//引入模块
var http = require(‘http‘),
url = require(‘url‘),
querystring = require(‘querystring‘),
fs = require(‘fs‘),
dns = require(‘dns‘);
//展现填写页面。由res.end输出查询的form表单
var goIndex = function(req, res){
res.end("<html>" +
"<head>" +
"<title>DNS查询</title>" +
"<meta http-equiv=‘content-type‘ content=‘text/html;charset=utf-8‘>" +
"</head>" +
"<body>" +
"<form action=‘/parse‘ method=‘post‘>" +
"<input type=‘text‘ name=‘search_dns‘/>" +
"<input type=‘submit‘ value=‘查询‘ />" +
"</form>" +
"</body>" +
"</html>");
};
//dns解析函数。通过dns模块的dns.resolve解析，解析成功执行回调,回调中把值写到参数函数的入参中
var goDns = function(postData, callback){
var domainValue = querystring.parse(postData).search_dns; //获取post数据中的search_dns
dns.resolve(domainValue, function(err, addresses){
if(!addresses){
addresses = [‘域名不存在‘];
}
callback(domainValue, addresses);
});
};
//dns解析。获取post过来的数据，用dns模块进行解析，输出解析结果
var parseDns = function(req, res){
//读取post过来的数据
var postData = ‘‘;
//req请求对象有addListener方法，‘data‘事件是有数据传送到服务端时触发，‘end‘是在数据发送完毕时触发
req.addListener(‘data‘, function(dataChunk){
postData += dataChunk;
});
req.addListener(‘end‘, function(){//数据完全传送完毕，进行dns解析
goDns(postData, function(domain, addresses){//回调中输出解析结果展示页面
res.end("<html>" +
"<head>" +
"<meta http-equiv=‘content-type‘ content=‘text/html;charset=utf-8‘>" +
"</head>" +
"<div>" +
"domain: <span>" + domain + "</span>" +
"ip:" + addresses.join(‘,‘) +
"</div>" +
"</html>");
});
});
};
var router = function(req, res, pathname){
switch(pathname){
case ‘/parse‘ :
parseDns(req, res);
break;
default :
goIndex(req, res);
}
};
http.createServer(function(req, res){
//获取请求相对路径
var pathname = url.parse(req.url).pathname;
//将请求设置为utf-8防止乱码
req.setEncoding(‘utf8‘);
//写返回的头
res.writeHead(200, {‘Content-Type‘ : ‘text/html‘});
//router请求路径若为/parse则进行dns解析，若不是则展示填写页面
router(req, res, pathname);
})
.listen(3000, ‘127.0.0.1‘);
参考：《node.js开发实战详解》清华大学出版社，此文可以看作是此书的读书笔记
时间： 2024-10-25 15:54:02