1 package Catalyst::DispatchType::Chained;
4 use base qw/Catalyst::DispatchType/;
6 use Catalyst::ActionChain;
10 # please don't perltidy this. hairy code within.
14 Catalyst::DispatchType::Chained - Path Part DispatchType
18 # root action - captures one argument after it
19 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
20 my ( $self, $c, $foo_arg ) = @_;
24 # child action endpoint - takes one argument
25 sub bar : Chained('foo_setup') Args(1) {
26 my ( $self, $c, $bar_arg ) = @_;
36 =head2 $self->list($c)
38 Debug output for Path Part dispatch points
43 my ( $self, $c ) = @_;
45 return unless $self->{endpoints};
47 my $column_width = Catalyst::Utils::term_width() - 35 - 9;
48 my $paths = Text::SimpleTable->new(
49 [ 35, 'Path Spec' ], [ 36, 'Private' ], [ $column_width, 'Private' ]
52 ENDPOINT: foreach my $endpoint (
53 sort { $a->reverse cmp $b->reverse }
54 @{ $self->{endpoints} }
56 my $args = $endpoint->attributes->{Args}->[0];
57 my @parts = (defined($args) ? (("*") x $args) : '...');
62 if (my $cap = $curr->attributes->{CaptureArgs}) {
63 unshift(@parts, (("*") x $cap->[0]));
65 if (my $pp = $curr->attributes->{PartPath}) {
66 unshift(@parts, $pp->[0])
67 if (defined $pp->[0] && length $pp->[0]);
69 $parent = $curr->attributes->{Chained}->[0];
70 $curr = $self->{actions}{$parent};
71 unshift(@parents, $curr) if $curr;
73 next ENDPOINT unless $parent eq '/'; # skip dangling action
75 foreach my $p (@parents) {
77 if (my $cap = $p->attributes->{CaptureArgs}) {
78 $name .= ' ('.$cap->[0].')';
80 unless ($p eq $parents[0]) {
83 push(@rows, [ '', $name ]);
85 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
86 $rows[0][0] = join('/', '', @parts);
87 $paths->row(@$_) for @rows;
90 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
93 =head2 $self->match( $c, $path )
95 Calls C<recurse_match> to see if a chain matches the C<$path>.
100 my ( $self, $c, $path ) = @_;
102 return 0 if @{$c->req->args};
104 my @parts = split('/', $path);
106 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
107 push @{$c->req->args}, @$parts if $parts && @$parts;
109 return 0 unless $chain;
111 my $action = Catalyst::ActionChain->from_chain($chain);
113 $c->req->action("/${action}");
114 $c->req->match("/${action}");
115 $c->req->captures($captures);
117 $c->namespace( $action->namespace );
122 =head2 $self->recurse_match( $c, $parent, \@path_parts )
124 Recursive search for a matching chain.
129 my ( $self, $c, $parent, $path_parts ) = @_;
130 my $children = $self->{children_of}{$parent};
131 return () unless $children;
134 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
136 # $b then $a to try longest part first
137 my @parts = @$path_parts;
138 if (length $try_part) { # test and strip PathPart
140 ($try_part eq join('/', # assemble equal number of parts
141 splice( # and strip them off @parts as well
142 @parts, 0, scalar(@{[split('/', $try_part)]})
143 ))); # @{[]} to avoid split to @_
145 my @try_actions = @{$children->{$try_part}};
146 TRY_ACTION: foreach my $action (@try_actions) {
147 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
149 # Short-circuit if not enough remaining parts
150 next TRY_ACTION unless @parts >= $capture_attr->[0];
153 my @parts = @parts; # localise
155 # strip CaptureArgs into list
156 push(@captures, splice(@parts, 0, $capture_attr->[0]));
158 # try the remaining parts against children of this action
159 my ($actions, $captures, $action_parts) = $self->recurse_match(
160 $c, '/'.$action->reverse, \@parts
162 # No best action currently
163 # OR The action has less parts
164 # OR The action has equal parts but less captured data (ergo more defined)
167 $#$action_parts < $#{$best_action->{parts}} ||
168 ($#$action_parts == $#{$best_action->{parts}} &&
169 $#$captures < $#{$best_action->{captures}}))){
171 actions => [ $action, @$actions ],
172 captures=> [ @captures, @$captures ],
173 parts => $action_parts
179 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
180 next TRY_ACTION unless $action->match($c);
182 my $args_attr = $action->attributes->{Args}->[0];
184 # No best action currently
185 # OR This one matches with fewer parts left than the current best action,
186 # And therefore is a better match
187 # OR No parts and this expects 0
188 # The current best action might also be Args(0),
189 # but we couldn't chose between then anyway so we'll take the last seen
192 @parts < @{$best_action->{parts}} ||
193 (!@parts && $args_attr eq 0)){
195 actions => [ $action ],
203 return @$best_action{qw/actions captures parts/} if $best_action;
207 =head2 $self->register( $c, $action )
209 Calls register_path for every Path attribute for the given $action.
214 my ( $self, $c, $action ) = @_;
216 my @chained_attr = @{ $action->attributes->{Chained} || [] };
218 return 0 unless @chained_attr;
220 if (@chained_attr > 1) {
221 Catalyst::Exception->throw(
222 "Multiple Chained attributes not supported registering ${action}"
225 my $chained_to = $chained_attr[0];
227 Catalyst::Exception->throw(
228 "Actions cannot chain to themselves registering /${action}"
229 ) if ($chained_to eq '/' . $action);
231 my $children = ($self->{children_of}->{ $chained_to } ||= {});
233 my @path_part = @{ $action->attributes->{PathPart} || [] };
235 my $part = $action->name;
237 if (@path_part == 1 && defined $path_part[0]) {
238 $part = $path_part[0];
239 } elsif (@path_part > 1) {
240 Catalyst::Exception->throw(
241 "Multiple PathPart attributes not supported registering ${action}"
245 if ($part =~ m(^/)) {
246 Catalyst::Exception->throw(
247 "Absolute parameters to PathPart not allowed registering ${action}"
251 $action->attributes->{PartPath} = [ $part ];
253 unshift(@{ $children->{$part} ||= [] }, $action);
255 ($self->{actions} ||= {})->{'/'.$action->reverse} = $action;
257 unless ($action->attributes->{CaptureArgs}) {
258 unshift(@{ $self->{endpoints} ||= [] }, $action);
264 =head2 $self->uri_for_action($action, $captures)
266 Get the URI part for the action, using C<$captures> to fill
272 my ( $self, $action, $captures ) = @_;
274 return undef unless ($action->attributes->{Chained}
275 && !$action->attributes->{CaptureArgs});
278 my @captures = @$captures;
279 my $parent = "DUMMY";
282 if (my $cap = $curr->attributes->{CaptureArgs}) {
283 return undef unless @captures >= $cap->[0]; # not enough captures
285 unshift(@parts, splice(@captures, -$cap->[0]));
288 if (my $pp = $curr->attributes->{PartPath}) {
289 unshift(@parts, $pp->[0])
290 if (defined($pp->[0]) && length($pp->[0]));
292 $parent = $curr->attributes->{Chained}->[0];
293 $curr = $self->{actions}{$parent};
296 return undef unless $parent eq '/'; # fail for dangling action
298 return undef if @captures; # fail for too many captures
300 return join('/', '', @parts);
304 =head2 $c->expand_action($action)
306 Return a list of actions that represents a chained action. See
307 L<Catalyst::Dispatcher> for more info. You probably want to
308 use the expand_action it provides rather than this directly.
313 my ($self, $action) = @_;
315 return unless $action->attributes && $action->attributes->{Chained};
322 my $parent = $curr->attributes->{Chained}->[0];
323 $curr = $self->{'actions'}{$parent};
326 return Catalyst::ActionChain->from_chain([reverse @chain]);
333 The C<Chained> attribute allows you to chain public path parts together
334 by their private names. A chain part's path can be specified with
335 C<PathPart> and can be declared to expect an arbitrary number of
336 arguments. The endpoint of the chain specifies how many arguments it
337 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
338 C<:Args> without an integer would be unlimited. The path parts that
339 aren't endpoints are using C<CaptureArgs> to specify how many parameters
340 they expect to receive. As an example setup:
342 package MyApp::Controller::Greeting;
343 use base qw/ Catalyst::Controller /;
345 # this is the beginning of our chain
346 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
347 my ( $self, $c, $integer ) = @_;
348 $c->stash->{ message } = "Hello ";
349 $c->stash->{ arg_sum } = $integer;
352 # this is our endpoint, because it has no :CaptureArgs
353 sub world : PathPart('world') Chained('hello') Args(1) {
354 my ( $self, $c, $integer ) = @_;
355 $c->stash->{ message } .= "World!";
356 $c->stash->{ arg_sum } += $integer;
358 $c->response->body( join "<br/>\n" =>
359 $c->stash->{ message }, $c->stash->{ arg_sum } );
362 The debug output provides a separate table for chained actions, showing
363 the whole chain as it would match and the actions it contains. Here's an
364 example of the startup output with our actions above:
367 [debug] Loaded Path Part actions:
368 .-----------------------+------------------------------.
369 | Path Spec | Private |
370 +-----------------------+------------------------------+
371 | /hello/*/world/* | /greeting/hello (1) |
372 | | => /greeting/world |
373 '-----------------------+------------------------------'
376 As you can see, Catalyst only deals with chains as whole paths and
377 builds one for each endpoint, which are the actions with C<:Chained> but
378 without C<:CaptureArgs>.
380 Let's assume this application gets a request at the path
381 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
382 to the C<hello> action and pass the value C<23> as an argument to it
383 after the context. It does so because we have previously used
384 C<:CaptureArgs(1)> to declare that it has one path part after itself as
385 its argument. We told Catalyst that this is the beginning of the chain
386 by specifying C<:Chained('/')>. Also note that instead of saying
387 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
388 defaults to the name of the action.
390 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
391 action. This is the last action to be called: Catalyst knows this is an
392 endpoint because we did not specify a C<:CaptureArgs>
393 attribute. Nevertheless we specify that this action expects an argument,
394 but at this point we're using C<:Args(1)> to do that. We could also have
395 said C<:Args> or left it out altogether, which would mean this action
396 would get all arguments that are there. This action's C<:Chained>
397 attribute says C<hello> and tells Catalyst that the C<hello> action in
398 the current controller is its parent.
400 With this we have built a chain consisting of two public path parts.
401 C<hello> captures one part of the path as its argument, and also
402 specifies the path root as its parent. So this part is
403 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
404 argument. It sums up to the path part C<world/$arg>. This leads to a
405 complete chain of C</hello/$arg/world/$arg> which is matched against the
408 This example application would, if run and called by e.g.
409 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
410 value C<arg_sum> to "23". The C<world> action would then append "World!"
411 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
412 sake of simplicity no view is shown. Instead we just put the values of
413 the stash into our body. So the output would look like:
418 And our test server would have given us this debugging output for the
422 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
423 [debug] Path is "/greeting/world"
424 [debug] Arguments are "12"
425 [info] Request took 0.164113s (6.093/s)
426 .------------------------------------------+-----------.
428 +------------------------------------------+-----------+
429 | /greeting/hello | 0.000029s |
430 | /greeting/world | 0.000024s |
431 '------------------------------------------+-----------'
434 What would be common uses of this dispatch technique? It gives the
435 possibility to split up logic that contains steps that each depend on
436 each other. An example would be, for example, a wiki path like
437 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
440 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
441 my ( $self, $c, $page_name ) = @_;
442 # load the page named $page_name and put the object
446 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
447 my ( $self, $c, $revision_id ) = @_;
448 # use the page object in the stash to get at its
449 # revision with number $revision_id
452 sub view : PathPart Chained('rev') Args(0) {
453 my ( $self, $c ) = @_;
454 # display the revision in our stash. Another option
455 # would be to forward a compatible object to the action
456 # that displays the default wiki pages, unless we want
457 # a different interface here, for example restore
461 It would now be possible to add other endpoints, for example C<restore>
462 to restore this specific revision as the current state.
464 You don't have to put all the chained actions in one controller. The
465 specification of the parent through C<:Chained> also takes an absolute
466 action path as its argument. Just specify it with a leading C</>.
468 If you want, for example, to have actions for the public paths
469 C</foo/12/edit> and C</foo/12>, just specify two actions with
470 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
471 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
472 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
473 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
474 this debugging output:
477 [debug] Loaded Path Part actions:
478 .-----------------------+------------------------------.
479 | Path Spec | Private |
480 +-----------------------+------------------------------+
481 | /foo/* | /controller/foo_view |
482 | /foo/*/edit | /controller/foo_load (1) |
483 | | => /controller/edit |
484 '-----------------------+------------------------------'
487 Here's a more detailed specification of the attributes belonging to
496 Sets the name of this part of the chain. If it is specified without
497 arguments, it takes the name of the action as default. So basically
498 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
499 This can also contain slashes to bind to a deeper level. An action
500 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
501 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
502 effect as using C<:PathPart>, it would default to the action name.
506 Sets PathPart to the path_prefix of the current controller.
510 Has to be specified for every child in the chain. Possible values are
511 absolute and relative private action paths or a single slash C</> to
512 tell Catalyst that this is the root of a chain. The attribute
513 C<:Chained> without arguments also defaults to the C</> behavior.
514 Relative action paths may use C<../> to refer to actions in parent
517 Because you can specify an absolute path to the parent action, it
518 doesn't matter to Catalyst where that parent is located. So, if your
519 design requests it, you can redispatch a chain through any controller or
522 Another interesting possibility gives C<:Chained('.')>, which chains
523 itself to an action with the path of the current controller's namespace.
526 # in MyApp::Controller::Foo
527 sub bar : Chained CaptureArgs(1) { ... }
529 # in MyApp::Controller::Foo::Bar
530 sub baz : Chained('.') Args(1) { ... }
532 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
533 as the argument to Chained here chains the C<baz> action to an action
534 with the path of the current controller namespace, namely
535 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
536 chain comes out as the end product.
540 Chains an action to another action with the same name in the parent
541 controller. For Example:
543 # in MyApp::Controller::Foo
544 sub bar : Chained CaptureArgs(1) { ... }
546 # in MyApp::Controller::Foo::Moo
547 sub bar : ChainedParent Args(1) { ... }
549 This builds a chain like C</bar/*/bar/*>.
553 Must be specified for every part of the chain that is not an
554 endpoint. With this attribute Catalyst knows how many of the following
555 parts of the path (separated by C</>) this action wants to capture as
556 its arguments. If it doesn't expect any, just specify
557 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
558 after the context, but you can also find them as array references in
559 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
560 level of the action in the chain that captured the parts of the path.
562 An action that is part of a chain (that is, one that has a C<:Chained>
563 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
568 By default, endpoints receive the rest of the arguments in the path. You
569 can tell Catalyst through C<:Args> explicitly how many arguments your
570 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
571 also affects whether this chain is invoked on a request. A chain with an
572 endpoint specifying one argument will only match if exactly one argument
575 You can specify an exact number of arguments like C<:Args(3)>, including
576 C<0>. If you just say C<:Args> without any arguments, it is the same as
577 leaving it out altogether: The chain is matched regardless of the number
578 of path parts after the endpoint.
580 Just as with C<:CaptureArgs>, the arguments get passed to the action in
581 C<@_> after the context object. They can also be reached through
582 C<$c-E<gt>request-E<gt>arguments>.
586 =head2 Auto actions, dispatching and forwarding
588 Note that the list of C<auto> actions called depends on the private path
589 of the endpoint of the chain, not on the chained actions way. The
590 C<auto> actions will be run before the chain dispatching begins. In
591 every other aspect, C<auto> actions behave as documented.
593 The C<forward>ing to other actions does just what you would expect. But if
594 you C<detach> out of a chain, the rest of the chain will not get called
599 Catalyst Contributors, see Catalyst.pm
603 This program is free software, you can redistribute it and/or modify it under
604 the same terms as Perl itself.