Node.js dnsPromises.resolveAny() Method

The dnsPromises.resolveAny() method is an inbuilt application programming interface of the promises object of dns module which is used to resolve all records (i.e. ‘ANY’ or ‘*’) for the specified hostname using DNS protocol.

Syntax:

dnsPromises.resolveAny( hostname )

Parameters: This method accepts a single parameter as mentioned above and described below:

hostname: This parameter specifies a string which denotes the hostname to be resolved.

Return: This method returns error, records.
Records that may be returned are among

A: IPv4 address
AAAA: IPv6 address
ANY: Any records
CNAME: canonical name records
MX: mail exchange records
NAPTR: name authority pointer records
NS: name server records
PTR: pointer records
SOA: start of authority records
SRV: service records
TXT: text records

Below examples illustrate the use of dnsPromises.resolveAny() method in Node.js:

Example 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); 
});

Output:

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' } ]

Example 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);    
})();

Output:

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' } ]

Note: The above program will compile and run by using the node index.js command.

Reference: https://nodejs.org/api/dns.html#dns_dnspromises_resolveany_hostname

Article Tags :

Node.js

Web Technologies

Node.js-dns-module