3 # Copyright 2009 Chris Cormack and The Koha Dev Team
4 # Parts copyright 2012-2013 C & P Bibliography Services
6 # This file is part of Koha.
8 # Koha is free software; you can redistribute it and/or modify it
9 # under the terms of the GNU General Public License as published by
10 # the Free Software Foundation; either version 3 of the License, or
11 # (at your option) any later version.
13 # Koha is distributed in the hope that it will be useful, but
14 # WITHOUT ANY WARRANTY; without even the implied warranty of
15 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 # GNU General Public License for more details.
18 # You should have received a copy of the GNU General Public License
19 # along with Koha; if not, see <http://www.gnu.org/licenses>.
23 Koha::Cache - Handling caching of html and Objects for Koha
28 my $cache = Koha::Cache->new({cache_type => $cache_type, %params});
32 Koha caching routines. This class provides two interfaces for cache access.
33 The first, traditional OO interface provides the following functions:
41 use Module::Load::Conditional qw(can_load);
42 use Koha::Cache::Object;
44 use base qw(Class::Accessor);
46 __PACKAGE__->mk_ro_accessors(
47 qw( cache memcached_cache fastmmap_cache memory_cache ));
51 my $cache = Koha::Cache->get_instance();
53 This gets a shared instance of the cache, set up in a very default way. This is
54 the recommended way to fetch a cache object. If possible, it'll be
55 persistent across multiple instances.
62 $singleton_cache = $class->new() unless $singleton_cache;
63 return $singleton_cache;
68 Create a new Koha::Cache object. This is required for all cache-related functionality.
73 my ( $class, $self ) = @_;
74 $self->{'default_type'} =
76 || $ENV{CACHING_SYSTEM}
79 $ENV{DEBUG} && carp "Default caching system: $self->{'default_type'}";
81 $self->{'timeout'} ||= 0;
82 $self->{'namespace'} ||= $ENV{MEMCACHED_NAMESPACE} || 'koha';
84 if ( $self->{'default_type'} eq 'memcached'
85 && can_load( modules => { 'Cache::Memcached::Fast' => undef } )
86 && _initialize_memcached($self)
87 && defined( $self->{'memcached_cache'} ) )
89 $self->{'cache'} = $self->{'memcached_cache'};
92 if ( $self->{'default_type'} eq 'fastmmap'
93 && defined( $ENV{GATEWAY_INTERFACE} )
94 && can_load( modules => { 'Cache::FastMmap' => undef } )
95 && _initialize_fastmmap($self)
96 && defined( $self->{'fastmmap_cache'} ) )
98 $self->{'cache'} = $self->{'fastmmap_cache'};
101 # Unless memcache or fastmmap has already been picked, use memory_cache
102 unless ( defined( $self->{'cache'} ) ) {
103 if ( can_load( modules => { 'Cache::Memory' => undef } )
104 && _initialize_memory($self) )
106 $self->{'cache'} = $self->{'memory_cache'};
110 $ENV{DEBUG} && carp "Selected caching system: " . ($self->{'cache'} // 'none');
117 sub _initialize_memcached {
120 split /,/, $self->{'cache_servers'}
121 ? $self->{'cache_servers'}
122 : ($ENV{MEMCACHED_SERVERS} || '');
126 && carp "Memcached server settings: "
127 . join( ', ', @servers )
129 . $self->{'namespace'};
130 # Cache::Memcached::Fast doesn't allow a default expire time to be set
131 # so we force it on setting.
132 my $memcached = Cache::Memcached::Fast->new(
134 servers => \@servers,
135 compress_threshold => 10_000,
136 namespace => $self->{'namespace'},
140 # Ensure we can actually talk to the memcached server
141 my $ismemcached = $memcached->set('ismemcached','1');
142 return $self unless $ismemcached;
143 $self->{'memcached_cache'} = $memcached;
147 sub _initialize_fastmmap {
149 my ($cache, $share_file);
151 # Temporary workaround to catch fatal errors when: C4::Context module
152 # is not loaded beforehand, or Cache::FastMmap init fails for whatever
153 # other reason (e.g. due to permission issues - see Bug 13431)
155 $share_file = join( '-',
156 "/tmp/sharefile-koha", $self->{'namespace'},
157 C4::Context->config('hostname'), C4::Context->config('database') );
159 $cache = Cache::FastMmap->new(
160 'share_file' => $share_file,
161 'expire_time' => $self->{'timeout'},
162 'unlink_on_exit' => 0,
166 warn "FastMmap cache initialization failed: $@";
169 return unless defined $cache;
170 $self->{'fastmmap_cache'} = $cache;
174 sub _initialize_memory {
177 # Default cache time for memory is _always_ short unless it's specially
178 # defined, to allow it to work reliably in a persistent environment.
179 my $cache = Cache::Memory->new(
180 'namespace' => $self->{'namespace'},
181 'default_expires' => "$self->{'timeout'} sec" || "10 sec",
183 $self->{'memory_cache'} = $cache;
184 # Memory cache can't handle complex types for some reason, so we use its
185 # freeze and thaw functions.
186 $self->{ref($cache) . '_set'} = sub {
187 my ($key, $val, $exp) = @_;
188 # Refer to set_expiry in Cache::Entry for why we do this 'sec' thing.
189 $exp = "$exp sec" if defined $exp;
190 # Because we need to use freeze, it must be a reference type.
191 $cache->freeze($key, [$val], $exp);
193 $self->{ref($cache) . '_get'} = sub {
194 my $res = $cache->thaw(shift);
195 return unless defined $res;
201 =head2 is_cache_active
203 Routine that checks whether or not a default caching method is active on this
208 sub is_cache_active {
210 return $self->{'cache'} ? 1 : 0;
215 $cache->set_in_cache($key, $value, [$options]);
217 Save a value to the specified key in the cache. A hashref of options may be
220 The possible options are:
226 Expiry time of this cached entry in seconds.
230 If set, this will perform a deep copy of the item when it's retrieved. This
231 means that it'll be safe if something later modifies the result of the
232 function. Will be ignored in situations where the same behaviour comes from
233 the caching layer anyway.
237 The cache object to use if you want to provide your own. It should be an
238 instance of C<Cache::*> and follow the same interface as L<Cache::Memcache>.
245 my ( $self, $key, $value, $options, $_cache) = @_;
246 # This is a bit of a hack to support the old API in case things still use it
247 if (defined $options && (ref($options) ne 'HASH')) {
249 $new_options->{expiry} = $options;
250 $new_options->{cache} = $_cache if defined $_cache;
251 $options = $new_options;
254 # the key mustn't contain whitespace (or control characters) for memcache
255 # but shouldn't be any harm in applying it globally.
256 $key =~ s/[\x00-\x20]/_/g;
258 my $cache = $options->{cache} || 'cache';
259 croak "No key" unless $key;
260 $ENV{DEBUG} && carp "set_in_cache for $key";
262 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
263 my $expiry = $options->{expiry};
264 $expiry //= $self->{timeout};
265 my $set_sub = $self->{ref($self->{$cache}) . "_set"};
266 # We consider an expiry of 0 to be inifinite
269 ? $set_sub->( $key, $value, $expiry )
270 : $self->{$cache}->set( $key, $value, $expiry );
274 ? $set_sub->( $key, $value )
275 : $self->{$cache}->set( $key, $value );
279 =head2 get_from_cache
281 my $value = $cache->get_from_cache($key);
283 Retrieve the value stored under the specified key in the default cache.
288 my ( $self, $key, $cache ) = @_;
289 $key =~ s/[\x00-\x20]/_/g;
291 croak "No key" unless $key;
292 $ENV{DEBUG} && carp "get_from_cache for $key";
293 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
294 my $get_sub = $self->{ref($self->{$cache}) . "_get"};
295 return $get_sub ? $get_sub->($key) : $self->{$cache}->get($key);
298 =head2 clear_from_cache
300 $cache->clear_from_cache($key);
302 Remove the value identified by the specified key from the default cache.
306 sub clear_from_cache {
307 my ( $self, $key, $cache ) = @_;
308 $key =~ s/[\x00-\x20]/_/g;
310 croak "No key" unless $key;
311 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
312 return $self->{$cache}->delete($key)
313 if ( ref( $self->{$cache} ) =~ m'^Cache::Memcached' );
314 return $self->{$cache}->remove($key);
321 Clear the entire default cache.
326 my ( $self, $cache ) = shift;
328 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
329 return $self->{$cache}->flush_all()
330 if ( ref( $self->{$cache} ) =~ m'^Cache::Memcached' );
331 return $self->{$cache}->clear();
334 =head1 TIED INTERFACE
336 Koha::Cache also provides a tied interface which enables users to provide a
337 constructor closure and (after creation) treat cached data like normal reference
338 variables and rely on the cache Just Working and getting updated when it
341 my $cache = Koha::Cache->new();
342 my $data = 'whatever';
343 my $scalar = Koha::Cache->create_scalar(
347 'constructor' => sub { return $data; },
350 print "$$scalar\n"; # Prints "whatever"
351 $data = 'somethingelse';
352 print "$$scalar\n"; # Prints "whatever" because it is cached
353 sleep 2; # Wait until the cache entry has expired
354 print "$$scalar\n"; # Prints "somethingelse"
356 my $hash = Koha::Cache->create_hash(
360 'constructor' => sub { return $data; },
363 print "$$variable\n"; # Prints "whatever"
365 The gotcha with this interface, of course, is that the variable returned by
366 create_scalar and create_hash is a I<reference> to a tied variable and not a
367 tied variable itself.
369 The tied variable is configured by means of a hashref passed in to the
370 create_scalar and create_hash methods. The following parameters are supported:
376 Required. The key to use for identifying the variable in the cache.
380 Required. A closure (or reference to a function) that will return the value that
381 needs to be stored in the cache.
385 Optional. A closure (or reference to a function) that gets run to initialize
386 the cache when creating the tied variable.
390 Optional. Array reference with the arguments that should be passed to the
391 constructor function.
395 Optional. The cache timeout in seconds for the variable. Defaults to 600
400 Optional. Which type of cache to use for the variable. Defaults to whatever is
401 set in the environment variable CACHING_SYSTEM. If set to 'null', disables
402 caching for the tied variable.
406 Optional. Boolean flag to allow the variable to be updated directly. When this
407 is set and the variable is used as an l-value, the cache will be updated
408 immediately with the new value. Using this is probably a bad idea on a
409 multi-threaded system. When I<allowupdate> is not set to true, using the
410 tied variable as an l-value will have no effect.
414 Optional. A closure (or reference to a function) that should be called when the
415 tied variable is destroyed.
419 Optional. Boolean flag to tell the object to remove the variable from the cache
420 when it is destroyed or goes out of scope.
424 Optional. Boolean flag to tell the object not to refresh the variable from the
425 cache every time the value is desired, but rather only when the I<local> copy
426 of the variable is older than the timeout.
432 my $scalar = Koha::Cache->create_scalar(\%params);
434 Create scalar tied to the cache.
439 my ( $self, $args ) = @_;
441 $self->_set_tied_defaults($args);
443 tie my $scalar, 'Koha::Cache::Object', $args;
448 my ( $self, $args ) = @_;
450 $self->_set_tied_defaults($args);
452 tie my %hash, 'Koha::Cache::Object', $args;
456 sub _set_tied_defaults {
457 my ( $self, $args ) = @_;
459 $args->{'timeout'} = '600' unless defined( $args->{'timeout'} );
460 $args->{'inprocess'} = '0' unless defined( $args->{'inprocess'} );
461 unless ( $args->{cache_type} and lc( $args->{cache_type} ) eq 'null' ) {
462 $args->{'cache'} = $self;
463 $args->{'cache_type'} ||= $ENV{'CACHING_SYSTEM'};
479 Chris Cormack, E<lt>chris@bigballofwax.co.nzE<gt>
480 Paul Poulain, E<lt>paul.poulain@biblibre.comE<gt>
481 Jared Camins-Esakov, E<lt>jcamins@cpbibliography.comE<gt>