3 package Catalyst::Plugin::Cache;
4 use base qw(Class::Accessor::Fast Class::Data::Inheritable);
12 use Catalyst::Utils ();
16 use Catalyst::Plugin::Cache::Curried;
18 __PACKAGE__->mk_classdata( "_cache_backends" );
19 __PACKAGE__->mk_accessors( "_default_curried_cache" );
24 # set it once per app, not once per plugin,
25 # and don't overwrite if some plugin was wicked
26 $app->_cache_backends({}) unless $app->_cache_backends;
28 my $ret = $app->maybe::next::method( @_ );
30 $app->setup_cache_backends;
36 sub _get_cache_plugin_config {
38 my $config = $app->config->{'Plugin::Cache'};
40 $config = $app->config->{cache};
41 my $appname = ref($app);
42 if (! $has_warned_for{$appname}++ ) {
43 $app->log->warn($config ?
44 'Catalyst::Plugin::Cache config found in deprecated $c->config->{cache}, please move to $c->config->{"Plugin::Cache"}.'
45 : 'Catalyst::Plugin::Cache config not found, using empty config!'
53 sub get_default_cache_backend_config {
54 my ( $app, $name ) = @_;
55 $app->_get_cache_plugin_config->{backend} || $app->get_cache_backend_config("default");
58 sub get_cache_backend_config {
59 my ( $app, $name ) = @_;
60 $app->_get_cache_plugin_config->{backends}{$name};
63 sub setup_cache_backends {
66 # give plugins a chance to find things for themselves
67 $app->maybe::next::method;
69 # FIXME - Don't know why the _get_cache_plugin_config method doesn't work here!
70 my $conf = $app->_get_cache_plugin_config->{backends};
71 foreach my $name ( keys %$conf ) {
72 next if $app->get_cache_backend( $name );
73 $app->setup_generic_cache_backend( $name, $app->get_cache_backend_config( $name ) || {} );
76 if ( !$app->get_cache_backend("default") ) {
77 ### XXX currently we dont have a fallback scenario
78 ### so die here with the error message. Once we have
79 ### an in memory fallback, we may consider silently
80 ### logging the error and falling back to that.
81 ### If we dont die here, the app will silently start
82 ### up and then explode at the first cache->get or
83 ### cache->set request with a FIXME error
86 $app->setup_generic_cache_backend( default => $app->get_default_cache_backend_config || {} );
92 sub default_cache_store {
94 $app->_get_cache_plugin_config->{default_store} || $app->guess_default_cache_store;
97 sub guess_default_cache_store {
100 my @stores = map { /Cache::Store::(.*)$/ ? $1 : () } $app->registered_plugins;
102 if ( @stores == 1 ) {
105 Carp::croak "You must configure a default store type unless you use exactly one store plugin.";
109 sub setup_generic_cache_backend {
110 my ( $app, $name, $config ) = @_;
111 my %config = %$config;
113 if ( my $class = delete $config{class} ) {
115 ### try as list and as hashref, collect the
116 ### error if things go wrong
117 ### if all goes well, exit the loop
119 for my $aref ( [%config], [\%config] ) {
120 eval { $app->setup_cache_backend_by_class(
121 $name, $class, @$aref
123 } ? do { @errors = (); last }
124 : push @errors, "\t$@";
127 ### and die with the errors if we have any
128 die "Couldn't construct $class with either list style or hash ref style param passing:\n @errors" if @errors;
130 } elsif ( my $store = delete $config->{store} || $app->default_cache_store ) {
131 my $method = lc("setup_${store}_cache_backend");
133 Carp::croak "You must load the $store cache store plugin (if it exists). ".
134 "Please consult the Catalyst::Plugin::Cache documentation on how to configure hetrogeneous stores."
135 unless $app->can($method);
137 $app->$method( $name, \%config );
139 $app->log->warn("Couldn't setup the cache backend named '$name'");
143 sub setup_cache_backend_by_class {
144 my ( $app, $name, $class, @args ) = @_;
145 Catalyst::Utils::ensure_class_loaded( $class );
146 $app->register_cache_backend( $name => $class->new( @args ) );
149 # end of spaghetti setup DWIM
152 my ( $c, @meta ) = @_;
156 return ( $c->get_preset_curried($name) || $c->get_cache_backend($name) );
158 # be nice and always return the same one for the simplest case
159 return ( $c->_default_curried_cache || $c->_default_curried_cache( $c->curry_cache( @meta ) ) );
161 return $c->curry_cache( @meta );
165 sub construct_curried_cache {
166 my ( $c, @meta ) = @_;
167 return $c->curried_cache_class( @meta )->new( @meta );
170 sub curried_cache_class {
171 my ( $c, @meta ) = @_;
172 $c->_get_cache_plugin_config->{curried_class} || "Catalyst::Plugin::Cache::Curried";
176 my ( $c, @meta ) = @_;
177 return $c->construct_curried_cache( $c, $c->_cache_caller_meta, @meta );
180 sub get_preset_curried {
181 my ( $c, $name ) = @_;
183 if ( ref( my $preset = $c->_get_cache_plugin_config->{profiles}{$name} ) ) {
184 return $preset if Scalar::Util::blessed($preset);
186 my @meta = ( ( ref $preset eq "HASH" ) ? %$preset : @$preset );
187 return $c->curry_cache( @meta );
193 sub get_cache_backend {
194 my ( $c, $name ) = @_;
195 $c->_cache_backends->{$name};
198 sub register_cache_backend {
199 my ( $c, $name, $backend ) = @_;
201 no warnings 'uninitialized';
202 Carp::croak("$backend does not look like a cache backend - "
203 . "it must be an object supporting get, set and remove")
204 unless eval { $backend->can("get") && $backend->can("set") && $backend->can("remove") };
206 $c->_cache_backends->{$name} = $backend;
209 sub unregister_cache_backend {
210 my ( $c, $name ) = @_;
211 delete $c->_cache_backends->{$name};
214 sub default_cache_backend {
216 $c->get_cache_backend( "default" ) || $c->temporary_cache_backend;
219 sub temporary_cache_backend {
221 die "FIXME - make up an in memory cache backend, that hopefully works well for the current engine";
224 sub _cache_caller_meta {
227 my ( $caller, $component, $controller );
229 for my $i ( 0 .. 15 ) { # don't look to far
230 my @info = caller(2 + $i) or last;
232 $caller ||= \@info unless $info[0] =~ /Plugin::Cache/;
233 $component ||= \@info if $info[0]->isa("Catalyst::Component");
234 $controller ||= \@info if $info[0]->isa("Catalyst::Controller");
236 last if $caller && $component && $controller;
239 my ( $caller_pkg, $component_pkg, $controller_pkg ) =
240 map { $_ ? $_->[0] : undef } $caller, $component, $controller;
243 'caller' => $caller_pkg,
244 component => $component_pkg,
245 controller => $controller_pkg,
246 caller_frame => $caller,
247 component_frame => $component,
248 controller_frame => $controller,
252 # this gets a shit name so that the plugins can override a good name
253 sub choose_cache_backend_wrapper {
254 my ( $c, @meta ) = @_;
256 Carp::croak("metadata must be an even sized list") unless @meta % 2 == 0;
260 unless ( exists $meta{'caller'} ) {
261 my %caller = $c->_cache_caller_meta;
262 @meta{keys %caller} = values %caller;
265 # allow the cache client to specify who it wants to cache with (but loeave room for a hook)
266 if ( exists $meta{backend} ) {
267 if ( Scalar::Util::blessed($meta{backend}) ) {
268 return $meta{backend};
270 return $c->get_cache_backend( $meta{backend} ) || $c->default_cache_backend;
274 if ( my $chosen = $c->choose_cache_backend( %meta ) ) {
275 $chosen = $c->get_cache_backend( $chosen ) unless Scalar::Util::blessed($chosen); # if it's a name find it
276 return $chosen if Scalar::Util::blessed($chosen); # only return if it was an object or name lookup worked
279 # die "no such backend"?
280 # currently, we fall back to default
283 return $c->default_cache_backend;
286 sub choose_cache_backend { shift->maybe::next::method( @_ ) } # a convenient fallback
289 my ( $c, $key, $value, %meta ) = @_;
290 $c->choose_cache_backend_wrapper( key => $key, value => $value, %meta )
291 ->set( $key, $value, exists $meta{expires} ? $meta{expires} : () );
295 my ( $c, $key, @meta ) = @_;
296 $c->choose_cache_backend_wrapper( key => $key, @meta )->get( $key );
300 my ( $c, $key, @meta ) = @_;
301 $c->choose_cache_backend_wrapper( key => $key, @meta )->remove( $key );
312 Catalyst::Plugin::Cache - Flexible caching support for Catalyst.
320 # configure a backend or use a store plugin
321 __PACKAGE__->config->{'Plugin::Cache'}{backend} = {
322 class => "Cache::Bounded",
323 # ... params for Cache::Bounded...
326 # typical example for Cache::Memcached::libmemcached
327 __PACKAGE__->config->{'Plugin::Cache'}{backend} = {
328 class => "Cache::Memcached::libmemcached",
329 servers => ['127.0.0.1:11211'],
337 my ( $self, $c, $id ) = @_;
339 my $cache = $c->cache;
343 unless ( $result = $cache->get( $id ) ) {
344 # ... calculate result ...
345 $c->cache->set( $id, $result );
351 This plugin gives you access to a variety of systems for caching
352 data. It allows you to use a very simple configuration API, while
353 maintaining the possibility of flexibility when you need it later.
355 Among its features are support for multiple backends, segmentation based
356 on component or controller, keyspace partitioning, and so more, in
357 various subsidiary plugins.
363 =item cache $profile_name
367 Return a curried object with metadata from C<$profile_name> or as
368 explicitly specified.
370 If a profile by the name C<$profile_name> doesn't exist, but a backend
371 object by that name does exist, the backend will be returned instead,
372 since the interface for curried caches and backends is almost identical.
374 This method can also be called without arguments, in which case is
375 treated as though the C<%meta> hash was empty.
377 See L</METADATA> for details.
379 =item curry_cache %meta
381 Return a L<Catalyst::Plugin::Cache::Curried> object, curried with C<%meta>.
383 See L</METADATA> for details.
385 =item cache_set $key, $value, %meta
387 =item cache_get $key, %meta
389 =item cache_remove $key, %meta
391 These cache operations will call L<choose_cache_backend> with %meta, and
392 then call C<set>, C<get>, or C<remove> on the resulting backend object.
394 =item choose_cache_backend %meta
396 Select a backend object. This should return undef if no specific backend
397 was selected - its caller will handle getting C<default_cache_backend>
400 This method is typically used by plugins.
402 =item get_cache_backend $name
404 Get a backend object by name.
406 =item default_cache_backend
408 Return the default backend object.
410 =item temporary_cache_backend
412 When no default cache backend is configured this method might return a
413 backend known to work well with the current L<Catalyst::Engine>. This is
424 Whenever you set or retrieve a key you may specify additional metadata
425 that will be used to select a specific backend.
427 This metadata is very freeform, and the only key that has any meaning by
428 default is the C<backend> key which can be used to explicitly choose a backend
431 The C<choose_cache_backend> method can be overridden in order to
432 facilitate more intelligent backend selection. For example,
433 L<Catalyst::Plugin::Cache::Choose::KeyRegexes> overrides that method to
434 select a backend based on key regexes.
436 Another example is a L<Catalyst::Plugin::Cache::ControllerNamespacing>,
437 which wraps backends in objects that perform key mangling, in order to
438 keep caches namespaced per controller.
440 However, this is generally left as a hook for larger, more complex
441 applications. Most configurations should make due XXXX
443 The simplest way to dynamically select a backend is based on the
444 L</Cache Profiles> configuration.
446 =head2 Meta Data Keys
448 C<choose_cache_backend> is called with some default keys.
454 Supplied by C<cache_get>, C<cache_set>, and C<cache_remove>.
458 Supplied by C<cache_set>.
462 The package name of the innermost caller that doesn't match
463 C<qr/Plugin::Cache/>.
467 The entire C<caller($i)> frame of C<caller>.
471 The package name of the innermost caller who C<isa>
472 L<Catalyst::Component>.
474 =item component_frame
476 This entire C<caller($i)> frame of C<component>.
480 The package name of the innermost caller who C<isa>
481 L<Catalyst::Controller>.
483 =item controller_frame
485 This entire C<caller($i)> frame of C<controller>.
489 =head2 Metadata Currying
491 In order to avoid specifying C<%meta> over and over again you may call
492 C<cache> or C<curry_cache> with C<%meta> once, and get back a B<curried
493 cache object>. This object responds to the methods C<get>, C<set>, and
494 C<remove>, by appending its captured metadata and delegating them to
495 C<cache_get>, C<cache_set>, and C<cache_remove>.
497 This is simpler than it sounds.
499 Here is an example using currying:
501 my $cache = $c->cache( %meta ); # cache is curried
503 $cache->set( $key, $value );
507 And here is an example without using currying:
509 $c->cache_set( $key, $value, %meta );
511 $c->cache_get( $key, %meta );
513 See L<Catalyst::Plugin::Cache::Curried> for details.
517 $c->config->{'Plugin::Cache'} = {
521 All configuration parameters should be provided in a hash reference
522 under the C<Plugin::Cache> key in the C<config> hash.
524 =head2 Backend Configuration
526 Configuring backend objects is done by adding hash entries under the
527 C<backends> key in the main config.
529 A special case is that the hash key under the C<backend> (singular) key
530 of the main config is assumed to be the backend named C<default>.
536 Instantiate a backend from a L<Cache> compatible class. E.g.
538 $c->config->{'Plugin::Cache'}{backends}{small_things} = {
539 class => "Cache::Bounded",
544 $c->config->{'Plugin::Cache'}{backends}{large_things} = {
545 class => "Cache::Memcached",
546 data => '1.2.3.4:1234',
549 The options in the hash are passed to the class's C<new> method.
551 The class will be C<required> as necessary during setup time.
555 Instantiate a backend using a store plugin, e.g.
557 $c->config->{'Plugin::Cache'}{backend} = {
561 Store plugins typically require less configuration because they are
562 specialized for L<Catalyst> applications. For example
563 L<Catalyst::Plugin::Cache::Store::FastMmap> will specify a default
564 C<share_file>, and additionally use a subclass of L<Cache::FastMmap>
565 that can also store non reference data.
567 The store plugin must be loaded.
571 =head2 Cache Profiles
577 Supply your own predefined profiles for cache metadata, when using the
580 For example when you specify
582 $c->config->{'Plugin::Cache'}{profiles}{thumbnails} = {
583 backend => "large_things",
586 And then get a cache object like this:
588 $c->cache("thumbnails");
590 It is the same as if you had done:
592 $c->cache( backend => "large_things" );
596 =head2 Miscellaneous Configuration
602 When you do not specify a C<store> parameter in the backend
603 configuration this one will be used instead. This configuration
604 parameter is not necessary if only one store plugin is loaded.
614 An object that responds to the methods detailed in
615 L<Catalyst::Plugin::Cache::Backend> (or more).
619 A plugin that provides backends of a certain type. This is a bit like a
624 Stored key/value pairs of data for easy re-access.
628 "Extra" information about the item being stored, which can be used to
629 locate an appropriate backend.
633 my $cache = $c->cache(type => 'thumbnails');
634 $cache->set('pic01', $thumbnaildata);
636 A cache which has been pre-configured with a particular set of
637 namespacing data. In the example the cache returned could be one
638 specifically tuned for storing thumbnails.
640 An object that responds to C<get>, C<set>, and C<remove>, and will
641 automatically add metadata to calls to C<< $c->cache_get >>, etc.
647 L<Cache> - the generic cache API on CPAN.
649 L<Catalyst::Plugin::Cache::Store> - how to write a store plugin.
651 L<Catalyst::Plugin::Cache::Curried> - the interface for curried caches.
653 L<Catalyst::Plugin::Cache::Choose::KeyRegexes> - choose a backend based on
654 regex matching on the keys. Can be used to partition the keyspace.
656 L<Catalyst::Plugin::Cache::ControllerNamespacing> - wrap backend objects in a
657 name mangler so that every controller gets its own keyspace.
661 Yuval Kogman, C<nothingmuch@woobling.org>
663 Jos Boumans, C<kane@cpan.org>
665 =head1 COPYRIGHT & LICENSE
667 Copyright (c) Yuval Kogman, 2006. All rights reserved.
669 This library is free software, you can redistribute it and/or modify it under
670 the same terms as Perl itself, as well as under the terms of the MIT license.