Node.js dns.resolveAny()方法

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

dns.resolveAny()方法是 dns 模块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:

dns.resolveAny( hostname, callback )

参数:该方法有两个参数，如上所述，如下所述:

  • Hostname: This parameter specifies a string that represents the hostname to be resolved.
  • Callback: Specifies the function to be called after DNS resolution of the host name.
    • Error: The specified generation error.
    • ret: It is an object that represents the return record of the host name.

返回值:此方法返回错误，通过回调函数记录。这些数据作为参数传递给回调函数。

可以返回的记录有:

  • 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 dns.resolveAny()方法的使用:

例 1:

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

// Accessing dns module
const dns = require('dns');

// Calling dns.resolveAny() method for 
// hostname geeksforgeeks.org and displaying
// them in console as a callback
dns.resolveAny('geeksforgeeks.org', (err, 
    ret) => console.log('records: %j', ret));

输出:

records: [
    {"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"}
]

例 2:

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

// Accessing dns module
const dns = require('dns');

// Calling dns.resolveAny() method for 
// hostname localhost and displaying
// them in console as a callback
dns.resolveAny('localhost', (err, 
    ret) => console.log('records: %j', ret));

输出:

records: [
    {"address":"127.0.0.1", "ttl":0, "type":"A"}
]

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 _ DNS _ resolveany _ hostname _ callback

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