开发一个node应用.md

前端时间遇到一个面试题，你用node做过哪些应用？当时脑袋有一丢丢空白，莫名语塞。以前会认为node是一个环境，但是没有基于此更完善地磨轮子，学得零零散散。今天开发个node应用，来巩固更完善的node知识。

搭建node环境（自行百度）

开发node应用

一个简单的http请求

• touch server.js

var http = require('http');

http.createServer(function(req, resp){
    resp.writeHead(200, {"Content-Type": "text-plain"});
    resp.write('hello node-app');
    resp.end();
}).listen(8080);

这是个基于事件驱动的回调。你调用了http.createServer()返回了个对象，并且监听(listen)了8080端口，成功请求后，返回做了匿名函数做的事。

• 让server.js变成一个模块

var http = require('http');

function start(){
    function onRequest(req, resp){
        resp.writeHead(200, {"Content-Type": "text-plain"});
        resp.write('hello node-app');
        resp.end();
    };
    http.createServer(onRequest).listen(8080);
}


exports.start = start;

• touch index.js

var server = require('./server');
server.start();

• 修改server.js，获取浏览请求的url

var http = require('http');
var url = require('url');

function start(){
    function onRequest(req, resp){
        var pathname = url.parse(req.url).pathname;
        console.log('request for' + pathname + 'received');
        resp.writeHead(200, {"Content-Type": "text-plain"});
        resp.write('hello node-app');
        resp.end();
    };
    http.createServer(onRequest).listen(8081);
}


exports.start = start;

• 认识路由，让不同路由执行不同的业务操作

  • touch router.js

    传入动作handle以及pathname（路由名称）

    如果传入的handle是个方法，便执行，否则log。

     function route(handle, pathname){
         console.log('this is a router for request ' + pathname);
         if(typeof handle[pathname] === 'function'){
             handle[pathname]()
         }else{
             console.log('no request for' + pathname);
         }
     }
     
     exports.route = route;

  • touch requestHandlers.js

    写入两个方法，不同的方法处理不同的逻辑。

     function start(){
         console.log('this is start func logic');
     }
     
     function upload(){
         console.log('this is upload func logic');
     }
     
     exports.start = start;
     exports.upload = upload;

  • 修改index.js

    定义一个对象handel，把requestHandlers对应的方法作为（value）赋值给相应的路由名（key），并且把对象传递给server调用的函数start。

     var server = require('./server');
     var router = require('./router');
     var requestHandlers = require("./requestHandlers");
     
     var handler = {};
     handler['/'] = requestHandlers.start;
     handler['/start'] = requestHandlers.start;
     handler['/upload'] = requestHandlers.upload;
     
     server.start(router.route, handler);

  • 修改server.js

    接收传递进来的参数handel，传回给router调用。

     var http = require('http');
     var url = require('url');
     
     function start(route, handle){
         function onRequest(req, resp){
             var pathname = url.parse(req.url).pathname;
             route(handle, pathname);
             resp.writeHead(200, {"Content-Type": "text-plain"});
             resp.write('hello node-app');
             resp.end();
         };
         http.createServer(onRequest).listen(8081);
     }
     
     exports.start = start;
     

• 在不同路由上做不同的事情

  • 修改server.js，将resp作为参数传给router

     var http = require('http');
     var url = require('url');
     
     function start(route, handle){
         function onRequest(req, resp){
             var pathname = url.parse(req.url).pathname;
             route(handle, pathname, resp);
             // resp.writeHead(200, {"Content-Type": "text-plain"});
             // resp.write('hello node-app');
             // resp.end();
         };
         http.createServer(onRequest).listen(8081);
     }
     
     
     exports.start = start;

  • 修改router.js，将resp传入给handler

     function route(handle, pathname, reps){
         console.log('this is a router for request ' + pathname);
         if(typeof handle[pathname] === 'function'){
             handle[pathname](reps)
         }else{
             console.log('no request for' + pathname);
         }
     }
     
     exports.route = route;

  • 修改requestHandler.js 对resp做不同的处理。

     var exec = require("child_process").exec;
    
     function start(response) {
       console.log("Request handler 'start' was called.");
     
       exec("ls -lah", function (error, stdout, stderr) {
         response.writeHead(200, {"Content-Type": "text/plain"});
         response.write(stdout);
         response.end();
       });
     }
     
     function upload(response) {
       console.log("Request handler 'upload' was called.");
       response.writeHead(200, {"Content-Type": "text/plain"});
       response.write("Hello Upload");
       response.end();
     }
     
     exports.start = start;
     exports.upload = upload;

不同路由请求展示不同界面。 请欣赏渣渣demo

• 再此基础上，做个表单发送请求并返回展示 略。