node . js dnspromses . resolveany()方法

原文:https://www . geesforgeks . org/node-js-dnspromses-resolve any-method/

dnsPromises.resolveAny()方法是 dns 模块 Promises 对象的内置应用编程接口，用于使用 DNS 协议解析指定主机名的所有记录(即“Any”或“*”)。

语法:

dnsPromises.resolveAny( hostname )

参数:该方法接受如上所述的单个参数，如下所述:

• 主机名:该参数指定一个字符串，该字符串表示要解析的主机名。

返回:此方法返回错误，记录。 可能归还的记录包括

• A: IPv4 地址
• AAAA: IPv6 地址
• 任意:任意记录
• CNAME: 典名记载
• MX: 邮件交换记录
• NAPTR: 名称权限指针记录
• NS: 名称服务器记录
• PTR: 指针记录
• SOA: 权限记录的开始
• SRV: 服务记录
• TXT: 文字记录

下面的例子说明了在 Node.js 中使用 dnsPromises.resolveAny()方法:

例 1:

// Node.js program to demonstrate the   
// dnsPromises.resolveAny() method

// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;

// Calling dnsPromises.resolveAny() method 
dnsPromises.resolveAny('geeksforgeeks.org').then((res) => {
    console.log("for geeksforgeeks : ");
    console.log(res);
});

// Calling dnsPromises.resolveAny() method 
dnsPromises.resolveAny('localhost').then((res) => {
    console.log("for localhost : ");
    console.log(res);
});

输出:

for localhost :
[ { address: '127.0.0.1', ttl: 0, type: 'A' } ]
for geeksforgeeks :
[ { exchange: 'alt1.aspmx.l.google.com', priority: 5, type: 'MX' },
  { exchange: 'alt2.aspmx.l.google.com', priority: 5, type: 'MX' },
  { exchange: 'aspmx.l.google.com', priority: 1, type: 'MX' },
  { exchange: 'alt3.aspmx.l.google.com', priority: 10, type: 'MX' },
  { exchange: 'alt4.aspmx.l.google.com', priority: 10, type: 'MX' },
  { value: 'ns-1520.awsdns-62.org', type: 'NS' },
  { value: 'ns-1569.awsdns-04.co.uk', type: 'NS' },
  { value: 'ns-245.awsdns-30.com', type: 'NS' },
  { value: 'ns-869.awsdns-44.net', type: 'NS' },
  { entries:
     [ 'v=spf1 include:amazonses.com include:_spf.google.com -all' ],
    type: 'TXT' },
  { entries: [ 'fob1m1abcdp777bf2ncvnjm08n' ], type: 'TXT' },
  { nsname: 'ns-869.awsdns-44.net',
    hostmaster: 'awsdns-hostmaster.amazon.com',
    serial: 1,
    refresh: 7200,
    retry: 900,
    expire: 1209600,
    minttl: 86400,
    type: 'SOA' } ]

例 2:

// Node.js program to demonstrate the   
// dnsPromises.resolveAny() method

// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;

// Calling dnsPromises.resolveAny() method 
// asynchronously 
(async function() {

    // Records from resolveAny function
    const records = await dnsPromises.resolveAny('geeksforgeeks.org');

    // Printing  records
    console.log("from async: ");
    console.log(records);   
})();

输出:

from async:
[ { exchange: 'alt4.aspmx.l.google.com', priority: 10, type: 'MX' },
  { exchange: 'alt1.aspmx.l.google.com', priority: 5, type: 'MX' },
  { exchange: 'alt2.aspmx.l.google.com', priority: 5, type: 'MX' },
  { exchange: 'aspmx.l.google.com', priority: 1, type: 'MX' },
  { exchange: 'alt3.aspmx.l.google.com', priority: 10, type: 'MX' },
  { value: 'ns-869.awsdns-44.net', type: 'NS' },
  { value: 'ns-1520.awsdns-62.org', type: 'NS' },
  { value: 'ns-245.awsdns-30.com', type: 'NS' },
  { value: 'ns-1569.awsdns-04.co.uk', type: 'NS' },
  { entries:
     [ 'v=spf1 include:amazonses.com include:_spf.google.com -all' ],
    type: 'TXT' },
  { entries: [ 'fob1m1abcdp777bf2ncvnjm08n' ], type: 'TXT' },
  { nsname: 'ns-869.awsdns-44.net',
    hostmaster: 'awsdns-hostmaster.amazon.com',
    serial: 1,
    refresh: 7200,
    retry: 900,
    expire: 1209600,
    minttl: 86400,
    type: 'SOA' } ]

注意:以上程序使用node index.js命令编译运行。

参考:https://nodejs . org/API/DNS . html # DNS _ dnsprymes _ resolve any _ hostname

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