Node.js Manual & Documentation

Table Of Contents

DNS DNS模块

Use require('dns') to access this module.

使用require('dns')来访问这个模块。

Here is an example which resolves 'www.google.com' then reverse resolves the IP addresses which are returned.

下面这个例子首先将'www.google.com'解析为IP地址，再对返回的IP地址做反向解析。

var dns = require('dns');

dns.resolve4('www.google.com', function (err, addresses) {
  if (err) throw err;

  console.log('addresses: ' + JSON.stringify(addresses));

  addresses.forEach(function (a) {
    dns.reverse(a, function (err, domains) {
      if (err) {
        console.log('reverse for ' + a + ' failed: ' +
          err.message);
      } else {
        console.log('reverse for ' + a + ': ' +
          JSON.stringify(domains));
      }
    });
  });
});

dns.lookup(domain, family=null, callback)

Resolves a domain (e.g. 'google.com') into the first found A (IPv4) or AAAA (IPv6) record.

将一个域名(例如'google.com')解析成为找到的第一个A(IPv4)或者AAAA(IPv6)记录。

The callback has arguments (err, address, family). The address argument is a string representation of a IP v4 or v6 address. The family argument is either the integer 4 or 6 and denotes the family of address (not necessarily the value initially passed to lookup).

回调函数有(err, address, family)这三个参数。address参数是一个代表IPv4或IPv6地址的字符串。family是一个表示地址版本的整数4或6(并不一定和调用lookup时传入的family参数值相同)。

dns.resolve(domain, rrtype='A', callback)

Resolves a domain (e.g. 'google.com') into an array of the record types specified by rrtype. Valid rrtypes are A (IPV4 addresses), AAAA (IPV6 addresses), MX (mail exchange records), TXT (text records), SRV (SRV records), and PTR (used for reverse IP lookups).

将域名(比如'google.com')按照参数rrtype所指定类型的解析结果放到一个数组中。合法的类型为A（IPV4地址），AAAA（IPV6地址），MX（邮件交换记录），TXT（文本记录），SRV（SRV记录），和PTR（用于反向IP解析）。

The callback has arguments (err, addresses). The type of each item in addresses is determined by the record type, and described in the documentation for the corresponding lookup methods below.

回调函数接受两个参数：(err, addresses)。参数address中的每一项的类型根据所要求的记录类型进行判断，在下面相应的解析方法的文档里有详细的解释。

On error, err would be an instanceof Error object, where err.errno is one of the error codes listed below and err.message is a string describing the error in English.

当有错误发生时，参数err的内容是一个Error对象的实例，err.errno属性是下面错误代码列表中的一个，err.message属性是一个用英语表述的错误解释。

dns.resolve4(domain, callback)

The same as dns.resolve(), but only for IPv4 queries (A records). addresses is an array of IPv4 addresses (e.g. ['74.125.79.104', '74.125.79.105', '74.125.79.106']).

与dns.resolve()类似，但是仅对IPV4地址进行查询（A记录）。addresses是一个IPV4地址数组（例如['74.125.79.104', '74.125.79.105', '74.125.79.106']）。

dns.resolve6(domain, callback)

The same as dns.resolve4() except for IPv6 queries (an AAAA query).

除了这个函数是对IPV6地址的查询（一个AAAA查询）外与dns.resolve4()很类似。

dns.resolveMx(domain, callback)

The same as dns.resolve(), but only for mail exchange queries (MX records).

与dns.resolve()很类似，但是仅做邮件交换地址查询（MX类型记录）。

addresses is an array of MX records, each with a priority and an exchange attribute (e.g. [{'priority': 10, 'exchange': 'mx.example.com'},...]).

回调函数的参数addresses是一个MX类型记录的数组，每个记录有一个优先级属性和一个交换属性（类似[{'priority': 10, 'exchange': 'mx.example.com'},...]）。

dns.resolveTxt(domain, callback)

The same as dns.resolve(), but only for text queries (TXT records). addresses is an array of the text records available for domain (e.g., ['v=spf1 ip4:0.0.0.0 ~all']).

与dns.resolve()很相似，但是仅可以进行文本查询（TXT记录）。addressed是一个对于domain域有效的文本记录数组（类似['v=spf1 ip4:0.0.0.0 ~all']）。

dns.resolveSrv(domain, callback)

The same as dns.resolve(), but only for service records (SRV records). addresses is an array of the SRV records available for domain. Properties of SRV records are priority, weight, port, and name (e.g., [{'priority': 10, {'weight': 5, 'port': 21223, 'name': 'service.example.com'}, ...]).

与dns.resolve()很类似，但仅是只查询服务记录（SRV类型记录）。addresses是一个对于域来说有效的SRV记录的数组，SRV记录的属性有优先级、权重、端口，名字（例如[{'priority': 10, {'weight': 5, 'port': 21223, 'name': 'service.example.com'}, ...]）。

dns.reverse(ip, callback)

Reverse resolves an ip address to an array of domain names.

反向解析一个IP地址到一个域名数组。

The callback has arguments (err, domains).

回调函数的参数为 (err, domains)。

If there an an error, err will be non-null and an instanceof the Error object.

如果发生了错误，err将被置为一个非空的Error对象实例。

Each DNS query can return an error code.

每个DNS查询可以返回如下错误代码：