dns.lookupService(address, port, callback)

• address <string>
• port <number>
• callback <Function>
  • err <Error>
  • hostname <string> 例如 example.com
  • service <string> 例如 http

使用操作系统的底层 getnameinfo 实现将给定的 address 和 port 解析为主机名和服务。

如果 address 不是有效的 IP 地址，则会抛出 TypeError。 port 将被强制为数字。 如果不是合法的端口，则会抛出 TypeError。

出错时，err 是 Error 对象，其中 err.code 是错误码。

const dns = require('dns');
dns.lookupService('127.0.0.1', 22, (err, hostname, service) => {
  console.log(hostname, service);
  // 打印: localhost ssh
});

如果此方法作为其 util.promisify() 版本被调用，则其将为具有 hostname 和 service 属性的 Object 返回 Promise。

• address <string>
• port <number>
• callback <Function>
  • err <Error>
  • hostname <string> e.g. example.com
  • service <string> e.g. http

Resolves the given address and port into a host name and service using the operating system's underlying getnameinfo implementation.

If address is not a valid IP address, a TypeError will be thrown. The port will be coerced to a number. If it is not a legal port, a TypeError will be thrown.

On an error, err is an Error object, where err.code is the error code.

const dns = require('dns');
dns.lookupService('127.0.0.1', 22, (err, hostname, service) => {
  console.log(hostname, service);
  // Prints: localhost ssh
});

If this method is invoked as its util.promisify()ed version, it returns a Promise for an Object with hostname and service properties.