Class: ActiveSupport::Cache::Store
- Defined in:
- lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb
Overview
An abstract cache store class. There are multiple cache store implementations, each having its own additional features. See the classes under the ActiveSupport::Cache module, e.g. ActiveSupport::Cache::MemCacheStore. MemCacheStore is currently the most popular cache store for large production websites.
Some implementations may not support all methods beyond the basic cache methods of #fetch, #write, #read, #exist?, and #delete.
ActiveSupport::Cache::Store can store any Ruby object that is supported by its coder
‘s dump
and load
methods.
cache = ActiveSupport::Cache::MemoryStore.new
cache.read('city') # => nil
cache.write('city', "Duckburgh")
cache.read('city') # => "Duckburgh"
cache.write('not serializable', Proc.new {}) # => TypeError
Keys are always translated into Strings and are case sensitive. When an object is specified as a key and has a cache_key
method defined, this method will be called to define the key. Otherwise, the to_param
method will be called. Hashes and Arrays can also be used as keys. The elements will be delimited by slashes, and the elements within a Hash will be sorted by key so they are consistent.
cache.read('city') == cache.read(:city) # => true
Nil values can be cached.
If your cache is on a shared infrastructure, you can define a namespace for your cache entries. If a namespace is defined, it will be prefixed on to every key. The namespace can be either a static value or a Proc. If it is a Proc, it will be invoked when each key is evaluated so that you can use application logic to invalidate keys.
cache.namespace = -> { @last_mod_time } # Set the namespace to a variable
@last_mod_time = Time.now # Invalidate the entire cache by changing namespace
Direct Known Subclasses
FileStore, MemCacheStore, MemoryStore, NullStore, RedisCacheStore
Instance Attribute Summary collapse
-
#options ⇒ Object
readonly
Returns the value of attribute options.
-
#silence ⇒ Object
(also: #silence?)
readonly
Returns the value of attribute silence.
Instance Method Summary collapse
-
#cleanup(options = nil) ⇒ Object
Cleans up the cache by removing expired entries.
-
#clear(options = nil) ⇒ Object
Clears the entire cache.
-
#decrement(name, amount = 1, options = nil) ⇒ Object
Decrements an integer value in the cache.
-
#delete(name, options = nil) ⇒ Object
Deletes an entry in the cache.
-
#delete_matched(matcher, options = nil) ⇒ Object
Deletes all entries with keys matching the pattern.
-
#delete_multi(names, options = nil) ⇒ Object
Deletes multiple entries in the cache.
-
#exist?(name, options = nil) ⇒ Boolean
Returns
true
if the cache contains an entry for the given key. -
#fetch(name, options = nil, &block) ⇒ Object
Fetches data from the cache, using the given key.
-
#fetch_multi(*names) ⇒ Object
Fetches data from the cache, using the given keys.
-
#increment(name, amount = 1, options = nil) ⇒ Object
Increments an integer value in the cache.
-
#initialize(options = nil) ⇒ Store
constructor
Creates a new cache.
-
#mute ⇒ Object
Silences the logger within a block.
-
#new_entry(value, options = nil) ⇒ Object
:nodoc:.
-
#read(name, options = nil) ⇒ Object
Reads data from the cache, using the given key.
-
#read_multi(*names) ⇒ Object
Reads multiple values at once from the cache.
-
#silence! ⇒ Object
Silences the logger.
-
#write(name, value, options = nil) ⇒ Object
Writes the value to the cache with the key.
-
#write_multi(hash, options = nil) ⇒ Object
Cache Storage API to write multiple values at once.
Constructor Details
#initialize(options = nil) ⇒ Store
Creates a new cache.
Options
-
:namespace
- Sets the namespace for the cache. This option is especially useful if your application shares a cache with other applications. -
:coder
- Replaces the default cache entry serialization mechanism with a custom one. Thecoder
must respond todump
andload
. Using a custom coder disables automatic compression.
Any other specified options are treated as default options for the relevant cache operations, such as #read, #write, and #fetch.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 211 def initialize( = nil) @options = ? () : {} @options[:compress] = true unless @options.key?(:compress) @options[:compress_threshold] = DEFAULT_COMPRESS_LIMIT unless @options.key?(:compress_threshold) @coder = @options.delete(:coder) { default_coder } || NullCoder @coder_supports_compression = @coder.respond_to?(:dump_compressed) end |
Instance Attribute Details
#options ⇒ Object (readonly)
Returns the value of attribute options.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 178 def @options end |
#silence ⇒ Object (readonly) Also known as: silence?
Returns the value of attribute silence.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 178 def silence @silence end |
Instance Method Details
#cleanup(options = nil) ⇒ Object
Cleans up the cache by removing expired entries.
Options are passed to the underlying cache implementation.
Some implementations may not support this method.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 582 def cleanup( = nil) raise NotImplementedError.new("#{self.class.name} does not support cleanup") end |
#clear(options = nil) ⇒ Object
Clears the entire cache. Be careful with this method since it could affect other processes if shared cache is being used.
The options hash is passed to the underlying cache implementation.
Some implementations may not support this method.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 592 def clear( = nil) raise NotImplementedError.new("#{self.class.name} does not support clear") end |
#decrement(name, amount = 1, options = nil) ⇒ Object
Decrements an integer value in the cache.
Options are passed to the underlying cache implementation.
Some implementations may not support this method.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 573 def decrement(name, amount = 1, = nil) raise NotImplementedError.new("#{self.class.name} does not support decrement") end |
#delete(name, options = nil) ⇒ Object
Deletes an entry in the cache. Returns true
if an entry is deleted.
Options are passed to the underlying cache implementation.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 514 def delete(name, = nil) = () instrument(:delete, name) do delete_entry(normalize_key(name, ), **) end end |
#delete_matched(matcher, options = nil) ⇒ Object
Deletes all entries with keys matching the pattern.
Options are passed to the underlying cache implementation.
Some implementations may not support this method.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 555 def delete_matched(matcher, = nil) raise NotImplementedError.new("#{self.class.name} does not support delete_matched") end |
#delete_multi(names, options = nil) ⇒ Object
Deletes multiple entries in the cache.
Options are passed to the underlying cache implementation.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 525 def delete_multi(names, = nil) = () names.map! { |key| normalize_key(key, ) } instrument :delete_multi, names do delete_multi_entries(names, **) end end |
#exist?(name, options = nil) ⇒ Boolean
Returns true
if the cache contains an entry for the given key.
Options are passed to the underlying cache implementation.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 537 def exist?(name, = nil) = () instrument(:exist?, name) do |payload| entry = read_entry(normalize_key(name, ), **, event: payload) (entry && !entry.expired? && !entry.mismatched?(normalize_version(name, ))) || false end end |
#fetch(name, options = nil, &block) ⇒ Object
Fetches data from the cache, using the given key. If there is data in the cache with the given key, then that data is returned.
If there is no such data in the cache (a cache miss), then nil
will be returned. However, if a block has been passed, that block will be passed the key and executed in the event of a cache miss. The return value of the block will be written to the cache under the given cache key, and that return value will be returned.
cache.write('today', 'Monday')
cache.fetch('today') # => "Monday"
cache.fetch('city') # => nil
cache.fetch('city') do
'Duckburgh'
end
cache.fetch('city') # => "Duckburgh"
Options
Internally, fetch
calls #read_entry, and calls #write_entry on a cache miss. Thus, fetch
supports the same options as #read and #write. Additionally, fetch
supports the following options:
-
force: true
- Forces a cache “miss,” meaning we treat the cache value as missing even if it’s present. Passing a block is required whenforce
is true so this always results in a cache write.cache.write('today', 'Monday') cache.fetch('today', force: true) { 'Tuesday' } # => 'Tuesday' cache.fetch('today', force: true) # => ArgumentError
The
:force
option is useful when you’re calling some other method to ask whether you should force a cache write. Otherwise, it’s clearer to just callwrite
. -
skip_nil: true
- Prevents caching a nil result:cache.fetch('foo') { nil } cache.fetch('bar', skip_nil: true) { nil } cache.exist?('foo') # => true cache.exist?('bar') # => false
-
:race_condition_ttl
- Specifies the number of seconds during which an expired value can be reused while a new value is being generated. This can be used to prevent race conditions when cache entries expire, by preventing multiple processes from simultaneously regenerating the same entry (also known as the dog pile effect).When a process encounters a cache entry that has expired less than
:race_condition_ttl
seconds ago, it will bump the expiration time by:race_condition_ttl
seconds before generating a new value. During this extended time window, while the process generates a new value, other processes will continue to use the old value. After the first process writes the new value, other processes will then use it.If the first process errors out while generating a new value, another process can try to generate a new value after the extended time window has elapsed.
# Set all values to expire after one minute. cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 1.minute) cache.write('foo', 'original value') val_1 = nil val_2 = nil sleep 60 Thread.new do val_1 = cache.fetch('foo', race_condition_ttl: 10.seconds) do sleep 1 'new value 1' end end Thread.new do val_2 = cache.fetch('foo', race_condition_ttl: 10.seconds) do 'new value 2' end end cache.fetch('foo') # => "original value" sleep 10 # First thread extended the life of cache by another 10 seconds cache.fetch('foo') # => "new value 1" val_1 # => "new value 1" val_2 # => "original value"
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 321 def fetch(name, = nil, &block) if block_given? = () key = normalize_key(name, ) entry = nil instrument(:read, name, ) do |payload| cached_entry = read_entry(key, **, event: payload) unless [:force] entry = handle_expired_entry(cached_entry, key, ) entry = nil if entry && entry.mismatched?(normalize_version(name, )) payload[:super_operation] = :fetch if payload payload[:hit] = !!entry if payload end if entry get_entry_value(entry, name, ) else save_block_result_to_cache(name, , &block) end elsif && [:force] raise ArgumentError, "Missing block: Calling `Cache#fetch` with `force: true` requires a block." else read(name, ) end end |
#fetch_multi(*names) ⇒ Object
Fetches data from the cache, using the given keys. If there is data in the cache with the given keys, then that data is returned. Otherwise, the supplied block is called for each key for which there was no data, and the result will be written to the cache and returned. Therefore, you need to pass a block that returns the data to be written to the cache. If you do not want to write the cache when the cache is not found, use #read_multi.
Returns a hash with the data for each of the names. For example:
cache.write("bim", "bam")
cache.fetch_multi("bim", "unknown_key") do |key|
"Fallback value for key: #{key}"
end
# => { "bim" => "bam",
# "unknown_key" => "Fallback value for key: unknown_key" }
Options are passed to the underlying cache implementation. For example:
cache.fetch_multi("fizz", expires_in: 5.seconds) do |key|
"buzz"
end
# => {"fizz"=>"buzz"}
cache.read("fizz")
# => "buzz"
sleep(6)
cache.read("fizz")
# => nil
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 447 def fetch_multi(*names) raise ArgumentError, "Missing block: `Cache#fetch_multi` requires a block." unless block_given? = names. = () instrument :read_multi, names, do |payload| reads = read_multi_entries(names, **) writes = {} ordered = names.index_with do |name| reads.fetch(name) { writes[name] = yield(name) } end payload[:hits] = reads.keys payload[:super_operation] = :fetch_multi write_multi(writes, ) ordered end end |
#increment(name, amount = 1, options = nil) ⇒ Object
Increments an integer value in the cache.
Options are passed to the underlying cache implementation.
Some implementations may not support this method.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 564 def increment(name, amount = 1, = nil) raise NotImplementedError.new("#{self.class.name} does not support increment") end |
#mute ⇒ Object
Silences the logger within a block.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 227 def mute previous_silence, @silence = defined?(@silence) && @silence, true yield ensure @silence = previous_silence end |
#new_entry(value, options = nil) ⇒ Object
:nodoc:
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 546 def new_entry(value, = nil) # :nodoc: Entry.new(value, **()) end |
#read(name, options = nil) ⇒ Object
Reads data from the cache, using the given key. If there is data in the cache with the given key, then that data is returned. Otherwise, nil
is returned.
Note, if data was written with the :expires_in
or :version
options, both of these conditions are applied before the data is returned.
Options
-
:version
- Specifies a version for the cache entry. If the cached version does not match the requested version, the read will be treated as a cache miss. This feature is used to support recyclable cache keys.
Other options will be handled by the specific cache store implementation.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 362 def read(name, = nil) = () key = normalize_key(name, ) version = normalize_version(name, ) instrument(:read, name, ) do |payload| entry = read_entry(key, **, event: payload) if entry if entry.expired? delete_entry(key, **) payload[:hit] = false if payload nil elsif entry.mismatched?(version) payload[:hit] = false if payload nil else payload[:hit] = true if payload entry.value end else payload[:hit] = false if payload nil end end end |
#read_multi(*names) ⇒ Object
Reads multiple values at once from the cache. Options can be passed in the last argument.
Some cache implementation may optimize this method.
Returns a hash mapping the names provided to the values found.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 395 def read_multi(*names) = names. = () instrument :read_multi, names, do |payload| read_multi_entries(names, **, event: payload).tap do |results| payload[:hits] = results.keys end end end |
#silence! ⇒ Object
Silences the logger.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 221 def silence! @silence = true self end |
#write(name, value, options = nil) ⇒ Object
Writes the value to the cache with the key. The value must be supported by the coder
‘s dump
and load
methods.
By default, cache entries larger than 1kB are compressed. Compression allows more data to be stored in the same memory footprint, leading to fewer cache evictions and higher hit rates.
Options
-
compress: false
- Disables compression of the cache entry. -
:compress_threshold
- The compression threshold, specified in bytes. Cache entries larger than this threshold will be compressed. Defaults to1.kilobyte
. -
:expires_in
- Sets a relative expiration time for the cache entry, specified in seconds.:expire_in
and:expired_in
are aliases for:expires_in
.cache = ActiveSupport::Cache::MemoryStore.new(expires_in: 5.minutes) cache.write(key, value, expires_in: 1.minute) # Set a lower value for one entry
-
:expires_at
- Sets an absolute expiration time for the cache entry.cache = ActiveSupport::Cache::MemoryStore.new cache.write(key, value, expires_at: Time.now.at_end_of_hour)
-
:version
- Specifies a version for the cache entry. When reading from the cache, if the cached version does not match the requested version, the read will be treated as a cache miss. This feature is used to support recyclable cache keys.
Other options will be handled by the specific cache store implementation.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 502 def write(name, value, = nil) = () instrument(:write, name, ) do entry = Entry.new(value, **.merge(version: normalize_version(name, ))) write_entry(normalize_key(name, ), entry, **) end end |
#write_multi(hash, options = nil) ⇒ Object
Cache Storage API to write multiple values at once.
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# File 'lib/rubypitaya/app-template/vendor/bundle/ruby/3.1.0/gems/activesupport-7.0.4/lib/active_support/cache.rb', line 407 def write_multi(hash, = nil) = () instrument :write_multi, hash, do |payload| entries = hash.each_with_object({}) do |(name, value), memo| memo[normalize_key(name, )] = Entry.new(value, **.merge(version: normalize_version(name, ))) end write_multi_entries entries, ** end end |