dns.lookup(hostname[, options], callback)
-
hostname
<string> -
-
family
<integer> | <string> 记录族。必须是4
、6
或0
。出于向后兼容的原因,'IPv4'
和'IPv6'
分别被解释为4
和6
。值0
指示返回 IPv4 或 IPv6 地址。如果值0
与{ all: true }
一起使用(见下文),则返回 IPv4 和 IPv6 地址之一或两者,具体取决于系统的 DNS 解析器。默认值:0
。¥
family
<integer> | <string> The record family. Must be4
,6
, or0
. For backward compatibility reasons,'IPv4'
and'IPv6'
are interpreted as4
and6
respectively. The value0
indicates that either an IPv4 or IPv6 address is returned. If the value0
is used with{ all: true }
(see below), either one of or both IPv4 and IPv6 addresses are returned, depending on the system's DNS resolver. Default:0
. -
hints
<number> 一个或多个 支持的getaddrinfo
标志。多个标志可以通过按位OR
其值来传入。¥
hints
<number> One or more supportedgetaddrinfo
flags. Multiple flags may be passed by bitwiseOR
ing their values. -
all
<boolean> 当为true
时,回调返回数组中所有已解析的地址。否则,返回单个地址。默认值:false
。¥
all
<boolean> Whentrue
, the callback returns all resolved addresses in an array. Otherwise, returns a single address. Default:false
. -
order
<string> 当verbatim
时,解析的地址未排序地返回。当ipv4first
时,解析的地址按将 IPv4 地址置于 IPv6 地址之前的方式排序。当ipv6first
时,解析的地址通过将 IPv6 地址置于 IPv4 地址之前进行排序。默认值:verbatim
(地址未重新排序)。默认值可使用dns.setDefaultResultOrder()
或--dns-result-order
进行配置。¥
order
<string> Whenverbatim
, the resolved addresses are return unsorted. Whenipv4first
, the resolved addresses are sorted by placing IPv4 addresses before IPv6 addresses. Whenipv6first
, the resolved addresses are sorted by placing IPv6 addresses before IPv4 addresses. Default:verbatim
(addresses are not reordered). Default value is configurable usingdns.setDefaultResultOrder()
or--dns-result-order
. -
verbatim
<boolean> 当为true
时,回调按照 DNS 解析器返回的顺序接收 IPv4 和 IPv6 地址。当为false
时,IPv4 地址位于 IPv6 地址之前。此选项将被弃用,取而代之的是order
。当两者都指定时,order
具有更高的优先级。新代码应仅使用order
。默认值:true
(地址未重新排序)。默认值可使用dns.setDefaultResultOrder()
或--dns-result-order
进行配置。¥
verbatim
<boolean> Whentrue
, the callback receives IPv4 and IPv6 addresses in the order the DNS resolver returned them. Whenfalse
, IPv4 addresses are placed before IPv6 addresses. This option will be deprecated in favor oforder
. When both are specified,order
has higher precedence. New code should only useorder
. Default:true
(addresses are not reordered). Default value is configurable usingdns.setDefaultResultOrder()
or--dns-result-order
.
-
-
callback
<Function>-
err
<Error> -
address
<string> IPv4 或 IPv6 地址的字符串表示形式。¥
address
<string> A string representation of an IPv4 or IPv6 address. -
family
<integer>4
或6
,表示address
族,如果地址不是 IPv4 或 IPv6 地址,则表示为0
。0
可能是操作系统使用的名称解析服务中存在错误的指示符。¥
family
<integer>4
or6
, denoting the family ofaddress
, or0
if the address is not an IPv4 or IPv6 address.0
is a likely indicator of a bug in the name resolution service used by the operating system.
-
将主机名(例如 'nodejs.org'
)解析为第一个找到的 A (IPv4) 或 AAAA (IPv6) 记录。所有 option
属性都是可选的。如果 options
是整数,则它必须是 4
或 6
– 如果未提供 options
,则返回 IPv4 或 IPv6 地址,或两者(如果找到)。
¥Resolves a host name (e.g. 'nodejs.org'
) into the first found A (IPv4) or
AAAA (IPv6) record. All option
properties are optional. If options
is an
integer, then it must be 4
or 6
– if options
is not provided, then
either IPv4 or IPv6 addresses, or both, are returned if found.
将 all
选项设置为 true
,callback
的参数更改为 (err, addresses)
,addresses
是具有属性 address
和 family
的对象数组。
¥With the all
option set to true
, the arguments for callback
change to
(err, addresses)
, with addresses
being an array of objects with the
properties address
and family
.
出错时,err
是 Error
对象,其中 err.code
是错误码。记住,err.code
将设置为 'ENOTFOUND'
,不仅当主机名不存在时,而且当查找以其他方式失败时,例如没有可用的文件描述符。
¥On error, err
is an Error
object, where err.code
is the error code.
Keep in mind that err.code
will be set to 'ENOTFOUND'
not only when
the host name does not exist but also when the lookup fails in other ways
such as no available file descriptors.
dns.lookup()
不一定与域名系统协议有任何关系。该实现使用一种操作系统工具,可以将名称与地址关联起来,反之亦然。这种实现会对任何 Node.js 程序的行为产生微妙但重要的影响。在使用 dns.lookup()
之前,请花一些时间查阅 实现的注意事项章节。
¥dns.lookup()
does not necessarily have anything to do with the DNS protocol.
The implementation uses an operating system facility that can associate names
with addresses and vice versa. This implementation can have subtle but
important consequences on the behavior of any Node.js program. Please take some
time to consult the Implementation considerations section before using
dns.lookup()
.
用法示例:
¥Example usage:
import dns from 'node:dns';
const options = {
family: 6,
hints: dns.ADDRCONFIG | dns.V4MAPPED,
};
dns.lookup('example.org', options, (err, address, family) =>
console.log('address: %j family: IPv%s', address, family));
// address: "2606:2800:21f:cb07:6820:80da:af6b:8b2c" family: IPv6
// When options.all is true, the result will be an Array.
options.all = true;
dns.lookup('example.org', options, (err, addresses) =>
console.log('addresses: %j', addresses));
// addresses: [{"address":"2606:2800:21f:cb07:6820:80da:af6b:8b2c","family":6}]
const dns = require('node:dns');
const options = {
family: 6,
hints: dns.ADDRCONFIG | dns.V4MAPPED,
};
dns.lookup('example.org', options, (err, address, family) =>
console.log('address: %j family: IPv%s', address, family));
// address: "2606:2800:21f:cb07:6820:80da:af6b:8b2c" family: IPv6
// When options.all is true, the result will be an Array.
options.all = true;
dns.lookup('example.org', options, (err, addresses) =>
console.log('addresses: %j', addresses));
// addresses: [{"address":"2606:2800:21f:cb07:6820:80da:af6b:8b2c","family":6}]
如果此方法作为其 util.promisify()
版本被调用,并且 all
未设置为 true
,则它为具有 address
和 family
属性的 Object
返回 Promise
。
¥If this method is invoked as its util.promisify()
ed version, and all
is not set to true
, it returns a Promise
for an Object
with address
and
family
properties.