node.js入门1

参考：

Node入门 » 一本全面的Node.js教程  https://www.nodebeginner.org/index-zh-cn.html

用node.js实现简单的web服务器 - loogn - 博客园  https://www.cnblogs.com/loogn/p/3362475.html

安装：

https://nodejs.org/en/ 下载64位安装。安装完后，会添加node.js和node.js command prompt。

Hello World：

编辑一个hello.js文件，内容只有一句

console.log("Hello World");

运行

node hello.js

一个完整的基于node.js的web应用

1、服务器模块

项目的根目录下创建一个server.js

var http = require("http");
http.createServer(function(request, response) {
  response.writeHead(200, {"Content-Type": "text/plain"});
  response.write("Hello World");
  response.end();
}).listen(8888);

运行node server.js，打开浏览器访问http://localhost:8888/，浏览器会出现Hello World。

包装server.js变成模块

var http = require("http");
function start() {
  function onRequest(request, response) {
    console.log("Request received.");
    response.writeHead(200, {"Content-Type": "text/plain"});
    response.write("Hello World");
    response.end();
  }
  http.createServer(onRequest).listen(8888);
  console.log("Server has started.");
}
exports.start = start;

创建index.js，内容

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

2、路由

改写server.js

var http = require("http");
var url = require("url");
function start() {
  function onRequest(request, response) {
    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");
    response.writeHead(200, {"Content-Type": "text/plain"});
    response.write("Hello World");
    response.end();
  }
  http.createServer(onRequest).listen(8888);
  console.log("Server has started.");
}
exports.start = start;

新建route.js文件

function route(pathname) {
  console.log("About to route a request for " + pathname);
}
exports.route = route;

使用依赖注入改写server.js

var http = require("http");
var url = require("url");
function start(route) {
  function onRequest(request, response) {
    var pathname = url.parse(request.url).pathname;
    console.log("Request for " + pathname + " received.");
    route(pathname);
    response.writeHead(200, {"Content-Type": "text/plain"});
    response.write("Hello World");
    response.end();
  }
  http.createServer(onRequest).listen(8888);
  console.log("Server has started.");
}
exports.start = start;

相应的index.js也要改写

var server = require("./server");
var router = require("./router");

server.start(router.route);