node.js处理url常用方法

处理非阻塞I/O
/*
*回调函数的方法 异步
*/
/*
function f(cb){
 fs.readFile('./4',(err,data)=>{
     cb(data.toString()); //回调
})
}

f(function(data){
  console.log(data);
});

*/
function f(){
  fs.readFile('./4',(err,data)=>{
    myEvent.emit('talk',data.toString());//事件进行绑定
})
}

//执行 ----发布者

f();
myEvent.on('talk',(data)=>{
  console.log(data); //data == data.toString()
})

三URL模块 和queryString模块;
var queryString = require('quirestring');
//查询字符串， 
//queryString.parse(string)将字符串解析成对象；
let str = 'name:idhorse?age:18?gender:male';
let obj = queryString.parse(str,'?',':')
//默认情况下 第二个参数是&，第三个是=
//解析结果 {name:'idhorse',age:'18',gender:'male'};
//queryString.stringify()将一个对象解析成一个字符串
let str2 = queryString.stringify(obj,'&','=');
//'name=idhorse&age=18&gender=male'

 querystring模块

 querystring.eacape( "" );对给定的 str 进行 URL 编码

 querystring.uneacape( "" );对给定的 str 进行解码

 querystring.stringify()   方法  将一个对象转成字符串

 querystring.parse()  方法  将一个字符串转成对象  

let a = encodeURIComponent(str)//进行编码加密处理
let b = decodeURIComponent(a);//进行解码处理


解析url 
var http = require('http'),
    urlApi = require('url'),
    server;
server = http.createSever((request,response)=>{
    response.writeHead(200,{'Content-type':'text/plain;charset=UTF-8'});

if(request.url!='/favicon.ico'){
   let url = urlApi.parse(request.url,true);
   cosoleo.log(url);
   if(url.pathname=='/a.html'){
    res.end('这里请求的是a.html，请求的参数是')
   }
}
 response.end('收到请求！');

}).listen(3000,()=>{
   console.log('start')
})

//====

解析url
 var http = require('http'),
     server;
 sever = http.createServer(function(request,response){
    response.writeHead(200,{'Content-type':'text/plain;charset=UTF-8'});
    let url = request.url;
    if(url！= '/favicon.ico'){
     let arr1 = url.split('?');
     let arr2 = arr1[1].split('&');
     let Obj = {};
     arr2.map(function(data,i){
     Obj[data.split('=')[0]]=data.split('=')[1];
})
     if(arr1[0]=='/a.html'){
       response.end('这里请求的是a.html,请求的参数是'+JSON.stringify(Obj));
     }
  }
  response.end('收到请求！');
}).listen(3000);
//=======
处理post请求
var http = require('http');
var server = http.createServer((req,res)=>{
 res.writeHead(200,{'Content-type':'text/plain;charset=UTF-8'});
   console.log('req,url');
   let str = '';
   res.on(data,(data)=>{
   'use strict';
   str+= data;
  });
  res.on('end',()=>{
   console.log(str);
  });
  res.write('收到请求！');
  res.end();
}).listen(3000);
// 项目文件上传 formidable
  let http = require('http');
  let urlLib = require('url');
  let fs = require('fs');
  let pathLib = require('path');
  let formidable = reqiure('formidable');

  let server = http.createServer((req,res)=>{
  let urlObj = urlLib.parse(req.url,true);
   if(urlObj.pathname==='/'){
     res.readFile('./template/form.html',(err,data)=>{
   res.write(data);
   res.end();
    })
   }
    if(urlObj==='/upload'){
      let form = formidable.IncomingForm();
      form.encoding = 'utf-8';
      form.upLoadDir = _dirname+'/folder';
      form.parse(req,function(err,fields,files){
    if(err)throw err;
    console.log(files);
    let ext = pathLib.exname(files.wangpengde.name);
    let oldPath = files.wangpengde.path;
    let newPath = pathLib.join(_dirname,'/folder/')+files.wangpengde.name;
    fs.rename(oldPath,newPath,(err)=>{
     if(err)throw err;
     console.log(ext);
     res.writeHead(200,{'content-type':'text/plain;charset=UTF-8'});
     res.write('成功！');
     res.end();
    })
   })
   }
})
  
 server.listen(3000,()=>{
  console.log('start');
  })

  三. http模块
  const http = require('http');
  const  cheerio = require('cheerio');
  http.get('http://www.easyvoa.com',function(res){
    if(res.statusCode ==200){
      let str = '';
      res.on('data',(data)=>{
          str += data;
      });
      res.on('end',()=>{
        const $ = cheerio.load(str);
        const titles = $('.title_a');
      for(let i = 0; i<titles.length ;i++){
         console.log(titles.eq(i).text());
      }
      })
    }
})