1 package Catalyst::DispatchType::Chained;
4 extends 'Catalyst::DispatchType';
7 #use base qw/Catalyst::DispatchType/;
9 use Catalyst::ActionChain;
12 # please don't perltidy this. hairy code within.
16 Catalyst::DispatchType::Chained - Path Part DispatchType
20 # root action - captures one argument after it
21 sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) {
22 my ( $self, $c, $foo_arg ) = @_;
26 # child action endpoint - takes one argument
27 sub bar : Chained('foo_setup') Args(1) {
28 my ( $self, $c, $bar_arg ) = @_;
38 =head2 $self->list($c)
40 Debug output for Path Part dispatch points
45 my ( $self, $c ) = @_;
47 return unless $self->{endpoints};
49 my $paths = Text::SimpleTable->new(
50 [ 35, 'Path Spec' ], [ 36, 'Private' ]
53 ENDPOINT: foreach my $endpoint (
54 sort { $a->reverse cmp $b->reverse }
55 @{ $self->{endpoints} }
57 my $args = $endpoint->attributes->{Args}->[0];
58 my @parts = (defined($args) ? (("*") x $args) : '...');
63 if (my $cap = $curr->attributes->{CaptureArgs}) {
64 unshift(@parts, (("*") x $cap->[0]));
66 if (my $pp = $curr->attributes->{PartPath}) {
67 unshift(@parts, $pp->[0])
68 if (defined $pp->[0] && length $pp->[0]);
70 $parent = $curr->attributes->{Chained}->[0];
71 $curr = $self->{actions}{$parent};
72 unshift(@parents, $curr) if $curr;
74 next ENDPOINT unless $parent eq '/'; # skip dangling action
76 foreach my $p (@parents) {
78 if (my $cap = $p->attributes->{CaptureArgs}) {
79 $name .= ' ('.$cap->[0].')';
81 unless ($p eq $parents[0]) {
84 push(@rows, [ '', $name ]);
86 push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]);
87 $rows[0][0] = join('/', '', @parts);
88 $paths->row(@$_) for @rows;
91 $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" );
94 =head2 $self->match( $c, $path )
96 Calls C<recurse_match> to see if a chain matches the C<$path>.
101 my ( $self, $c, $path ) = @_;
103 return 0 if @{$c->req->args};
105 my @parts = split('/', $path);
107 my ($chain, $captures, $parts) = $self->recurse_match($c, '/', \@parts);
108 push @{$c->req->args}, @$parts if $parts && @$parts;
110 return 0 unless $chain;
112 my $action = Catalyst::ActionChain->from_chain($chain);
114 $c->req->action("/${action}");
115 $c->req->match("/${action}");
116 $c->req->captures($captures);
118 $c->namespace( $action->namespace );
123 =head2 $self->recurse_match( $c, $parent, \@path_parts )
125 Recursive search for a matching chain.
130 my ( $self, $c, $parent, $path_parts ) = @_;
131 my $children = $self->{children_of}{$parent};
132 return () unless $children;
135 TRY: foreach my $try_part (sort { length($b) <=> length($a) }
137 # $b then $a to try longest part first
138 my @parts = @$path_parts;
139 if (length $try_part) { # test and strip PathPart
141 ($try_part eq join('/', # assemble equal number of parts
142 splice( # and strip them off @parts as well
143 @parts, 0, scalar(@{[split('/', $try_part)]})
144 ))); # @{[]} to avoid split to @_
146 my @try_actions = @{$children->{$try_part}};
147 TRY_ACTION: foreach my $action (@try_actions) {
148 if (my $capture_attr = $action->attributes->{CaptureArgs}) {
150 # Short-circuit if not enough remaining parts
151 next TRY_ACTION unless @parts >= $capture_attr->[0];
154 my @parts = @parts; # localise
156 # strip CaptureArgs into list
157 push(@captures, splice(@parts, 0, $capture_attr->[0]));
159 # try the remaining parts against children of this action
160 my ($actions, $captures, $action_parts) = $self->recurse_match(
161 $c, '/'.$action->reverse, \@parts
163 if ($actions && (!$best_action || $#$action_parts < $#{$best_action->{parts}})){
165 actions => [ $action, @$actions ],
166 captures=> [ @captures, @$captures ],
167 parts => $action_parts
173 local $c->req->{arguments} = [ @{$c->req->args}, @parts ];
174 next TRY_ACTION unless $action->match($c);
176 my $args_attr = $action->attributes->{Args}->[0];
178 # No best action currently
179 # OR This one matches with fewer parts left than the current best action,
180 # And therefore is a better match
181 # OR No parts and this expects 0
182 # The current best action might also be Args(0),
183 # but we couldn't chose between then anyway so we'll take the last seen
186 @parts < @{$best_action->{parts}} ||
187 (!@parts && $args_attr eq 0)){
189 actions => [ $action ],
197 return @$best_action{qw/actions captures parts/} if $best_action;
201 =head2 $self->register( $c, $action )
203 Calls register_path for every Path attribute for the given $action.
208 my ( $self, $c, $action ) = @_;
210 my @chained_attr = @{ $action->attributes->{Chained} || [] };
212 return 0 unless @chained_attr;
214 if (@chained_attr > 2) {
215 Catalyst::Exception->throw(
216 "Multiple Chained attributes not supported registering ${action}"
220 my $parent = $chained_attr[0];
222 if (defined($parent) && length($parent)) {
223 if ($parent eq '.') {
224 $parent = '/'.$action->namespace;
225 } elsif ($parent !~ m/^\//) {
226 if ($action->namespace) {
227 $parent = '/'.join('/', $action->namespace, $parent);
229 $parent = '/'.$parent; # special case namespace '' (root)
236 $action->attributes->{Chained} = [ $parent ];
238 my $children = ($self->{children_of}{$parent} ||= {});
240 my @path_part = @{ $action->attributes->{PathPart} || [] };
242 my $part = $action->name;
244 if (@path_part == 1 && defined $path_part[0]) {
245 $part = $path_part[0];
246 } elsif (@path_part > 1) {
247 Catalyst::Exception->throw(
248 "Multiple PathPart attributes not supported registering ${action}"
252 if ($part =~ m(^/)) {
253 Catalyst::Exception->throw(
254 "Absolute parameters to PathPart not allowed registering ${action}"
258 $action->attributes->{PartPath} = [ $part ];
260 unshift(@{ $children->{$part} ||= [] }, $action);
262 ($self->{actions} ||= {})->{'/'.$action->reverse} = $action;
264 unless ($action->attributes->{CaptureArgs}) {
265 unshift(@{ $self->{endpoints} ||= [] }, $action);
271 =head2 $self->uri_for_action($action, $captures)
273 Get the URI part for the action, using C<$captures> to fill
279 my ( $self, $action, $captures ) = @_;
281 return undef unless ($action->attributes->{Chained}
282 && !$action->attributes->{CaptureArgs});
285 my @captures = @$captures;
286 my $parent = "DUMMY";
289 if (my $cap = $curr->attributes->{CaptureArgs}) {
290 return undef unless @captures >= $cap->[0]; # not enough captures
292 unshift(@parts, splice(@captures, -$cap->[0]));
295 if (my $pp = $curr->attributes->{PartPath}) {
296 unshift(@parts, $pp->[0])
297 if (defined($pp->[0]) && length($pp->[0]));
299 $parent = $curr->attributes->{Chained}->[0];
300 $curr = $self->{actions}{$parent};
303 return undef unless $parent eq '/'; # fail for dangling action
305 return undef if @captures; # fail for too many captures
307 return join('/', '', @parts);
315 The C<Chained> attribute allows you to chain public path parts together
316 by their private names. A chain part's path can be specified with
317 C<PathPart> and can be declared to expect an arbitrary number of
318 arguments. The endpoint of the chain specifies how many arguments it
319 gets through the C<Args> attribute. C<:Args(0)> would be none at all,
320 C<:Args> without an integer would be unlimited. The path parts that
321 aren't endpoints are using C<CaptureArgs> to specify how many parameters
322 they expect to receive. As an example setup:
324 package MyApp::Controller::Greeting;
325 use base qw/ Catalyst::Controller /;
327 # this is the beginning of our chain
328 sub hello : PathPart('hello') Chained('/') CaptureArgs(1) {
329 my ( $self, $c, $integer ) = @_;
330 $c->stash->{ message } = "Hello ";
331 $c->stash->{ arg_sum } = $integer;
334 # this is our endpoint, because it has no :CaptureArgs
335 sub world : PathPart('world') Chained('hello') Args(1) {
336 my ( $self, $c, $integer ) = @_;
337 $c->stash->{ message } .= "World!";
338 $c->stash->{ arg_sum } += $integer;
340 $c->response->body( join "<br/>\n" =>
341 $c->stash->{ message }, $c->stash->{ arg_sum } );
344 The debug output provides a separate table for chained actions, showing
345 the whole chain as it would match and the actions it contains. Here's an
346 example of the startup output with our actions above:
349 [debug] Loaded Path Part actions:
350 .-----------------------+------------------------------.
351 | Path Spec | Private |
352 +-----------------------+------------------------------+
353 | /hello/*/world/* | /greeting/hello (1) |
354 | | => /greeting/world |
355 '-----------------------+------------------------------'
358 As you can see, Catalyst only deals with chains as whole paths and
359 builds one for each endpoint, which are the actions with C<:Chained> but
360 without C<:CaptureArgs>.
362 Let's assume this application gets a request at the path
363 C</hello/23/world/12>. What happens then? First, Catalyst will dispatch
364 to the C<hello> action and pass the value C<23> as an argument to it
365 after the context. It does so because we have previously used
366 C<:CaptureArgs(1)> to declare that it has one path part after itself as
367 its argument. We told Catalyst that this is the beginning of the chain
368 by specifying C<:Chained('/')>. Also note that instead of saying
369 C<:PathPart('hello')> we could also just have said C<:PathPart>, as it
370 defaults to the name of the action.
372 After C<hello> has run, Catalyst goes on to dispatch to the C<world>
373 action. This is the last action to be called: Catalyst knows this is an
374 endpoint because we did not specify a C<:CaptureArgs>
375 attribute. Nevertheless we specify that this action expects an argument,
376 but at this point we're using C<:Args(1)> to do that. We could also have
377 said C<:Args> or left it out altogether, which would mean this action
378 would get all arguments that are there. This action's C<:Chained>
379 attribute says C<hello> and tells Catalyst that the C<hello> action in
380 the current controller is its parent.
382 With this we have built a chain consisting of two public path parts.
383 C<hello> captures one part of the path as its argument, and also
384 specifies the path root as its parent. So this part is
385 C</hello/$arg>. The next part is the endpoint C<world>, expecting one
386 argument. It sums up to the path part C<world/$arg>. This leads to a
387 complete chain of C</hello/$arg/world/$arg> which is matched against the
390 This example application would, if run and called by e.g.
391 C</hello/23/world/12>, set the stash value C<message> to "Hello" and the
392 value C<arg_sum> to "23". The C<world> action would then append "World!"
393 to C<message> and add C<12> to the stash's C<arg_sum> value. For the
394 sake of simplicity no view is shown. Instead we just put the values of
395 the stash into our body. So the output would look like:
400 And our test server would have given us this debugging output for the
404 [debug] "GET" request for "hello/23/world/12" from "127.0.0.1"
405 [debug] Path is "/greeting/world"
406 [debug] Arguments are "12"
407 [info] Request took 0.164113s (6.093/s)
408 .------------------------------------------+-----------.
410 +------------------------------------------+-----------+
411 | /greeting/hello | 0.000029s |
412 | /greeting/world | 0.000024s |
413 '------------------------------------------+-----------'
416 What would be common uses of this dispatch technique? It gives the
417 possibility to split up logic that contains steps that each depend on
418 each other. An example would be, for example, a wiki path like
419 C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with
422 sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) {
423 my ( $self, $c, $page_name ) = @_;
424 # load the page named $page_name and put the object
428 sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) {
429 my ( $self, $c, $revision_id ) = @_;
430 # use the page object in the stash to get at its
431 # revision with number $revision_id
434 sub view : PathPart Chained('rev') Args(0) {
435 my ( $self, $c ) = @_;
436 # display the revision in our stash. Another option
437 # would be to forward a compatible object to the action
438 # that displays the default wiki pages, unless we want
439 # a different interface here, for example restore
443 It would now be possible to add other endpoints, for example C<restore>
444 to restore this specific revision as the current state.
446 You don't have to put all the chained actions in one controller. The
447 specification of the parent through C<:Chained> also takes an absolute
448 action path as its argument. Just specify it with a leading C</>.
450 If you want, for example, to have actions for the public paths
451 C</foo/12/edit> and C</foo/12>, just specify two actions with
452 C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former
453 path needs a C<:CaptureArgs(1)> attribute and a endpoint with
454 C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give
455 the action just a C<:Args(1)> to mark it as endpoint. This sums up to
456 this debugging output:
459 [debug] Loaded Path Part actions:
460 .-----------------------+------------------------------.
461 | Path Spec | Private |
462 +-----------------------+------------------------------+
463 | /foo/* | /controller/foo_view |
464 | /foo/*/edit | /controller/foo_load (1) |
465 | | => /controller/edit |
466 '-----------------------+------------------------------'
469 Here's a more detailed specification of the attributes belonging to
478 Sets the name of this part of the chain. If it is specified without
479 arguments, it takes the name of the action as default. So basically
480 C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical.
481 This can also contain slashes to bind to a deeper level. An action
482 with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to
483 C</foo/bar/...>. If you don't specify C<:PathPart> it has the same
484 effect as using C<:PathPart>, it would default to the action name.
488 Has to be specified for every child in the chain. Possible values are
489 absolute and relative private action paths, with the relatives pointing
490 to the current controller, or a single slash C</> to tell Catalyst that
491 this is the root of a chain. The attribute C<:Chained> without arguments
492 also defaults to the C</> behavior.
494 Because you can specify an absolute path to the parent action, it
495 doesn't matter to Catalyst where that parent is located. So, if your
496 design requests it, you can redispatch a chain through any controller or
499 Another interesting possibility gives C<:Chained('.')>, which chains
500 itself to an action with the path of the current controller's namespace.
503 # in MyApp::Controller::Foo
504 sub bar : Chained CaptureArgs(1) { ... }
506 # in MyApp::Controller::Foo::Bar
507 sub baz : Chained('.') Args(1) { ... }
509 This builds up a chain like C</bar/*/baz/*>. The specification of C<.>
510 as the argument to Chained here chains the C<baz> action to an action
511 with the path of the current controller namespace, namely
512 C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*>
513 chain comes out as the end product.
517 Must be specified for every part of the chain that is not an
518 endpoint. With this attribute Catalyst knows how many of the following
519 parts of the path (separated by C</>) this action wants to capture as
520 its arguments. If it doesn't expect any, just specify
521 C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right
522 after the context, but you can also find them as array references in
523 C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the
524 level of the action in the chain that captured the parts of the path.
526 An action that is part of a chain (that is, one that has a C<:Chained>
527 attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst
532 By default, endpoints receive the rest of the arguments in the path. You
533 can tell Catalyst through C<:Args> explicitly how many arguments your
534 endpoint expects, just like you can with C<:CaptureArgs>. Note that this
535 also affects whether this chain is invoked on a request. A chain with an
536 endpoint specifying one argument will only match if exactly one argument
539 You can specify an exact number of arguments like C<:Args(3)>, including
540 C<0>. If you just say C<:Args> without any arguments, it is the same as
541 leaving it out altogether: The chain is matched regardless of the number
542 of path parts after the endpoint.
544 Just as with C<:CaptureArgs>, the arguments get passed to the action in
545 C<@_> after the context object. They can also be reached through
546 C<$c-E<gt>request-E<gt>arguments>.
550 =head2 Auto actions, dispatching and forwarding
552 Note that the list of C<auto> actions called depends on the private path
553 of the endpoint of the chain, not on the chained actions way. The
554 C<auto> actions will be run before the chain dispatching begins. In
555 every other aspect, C<auto> actions behave as documented.
557 The C<forward>ing to other actions does just what you would expect. But if
558 you C<detach> out of a chain, the rest of the chain will not get called
563 Matt S Trout <mst@shadowcatsystems.co.uk>
567 This program is free software, you can redistribute it and/or modify it under
568 the same terms as Perl itself.