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});
30 # see also Koha::Caches->get_instance;
34 Koha caching routines. This class provides two interfaces for cache access.
35 The first, traditional OO interface provides the following functions:
44 use Module::Load::Conditional qw(can_load);
48 use Koha::Cache::Object;
51 use base qw(Class::Accessor);
53 __PACKAGE__->mk_ro_accessors(
54 qw( cache memcached_cache fastmmap_cache memory_cache ));
57 our $L1_encoder = Sereal::Encoder->new;
58 our $L1_decoder = Sereal::Decoder->new;
62 Create a new Koha::Cache object. This is required for all cache-related functionality.
67 my ( $class, $self, $params ) = @_;
68 $self->{'default_type'} =
70 || $ENV{CACHING_SYSTEM} # DELME What about this?
73 my $subnamespace = $params->{subnamespace} // '';
75 $ENV{DEBUG} && carp "Default caching system: $self->{'default_type'}";
77 $self->{'timeout'} ||= 0;
78 # Should we continue to support MEMCACHED ENV vars?
79 $self->{'namespace'} ||= $ENV{MEMCACHED_NAMESPACE};
80 my @servers = split /,/, $ENV{MEMCACHED_SERVERS} || '';
81 unless ( $self->{namespace} and @servers ) {
82 my $koha_config = Koha::Config->read_from_file( Koha::Config->guess_koha_conf() );
83 $self->{namespace} ||= $koha_config->{config}{memcached_namespace} || 'koha';
84 @servers = split /,/, $koha_config->{config}{memcached_servers} // ''
87 $self->{namespace} .= ":$subnamespace:";
89 if ( $self->{'default_type'} eq 'memcached'
90 && can_load( modules => { 'Cache::Memcached::Fast' => undef } )
91 && _initialize_memcached($self, @servers)
92 && defined( $self->{'memcached_cache'} ) )
94 $self->{'cache'} = $self->{'memcached_cache'};
97 if ( $self->{'default_type'} eq 'fastmmap'
98 && defined( $ENV{GATEWAY_INTERFACE} )
99 && can_load( modules => { 'Cache::FastMmap' => undef } )
100 && _initialize_fastmmap($self)
101 && defined( $self->{'fastmmap_cache'} ) )
103 $self->{'cache'} = $self->{'fastmmap_cache'};
106 $ENV{DEBUG} && carp "Selected caching system: " . ($self->{'cache'} // 'none');
113 sub _initialize_memcached {
114 my ($self, @servers) = @_;
116 return unless @servers;
119 && carp "Memcached server settings: "
120 . join( ', ', @servers )
122 . $self->{'namespace'};
123 # Cache::Memcached::Fast doesn't allow a default expire time to be set
124 # so we force it on setting.
125 my $memcached = Cache::Memcached::Fast->new(
127 servers => \@servers,
128 compress_threshold => 10_000,
129 namespace => $self->{'namespace'},
133 # Ensure we can actually talk to the memcached server
134 my $ismemcached = $memcached->set('ismemcached','1');
135 return $self unless $ismemcached;
136 $self->{'memcached_cache'} = $memcached;
140 sub _initialize_fastmmap {
142 my ($cache, $share_file);
144 # Temporary workaround to catch fatal errors when: C4::Context module
145 # is not loaded beforehand, or Cache::FastMmap init fails for whatever
146 # other reason (e.g. due to permission issues - see Bug 13431)
148 $share_file = join( '-',
149 "/tmp/sharefile-koha", $self->{'namespace'},
150 C4::Context->config('hostname'), C4::Context->config('database') );
152 $cache = Cache::FastMmap->new(
153 'share_file' => $share_file,
154 'expire_time' => $self->{'timeout'},
155 'unlink_on_exit' => 0,
159 warn "FastMmap cache initialization failed: $@";
162 return unless defined $cache;
163 $self->{'fastmmap_cache'} = $cache;
167 =head2 is_cache_active
169 Routine that checks whether or not a default caching method is active on this
174 sub is_cache_active {
176 return $self->{'cache'} ? 1 : 0;
181 $cache->set_in_cache($key, $value, [$options]);
183 Save a value to the specified key in the cache. A hashref of options may be
186 The possible options are:
192 Expiry time of this cached entry in seconds.
196 The cache object to use if you want to provide your own. It should be an
197 instance of C<Cache::*> and follow the same interface as L<Cache::Memcache>.
204 my ( $self, $key, $value, $options ) = @_;
206 my $unsafe = $options->{unsafe} || 0;
208 # the key mustn't contain whitespace (or control characters) for memcache
209 # but shouldn't be any harm in applying it globally.
210 $key =~ s/[\x00-\x20]/_/g;
212 my $cache = $options->{cache} || 'cache';
213 croak "No key" unless $key;
214 $ENV{DEBUG} && carp "set_in_cache for $key";
216 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
217 my $expiry = $options->{expiry};
218 $expiry //= $self->{timeout};
219 my $set_sub = $self->{ref($self->{$cache}) . "_set"};
221 my $flag = '-CF0'; # 0: scalar, 1: frozen data structure
223 # Set in L1 cache as a data structure
224 # We only save the frozen form: we do want to save $value in L1
225 # directly in order to protect it. And thawing now may not be
226 # needed, so improves performance.
227 $value = $L1_encoder->encode($value);
228 $L1_cache{$self->{namespace}}{$key}->{frozen} = $value;
231 # Set in L1 cache as a scalar; exit if we are caching an undef
232 $L1_cache{$self->{namespace}}{$key} = $value;
233 return if !defined $value;
237 # We consider an expiry of 0 to be infinite
240 ? $set_sub->( $key, $value, $expiry )
241 : $self->{$cache}->set( $key, $value, $expiry );
245 ? $set_sub->( $key, $value )
246 : $self->{$cache}->set( $key, $value );
250 =head2 get_from_cache
252 my $value = $cache->get_from_cache($key, [ $options ]);
254 Retrieve the value stored under the specified key in the cache.
256 The possible options are:
262 If set, this will avoid performing a deep copy of the item. This
263 means that it won't be safe if something later modifies the result of the
264 function. It should be used with caution, and could save processing time
265 in some situations where is safe to use it. Make sure you know what you are doing!
269 The cache object to use if you want to provide your own. It should be an
270 instance of C<Cache::*> and follow the same interface as L<Cache::Memcache>.
277 my ( $self, $key, $options ) = @_;
278 my $cache = $options->{cache} || 'cache';
279 my $unsafe = $options->{unsafe} || 0;
280 $key =~ s/[\x00-\x20]/_/g;
281 croak "No key" unless $key;
282 $ENV{DEBUG} && carp "get_from_cache for $key";
283 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
285 # Return L1 cache value if exists
286 if ( exists $L1_cache{$self->{namespace}}{$key} ) {
287 if (ref($L1_cache{$self->{namespace}}{$key})) {
289 # ONLY use thawed for unsafe calls !!!
290 $L1_cache{$self->{namespace}}{$key}->{thawed} ||= $L1_decoder->decode($L1_cache{$self->{namespace}}{$key}->{frozen});
291 return $L1_cache{$self->{namespace}}{$key}->{thawed};
293 return $L1_decoder->decode($L1_cache{$self->{namespace}}{$key}->{frozen});
296 # No need to thaw if it's a scalar
297 return $L1_cache{$self->{namespace}}{$key};
301 my $get_sub = $self->{ref($self->{$cache}) . "_get"};
302 my $L2_value = $get_sub ? $get_sub->($key) : $self->{$cache}->get($key);
304 return if ref($L2_value);
305 return unless (defined($L2_value) && length($L2_value) >= 4);
307 my $flag = substr($L2_value, -4, 4, '');
308 if ($flag eq '-CF0') {
310 $L1_cache{$self->{namespace}}{$key} = $L2_value;
312 } elsif ($flag eq '-CF1') {
313 # it's a frozen data structure
315 eval { $thawed = $L1_decoder->decode($L2_value); };
317 $L1_cache{$self->{namespace}}{$key}->{frozen} = $L2_value;
318 # ONLY save thawed for unsafe calls !!!
319 $L1_cache{$self->{namespace}}{$key}->{thawed} = $thawed if $unsafe;
323 # Unknown value / data type returned from L2 cache
327 =head2 clear_from_cache
329 $cache->clear_from_cache($key);
331 Remove the value identified by the specified key from the default cache.
335 sub clear_from_cache {
336 my ( $self, $key, $cache ) = @_;
337 $key =~ s/[\x00-\x20]/_/g;
339 croak "No key" unless $key;
340 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
342 # Clear from L1 cache
343 delete $L1_cache{$self->{namespace}}{$key};
345 return $self->{$cache}->delete($key)
346 if ( ref( $self->{$cache} ) =~ m'^Cache::Memcached' );
347 return $self->{$cache}->remove($key);
354 Clear the entire default cache.
359 my ( $self, $cache ) = shift;
361 return unless ( $self->{$cache} && ref( $self->{$cache} ) =~ m/^Cache::/ );
363 $self->flush_L1_cache();
365 return $self->{$cache}->flush_all()
366 if ( ref( $self->{$cache} ) =~ m'^Cache::Memcached' );
367 return $self->{$cache}->clear();
372 delete $L1_cache{$self->{namespace}};
375 =head1 TIED INTERFACE
377 Koha::Cache also provides a tied interface which enables users to provide a
378 constructor closure and (after creation) treat cached data like normal reference
379 variables and rely on the cache Just Working and getting updated when it
382 my $cache = Koha::Cache->new();
383 my $data = 'whatever';
384 my $scalar = Koha::Cache->create_scalar(
388 'constructor' => sub { return $data; },
391 print "$$scalar\n"; # Prints "whatever"
392 $data = 'somethingelse';
393 print "$$scalar\n"; # Prints "whatever" because it is cached
394 sleep 2; # Wait until the cache entry has expired
395 print "$$scalar\n"; # Prints "somethingelse"
397 my $hash = Koha::Cache->create_hash(
401 'constructor' => sub { return $data; },
404 print "$$variable\n"; # Prints "whatever"
406 The gotcha with this interface, of course, is that the variable returned by
407 create_scalar and create_hash is a I<reference> to a tied variable and not a
408 tied variable itself.
410 The tied variable is configured by means of a hashref passed in to the
411 create_scalar and create_hash methods. The following parameters are supported:
417 Required. The key to use for identifying the variable in the cache.
421 Required. A closure (or reference to a function) that will return the value that
422 needs to be stored in the cache.
426 Optional. A closure (or reference to a function) that gets run to initialize
427 the cache when creating the tied variable.
431 Optional. Array reference with the arguments that should be passed to the
432 constructor function.
436 Optional. The cache timeout in seconds for the variable. Defaults to 600
441 Optional. Which type of cache to use for the variable. Defaults to whatever is
442 set in the environment variable CACHING_SYSTEM. If set to 'null', disables
443 caching for the tied variable.
447 Optional. Boolean flag to allow the variable to be updated directly. When this
448 is set and the variable is used as an l-value, the cache will be updated
449 immediately with the new value. Using this is probably a bad idea on a
450 multi-threaded system. When I<allowupdate> is not set to true, using the
451 tied variable as an l-value will have no effect.
455 Optional. A closure (or reference to a function) that should be called when the
456 tied variable is destroyed.
460 Optional. Boolean flag to tell the object to remove the variable from the cache
461 when it is destroyed or goes out of scope.
465 Optional. Boolean flag to tell the object not to refresh the variable from the
466 cache every time the value is desired, but rather only when the I<local> copy
467 of the variable is older than the timeout.
473 my $scalar = Koha::Cache->create_scalar(\%params);
475 Create scalar tied to the cache.
480 my ( $self, $args ) = @_;
482 $self->_set_tied_defaults($args);
484 tie my $scalar, 'Koha::Cache::Object', $args;
489 my ( $self, $args ) = @_;
491 $self->_set_tied_defaults($args);
493 tie my %hash, 'Koha::Cache::Object', $args;
497 sub _set_tied_defaults {
498 my ( $self, $args ) = @_;
500 $args->{'timeout'} = '600' unless defined( $args->{'timeout'} );
501 $args->{'inprocess'} = '0' unless defined( $args->{'inprocess'} );
502 unless ( $args->{cache_type} and lc( $args->{cache_type} ) eq 'null' ) {
503 $args->{'cache'} = $self;
504 $args->{'cache_type'} ||= $ENV{'CACHING_SYSTEM'};
520 Chris Cormack, E<lt>chris@bigballofwax.co.nzE<gt>
521 Paul Poulain, E<lt>paul.poulain@biblibre.comE<gt>
522 Jared Camins-Esakov, E<lt>jcamins@cpbibliography.comE<gt>