Node.js dnsPromises.resolve() Method
Last Updated :
10 Sep, 2024
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The
dnsPromises.resolve() method
is an inbuilt application programming interface of the promises object of dns module which is used to resolve hostname into an array of the resource records.
Syntax:
dnsPromises.resolve( hostname, rrtype )Parameters:
This method has two parameters as mentioned above and described below:
- hostname: This parameter specifies a string which denotes the hostname to be resolved.
- rrtype: It specifies resource record type. Its default value is 'A'. The values are from 'A', 'AAAA', 'ANY', 'CNAME', 'MX', 'TXT', 'NS', 'NAPTR', 'PTR', 'SOA', 'SRV'.
- 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
Return Value:
This method returns error, records. Below examples illustrate the use of
dnsPromises.resolve() method
in Node.js:
Example 1:
// Node.js program to demonstrate the
// dnsPromises.resolve() method
// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;
// Set the rrtype value for
// dnsPromises.resolve() method
const rrtype="NS";
// Calling dnsPromises.resolve() method
dnsPromises.resolve('geeksforgeeks.org', rrtype).then((res) => {
console.log(res);
});
Output:
[ 'ns-869.awsdns-44.net',
'ns-245.awsdns-30.com',
'ns-1520.awsdns-62.org',
'ns-1569.awsdns-04.co.uk' ]
Example 2:
// Node.js program to demonstrate the
// dnsPromises.resolve() method
// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;
// Setting rrtype for dnsPromises.resolve() method
const rrtype = "MX";
// Calling dnsPromises.resolve() method asynchronously
(async function() {
// Records from resolve function
const records = await dnsPromises.resolve('geeksforgeeks.org', rrtype);
// Printing records
console.log("from async: ");
console.log(records);
})();
Output:
from async:
[ { exchange: 'alt2.aspmx.l.google.com', priority: 5 },
{ exchange: 'aspmx.l.google.com', priority: 1 },
{ exchange: 'alt3.aspmx.l.google.com', priority: 10 },
{ exchange: 'alt4.aspmx.l.google.com', priority: 10 },
{ exchange: 'alt1.aspmx.l.google.com', priority: 5 }
]
Example 3:
// Node.js program to demonstrate the
// dnsPromises.resolve() method
// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;
// Set the rrtype for dnsPromises.resolve() method
const rrtype = "A";
// Calling dnsPromises.resolve() method
dnsPromises.resolve('geeksforgeeks.org', rrtype).then((res) => {
console.log(res);
});
Output:
[ '8.8.8.8' ]
Example 4:
// Node.js program to demonstrate the
// dnsPromises.resolve() method
// Accessing promises object from dns module
const dns = require('dns');
const dnsPromises = dns.promises;
// Set the rrtype for dnsPromises.resolve() method
const rrtype = "TXT";
// Calling dnsPromises.resolve() method
dnsPromises.resolve('geeksforgeeks.org', rrtype).then((res) => {
console.log(res);
});
Output:
(node:12752) ExperimentalWarning: The dns.promises API is experimental
[ [ 'v=spf1 include:amazonses.com include:_spf.google.com -all' ],
[ 'fob1m1abcdp777bf2ncvnjm08n' ] ]
Note:
The above program will compile and run by using the
node index.js
command.
Reference:
https://nodejs.org/api/dns.html#dns_dnspromises_resolve_hostname_rrtype
