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# frozen_string_literal: true
module Dalli
module Protocol
##
# 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.
##
class TtlSanitizer
# https://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.
MAX_ACCEPTABLE_EXPIRATION_INTERVAL = 30 * 24 * 60 * 60 # 30 days
# Ensures the TTL passed to Memcached is a valid TTL in the expected format.
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
def self.less_than_max_expiration_interval?(ttl_as_i)
ttl_as_i <= MAX_ACCEPTABLE_EXPIRATION_INTERVAL
end
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
# Pulled out into a method so it's easy to stub time
def self.current_timestamp
Time.now.to_i
end
end
end
end
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