class Dalli::Protocol::TtlSanitizer

Utility class for sanitizing TTL arguments based on Memcached rules. TTLs are either expirations times in seconds (with a maximum value of 30 days) or expiration timestamps. This class sanitizes TTLs to ensure they meet those restrictions.

Constants

MAX_ACCEPTABLE_EXPIRATION_INTERVAL

github.com/memcached/memcached/blob/master/doc/protocol.txt#L79 > An expiration time, in seconds. Can be up to 30 days. After 30 days, is

treated as a unix timestamp of an exact date.

Public Class Methods

as_timestamp(ttl_as_i) click to toggle source
# File lib/dalli/protocol/ttl_sanitizer.rb, line 28
def self.as_timestamp(ttl_as_i)
  now = current_timestamp
  return ttl_as_i if ttl_as_i > now # Already a timestamp

  Dalli.logger.debug "Expiration interval (#{ttl_as_i}) too long for Memcached " \
                     'and too short to be a future timestamp,' \
                     'converting to an expiration timestamp'
  now + ttl_as_i
end
current_timestamp() click to toggle source

Pulled out into a method so it's easy to stub time

# File lib/dalli/protocol/ttl_sanitizer.rb, line 39
def self.current_timestamp
  Time.now.to_i
end
less_than_max_expiration_interval?(ttl_as_i) click to toggle source
# File lib/dalli/protocol/ttl_sanitizer.rb, line 24
def self.less_than_max_expiration_interval?(ttl_as_i)
  ttl_as_i <= MAX_ACCEPTABLE_EXPIRATION_INTERVAL
end
sanitize(ttl) click to toggle source

Ensures the TTL passed to Memcached is a valid TTL in the expected format.

# File lib/dalli/protocol/ttl_sanitizer.rb, line 17
def self.sanitize(ttl)
  ttl_as_i = ttl.to_i
  return ttl_as_i if less_than_max_expiration_interval?(ttl_as_i)

  as_timestamp(ttl_as_i)
end