this is an
471 endpoint because we did not specify a C<:CaptureArgs>
472 attribute. Nevertheless we specify that this action expects an argument,
473 but at this point we're using C<:Args(1)> to do that. We could also have
474 said C<:Args> or left it out altogether, which would mean this action
475 would get all arguments that are there. This action's C<:Chained>
476 attribute says C<hello> and tells Catalyst that the C<hello> action in
477 the current controller is its parent.
479 With this we have built a chain consisting of two public path parts.
480 C<hello> captures one part of the path as its argument, and also
481 specifies the path root as its parent. So this part is
482 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
483 argument. It sums up to the path part C<world/$arg>. This leads to a
484 complete chain of C</hello/$arg/world/$arg> which is matched against the
487 This example application would, if run and called by e.g.
488 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
489 value C<arg_sum> to "23". The C<world> action would then append "World!"
490 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
491 sake of simplicity no view is shown. Instead we just put the values of
492 the stash into our body. So the output would look like:
497 And our test server would have given us this debugging output for the
501 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
502 [debug] Path is "/greeting/world"
503 [debug] Arguments are "12"
504 [info] Request took 0.164113s (6.093/s)
505 .------------------------------------------+-----------.
507 +------------------------------------------+-----------+
508 | /greeting/hello | 0.000029s |
509 | /greeting/world | 0.000024s |
510 '------------------------------------------+-----------'
513 What would be common uses of this dispatch technique? It gives the
514 possibility to split up logic that contains steps that each depend on
515 each other. An example would be, for example, a wiki path like
516 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
519 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
520 my ( $self, $c, $page_name ) = @_;
521 # load the page named $page_name and put the object
525 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
526 my ( $self, $c, $revision_id ) = @_;
527 # use the page object in the stash to get at its
528 # revision with number $revision_id
531 sub view : PathPart Chained('rev') Args(0) {
532 my ( $self, $c ) = @_;
533 # display the revision in our stash. Another option
534 # would be to forward a compatible object to the action
535 # that displays the default wiki pages, unless we want
536 # a different interface here, for example restore
540 It would now be possible to add other endpoints, for example C<restore>
541 to restore this specific revision as the current state.
543 You don't have to put all the chained actions in one controller. The
544 specification of the parent through C<:Chained> also takes an absolute
545 action path as its argument. Just specify it with a leading C</>.
547 If you want, for example, to have actions for the public paths
548 C</foo/12/edit> and C</foo/12>, just specify two actions with
549 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
550 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
551 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
552 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
553 this debugging output:
556 [debug] Loaded Path Part actions:
557 .-----------------------+------------------------------.
558 | Path Spec | Private |
559 +-----------------------+------------------------------+
560 | /foo/* | /controller/foo_view |
561 | /foo/*/edit | /controller/foo_load (1) |
562 | | => /controller/edit |
563 '-----------------------+------------------------------'
566 Here's a more detailed specification of the attributes belonging to
575 Sets the name of this part of the chain. If it is specified without
576 arguments, it takes the name of the action as default. So basically
577 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
578 This can also contain slashes to bind to a deeper level. An action
579 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
580 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
581 effect as using C<:PathPart>, it would default to the action name.
585 Sets PathPart to the path_prefix of the current controller.
589 Has to be specified for every child in the chain. Possible values are
590 absolute and relative private action paths or a single slash C</> to
591 tell Catalyst that this is the root of a chain. The attribute
592 C<:Chained> without arguments also defaults to the C</> behavior.
593 Relative action paths may use C<../> to refer to actions in parent
596 Because you can specify an absolute path to the parent action, it
597 doesn't matter to Catalyst where that parent is located. So, if your
598 design requests it, you can redispatch a chain through any controller or
601 Another interesting possibility gives C<:Chained('.')>, which chains
602 itself to an action with the path of the current controller's namespace.
605 # in MyApp::Controller::Foo
606 sub bar : Chained CaptureArgs(1) { ... }
608 # in MyApp::Controller::Foo::Bar
609 sub baz : Chained('.') Args(1) { ... }
611 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
612 as the argument to Chained here chains the C<baz> action to an action
613 with the path of the current controller namespace, namely
614 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
615 chain comes out as the end product.
619 Chains an action to another action with the same name in the parent
620 controller. For Example:
622 # in MyApp::Controller::Foo
623 sub bar : Chained CaptureArgs(1) { ... }
625 # in MyApp::Controller::Foo::Moo
626 sub bar : ChainedParent Args(1) { ... }
628 This builds a chain like C</bar/*/bar/*>.
632 Must be specified for every part of the chain that is not an
633 endpoint. With this attribute Catalyst knows how many of the following
634 parts of the path (separated by C</>) this action wants to capture as
635 its arguments. If it doesn't expect any, just specify
636 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
637 after the context, but you can also find them as array references in
638 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
639 level of the action in the chain that captured the parts of the path.
641 An action that is part of a chain (that is, one that has a C<:Chained>
642 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
647 By default, endpoints receive the rest of the arguments in the path. You
648 can tell Catalyst through C<:Args> explicitly how many arguments your
649 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
650 also affects whether this chain is invoked on a request. A chain with an
651 endpoint specifying one argument will only match if exactly one argument
654 You can specify an exact number of arguments like C<:Args(3)>, including
655 C<0>. If you just say C<:Args> without any arguments, it is the same as
656 leaving it out altogether: The chain is matched regardless of the number
657 of path parts after the endpoint.
659 Just as with C<:CaptureArgs>, the arguments get passed to the action in
660 C<@_> after the context object. They can also be reached through
661 C<$c-E<gt>request-E<gt>arguments>.
665 =head2 Auto actions, dispatching and forwarding
667 Note that the list of C<auto> actions called depends on the private path
668 of the endpoint of the chain, not on the chained actions way. The
669 C<auto> actions will be run before the chain dispatching begins. In
670 every other aspect, C<auto> actions behave as documented.
672 The C<forward>ing to other actions does just what you would expect. But if
673 you C<detach> out of a chain, the rest of the chain will not get called
678 Catalyst Contributors, see Catalyst.pm
682 This library is free software. You can redistribute it and/or modify it under
683 the same terms as Perl itself.