node 循序渐进

1. 执行   

node helloworld.js

2. http  服务器 

建 server.js 文件 -  node server.js  跑起来 -  浏览器访问  http://localhost:8888/  （服务器控制台观看访问次数）

var http = require("http");
var count=(function(){
  var num=0;
  return function(){
    num++;
    return num;
  }
}());
http.createServer(function (request, response) {
  response.writeHead(200, {
    "Content-Type": "text/plain"
  });
  response.write("Hello World");
  response.end();
  console.log('server'+count());
}).listen(8888);

3. http  服务器   模块化方式实现

建主文件 入口  index.js   -   写模块化功能并导出对应接口 server.js  -   运行 node index  -  访问 http://localhost:8888/ 

index.js

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

start.start();

server.js

function handle(request, response) {
  response.writeHead(200, {
    "Content-Type": "text/plain"
  });
  response.write("Hello World");
  response.end();
  console.log('server' + count());
}

var count = (function () {
  var num = 0;
  return function () {
    num++;
    return num;
  }
}());

var http = require("http");

function start(){
  http.createServer(handle).listen(8888);
  console.log("Server working.");
}

exports.start = start;

 4. http 服务器 + router 模块化 整合

index.js

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

var route=require('./router');

server.server(route.route);

 

router.js

function route(pathname) {

console.log("About to route a request for " + pathname);

}

exports.route = route;

 

server.js

var count = (function () {
  var num = 0;
  return function () {
    num++;
    return num;
  }
}());

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

function server(route){
  function handle(request, response) {
    var pathname = url.parse(request.url).pathname;
    route(pathname);
    response.writeHead(200, {
      "Content-Type": "text/plain"
    });
    response.write("Hello World");
    response.end();
    console.log('server' + count());
  }
  http.createServer(handle).listen(8888);
  console.log("Server working.");
}

exports.server = server;

 5. 低耦合 http 服务器

index.js

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

var router = require('./router');

var requestHandlers = require("./requestHandlers");

var handle = {};

handle["/"] = requestHandlers.start;

handle["/start"] = requestHandlers.start;

handle["/upload"] = requestHandlers.upload;

server.server(router.route, handle);

 

server.js

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

function server(route, handle){
  function requestHandle(request, response) {
    var pathname = url.parse(request.url).pathname;
    route(handle, pathname);
    response.writeHead(200, {
      "Content-Type": "text/plain"
    });
    response.write("Hello World");
    response.end();
  }
  http.createServer(requestHandle).listen(8888);
  console.log("Server working.");
}

exports.server = server;

router.js

function route(handle, pathname) {

console.log("About to route a request for " + pathname);

if (typeof handle[pathname] === 'function') {

handle[pathname]();

} else {

console.log("No request handler found for " + pathname);

}

}

exports.route = route;

 

requestHandlers.js

function start() {
  console.log("Request handler 'start' was called.");
}

function upload() {
  console.log("Request handler 'upload' was called.");
}
exports.start = start;
exports.upload = upload;

 改变为

function start() {

var now = new Date().getTime();

while (new Date().getTime() < now + 10000) {

}

return 'start';

}

多标签页顺序访问    http://localhost:8888/start    http://localhost:8888/upload    演示阻塞。