Resolv::DNS

Parent:Object

Resolv :: DNS是一个DNS存根解析器。

从以下地点获取信息：

• STD0013

• RFC 1035

• etc.

常量

端口

默认DNS端口

UDPSize

默认DNS UDP数据包大小

公共类方法

new(config_info=nil) Show source

创建一个新的DNS解析器。

config_info 可以为：

零

Uses /etc/resolv.conf.

字符串

使用/etc/resolv.conf格式的文件路径。

Hash

必须包含：nameserver，：search和：ndots键。

：nameserver_port可用于指定名称服务器地址的端口号。

nameserver的值应该是地址字符串或地址字符串数组。

• :nameserver => '8.8.8.8'

• :nameserver => '8.8.8.8', '8.8.4.4'

nameserver_port的值应该是一对名称服务器地址和端口号的数组。

:nameserver_port => ['8.8.8.8', 53, '8.8.4.4', 53]Example:Resolv::DNS.new(:nameserver => ['210.251.121.21'],
                :search => ['ruby-lang.org'],
                :ndots => 1)# File lib/resolv.rb, line 333
def initialize(config_info=nil)
  @mutex = Thread::Mutex.new
  @config = Config.new(config_info)
  @initialized = nil
end open(*args) { |dns| ... } 

显示源创建一个新的DNS解析器。 有关详细信息，请参阅:: new。如果已提供，请将创建的DNS解析器解析为块，否则返回该解析器。

# File lib/resolv.rb, line 298
def self.open(*args)
  dns = new(*args)
  return dns unless block_given?
  begin
    yield dns
  ensure
    dns.close
  end
endPublic Instance Methods close() Show source Closes the DNS resolver.# File lib/resolv.rb, line 367
def close
  @mutex.synchronize {
    if @initialized
      @initialized = false
    end
  }
end each_address(name) { |address| ... } Show source Iterates over all IP addresses for name retrieved from the DNS resolver.name can be a Resolv::DNS::Name or a String. Retrieved addresses will be a Resolv::IPv4 or Resolv::IPv6# File lib/resolv.rb, line 405
def each_address(name)
  each_resource(name, Resource::IN::A) {|resource| yield resource.address}
  if use_ipv6?
    each_resource(name, Resource::IN::AAAA) {|resource| yield resource.address}
  end
end each_name(address) { |name| ... } Show source Iterates over all hostnames for address retrieved from the DNS resolver.address must be a Resolv::IPv4, Resolv::IPv6 or a String. Retrieved names will be Resolv::DNS::Name instances.# File lib/resolv.rb, line 452
def each_name(address)
  case address
  when Name
    ptr = address
  when IPv4::Regex
    ptr = IPv4.create(address).to_name
  when IPv6::Regex
    ptr = IPv6.create(address).to_name
  else
    raise ResolvError.new("cannot interpret as address: #{address}")
  end
  each_resource(ptr, Resource::IN::PTR) {|resource| yield resource.name}
end each_resource(name, typeclass, &proc) Show source Iterates over all typeclass DNS resources for name. See getresource for argument details.# File lib/resolv.rb, line 508
def each_resource(name, typeclass, &proc)
  fetch_resource(name, typeclass) {|reply, reply_name|
    extract_resources(reply, reply_name, typeclass, &proc)
  }
end fetch_resource(name, typeclass) { |reply, reply_name| ... } Show source # File lib/resolv.rb, line 514
def fetch_resource(name, typeclass)
  lazy_initialize
  requester = make_udp_requester
  senders = {}
  begin
    @config.resolv(name) {|candidate, tout, nameserver, port|
      msg = Message.new
      msg.rd = 1
      msg.add_question(candidate, typeclass)
      unless sender = senders[[candidate, nameserver, port]]
        sender = requester.sender(msg, candidate, nameserver, port)
        next if !sender
        senders[[candidate, nameserver, port]] = sender
      end
      reply, reply_name = requester.request(sender, tout)
      case reply.rcode
      when RCode::NoError
        if reply.tc == 1 and not Requester::TCP === requester
          requester.close
          # Retry via TCP:
          requester = make_tcp_requester(nameserver, port)
          senders = {}
          # This will use TCP for all remaining candidates (assuming the
          # current candidate does not already respond successfully via
          # TCP).  This makes sense because we already know the full
          # response will not fit in an untruncated UDP packet.
          redo
        else
          yield(reply, reply_name)
        end
        return
      when RCode::NXDomain
        raise Config::NXDomain.new(reply_name.to_s)
      else
        raise Config::OtherResolvError.new(reply_name.to_s)
      end
    }
  ensure
    requester.close
  end
end getaddress(name) Show source Gets the IP address of name from the DNS resolver.name can be a Resolv::DNS::Name or a String. Retrieved address will be a Resolv::IPv4 or Resolv::IPv6# File lib/resolv.rb, line 381
def getaddress(name)
  each_address(name) {|address| return address}
  raise ResolvError.new("DNS result has no information for #{name}")
end getaddresses(name) Show source Gets all IP addresses for name from the DNS resolver.name can be a Resolv::DNS::Name or a String. Retrieved addresses will be a Resolv::IPv4 or Resolv::IPv6# File lib/resolv.rb, line 392
def getaddresses(name)
  ret = []
  each_address(name) {|address| ret << address}
  return ret
end getname(address) Show source Gets the hostname for address from the DNS resolver.address must be a Resolv::IPv4, Resolv::IPv6 or a String. Retrieved name will be a Resolv::DNS::Name.# File lib/resolv.rb, line 428
def getname(address)
  each_name(address) {|name| return name}
  raise ResolvError.new("DNS result has no information for #{address}")
end getnames(address) Show source Gets all hostnames for address from the DNS resolver.address must be a Resolv::IPv4, Resolv::IPv6 or a String. Retrieved names will be Resolv::DNS::Name instances.# File lib/resolv.rb, line 439
def getnames(address)
  ret = []
  each_name(address) {|name| ret << name}
  return ret
end getresource(name, typeclass) 

显示源查找name.name的类型类DNS资源必须是Resolv :: DNS :: Name或String.typeclass应该是以下之一：

• Resolv::DNS::Resource::IN::A

• Resolv::DNS::Resource::IN::AAAA

• Resolv::DNS::Resource::IN::ANY

• Resolv::DNS::Resource::IN::CNAME

• Resolv::DNS::Resource::IN::HINFO

• Resolv::DNS::Resource::IN::MINFO

• Resolv::DNS::Resource::IN::MX

• Resolv::DNS::Resource::IN::NS

• Resolv::DNS::Resource::IN::PTR

• Resolv::DNS::Resource::IN::SOA

• Resolv::DNS::Resource::IN::TXT

• Resolv::DNS::Resource::IN::WKS

返回的资源表示为Resolv :: DNS :: Resource实例，即Resolv :: DNS :: Resource :: IN :: A。

# File lib/resolv.rb, line 489
def getresource(name, typeclass)
  each_resource(name, typeclass) {|resource| return resource}
  raise ResolvError.new("DNS result has no information for #{name}")
end

getresources(name, typeclass) Show source

查找所有typeclassDNS资源name。有关参数详情，请参阅getresource。

# File lib/resolv.rb, line 498
def getresources(name, typeclass)
  ret = []
  each_resource(name, typeclass) {|resource| ret << resource}
  return ret
end

timeouts=(values) Show source

设置解析器超时。 这可能是一个单一的正数或表示超时秒数的正数的数组。 如果指定了数组，则DNS请求将重试并等待数组中的每个连续时间间隔，直到收到成功的响应。 指定nil将恢复为默认超时：

5, second = 5 * 2 / nameserver_count, 2 * second, 4 * second

例：

dns.timeouts = 3

# File lib/resolv.rb, line 350
def timeouts=(values)
  @config.timeouts = values
end