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1 | package Catalyst::DispatchType::Chained; |
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2 | |
3 | use strict; |
4 | use base qw/Catalyst::DispatchType/; |
5 | use Text::SimpleTable; |
6 | use Catalyst::ActionChain; |
7 | use URI; |
8 | |
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9 | # please don't perltidy this. hairy code within. |
10 | |
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11 | =head1 NAME |
12 | |
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13 | Catalyst::DispatchType::Chained - Path Part DispatchType |
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14 | |
15 | =head1 SYNOPSIS |
16 | |
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17 | # root action - captures one argument after it |
18 | sub foo_setup : Chained('/') PathPart('foo') CaptureArgs(1) { |
19 | my ( $self, $c, $foo_arg ) = @_; |
20 | ... |
21 | } |
22 | |
23 | # child action endpoint - takes one argument |
24 | sub bar : Chained('foo_setup') Args(1) { |
25 | my ( $self, $c, $bar_arg ) = @_; |
26 | ... |
27 | } |
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28 | |
29 | =head1 DESCRIPTION |
30 | |
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31 | See L</USAGE>. |
32 | |
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33 | =head1 METHODS |
34 | |
35 | =head2 $self->list($c) |
36 | |
37 | Debug output for Path Part dispatch points |
38 | |
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39 | =cut |
40 | |
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41 | sub list { |
42 | my ( $self, $c ) = @_; |
43 | |
44 | return unless $self->{endpoints}; |
45 | |
46 | my $paths = Text::SimpleTable->new( |
47 | [ 35, 'Path Spec' ], [ 36, 'Private' ] |
48 | ); |
49 | |
50 | ENDPOINT: foreach my $endpoint ( |
51 | sort { $a->reverse cmp $b->reverse } |
52 | @{ $self->{endpoints} } |
53 | ) { |
54 | my $args = $endpoint->attributes->{Args}->[0]; |
55 | my @parts = (defined($args) ? (("*") x $args) : '...'); |
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56 | my @parents = (); |
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57 | my $parent = "DUMMY"; |
58 | my $curr = $endpoint; |
59 | while ($curr) { |
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60 | if (my $cap = $curr->attributes->{CaptureArgs}) { |
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61 | unshift(@parts, (("*") x $cap->[0])); |
62 | } |
63 | if (my $pp = $curr->attributes->{PartPath}) { |
64 | unshift(@parts, $pp->[0]) |
65 | if (defined $pp->[0] && length $pp->[0]); |
66 | } |
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67 | $parent = $curr->attributes->{Chained}->[0]; |
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68 | $curr = $self->{actions}{$parent}; |
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69 | unshift(@parents, $curr) if $curr; |
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70 | } |
71 | next ENDPOINT unless $parent eq '/'; # skip dangling action |
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72 | my @rows; |
73 | foreach my $p (@parents) { |
74 | my $name = "/${p}"; |
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75 | if (my $cap = $p->attributes->{CaptureArgs}) { |
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76 | $name .= ' ('.$cap->[0].')'; |
77 | } |
78 | unless ($p eq $parents[0]) { |
79 | $name = "-> ${name}"; |
80 | } |
81 | push(@rows, [ '', $name ]); |
82 | } |
83 | push(@rows, [ '', (@rows ? "=> " : '')."/${endpoint}" ]); |
84 | $rows[0][0] = join('/', '', @parts); |
85 | $paths->row(@$_) for @rows; |
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86 | } |
87 | |
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88 | $c->log->debug( "Loaded Chained actions:\n" . $paths->draw . "\n" ); |
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89 | } |
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90 | |
91 | =head2 $self->match( $c, $path ) |
92 | |
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93 | Calls C<recurse_match> to see if a chain matches the C<$path>. |
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94 | |
95 | =cut |
96 | |
97 | sub match { |
98 | my ( $self, $c, $path ) = @_; |
99 | |
100 | return 0 if @{$c->req->args}; |
101 | |
102 | my @parts = split('/', $path); |
103 | |
104 | my ($chain, $captures) = $self->recurse_match($c, '/', \@parts); |
105 | |
106 | return 0 unless $chain; |
107 | |
108 | my $action = Catalyst::ActionChain->from_chain($chain); |
109 | |
110 | $c->req->action("/${action}"); |
111 | $c->req->match("/${action}"); |
112 | $c->req->captures($captures); |
113 | $c->action($action); |
114 | $c->namespace( $action->namespace ); |
115 | |
116 | return 1; |
117 | } |
118 | |
119 | =head2 $self->recurse_match( $c, $parent, \@path_parts ) |
120 | |
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121 | Recursive search for a matching chain. |
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122 | |
123 | =cut |
124 | |
125 | sub recurse_match { |
126 | my ( $self, $c, $parent, $path_parts ) = @_; |
127 | my $children = $self->{children_of}{$parent}; |
128 | return () unless $children; |
129 | my @captures; |
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130 | TRY: foreach my $try_part (sort { length($b) <=> length($a) } |
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131 | keys %$children) { |
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132 | # $b then $a to try longest part first |
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133 | my @parts = @$path_parts; |
134 | if (length $try_part) { # test and strip PathPart |
135 | next TRY unless |
136 | ($try_part eq join('/', # assemble equal number of parts |
137 | splice( # and strip them off @parts as well |
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138 | @parts, 0, scalar(@{[split('/', $try_part)]}) |
139 | ))); # @{[]} to avoid split to @_ |
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140 | } |
141 | my @try_actions = @{$children->{$try_part}}; |
142 | TRY_ACTION: foreach my $action (@try_actions) { |
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143 | if (my $capture_attr = $action->attributes->{CaptureArgs}) { |
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144 | |
145 | # Short-circuit if not enough remaining parts |
146 | next TRY_ACTION unless @parts >= $capture_attr->[0]; |
147 | |
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148 | my @captures; |
149 | my @parts = @parts; # localise |
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150 | |
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151 | # strip CaptureArgs into list |
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152 | push(@captures, splice(@parts, 0, $capture_attr->[0])); |
153 | |
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154 | # try the remaining parts against children of this action |
155 | my ($actions, $captures) = $self->recurse_match( |
156 | $c, '/'.$action->reverse, \@parts |
157 | ); |
158 | if ($actions) { |
159 | return [ $action, @$actions ], [ @captures, @$captures ]; |
160 | } |
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161 | } else { |
162 | { |
163 | local $c->req->{arguments} = [ @{$c->req->args}, @parts ]; |
164 | next TRY_ACTION unless $action->match($c); |
165 | } |
166 | push(@{$c->req->args}, @parts); |
167 | return [ $action ], [ ]; |
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168 | } |
169 | } |
170 | } |
171 | return (); |
172 | } |
173 | |
174 | =head2 $self->register( $c, $action ) |
175 | |
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176 | Calls register_path for every Path attribute for the given $action. |
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177 | |
178 | =cut |
179 | |
180 | sub register { |
181 | my ( $self, $c, $action ) = @_; |
182 | |
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183 | my @chained_attr = @{ $action->attributes->{Chained} || [] }; |
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184 | |
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185 | return 0 unless @chained_attr; |
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186 | |
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187 | if (@chained_attr > 2) { |
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188 | Catalyst::Exception->throw( |
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189 | "Multiple Chained attributes not supported registering ${action}" |
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190 | ); |
191 | } |
192 | |
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193 | my $parent = $chained_attr[0]; |
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194 | |
195 | if (defined($parent) && length($parent)) { |
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196 | if ($parent eq '.') { |
197 | $parent = '/'.$action->namespace; |
198 | } elsif ($parent !~ m/^\//) { |
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199 | if ($action->namespace) { |
200 | $parent = '/'.join('/', $action->namespace, $parent); |
201 | } else { |
202 | $parent = '/'.$parent; # special case namespace '' (root) |
203 | } |
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204 | } |
205 | } else { |
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206 | $parent = '/' |
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207 | } |
208 | |
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209 | $action->attributes->{Chained} = [ $parent ]; |
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210 | |
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211 | my $children = ($self->{children_of}{$parent} ||= {}); |
212 | |
213 | my @path_part = @{ $action->attributes->{PathPart} || [] }; |
214 | |
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215 | my $part = $action->name; |
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216 | |
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217 | if (@path_part == 1 && defined $path_part[0]) { |
218 | $part = $path_part[0]; |
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219 | } elsif (@path_part > 1) { |
220 | Catalyst::Exception->throw( |
221 | "Multiple PathPart attributes not supported registering ${action}" |
222 | ); |
223 | } |
224 | |
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225 | if ($part =~ m(^/)) { |
226 | Catalyst::Exception->throw( |
227 | "Absolute parameters to PathPart not allowed registering ${action}" |
228 | ); |
229 | } |
230 | |
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231 | $action->attributes->{PartPath} = [ $part ]; |
232 | |
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233 | unshift(@{ $children->{$part} ||= [] }, $action); |
234 | |
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235 | ($self->{actions} ||= {})->{'/'.$action->reverse} = $action; |
236 | |
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237 | unless ($action->attributes->{CaptureArgs}) { |
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238 | unshift(@{ $self->{endpoints} ||= [] }, $action); |
239 | } |
240 | |
241 | return 1; |
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242 | } |
243 | |
244 | =head2 $self->uri_for_action($action, $captures) |
245 | |
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246 | Get the URI part for the action, using C<$captures> to fill |
247 | the capturing parts. |
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248 | |
249 | =cut |
250 | |
251 | sub uri_for_action { |
252 | my ( $self, $action, $captures ) = @_; |
253 | |
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254 | return undef unless ($action->attributes->{Chained} |
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255 | && !$action->attributes->{CaptureArgs}); |
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256 | |
257 | my @parts = (); |
258 | my @captures = @$captures; |
259 | my $parent = "DUMMY"; |
260 | my $curr = $action; |
261 | while ($curr) { |
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262 | if (my $cap = $curr->attributes->{CaptureArgs}) { |
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263 | return undef unless @captures >= $cap->[0]; # not enough captures |
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264 | if ($cap->[0]) { |
265 | unshift(@parts, splice(@captures, -$cap->[0])); |
266 | } |
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267 | } |
268 | if (my $pp = $curr->attributes->{PartPath}) { |
269 | unshift(@parts, $pp->[0]) |
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270 | if (defined($pp->[0]) && length($pp->[0])); |
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271 | } |
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272 | $parent = $curr->attributes->{Chained}->[0]; |
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273 | $curr = $self->{actions}{$parent}; |
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274 | } |
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275 | |
276 | return undef unless $parent eq '/'; # fail for dangling action |
277 | |
278 | return undef if @captures; # fail for too many captures |
279 | |
280 | return join('/', '', @parts); |
281 | |
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282 | } |
283 | |
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284 | =head1 USAGE |
285 | |
286 | =head2 Introduction |
287 | |
288 | The C<Chained> attribute allows you to chain public path parts together |
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289 | by their private names. A chain part's path can be specified with |
290 | C<PathPart> and can be declared to expect an arbitrary number of |
291 | arguments. The endpoint of the chain specifies how many arguments it |
292 | gets through the C<Args> attribute. C<:Args(0)> would be none at all, |
293 | C<:Args> without an integer would be unlimited. The path parts that |
294 | aren't endpoints are using C<CaptureArgs> to specify how many parameters |
295 | they expect to receive. As an example setup: |
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296 | |
297 | package MyApp::Controller::Greeting; |
298 | use base qw/ Catalyst::Controller /; |
299 | |
300 | # this is the beginning of our chain |
301 | sub hello : PathPart('hello') Chained('/') CaptureArgs(1) { |
302 | my ( $self, $c, $integer ) = @_; |
303 | $c->stash->{ message } = "Hello "; |
304 | $c->stash->{ arg_sum } = $integer; |
305 | } |
306 | |
307 | # this is our endpoint, because it has no :CaptureArgs |
308 | sub world : PathPart('world') Chained('hello') Args(1) { |
309 | my ( $self, $c, $integer ) = @_; |
310 | $c->stash->{ message } .= "World!"; |
311 | $c->stash->{ arg_sum } += $integer; |
312 | |
313 | $c->response->body( join "<br/>\n" => |
314 | $c->stash->{ message }, $c->stash->{ arg_sum } ); |
315 | } |
316 | |
317 | The debug output provides a separate table for chained actions, showing |
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318 | the whole chain as it would match and the actions it contains. Here's an |
319 | example of the startup output with our actions above: |
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320 | |
321 | ... |
322 | [debug] Loaded Path Part actions: |
323 | .-----------------------+------------------------------. |
324 | | Path Spec | Private | |
325 | +-----------------------+------------------------------+ |
326 | | /hello/*/world/* | /greeting/hello (1) | |
327 | | | => /greeting/world | |
328 | '-----------------------+------------------------------' |
329 | ... |
330 | |
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331 | As you can see, Catalyst only deals with chains as whole paths and |
332 | builds one for each endpoint, which are the actions with C<:Chained> but |
333 | without C<:CaptureArgs>. |
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334 | |
335 | Let's assume this application gets a request at the path |
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336 | C</hello/23/world/12>. What happens then? First, Catalyst will dispatch |
337 | to the C<hello> action and pass the value C<23> as an argument to it |
338 | after the context. It does so because we have previously used |
339 | C<:CaptureArgs(1)> to declare that it has one path part after itself as |
340 | its argument. We told Catalyst that this is the beginning of the chain |
341 | by specifying C<:Chained('/')>. Also note that instead of saying |
342 | C<:PathPart('hello')> we could also just have said C<:PathPart>, as it |
343 | defaults to the name of the action. |
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344 | |
345 | After C<hello> has run, Catalyst goes on to dispatch to the C<world> |
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346 | action. This is the last action to be called: Catalyst knows this is an |
347 | endpoint because we did not specify a C<:CaptureArgs> |
348 | attribute. Nevertheless we specify that this action expects an argument, |
349 | but at this point we're using C<:Args(1)> to do that. We could also have |
350 | said C<:Args> or left it out altogether, which would mean this action |
351 | would get all arguments that are there. This action's C<:Chained> |
352 | attribute says C<hello> and tells Catalyst that the C<hello> action in |
353 | the current controller is its parent. |
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354 | |
355 | With this we have built a chain consisting of two public path parts. |
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356 | C<hello> captures one part of the path as its argument, and also |
357 | specifies the path root as its parent. So this part is |
358 | C</hello/$arg>. The next part is the endpoint C<world>, expecting one |
359 | argument. It sums up to the path part C<world/$arg>. This leads to a |
360 | complete chain of C</hello/$arg/world/$arg> which is matched against the |
361 | requested paths. |
362 | |
363 | This example application would, if run and called by e.g. |
364 | C</hello/23/world/12>, set the stash value C<message> to "Hello" and the |
365 | value C<arg_sum> to "23". The C<world> action would then append "World!" |
366 | to C<message> and add C<12> to the stash's C<arg_sum> value. For the |
367 | sake of simplicity no view is shown. Instead we just put the values of |
368 | the stash into our body. So the output would look like: |
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369 | |
370 | Hello World! |
371 | 35 |
372 | |
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373 | And our test server would have given us this debugging output for the |
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374 | request: |
375 | |
376 | ... |
377 | [debug] "GET" request for "hello/23/world/12" from "127.0.0.1" |
378 | [debug] Path is "/greeting/world" |
379 | [debug] Arguments are "12" |
380 | [info] Request took 0.164113s (6.093/s) |
381 | .------------------------------------------+-----------. |
382 | | Action | Time | |
383 | +------------------------------------------+-----------+ |
384 | | /greeting/hello | 0.000029s | |
385 | | /greeting/world | 0.000024s | |
386 | '------------------------------------------+-----------' |
387 | ... |
388 | |
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389 | What would be common uses of this dispatch technique? It gives the |
390 | possibility to split up logic that contains steps that each depend on |
391 | each other. An example would be, for example, a wiki path like |
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392 | C</wiki/FooBarPage/rev/23/view>. This chain can be easily built with |
393 | these actions: |
394 | |
395 | sub wiki : PathPart('wiki') Chained('/') CaptureArgs(1) { |
396 | my ( $self, $c, $page_name ) = @_; |
397 | # load the page named $page_name and put the object |
398 | # into the stash |
399 | } |
400 | |
401 | sub rev : PathPart('rev') Chained('wiki') CaptureArgs(1) { |
402 | my ( $self, $c, $revision_id ) = @_; |
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403 | # use the page object in the stash to get at its |
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404 | # revision with number $revision_id |
405 | } |
406 | |
407 | sub view : PathPart Chained('rev') Args(0) { |
408 | my ( $self, $c ) = @_; |
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409 | # display the revision in our stash. Another option |
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410 | # would be to forward a compatible object to the action |
411 | # that displays the default wiki pages, unless we want |
412 | # a different interface here, for example restore |
413 | # functionality. |
414 | } |
415 | |
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416 | It would now be possible to add other endpoints, for example C<restore> |
417 | to restore this specific revision as the current state. |
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418 | |
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419 | You don't have to put all the chained actions in one controller. The |
420 | specification of the parent through C<:Chained> also takes an absolute |
421 | action path as its argument. Just specify it with a leading C</>. |
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422 | |
423 | If you want, for example, to have actions for the public paths |
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424 | C</foo/12/edit> and C</foo/12>, just specify two actions with |
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425 | C<:PathPart('foo')> and C<:Chained('/')>. The handler for the former |
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426 | path needs a C<:CaptureArgs(1)> attribute and a endpoint with |
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427 | C<:PathPart('edit')> and C<:Chained('foo')>. For the latter path give |
428 | the action just a C<:Args(1)> to mark it as endpoint. This sums up to |
429 | this debugging output: |
430 | |
431 | ... |
432 | [debug] Loaded Path Part actions: |
433 | .-----------------------+------------------------------. |
434 | | Path Spec | Private | |
435 | +-----------------------+------------------------------+ |
436 | | /foo/* | /controller/foo_view | |
437 | | /foo/*/edit | /controller/foo_load (1) | |
438 | | | => /controller/edit | |
439 | '-----------------------+------------------------------' |
440 | ... |
441 | |
442 | Here's a more detailed specification of the attributes belonging to |
443 | C<:Chained>: |
444 | |
445 | =head2 Attributes |
446 | |
447 | =over 8 |
448 | |
449 | =item PathPart |
450 | |
451 | Sets the name of this part of the chain. If it is specified without |
452 | arguments, it takes the name of the action as default. So basically |
453 | C<sub foo :PathPart> and C<sub foo :PathPart('foo')> are identical. |
454 | This can also contain slashes to bind to a deeper level. An action |
455 | with C<sub bar :PathPart('foo/bar') :Chained('/')> would bind to |
456 | C</foo/bar/...>. If you don't specify C<:PathPart> it has the same |
457 | effect as using C<:PathPart>, it would default to the action name. |
458 | |
459 | =item Chained |
460 | |
461 | Has to be specified for every child in the chain. Possible values are |
462 | absolute and relative private action paths, with the relatives pointing |
463 | to the current controller, or a single slash C</> to tell Catalyst that |
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464 | this is the root of a chain. The attribute C<:Chained> without arguments |
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465 | also defaults to the C</> behavior. |
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466 | |
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467 | Because you can specify an absolute path to the parent action, it |
468 | doesn't matter to Catalyst where that parent is located. So, if your |
469 | design requests it, you can redispatch a chain through any controller or |
470 | namespace you want. |
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471 | |
472 | Another interesting possibility gives C<:Chained('.')>, which chains |
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473 | itself to an action with the path of the current controller's namespace. |
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474 | For example: |
475 | |
476 | # in MyApp::Controller::Foo |
477 | sub bar : Chained CaptureArgs(1) { ... } |
478 | |
479 | # in MyApp::Controller::Foo::Bar |
480 | sub baz : Chained('.') Args(1) { ... } |
481 | |
482 | This builds up a chain like C</bar/*/baz/*>. The specification of C<.> |
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483 | as the argument to Chained here chains the C<baz> action to an action |
484 | with the path of the current controller namespace, namely |
485 | C</foo/bar>. That action chains directly to C</>, so the C</bar/*/baz/*> |
486 | chain comes out as the end product. |
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487 | |
488 | =item CaptureArgs |
489 | |
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490 | Must be specified for every part of the chain that is not an |
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491 | endpoint. With this attribute Catalyst knows how many of the following |
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492 | parts of the path (separated by C</>) this action wants to capture as |
493 | its arguments. If it doesn't expect any, just specify |
494 | C<:CaptureArgs(0)>. The captures get passed to the action's C<@_> right |
495 | after the context, but you can also find them as array references in |
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496 | C<$c-E<gt>request-E<gt>captures-E<gt>[$level]>. The C<$level> is the |
497 | level of the action in the chain that captured the parts of the path. |
498 | |
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499 | An action that is part of a chain (that is, one that has a C<:Chained> |
500 | attribute) but has no C<:CaptureArgs> attribute is treated by Catalyst |
501 | as a chain end. |
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502 | |
503 | =item Args |
504 | |
505 | By default, endpoints receive the rest of the arguments in the path. You |
506 | can tell Catalyst through C<:Args> explicitly how many arguments your |
507 | endpoint expects, just like you can with C<:CaptureArgs>. Note that this |
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508 | also affects whether this chain is invoked on a request. A chain with an |
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509 | endpoint specifying one argument will only match if exactly one argument |
510 | exists in the path. |
511 | |
512 | You can specify an exact number of arguments like C<:Args(3)>, including |
513 | C<0>. If you just say C<:Args> without any arguments, it is the same as |
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514 | leaving it out altogether: The chain is matched regardless of the number |
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515 | of path parts after the endpoint. |
516 | |
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517 | Just as with C<:CaptureArgs>, the arguments get passed to the action in |
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518 | C<@_> after the context object. They can also be reached through |
519 | C<$c-E<gt>request-E<gt>arguments>. |
520 | |
521 | =back |
522 | |
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523 | =head2 Auto actions, dispatching and forwarding |
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524 | |
525 | Note that the list of C<auto> actions called depends on the private path |
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526 | of the endpoint of the chain, not on the chained actions way. The |
527 | C<auto> actions will be run before the chain dispatching begins. In |
528 | every other aspect, C<auto> actions behave as documented. |
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529 | |
530 | The C<forward>ing to other actions does just what you would expect. But if |
531 | you C<detach> out of a chain, the rest of the chain will not get called |
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532 | after the C<detach>. |
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533 | |
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534 | =head1 AUTHOR |
535 | |
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536 | Matt S Trout <mst@shadowcatsystems.co.uk> |
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537 | |
538 | =head1 COPYRIGHT |
539 | |
540 | This program is free software, you can redistribute it and/or modify it under |
541 | the same terms as Perl itself. |
542 | |
543 | =cut |
544 | |
545 | 1; |