用NodeJS创建一个聊天服务器

Node 是专注于创建网络应用的，网络应用就需要许多I/O(输入/输出)操作。让我们用Node实现有多么简单，并且还能轻松扩展。

创建一个TCP服务器

var net = require('net');
var chatServer = net.createServer();

chatServer.on("connection", function(client) {
    client.write('Hi!
');
    client.on('data', function(data) {
        console.log(data);

    });

});
chatServer.listen(9000);

我们用Telnet 连接上localhost:9000,向服务器发送hi,Node显示出一堆二进制的数据，原来Javascript无法很好的处理的二进制数据，所以引入Buffer库来处理。

客户端互相发送消息

var net = require('net');
var chatServer = net.createServer();
clientList = [];
chatServer.on("connection", function(client) {
    client.write('Hi!
');
    client.name = client.remoteAddress + ":" + client.remotePort;
    client.write('Hi' + client.name + '
');
    clientList.push(client);
    client.on('data', function(data) {
        broadcast(data, client);
    });

});

function broadcast(msg, client) {
    for (var i = 0, clen = clientList.length; i < clen; i++) {
        if (client !== clientList[i]) {
            clientList[i].write(client.name + " says " + msg + "
");
        }

    }
}
chatServer.listen(9000);

当我们断开其中的一个客户端的话，服务器会报如下错误：

检查socket可写状态将程序变得更健壮

var net = require('net');
var chatServer = net.createServer();
clientList = [];
chatServer.on("connection", function(client) {
    client.write('Hi!
');
    client.name = client.remoteAddress + ":" + client.remotePort;
    client.write('Hi' + client.name + '
');
    clientList.push(client);
    client.on('data', function(data) {
        broadcast(data, client);
    });
    //客户端退出
    client.on('end', function() {
        console.log(client.name + " quit");
        clientList.splice(clientList.indexOf(client), 1);
    });

});

function broadcast(msg, client) {
    var cleanup = [];
    for (var i = 0, clen = clientList.length; i < clen; i++) {
        if (client !== clientList[i]) {
            //检查socket是否可写
            if (clientList[i].writable) {
                clientList[i].write(client.name + " says " + msg + "
");
            } else {
                cleanup.push(clientList[i]);
                clientList[i].destroy(); //对断开连接的socket进行销毁
            }
        }
    }
    //在写入循环中删除死节点，消除垃圾索引
    for (var i = 0, clenuplen = cleanup.length; i < clenuplen; i++) {
        clientList.splice(clientList.indexOf(cleanup[i]), 1);
    }
}
chatServer.listen(9000);

记录错误日志

 //记录错误日志
    client.on('error', function(e) {
        console.log(e);
    })

为client对象添加error事件后，客户端发生的任何错误都会被记录下来。