Class: Cache

Inherits:
Object
  • Object
show all
Defined in:
lib/cache.rb,
lib/cache/config.rb,
lib/cache/version.rb

Defined Under Namespace

Modules: ActiveSupportCacheDalliStore, ActiveSupportCacheFileStore, ActiveSupportCacheMemCacheStore, ActiveSupportCacheMemoryStore, ActiveSupportCacheNullStore, ActiveSupportCacheStore, DalliClient, MemCache, Memcached, MemcachedRails, Nothing, Redis, RedisNamespace Classes: Config, DriverNotFound, Error

Constant Summary collapse

VERSION = 
"0.3.7"

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(metal) ⇒ Cache

Create a new Cache instance by wrapping a client of your choice.

Supported memcached clients:

  • memcached (either a Memcached or a Memcached::Rails)

  • dalli (either a Dalli::Client or an ActiveSupport::Cache::DalliStore)

  • memcache-client (MemCache, the one commonly used by Rails)

Supported Redis clients:

metal - Either an instance of one of the above classes, or :nothing if you

want to use the Cache API but not actually cache anything.

Examples:

# Use Memcached
raw_client = Memcached.new('127.0.0.1:11211')
cache = Cache.new(raw_client)
cache.get(...)
cache.set(...)

# Don't cache anything
cache = Cache.new(:nothing)
cache.get(...)
cache.set(...)



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# File 'lib/cache.rb', line 50

def initialize(metal)
  @pid = ::Process.pid
  @config = Config.new
  if metal != :nothing
    @metal = Cache === metal ? metal.metal : metal
  end
  if @metal
    client_class = @metal.class.to_s
    driver_class = client_class.gsub('::', '')
  else
    client_class = 'Nothing'
    driver_class = 'Nothing'
  end
  filename = client_class.
    gsub(/([a-z])([A-Z]+)/) { [$1.downcase, $2.downcase].join('_') }.
    gsub('::', '_').downcase
  begin
    require "cache/#{filename}"
    extend Cache.const_get(driver_class)
  rescue LoadError, NameError => e
    puts "#{e.class}: #{e.message}"
    puts e.backtrace[0..5].join("\n")
    raise DriverNotFound, client_class
  end
end

Instance Attribute Details

#config ⇒ Object (readonly)

Returns the value of attribute config.



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# File 'lib/cache.rb', line 15

def config
  @config
end

#logger ⇒ Object

For compatibility with Rails 2.x



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# File 'lib/cache.rb', line 19

def logger
  @logger
end

#metal ⇒ Object (readonly)

Returns the value of attribute metal.



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# File 'lib/cache.rb', line 16

def metal
  @metal
end

Instance Method Details

#_cas(k, ttl, &blk) ⇒ Object

Default implementation of #cas which is overridden in some drivers



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# File 'lib/cache.rb', line 192

def _cas(k, ttl, &blk)
  if blk and _exist?(k)
    old_v = _get k
    new_v = blk.call old_v
    _set k, new_v, _get_ttl(ttl)
    new_v
  end
end

#_fetch(k, ttl, &blk) ⇒ Object

Default implementation of #fetch for drivers that do not define a method natively for it



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# File 'lib/cache.rb', line 170

def _fetch(k, ttl, &blk)
  if _exist? k
    _get k
  elsif blk
    v = blk.call
    _set k, v, ttl
    v
  end
end

#cas(k, ttl = nil, &blk) ⇒ Object Also known as: compare_and_swap

Get the current value (if any), pass it into a block, and set the result.

Example:

cache.cas 'hello' { |current| 'world' }



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# File 'lib/cache.rb', line 184

def cas(k, ttl = nil, &blk)
  handle_fork
  _cas(k, ttl, &blk)
end

#decrement(k, amount = 1, ignored_options = nil) ⇒ Object

Decrement a value.

Example:

cache.decrement 'high-fives'



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# File 'lib/cache.rb', line 153

def decrement(k, amount = 1, ignored_options = nil)
  increment k, -amount
end

#delete(k, ignored_options = nil) ⇒ Object

Delete a value.

Example:

cache.delete 'hello'



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# File 'lib/cache.rb', line 112

def delete(k, ignored_options = nil)
  handle_fork
  _delete k
end

#exist?(k, ignored_options = nil) ⇒ Boolean Also known as: exists?

Check if something exists.

Example:

cache.exist? 'hello'

Returns:

  • (Boolean) 


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# File 'lib/cache.rb', line 132

def exist?(k, ignored_options = nil)
  handle_fork
  _exist? k
end

#fetch(k, ttl = nil, &blk) ⇒ Object

Try to get a value and if it doesn’t exist, set it to the result of the block.

Accepts :expires_in for compatibility with Rails.

Example:

cache.fetch 'hello' { 'world' }



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# File 'lib/cache.rb', line 163

def fetch(k, ttl = nil, &blk)
  handle_fork
  _fetch(k, _get_ttl(ttl), &blk)
end

#flush ⇒ Object Also known as: clear

Flush the cache.

Example:

cache.flush



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# File 'lib/cache.rb', line 121

def flush
  handle_fork
  _flush
end

#get(k, ignored_options = nil) ⇒ Object Also known as: read

Get a value.

Example:

cache.get 'hello'



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# File 'lib/cache.rb', line 80

def get(k, ignored_options = nil)
  handle_fork
  _get k
end

#get_multi(*ks) ⇒ Object

Get multiple cache entries.

Example:

cache.get_multi 'hello', 'privyet'



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# File 'lib/cache.rb', line 91

def get_multi(*ks)
  handle_fork
  _get_multi ks
end

#increment(k, amount = 1, ignored_options = nil) ⇒ Object

Increment a value.

Example:

cache.increment 'high-fives'



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# File 'lib/cache.rb', line 142

def increment(k, amount = 1, ignored_options = nil)
  handle_fork
  new_v = _get(k).to_i + amount
  _set k, new_v, 0
  new_v
end

#set(k, v, ttl = nil, ignored_options = nil) ⇒ Object Also known as: write

Store a value. Note that this will Marshal it.

Example:

cache.set 'hello', 'world'
cache.set 'hello', 'world', 80 # seconds til it expires



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# File 'lib/cache.rb', line 101

def set(k, v, ttl = nil, ignored_options = nil)
  handle_fork
  _set k, v, _get_ttl(ttl)
end

#stats ⇒ Object

Get stats.

Example:

cache.stats



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# File 'lib/cache.rb', line 205

def stats
  handle_fork
  _stats
end