module Cache

A utility wrapper around the MemCache client to simplify cache access. All methods silently ignore MemCache errors.

This API is deprecated, please use the Rails.cache API or your own wrapper API around MemCache.

Public Class Methods

add(key, value, expiry = 0) click to toggle source

Sets value in the cache at key, with an optional expiry time in seconds. If key already exists in cache, returns nil.

# File lib/memcache_util.rb, line 69
def self.add(key, value, expiry = 0)
  start_time = Time.now
  response = CACHE.add key, value, expiry
  elapsed = Time.now - start_time
  logger.debug('MemCache Add (%0.6f)  %s' % [elapsed, key])
  (response == "STORED\r\n") ? value : nil
rescue MemCache::MemCacheError => err
  ActiveRecord::Base.logger.debug "MemCache Error: #{err.message}"
  nil
end

delete(key, delay = nil) click to toggle source

Deletes key from the cache in delay seconds.

# File lib/memcache_util.rb, line 83
def self.delete(key, delay = nil)
  start_time = Time.now
  CACHE.delete key, delay
  elapsed = Time.now - start_time
  logger.debug('MemCache Delete (%0.6f)  %s' %
                                  [elapsed, key])
  nil
rescue MemCache::MemCacheError => err
  logger.debug "MemCache Error: #{err.message}"
  nil
end

get(key, expiry = 0) { || ... } click to toggle source

Returns the object at key from the cache if successful, or nil if either the object is not in the cache or if there was an error attermpting to access the cache.

If there is a cache miss and a block is given the result of the block will be stored in the cache with optional expiry, using the add method rather than set.

# File lib/memcache_util.rb, line 31
def self.get(key, expiry = 0)
  start_time = Time.now
  value = CACHE.get key
  elapsed = Time.now - start_time
  logger.debug('MemCache Get (%0.6f)  %s' % [elapsed, key])
  if value.nil? and block_given? then
    value = yield
    add key, value, expiry
  end
  value
rescue MemCache::MemCacheError => err
  logger.debug "MemCache Error: #{err.message}"
  if block_given? then
    value = yield
    put key, value, expiry
  end
  value
end

logger() click to toggle source

Try to return a logger object that does not rely on ActiveRecord for logging.

# File lib/memcache_util.rb, line 13
def self.logger
  @logger ||= if defined? Rails.logger # Rails 2.1 +
    Rails.logger
  elsif defined? RAILS_DEFAULT_LOGGER # Rails 1.2.2 +
    RAILS_DEFAULT_LOGGER
  else
    ActiveRecord::Base.logger # ... very old Rails.
  end
end

put(key, value, expiry = 0) click to toggle source

Sets value in the cache at key, with an optional expiry time in seconds.

# File lib/memcache_util.rb, line 54
def self.put(key, value, expiry = 0)
  start_time = Time.now
  CACHE.set key, value, expiry
  elapsed = Time.now - start_time
  logger.debug('MemCache Set (%0.6f)  %s' % [elapsed, key])
  value
rescue MemCache::MemCacheError => err
  ActiveRecord::Base.logger.debug "MemCache Error: #{err.message}"
  nil
end

reset() click to toggle source

Resets all connections to MemCache servers.

# File lib/memcache_util.rb, line 98
def self.reset
  CACHE.reset
  logger.debug 'MemCache Connections Reset'
  nil
end