Node.js:DNS模块的使用

Nodejs的DNS模块包涵有关DNS查询和操作的方法,下面介绍该模块的基本用法以及实现一个DNS查询小工具。

1.获取DNS服务器地址

使用getServers方法,该方法返回一个IP地址组成的数组,如下所示:

const dns = require('dns');
const servers = dns.getServers();
console.log(servers);

返回结果为:

[ '114.114.114.114', '8.8.8.8',
'fec0:0:0:ffff::1', '114.114.114.114',
'8.8.8.8', '114.114.114.114',
'8.8.8.8' ]

2.使用系统特性域名解析获取IP地址

使用dns.lookup(hostname[, options], callback)方法,options参数包涵以下属性:

  • family:地址协议族,必须为4或6的整数
  • hints:设置getaddrinfo的标志,dns.ADDRCONFIG 或者 dns.V4MAPPED(ipv4映射成ipv6)
  • all:false(默认),布尔值,如设置为true,则返回IP数组,否则返回单个IP地址

callback回调函数有三个参数(err,address,family),如果options的all属性设置为true,则只有(err,addresses)参数且addresses为一个数组,数组元素为{address,family}对象。使用如下所示:

dns.lookup('www.baidu.com',(err,address,family)=>{
	if(err) throw err;
	console.log('百度网站的IP地址是:'+address+'地址协议族是:IPV'+family);
});

结果如下:

E:\developmentdocument\nodejsdemo>node dns-example.js
百度网站的IP地址是:14.215.177.37地址协议族是:IPV4

设置options的all为true时,结果如下:

dns.lookup('www.baidu.com',{family:4,all:!0,hints:dns.ADDRCONFIG|dns.V4MAPPED},(err,addresses)=>{
	if(err) throw err;
	addresses.forEach((ele,idx,arr)=>{
		console.log('百度网站的IP地址'+(idx+1)+'是:'+ele.address);
	});
});

结果如下:

E:\developmentdocument\nodejsdemo>node dns-example.js
百度网站的IP地址1是:14.215.177.38
百度网站的IP地址2是:14.215.177.37

3.根据IP和端口获取主机名

使用dns.lookupService(address, port, callback)方法,该方法依赖getnameinfo底层函数。
callback函数有三个参数(err, hostname, service),service是protocol,为http或https,使用如下所示:

dns.lookupService('127.0.0.1',80,(err,hostname,service)=>{
	if(err) console.log(err);
	console.log('该IP对应的主机为:'+hostname+' 协议为:'+service);
});

结果如下:

E:\developmentdocument\nodejsdemo>node dns-example.js
该IP对应的主机为:www.test.zmx.com 协议为:http

4.使用网络域名解析获取IP地址

使用dns.resolve(hostname[, rrtype], callback)方法,rrtype有以下选择:

  • 'A':IPV4,default
  • 'AAAA':IPV6
  • 'MX' - mail exchange records 邮件交换记录
  • 'TXT' - text records 域名配置说明
  • 'SRV' - SRV records 服务器提供的服务
  • 'PTR' - PTR records
  • 'NS' - name server records 域名服务器
  • 'CNAME' - canonical name records 别名记录
  • 'SOA' - start of authority record 起始授权机构
  • 'NAPTR' - name authority pointer record

callback函数有(err, addresses)两个参数,addresses是一个数组,具体成员需要看具体的rrtype,使用如下所示:

//获取IPV4
dns.resolve('www.qq.com','A',(err,address)=>{
	if(err) throw err;
	console.log(address);//结果为[ '14.17.32.211', '14.17.42.40', '59.37.96.63' ]
});
//获取IPV6
dns.resolve('www.qq.com','AAAA',(err,address)=>{
	if(err) throw err;
	console.log(address);//结果为[ '240e:ff:f040:28::a' ]
});
//获取SOA信息
dns.resolve('www.qq.com','SOA',(err,address)=>{
	if(err) throw err;
	console.log(address);
	//结果为
	{ nsname: 'ns-tel1.qq.com',
      hostmaster: 'webmaster.qq.com',
      serial: 1380440321,
      refresh: 300,
      retry: 600,
      expire: 86400,
      minttl: 300 }
});
//获取别名CNAME
dns.resolve('www.baidu.com','CNAME',(err,address)=>{
	if(err) throw err;
	console.log(address);//结果为[ 'www.a.shifen.com' ]
});

resovle还存在很多快捷方法,例如:resolve4,resolve6,resolveCname...等等

5.反向域名解析

使用dns.reverse(ip, callback)方法,callback有两个参数(err, hostnames),hostnames是一个域名数组,使用如下所示:

dns.reverse('114.114.114.114',(err,hostnames)=>{
	if(err) throw err;
	console.log(hostnames);//结果为[ 'public1.114dns.com' ]
});

学完了以上的知识后,可以做个DNS查询的小工具,如下所示:
第一步,写个HTML静态页面,如下:

<!DOCTYPE html>
<html lang="en">
<head>
	<meta charset="UTF-8">
	<title>DNS查询工具</title>
	<style type="text/css">
		html,body{ width: 100%; height: 100%; }
		body{ display: flex; align-items: center; justify-content: center; flex-direction: column; }
		*{ margin:0; padding: 0; }
		ul{ list-style: none; }
		.res{line-height: 24px; color:#333; }
		.clearfix:after{ display: block; content:''; height: 0; visibility: hidden; clear: both;}
		.fl{ float:left; }
		.g-wrap{  display: flex;  width:560px;  height: 40px; }
		.u-list{position: relative; flex:1;  }
		.u-inp{flex:3; border:1px solid #ccc; border-left: none; border-right:none; padding:11px 0 11px 10px;}
		.u-btn{ flex:1; }
		.list{ display: none; position: absolute; left: 0px; top:40px; width: 100%; border:1px solid #ccc; border-top:none; border-bottom:none; box-sizing: content-box; }
		.item{ height: 30px; line-height: 30px; text-align: center; color: #666; border-bottom: 1px solid #ccc; cursor:pointer;}
		.item:hover{ color:#0087dc; }
		.u-list .type{ display: block;  width: 100%;  line-height: 38px; border:1px solid #ccc;  text-align: center; color:#666; text-decoration: none; }
		.u-list .type:after{ content: ''; position: absolute; width:0; height:0; border:8px solid transparent; border-top-color:#ccc; right:4px; top:16px;}
		.u-inp input{ width: 100%; border:none; outline: none; height: 18px; line-height: 18px; color:#666; vertical-align: top; font-size: 14px; }
		.u-btn .btn{ display: block; line-height: 40px; text-align: center; background-color: #0087dc; color:#fff; font-size: 16px; cursor:pointer; transition: background-color .3s;}
		.u-btn .btn:hover{ background-color: #0060b2; }
	</style>
</head>
<body>
	<div id="res" class="res"></div>
	<div class="g-wrap clearfix">
		<div class="u-list fl">
			<a href="javascript:;" class="type" id="type" data-value="A">IPV4</a>
			<ul id="list" class="list">
				<li class="item" data-value="A">IPV4</li>
				<li class="item" data-value="AAAA">IPV6</li>
				<li class="item" data-value="CNAME">CNAME</li>
				<li class="item" data-value="SOA">SOA</li>
			</ul>
		</div>
		<div class="u-inp fl">
			<input type="text" class="host" id="host" placeholder="请输入域名">
		</div>
		<div class="u-btn fl">
			<span class="btn" id="btn">查询</span>
		</div>
	</div>
	<script>
		function hide(el){
			el.style.display = 'none';
		}
		function show(el){
			el.style.display = 'block';
		}
		function dealResult(responseText){
			var ips = [],
				result = '';
			ips = JSON.parse(responseText).ips;
			if(Array.isArray(ips)){
				result = ips.length > 0 ? ips.join('<br />') : '没有查询到结果';
			}else if({}.toString.call(ips) === '[object Object]'){
				result = JSON.stringify(ips);
			}
			res.innerHTML = result;
		}
		type.addEventListener('click',function(e){
			e.stopPropagation();
			show(list);
		},!1);
		[].slice.call(document.body.querySelectorAll('.item')).forEach(function(el,idx,arr){
			el.addEventListener('click',function(e){
				type.innerText = this.innerText;
				type.dataset.value = this.dataset.value;
			},!1);
		});
		document.body.addEventListener('click',function(e){
			if(list.style.display === 'block'){ hide(list); }
		},!1);
		btn.addEventListener('click',function(e){
			var hostname = host.value.trim(),
				rrtype   = type.dataset.value.toUpperCase();
			if(hostname == '') return;
			if(hostname.indexOf('http://') === 0) hostname = hostname.replace('http://','');
			var xhr = new XMLHttpRequest(),
				method = "POST",
				url = "/dnslookup";

			xhr.open(method, url, true);
			xhr.onreadystatechange = function() {
				if (xhr.readyState === XMLHttpRequest.DONE && xhr.status === 200) {
					dealResult(xhr.responseText);
				}
			};
			xhr.setRequestHeader("Content-Type","application/x-www-form-urlencoded");
			xhr.send('host='+hostname+'&rrtype='+rrtype);
		},!1);
	</script>
</body>
</html>

接着编写服务端代码,如下:

var http = require('http'),
	url  = require('url'),
	dns  = require('dns'),
	qs   = require('querystring'),
	fs   = require('fs');

function router(req,res,pathname){
	switch(pathname){
		case '/dnslookup':
			lookup(req,res);
			break;
		default:
			showIndex(req,res);
	}
}

function showIndex(req,res){
	var pagePath = __dirname+'/'+'dns-lookup.html';
	var html = fs.readFileSync(pagePath);
	res.end(html);
}

function lookup(req,res){
	var postData = '';
	req.on('data',function(data){
		postData+=data;
	});
	req.on('end',function(data){
		var json = qs.parse(postData);
		var hostname = json.host;
		var rrtype = json.rrtype;
		dns.resolve(hostname,rrtype,function(err,adresses){
			if(err){
				res.end(JSON.stringify({errcode:1,ips:[]}));
			}
			res.end(JSON.stringify({errcode:0,ips:adresses}));
		});
		
	});
}

http.createServer(function(req,res){
    var pathname = url.parse(req.url).pathname;
    req.setEncoding("utf8");
    res.writeHead(200,{'Content-Type':'text/html'});
    router(req,res,pathname);
}).listen(3000,'127.0.0.1');

运行效果如下:

到此这个小工具便完成了。

posted @ 2016-11-23 11:16  SniffRose  阅读(2406)  评论(1编辑  收藏