1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 use Catalyst::ActionChain;
11 use Encode 2.21 'decode_utf8';
36 # please don't perltidy this. hairy code within.
40 Catalyst::DispatchType::Chained - Path Part DispatchType
44 Path part matching, allowing several actions to sequentially take care of processing a request:
46 # root action - captures one argument after it
47 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
48 my ( $self, $c, $foo_arg ) = @_;
52 # child action endpoint - takes one argument
53 sub bar : Chained('foo_setup') Args(1) {
54 my ( $self, $c, $bar_arg ) = @_;
60 Dispatch type managing default behaviour. For more information on
65 =item * L<Catalyst::Manual::Intro> for how they affect application authors
67 =item * L<Catalyst::DispatchType> for implementation information.
73 =head2 $self->list($c)
75 Debug output for Path Part dispatch points
80 my ( $self, $c ) = @_;
82 return unless $self->_endpoints;
84 my $avail_width = Catalyst::Utils::term_width() - 9;
85 my $col1_width = ($avail_width * .50) < 35 ? 35 : int($avail_width * .50);
86 my $col2_width = $avail_width - $col1_width;
87 my $paths = Text::SimpleTable->new(
88 [ $col1_width, 'Path Spec' ], [ $col2_width, 'Private' ],
91 my $has_unattached_actions;
92 my $unattached_actions = Text::SimpleTable->new(
93 [ $col1_width, 'Private' ], [ $col2_width, 'Missing parent' ],
96 ENDPOINT: foreach my $endpoint (
97 sort { $a->reverse cmp $b->reverse }
98 @{ $self->_endpoints }
100 my $args = $endpoint->list_extra_info->{Args};
101 my @parts = (defined($args) ? (("*") x $args) : '...');
103 my $parent = "DUMMY";
104 my $extra = $self->_list_extra_http_methods($endpoint);
105 my $consumes = $self->_list_extra_consumes($endpoint);
106 my $scheme = $self->_list_extra_scheme($endpoint);
107 my $curr = $endpoint;
109 if (my $cap = $curr->list_extra_info->{CaptureArgs}) {
110 unshift(@parts, (("*") x $cap));
112 if (my $pp = $curr->attributes->{PathPart}) {
113 unshift(@parts, $pp->[0])
114 if (defined $pp->[0] && length $pp->[0]);
116 $parent = $curr->attributes->{Chained}->[0];
117 $curr = $self->_actions->{$parent};
118 unshift(@parents, $curr) if $curr;
120 if ($parent ne '/') {
121 $has_unattached_actions = 1;
122 $unattached_actions->row('/' . ($parents[0] || $endpoint)->reverse, $parent);
126 foreach my $p (@parents) {
129 if (defined(my $extra = $self->_list_extra_http_methods($p))) {
130 $name = "${extra} ${name}";
132 if (defined(my $cap = $p->list_extra_info->{CaptureArgs})) {
133 $name .= ' ('.$cap.')';
135 if (defined(my $ct = $p->list_extra_info->{Consumes})) {
138 if (defined(my $s = $p->list_extra_info->{Scheme})) {
142 unless ($p eq $parents[0]) {
143 $name = "-> ${name}";
145 push(@rows, [ '', $name ]);
147 push(@rows, [ '', (@rows ? "=> " : '').($extra ? "$extra " : ''). ($scheme ? "$scheme: ":'')."/${endpoint}". ($consumes ? " :$consumes":"" ) ]);
148 my @display_parts = map { $_ =~s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg; decode_utf8 $_ } @parts;
149 $rows[0][0] = join('/', '', @display_parts) || '/';
150 $paths->row(@$_) for @rows;
153 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
154 $c->log->debug( "Unattached Chained actions:\n", $unattached_actions->draw . "\n" )
155 if $has_unattached_actions;
158 sub _list_extra_http_methods {
159 my ( $self, $action ) = @_;
160 return unless defined $action->list_extra_info->{HTTP_METHODS};
161 return join(', ', @{$action->list_extra_info->{HTTP_METHODS}});
165 sub _list_extra_consumes {
166 my ( $self, $action ) = @_;
167 return unless defined $action->list_extra_info->{CONSUMES};
168 return join(', ', @{$action->list_extra_info->{CONSUMES}});
171 sub _list_extra_scheme {
172 my ( $self, $action ) = @_;
173 return unless defined $action->list_extra_info->{Scheme};
174 return uc $action->list_extra_info->{Scheme};
177 =head2 $self->match( $c, $path )
179 Calls C<recurse_match> to see if a chain matches the C<$path>.
184 my ( $self, $c, $path ) = @_;
186 my $request = $c->request;
187 return 0 if @{$request->args};
189 my @parts = split('/', $path);
191 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
193 if ($parts && @$parts) {
194 for my $arg (@$parts) {
195 $arg =~ s/%([0-9A-Fa-f]{2})/chr(hex($1))/eg;
196 push @{$request->args}, $arg;
200 return 0 unless $chain;
202 my $action = Catalyst::ActionChain->from_chain($chain);
204 $request->action("/${action}");
205 $request->match("/${action}");
206 $request->captures($captures);
208 $c->namespace( $action->namespace );
213 =head2 $self->recurse_match( $c, $parent, \@path_parts )
215 Recursive search for a matching chain.
220 my ( $self, $c, $parent, $path_parts ) = @_;
221 my $children = $self->_children_of->{$parent};
222 return () unless $children;
225 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
227 # $b then $a to try longest part first
228 my @parts = @$path_parts;
229 if (length $try_part) { # test and strip PathPart
231 ($try_part eq join('/', # assemble equal number of parts
232 splice( # and strip them off @parts as well
233 @parts, 0, scalar(@{[split('/', $try_part)]})
234 ))); # @{[]} to avoid split to @_
236 my @try_actions = @{$children->{$try_part}};
237 TRY_ACTION: foreach my $action (@try_actions) {
238 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
239 my $capture_count = $capture_attr->[0] || 0;
241 # Short-circuit if not enough remaining parts
242 next TRY_ACTION unless @parts >= $capture_count;
245 my @parts = @parts; # localise
247 # strip CaptureArgs into list
248 push(@captures, splice(@parts, 0, $capture_count));
250 # check if the action may fit, depending on a given test by the app
251 if ($action->can('match_captures')) { next TRY_ACTION unless $action->match_captures($c, \@captures) }
253 # try the remaining parts against children of this action
254 my ($actions, $captures, $action_parts, $n_pathparts) = $self->recurse_match(
255 $c, '/'.$action->reverse, \@parts
257 # No best action currently
258 # OR The action has less parts
259 # OR The action has equal parts but less captured data (ergo more defined)
262 $#$action_parts < $#{$best_action->{parts}} ||
263 ($#$action_parts == $#{$best_action->{parts}} &&
264 $#$captures < $#{$best_action->{captures}} &&
265 $n_pathparts > $best_action->{n_pathparts}))) {
266 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
268 actions => [ $action, @$actions ],
269 captures=> [ @captures, @$captures ],
270 parts => $action_parts,
271 n_pathparts => scalar(@pathparts) + $n_pathparts,
277 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
278 next TRY_ACTION unless $action->match($c);
280 my $args_attr = $action->attributes->{Args}->[0];
281 my @pathparts = split /\//, $action->attributes->{PathPart}->[0];
282 # No best action currently
283 # OR This one matches with fewer parts left than the current best action,
284 # And therefore is a better match
285 # OR No parts and this expects 0
286 # The current best action might also be Args(0),
287 # but we couldn't chose between then anyway so we'll take the last seen
290 @parts < @{$best_action->{parts}} ||
291 (!@parts && defined($args_attr) && $args_attr eq "0")){
293 actions => [ $action ],
296 n_pathparts => scalar(@pathparts),
302 return @$best_action{qw/actions captures parts n_pathparts/} if $best_action;
306 =head2 $self->register( $c, $action )
308 Calls register_path for every Path attribute for the given $action.
312 sub _check_args_attr {
313 my ( $self, $action, $name ) = @_;
315 return unless exists $action->attributes->{$name};
317 if (@{$action->attributes->{$name}} > 1) {
318 Catalyst::Exception->throw(
319 "Multiple $name attributes not supported registering " . $action->reverse()
322 my $args = $action->attributes->{$name}->[0];
323 if (defined($args) and not (
324 Scalar::Util::looks_like_number($args) and
325 int($args) == $args and $args >= 0
327 require Data::Dumper;
328 local $Data::Dumper::Terse = 1;
329 local $Data::Dumper::Indent = 0;
330 $args = Data::Dumper::Dumper($args);
331 Catalyst::Exception->throw(
332 "Invalid $name($args) for action " . $action->reverse() .
333 " (use '$name' or '$name(<number>)')"
339 my ( $self, $c, $action ) = @_;
341 my @chained_attr = @{ $action->attributes->{Chained} || [] };
343 return 0 unless @chained_attr;
345 if (@chained_attr > 1) {
346 Catalyst::Exception->throw(
347 "Multiple Chained attributes not supported registering ${action}"
350 my $chained_to = $chained_attr[0];
352 Catalyst::Exception->throw(
353 "Actions cannot chain to themselves registering /${action}"
354 ) if ($chained_to eq '/' . $action);
356 my $children = ($self->_children_of->{ $chained_to } ||= {});
358 my @path_part = @{ $action->attributes->{PathPart} || [] };
360 my $part = $action->name;
362 if (@path_part == 1 && defined $path_part[0]) {
363 $part = $path_part[0];
364 } elsif (@path_part > 1) {
365 Catalyst::Exception->throw(
366 "Multiple PathPart attributes not supported registering " . $action->reverse()
370 if ($part =~ m(^/)) {
371 Catalyst::Exception->throw(
372 "Absolute parameters to PathPart not allowed registering " . $action->reverse()
376 my $encoded_part = URI->new($part)->canonical;
377 $encoded_part =~ s{(?<=[^/])/+\z}{};
379 $action->attributes->{PathPart} = [ $encoded_part ];
381 unshift(@{ $children->{$encoded_part} ||= [] }, $action);
383 $self->_actions->{'/'.$action->reverse} = $action;
385 foreach my $name (qw(Args CaptureArgs)) {
386 $self->_check_args_attr($action, $name);
389 if (exists $action->attributes->{Args} and exists $action->attributes->{CaptureArgs}) {
390 Catalyst::Exception->throw(
391 "Combining Args and CaptureArgs attributes not supported registering " .
396 unless ($action->attributes->{CaptureArgs}) {
397 unshift(@{ $self->_endpoints }, $action);
403 =head2 $self->uri_for_action($action, $captures)
405 Get the URI part for the action, using C<$captures> to fill
411 my ( $self, $action, $captures ) = @_;
413 return undef unless ($action->attributes->{Chained}
414 && !$action->attributes->{CaptureArgs});
417 my @captures = @$captures;
418 my $parent = "DUMMY";
421 if (my $cap = $curr->attributes->{CaptureArgs}) {
422 return undef unless @captures >= ($cap->[0]||0); # not enough captures
424 unshift(@parts, splice(@captures, -$cap->[0]));
427 if (my $pp = $curr->attributes->{PathPart}) {
428 unshift(@parts, $pp->[0])
429 if (defined($pp->[0]) && length($pp->[0]));
431 $parent = $curr->attributes->{Chained}->[0];
432 $curr = $self->_actions->{$parent};
435 return undef unless $parent eq '/'; # fail for dangling action
437 return undef if @captures; # fail for too many captures
439 return join('/', '', @parts);
443 =head2 $c->expand_action($action)
445 Return a list of actions that represents a chained action. See
446 L<Catalyst::Dispatcher> for more info. You probably want to
447 use the expand_action it provides rather than this directly.
452 my ($self, $action) = @_;
454 return unless $action->attributes && $action->attributes->{Chained};
461 my $parent = $curr->attributes->{Chained}->[0];
462 $curr = $self->_actions->{$parent};
465 return Catalyst::ActionChain->from_chain([reverse @chain]);
468 __PACKAGE__->meta->make_immutable;
475 The C<Chained> attribute allows you to chain public path parts together
476 by their private names. A chain part's path can be specified with
477 C<PathPart> and can be declared to expect an arbitrary number of
478 arguments. The endpoint of the chain specifies how many arguments it
479 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
480 C<:Args> without an integer would be unlimited. The path parts that
481 aren't endpoints are using C<CaptureArgs> to specify how many parameters
482 they expect to receive. As an example setup:
484 package MyApp::Controller::Greeting;
485 use base qw/ Catalyst::Controller /;
487 # this is the beginning of our chain
488 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
489 my ( $self, $c, $integer ) = @_;
490 $c->stash->{ message } = "Hello ";
491 $c->stash->{ arg_sum } = $integer;
494 # this is our endpoint, because it has no :CaptureArgs
495 sub world : PathPart('world') Chained('hello') Args(1) {
496 my ( $self, $c, $integer ) = @_;
497 $c->stash->{ message } .= "World!";
498 $c->stash->{ arg_sum } += $integer;
500 $c->response->body( join "<br/>\n" =>
501 $c->stash->{ message }, $c->stash->{ arg_sum } );
504 The debug output provides a separate table for chained actions, showing
505 the whole chain as it would match and the actions it contains. Here's an
506 example of the startup output with our actions above:
509 [debug] Loaded Path Part actions:
510 .-----------------------+------------------------------.
511 | Path Spec | Private |
512 +-----------------------+------------------------------+
513 | /hello/*/world/* | /greeting/hello (1) |
514 | | => /greeting/world |
515 '-----------------------+------------------------------'
518 As you can see, Catalyst only deals with chains as whole paths and
519 builds one for each endpoint, which are the actions with C<:Chained> but
520 without C<:CaptureArgs>.
522 Let's assume this application gets a request at the path
523 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
524 to the C<hello> action and pass the value C<23> as an argument to it
525 after the context. It does so because we have previously used
526 C<:CaptureArgs(1)> to declare that it has one path part after itself as
527 its argument. We told Catalyst that this is the beginning of the chain
528 by specifying C<:Chained('/')>. Also note that instead of saying
529 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
530 defaults to the name of the action.
532 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
533 action. This is the last action to be called: Catalyst knows this is an
534 endpoint because we did not specify a C<:CaptureArgs>
535 attribute. Nevertheless we specify that this action expects an argument,
536 but at this point we're using C<:Args(1)> to do that. We could also have
537 said C<:Args> or left it out altogether, which would mean this action
538 would get all arguments that are there. This action's C<:Chained>
539 attribute says C<hello> and tells Catalyst that the C<hello> action in
540 the current controller is its parent.
542 With this we have built a chain consisting of two public path parts.
543 C<hello> captures one part of the path as its argument, and also
544 specifies the path root as its parent. So this part is
545 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
546 argument. It sums up to the path part C<world/$arg>. This leads to a
547 complete chain of C</hello/$arg/world/$arg> which is matched against the
550 This example application would, if run and called by e.g.
551 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
552 value C<arg_sum> to "23". The C<world> action would then append "World!"
553 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
554 sake of simplicity no view is shown. Instead we just put the values of
555 the stash into our body. So the output would look like:
560 And our test server would have given us this debugging output for the
564 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
565 [debug] Path is "/greeting/world"
566 [debug] Arguments are "12"
567 [info] Request took 0.164113s (6.093/s)
568 .------------------------------------------+-----------.
570 +------------------------------------------+-----------+
571 | /greeting/hello | 0.000029s |
572 | /greeting/world | 0.000024s |
573 '------------------------------------------+-----------'
576 What would be common uses of this dispatch technique? It gives the
577 possibility to split up logic that contains steps that each depend on
578 each other. An example would be, for example, a wiki path like
579 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
582 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
583 my ( $self, $c, $page_name ) = @_;
584 # load the page named $page_name and put the object
588 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
589 my ( $self, $c, $revision_id ) = @_;
590 # use the page object in the stash to get at its
591 # revision with number $revision_id
594 sub view : PathPart Chained('rev') Args(0) {
595 my ( $self, $c ) = @_;
596 # display the revision in our stash. Another option
597 # would be to forward a compatible object to the action
598 # that displays the default wiki pages, unless we want
599 # a different interface here, for example restore
603 It would now be possible to add other endpoints, for example C<restore>
604 to restore this specific revision as the current state.
606 You don't have to put all the chained actions in one controller. The
607 specification of the parent through C<:Chained> also takes an absolute
608 action path as its argument. Just specify it with a leading C</>.
610 If you want, for example, to have actions for the public paths
611 C</foo/12/edit> and C</foo/12>, just specify two actions with
612 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
613 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
614 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
615 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
616 this debugging output:
619 [debug] Loaded Path Part actions:
620 .-----------------------+------------------------------.
621 | Path Spec | Private |
622 +-----------------------+------------------------------+
623 | /foo/* | /controller/foo_view |
624 | /foo/*/edit | /controller/foo_load (1) |
625 | | => /controller/edit |
626 '-----------------------+------------------------------'
629 Here's a more detailed specification of the attributes belonging to
638 Sets the name of this part of the chain. If it is specified without
639 arguments, it takes the name of the action as default. So basically
640 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
641 This can also contain slashes to bind to a deeper level. An action
642 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
643 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
644 effect as using C<:PathPart>, it would default to the action name.
648 Sets PathPart to the path_prefix of the current controller.
652 Has to be specified for every child in the chain. Possible values are
653 absolute and relative private action paths or a single slash C</> to
654 tell Catalyst that this is the root of a chain. The attribute
655 C<:Chained> without arguments also defaults to the C</> behavior.
656 Relative action paths may use C<../> to refer to actions in parent
659 Because you can specify an absolute path to the parent action, it
660 doesn't matter to Catalyst where that parent is located. So, if your
661 design requests it, you can redispatch a chain through any controller or
664 Another interesting possibility gives C<:Chained('.')>, which chains
665 itself to an action with the path of the current controller's namespace.
668 # in MyApp::Controller::Foo
669 sub bar : Chained CaptureArgs(1) { ... }
671 # in MyApp::Controller::Foo::Bar
672 sub baz : Chained('.') Args(1) { ... }
674 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
675 as the argument to Chained here chains the C<baz> action to an action
676 with the path of the current controller namespace, namely
677 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
678 chain comes out as the end product.
682 Chains an action to another action with the same name in the parent
683 controller. For Example:
685 # in MyApp::Controller::Foo
686 sub bar : Chained CaptureArgs(1) { ... }
688 # in MyApp::Controller::Foo::Moo
689 sub bar : ChainedParent Args(1) { ... }
691 This builds a chain like C</bar/*/bar/*>.
695 Must be specified for every part of the chain that is not an
696 endpoint. With this attribute Catalyst knows how many of the following
697 parts of the path (separated by C</>) this action wants to capture as
698 its arguments. If it doesn't expect any, just specify
699 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
700 after the context, but you can also find them as array references in
701 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
702 level of the action in the chain that captured the parts of the path.
704 An action that is part of a chain (that is, one that has a C<:Chained>
705 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
710 By default, endpoints receive the rest of the arguments in the path. You
711 can tell Catalyst through C<:Args> explicitly how many arguments your
712 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
713 also affects whether this chain is invoked on a request. A chain with an
714 endpoint specifying one argument will only match if exactly one argument
717 You can specify an exact number of arguments like C<:Args(3)>, including
718 C<0>. If you just say C<:Args> without any arguments, it is the same as
719 leaving it out altogether: The chain is matched regardless of the number
720 of path parts after the endpoint.
722 Just as with C<:CaptureArgs>, the arguments get passed to the action in
723 C<@_> after the context object. They can also be reached through
724 C<$c-E<gt>request-E<gt>arguments>.
728 =head2 Auto actions, dispatching and forwarding
730 Note that the list of C<auto> actions called depends on the private path
731 of the endpoint of the chain, not on the chained actions way. The
732 C<auto> actions will be run before the chain dispatching begins. In
733 every other aspect, C<auto> actions behave as documented.
735 The C<forward>ing to other actions does just what you would expect. i.e.
736 only the target action is run. The actions that that action is chained
738 If you C<detach> out of a chain, the rest of the chain will not get
739 called after the C<detach>.
741 =head2 match_captures
743 A method which can optionally be implemented by actions to
746 See L<Catalyst::Action> for further details.
750 Catalyst Contributors, see Catalyst.pm
754 This library is free software. You can redistribute it and/or modify it under
755 the same terms as Perl itself.