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;
46 use base qw(Class::Accessor);
48 __PACKAGE__->mk_ro_accessors(
49 qw( cache memcached_cache fastmmap_cache memory_cache ));
52 our $L1_encoder = Sereal::Encoder->new;
53 our $L1_decoder = Sereal::Decoder->new;
57 my $cache = Koha::Caches->get_instance();
59 This gets a shared instance of the cache, set up in a very default way. This is
60 the recommended way to fetch a cache object. If possible, it'll be
61 persistent across multiple instances.
67 Create a new Koha::Cache object. This is required for all cache-related functionality.
72 my ( $class, $self, $subnamespace ) = @_;
73 $self->{'default_type'} =
75 || $ENV{CACHING_SYSTEM}
78 $ENV{DEBUG} && carp "Default caching system: $self->{'default_type'}";
80 $self->{'timeout'} ||= 0;
81 $self->{'namespace'} ||= $ENV{MEMCACHED_NAMESPACE} || 'koha';
82 $self->{namespace} .= ":$subnamespace:";
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 The cache object to use if you want to provide your own. It should be an
231 instance of C<Cache::*> and follow the same interface as L<Cache::Memcache>.
238 my ( $self, $key, $value, $options, $_cache) = @_;
239 # This is a bit of a hack to support the old API in case things still use it
240 if (defined $options && (ref($options) ne 'HASH')) {
242 $new_options->{expiry} = $options;
243 $new_options->{cache} = $_cache if defined $_cache;
244 $options = $new_options;
247 # the key mustn't contain whitespace (or control characters) for memcache
248 # but shouldn't be any harm in applying it globally.
249 $key =~ s/[\x00-\x20]/_/g;
251 my $cache = $options->{cache} || 'cache';
252 croak "No key" unless $key;
253 $ENV{DEBUG} && carp "set_in_cache for $key";
255 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
256 my $expiry = $options->{expiry};
257 $expiry //= $self->{timeout};
258 my $set_sub = $self->{ref($self->{$cache}) . "_set"};
260 my $flag = '-CF0'; # 0: scalar, 1: frozen data structure
262 # Set in L1 cache as a data structure, initially only in frozen form (for performance reasons)
263 $value = $L1_encoder->encode($value);
264 $L1_cache{$self->{namespace}}{$key}->{frozen} = $value;
267 # Set in L1 cache as a scalar; exit if we are caching an undef
268 $L1_cache{$self->{namespace}}{$key} = $value;
269 return if !defined $value;
273 # We consider an expiry of 0 to be inifinite
276 ? $set_sub->( $key, $value, $expiry )
277 : $self->{$cache}->set( $key, $value, $expiry );
281 ? $set_sub->( $key, $value )
282 : $self->{$cache}->set( $key, $value );
286 =head2 get_from_cache
288 my $value = $cache->get_from_cache($key, [ $options ]);
290 Retrieve the value stored under the specified key in the cache.
292 The possible options are:
298 If set, this will avoid performing a deep copy of the item. This
299 means that it won't be safe if something later modifies the result of the
300 function. It should be used with caution, and could save processing time
301 in some situations where is safe to use it. Make sure you know what you are doing!
305 The cache object to use if you want to provide your own. It should be an
306 instance of C<Cache::*> and follow the same interface as L<Cache::Memcache>.
313 my ( $self, $key, $options ) = @_;
314 my $cache = $options->{cache} || 'cache';
315 my $unsafe = $options->{unsafe} || 0;
316 $key =~ s/[\x00-\x20]/_/g;
317 croak "No key" unless $key;
318 $ENV{DEBUG} && carp "get_from_cache for $key";
319 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
321 # Return L1 cache value if exists
322 if ( exists $L1_cache{$self->{namespace}}{$key} ) {
323 if (ref($L1_cache{$self->{namespace}}{$key})) {
325 $L1_cache{$self->{namespace}}{$key}->{thawed} ||= $L1_decoder->decode($L1_cache{$self->{namespace}}{key}->{frozen});
326 return $L1_cache{$self->{namespace}}{$key}->{thawed};
328 return $L1_decoder->decode($L1_cache{$self->{namespace}}{$key}->{frozen});
331 # No need to thaw if it's a scalar
332 return $L1_cache{$self->{namespace}}{$key};
336 my $get_sub = $self->{ref($self->{$cache}) . "_get"};
337 my $L2_value = $get_sub ? $get_sub->($key) : $self->{$cache}->get($key);
339 return if ref($L2_value);
340 return unless (defined($L2_value) && length($L2_value) >= 4);
342 my $flag = substr($L2_value, -4, 4, '');
343 if ($flag eq '-CF0') {
345 $L1_cache{$self->{namespace}}{$key} = $L2_value;
347 } elsif ($flag eq '-CF1') {
348 # it's a frozen data structure
350 eval { $thawed = $L1_decoder->decode($L2_value); };
352 $L1_cache{$self->{namespace}}{$key}->{frozen} = $L2_value;
353 $L1_cache{$self->{namespace}}{$key}->{thawed} = $thawed if $unsafe;
357 # Unknown value / data type returned from L2 cache
361 =head2 clear_from_cache
363 $cache->clear_from_cache($key);
365 Remove the value identified by the specified key from the default cache.
369 sub clear_from_cache {
370 my ( $self, $key, $cache ) = @_;
371 $key =~ s/[\x00-\x20]/_/g;
373 croak "No key" unless $key;
374 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
376 # Clear from L1 cache
377 delete $L1_cache{$self->{namespace}}{$key};
379 return $self->{$cache}->delete($key)
380 if ( ref( $self->{$cache} ) =~ m'^Cache::Memcached' );
381 return $self->{$cache}->remove($key);
388 Clear the entire default cache.
393 my ( $self, $cache ) = shift;
395 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
397 $self->flush_L1_cache();
399 return $self->{$cache}->flush_all()
400 if ( ref( $self->{$cache} ) =~ m'^Cache::Memcached' );
401 return $self->{$cache}->clear();
406 $L1_cache{$self->{namespace}} = ();
409 =head1 TIED INTERFACE
411 Koha::Cache also provides a tied interface which enables users to provide a
412 constructor closure and (after creation) treat cached data like normal reference
413 variables and rely on the cache Just Working and getting updated when it
416 my $cache = Koha::Cache->new();
417 my $data = 'whatever';
418 my $scalar = Koha::Cache->create_scalar(
422 'constructor' => sub { return $data; },
425 print "$$scalar\n"; # Prints "whatever"
426 $data = 'somethingelse';
427 print "$$scalar\n"; # Prints "whatever" because it is cached
428 sleep 2; # Wait until the cache entry has expired
429 print "$$scalar\n"; # Prints "somethingelse"
431 my $hash = Koha::Cache->create_hash(
435 'constructor' => sub { return $data; },
438 print "$$variable\n"; # Prints "whatever"
440 The gotcha with this interface, of course, is that the variable returned by
441 create_scalar and create_hash is a I<reference> to a tied variable and not a
442 tied variable itself.
444 The tied variable is configured by means of a hashref passed in to the
445 create_scalar and create_hash methods. The following parameters are supported:
451 Required. The key to use for identifying the variable in the cache.
455 Required. A closure (or reference to a function) that will return the value that
456 needs to be stored in the cache.
460 Optional. A closure (or reference to a function) that gets run to initialize
461 the cache when creating the tied variable.
465 Optional. Array reference with the arguments that should be passed to the
466 constructor function.
470 Optional. The cache timeout in seconds for the variable. Defaults to 600
475 Optional. Which type of cache to use for the variable. Defaults to whatever is
476 set in the environment variable CACHING_SYSTEM. If set to 'null', disables
477 caching for the tied variable.
481 Optional. Boolean flag to allow the variable to be updated directly. When this
482 is set and the variable is used as an l-value, the cache will be updated
483 immediately with the new value. Using this is probably a bad idea on a
484 multi-threaded system. When I<allowupdate> is not set to true, using the
485 tied variable as an l-value will have no effect.
489 Optional. A closure (or reference to a function) that should be called when the
490 tied variable is destroyed.
494 Optional. Boolean flag to tell the object to remove the variable from the cache
495 when it is destroyed or goes out of scope.
499 Optional. Boolean flag to tell the object not to refresh the variable from the
500 cache every time the value is desired, but rather only when the I<local> copy
501 of the variable is older than the timeout.
507 my $scalar = Koha::Cache->create_scalar(\%params);
509 Create scalar tied to the cache.
514 my ( $self, $args ) = @_;
516 $self->_set_tied_defaults($args);
518 tie my $scalar, 'Koha::Cache::Object', $args;
523 my ( $self, $args ) = @_;
525 $self->_set_tied_defaults($args);
527 tie my %hash, 'Koha::Cache::Object', $args;
531 sub _set_tied_defaults {
532 my ( $self, $args ) = @_;
534 $args->{'timeout'} = '600' unless defined( $args->{'timeout'} );
535 $args->{'inprocess'} = '0' unless defined( $args->{'inprocess'} );
536 unless ( $args->{cache_type} and lc( $args->{cache_type} ) eq 'null' ) {
537 $args->{'cache'} = $self;
538 $args->{'cache_type'} ||= $ENV{'CACHING_SYSTEM'};
554 Chris Cormack, E<lt>chris@bigballofwax.co.nzE<gt>
555 Paul Poulain, E<lt>paul.poulain@biblibre.comE<gt>
556 Jared Camins-Esakov, E<lt>jcamins@cpbibliography.comE<gt>