Node.js dns.resolveCname() Method
The dns.resolveCname() method is an inbuilt application programming interface of the dns module which is used to resolve CNAME records for the specified hostname using DNS protocol.
Syntax:
dns.resolveCname( hostname, callback )
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.
- callback: It specifies a function to be called after DNS resolution of the hostnames.
- error: It specifies error if generated.
- addresses: It is an array of string that signifies the returned cname addresses for the hostname.
Return Value: This method returns error, addresses through callback function, These data are passed as parameters to the callback function.
Below examples illustrate the use of dns.resolveCname() method in Node.js:
Example 1:
// Node.js program to demonstrate the // dns.resolveAny() method // Accessing dns module const dns = require('dns'); // Calling dns.resolveCname() method for hostname // w3wiki.net and displaying them in // console as a callback dns.resolveCname('w3wiki.net', (err, addresses) => console.log('addresses: %j', addresses)); |
Output:
QueryReqWrap {
bindingName: 'queryCname',
callback: [Function],
hostname: 'w3wiki.net',
oncomplete: [Function: onresolve],
ttl: false,
channel: ChannelWrap {} }
addresses: undefined
Example 2:
// Node.js program to demonstrate the // dns.resolveAny() method // Accessing dns module const dns = require('dns'); // Calling dns.resolveCname() method for hostname // w3wiki.net and displaying them in // console as a callback dns.resolveCname('localhost', (err, addresses) => console.log('addresses: %j', addresses)); |
Output:
QueryReqWrap {
bindingName: 'queryCname',
callback: [Function],
hostname: 'localhost',
oncomplete: [Function: onresolve],
ttl: false,
channel: ChannelWrap {} }
addresses: undefined
Note: The above program will compile and run by using the node index.js command.
Reference: https://nodejs.org/api/dns.html#dns_dns_resolvecname_hostname_callback