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require "ftw/namespace"
require "socket" # for Socket.gethostbyname
require "ftw/singleton"
require "ftw/dns/dns"
# I wrap whatever Ruby provides because it is historically very
# inconsistent in implementation behavior across ruby platforms and versions.
# In the future, this will probably implement the DNS protocol, but for now
# chill in the awkward, but already-written, ruby stdlib.
#
# I didn't really want to write a DNS library, but a consistent API and
# behavior is necessary for my continued sanity :)
class FTW::DNS
extend FTW::Singleton
# The ipv4-in-ipv6 address space prefix.
V4_IN_V6_PREFIX = "0:" * 12
# An array of resolvers. By default this includes a FTW::DNS::DNS instance.
attr_reader :resolvers
private
# A new resolver.
#
# The default set of resolvers is only {FTW::DNS::DNS} which does DNS
# resolution.
def initialize
@resolvers = [FTW::DNS::DNS.new]
end # def initialize
# Resolve a hostname.
#
# Returns an array of all addresses for this host. Empty array resolution
# failure.
def resolve(hostname)
return @resolvers.reduce([]) do |memo, resolver|
result = resolver.resolve(hostname)
memo += result unless result.nil?
end
end # def resolve
# Resolve hostname and choose one of the results at random.
#
# Use this method if you are connecting to a hostname that resolves to
# multiple addresses.
def resolve_random(hostname)
addresses = resolve(hostname)
return addresses[rand(addresses.size)]
end # def resolve_random
public(:resolve, :resolve_random)
end # class FTW::DNS
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