使用 JavaScript 快速构建 高性能 可扩展 网络应用 的开发平台

四大金刚

三个好汉

woman.js

 1:  function Woman(name, age) {
 2:      Person.call(this, name);
 3:  
 4:      this.introduce = function(){
 5:          return this.name + " is " + (age - 10);
 6:      };
 7:  }
 8:  Woman.prototype = new Person();
 9:  Woman.prototype.constructor = Woman;
10:  
11:  var mary = new Woman("mary", 34);
12:  var rose = new Woman("rose", 45);
13:  console.log(mary.introduce());
14:  console.log(rose.introduce());
15:  //output: mary is 24
16:  //        rose is 35

wget http://nodejs.org/dist/v0.10.12/node-v0.10.12.tar.gz
tar xzf node-v0.10.12.tar.gz
./configure
make
sudo make install

~$ node -e 'console.log("hello node.js");'
hello node.js

按 CommonJS 模块规范 实现

woman_module.js

1:  var value = 10; //module private variable.
2:  exports.Woman = function (name, age) {
3:      this.name = name;
4:      this.introduce = function(){
5:          return this.name + " is " + (age - value);
6:      };
7:  };

woman_module_usage.js

1:  var Woman = require("./woman_module.js").Woman;
2:  var woman1 = new Woman("mary", 34);
3:  var woman2 = new Woman("rose", 45);
4:  console.log(woman1.introduce());
5:  console.log(woman2.introduce());

woman_class_module.js

1:  var value = 10; //module private variable.
2:  module.exports = function (name, age) {
3:      this.name = name;
4:      this.introduce = function(){
5:          return this.name + " is " + (age - value);
6:      };
7:  };

woman_class_module_usage.js

1:  var Woman = require("./woman_class_module.js");
2:  var woman1 = new Woman("mary", 34);
3:  var woman2 = new Woman("rose", 45);
4:  console.log(woman1.introduce());
5:  console.log(woman2.introduce());

按 CommonJS包规范 实现

Node.js是一个全新的开发平台

所有会阻塞的api都以异步回调的方式进行封装

1:  <?php
2:      echo "wait...\n";
3:      sleep(3);
4:      echo "wait...\n";
5:      sleep(5);
6:      echo "done\n";
7:  ?>

PHP: SLEEP IF YOU WANT

1:  console.log('wait...');
2:  setTimeout(function () {
3:      console.log('wait...');
4:      setTimeout(function () {
5:          console.log('done');
6:      }, 5000);
7:  }, 3000);

NODE: NO SLEEP

所有可以发出事件的对象都是events.EventEmitter类的实例，如：net.Server、fs.readStream。

 1:  var Woman = require('./woman_class_module.js');
 2:  var EventEmitter = require('events').EventEmitter;
 3:  var util = require('util');
 4:  
 5:  var Goddess = function (name, age) {
 6:      EventEmitter.call(this);
 7:  
 8:      this.woman = new Woman(name, age);
 9:      this.introduce = function () {
10:          var words = this.woman.introduce();
11:          this.emit('say', words);
12:      };
13:  };
14:  util.inherits(Goddess, EventEmitter);
15:  
16:  
17:  var goddess = new Goddess('刘亦菲', 25);
18:  goddess.on('say', function (words) {
19:                 console.log('转发： ' + words);
20:             });
21:  
22:  
23:  goddess.introduce();

net.Socket支持的事件：

connect

连接成功

data

收到数据

end

连接的另一端要求断开连接

timeout

连接空闲时间过长

drain

写缓冲区变空

error

有错误发生

close

连接已关闭

echo_server.js

 1:  var net = require('net');
 2:  
 3:  var server = net.createServer(
 4:      function (socket) {
 5:          socket.pipe(socket);
 6:      }
 7:  );
 8:  
 9:  server.listen(8001);
10:  console.log("Server running");

~$ node ./echo_server.js
Server running

~$ telnet 127.0.0.1 8001
hello
hello

在Node.js中，除了代码，一切都是并行的！

node ./echo_server.js

var net = require('net');

1:  var server = net.createServer(
2:      function (socket) {
3:          socket.pipe(socket);
4:      }
5:  );

server.listen(8001);

console.log("Server running");