很久沒寫博，最近用到了socket.io，在網上找了挺多例子都不太好懂，於是自己查了文件寫了個示例，僅當筆記記錄到CSDN。

伺服器示例程式碼：

'use strict';

const socket_io = require('socket.io');

const http = require('http');
const server = http.createServer();

const io = socket_io(server, {
	path : '/',
	// pingTimeout : 60000,
	// pingInterval : 25000, // 預設每隔 25 秒向客戶端發一次 ping 訊息
});

var sockets = {};

process.on('SIGINT', () =>
{
	// 不斷開與客戶端的連線，則客戶端預設會每隔 1~5 秒自動發起一次對伺服器的重連
	// for (let id in sockets)
	// {
		// sockets[id].removeAllListeners();
		// sockets[id].disconnect(true);
	// }

	// 關閉 socket.io 伺服器，不再接受客戶端連線
	server.close();
});

// 客戶端回撥
var cli_cb = function (...args)
{
	console.log('client callback:', ...args);
};

// 廣播訊息到除 socket 外的客戶端
var broadcast = function (socket, event, ...args)
{
	socket.broadcast.emit(event, ...args);
};

io.on('connect', (socket) =>
{
	console.log('connection:', socket.id);
	sockets[socket.id] = socket;

	// 給剛建立連線的 server 客戶端傳送訊息
	socket.emit('cli_event', socket.id, Math.random(), cli_cb);

	// 廣播到除客戶端 socket 自身外已連線 server 的所有客戶端
	broadcast(socket, 'cli_broadcast', socket.id, { hello : socket.id, world : { lilei : undefined } });

	// 廣播到所有連線 server 的客戶端
	io.emit('cli_whole', socket.id, { hello : 'wolrd' });

	// 處理客戶端發來的訊息
	socket.on('srv_event', (id, param, fn_ack) =>
	{
		console.log('%s srv_event', socket.id, id, param);

		// 向客戶端回覆訊息
		if (fn_ack)
		{
			fn_ack(socket.id, { srv_rpc : Math.random() });
		}
	});

	socket.on('disconnect', (reason) =>
	{
		broadcast(socket, 'cli_closed', socket.id);

		console.log('%s disconnected: %s', socket.id, reason);
		socket.removeAllListeners();
		socket.disconnect(true);
		delete sockets[socket.id];
	})
	.on('error', (err) =>
	{
		console.log('error: %s', err.stack);
	});
});

server.listen(12345);
 

'use strict'

const socket_io_client = require('socket.io-client');
const socket = socket_io_client('http://127.0.0.1:12345');
// const socket = socket_io_client('http://182.254.229.133:12345');

process.on('SIGINT', () =>
{
	socket.disconnect();
});

// 伺服器回覆的訊息
var srv_cb = function (...args)
{
	console.log('server callback:', ...args);
};

socket.on('connect', () =>
{
	console.log('%s connected', socket.id);
})
.on('disconnect', (reason) =>
{
	console.log('Disconnected: %s', reason);
	socket.disconnect();
})
.on('reconnect', (attempt) => // 重連成功會觸發此事件
{
	// attempt 為嘗試重連的次數
	console.log('reconnect', attempt);
})
.on('reconnect_attempt', () =>
{
	console.log('reconnect_attempt');
})
.on('reconnecting', (attempt) => // 正在重連時會觸發此事件
{
	console.log('reconnecting', attempt);
})
.on('reconnect_error', (err) =>
{
	console.log('reconnect_error', err);
})
.on('reconnect_failed', () =>
{
	console.log('reconnect_failed');
})
.on('ping', () =>
{
	console.log('ping received');
})
.on('pong', (latency) =>
{
	// latency 為從傳送 ping 後到收到伺服器迴應 pong 中間間隔的毫秒數
	console.log('pong %d ms', latency);
})
.on('error', (err) =>
{
	console.log('error: %s', err.stack);
})
// 伺服器發來一般訊息
.on('cli_event', (id, param, fn_ack) =>
{
	console.log('%s cli_event', id, param);

	socket.emit('srv_event', socket.id, param, srv_cb);

	// 回覆伺服器訊息
	if (fn_ack)
	{
		fn_ack(socket.id, { client : Math.random() });
	}
})
// 伺服器發來其他客戶端訊息
.on('cli_broadcast', (id, ...args) =>
{
	console.log('%s cli_broadcast', id, ...args);
})
// 伺服器發來廣播訊息
.on('cli_whole', (id, ...args) =>
{
	console.log('%s cli_whole', id, ...args);
})
// 伺服器要求客戶端斷開連線
.on('cli_closed', (id) =>
{
	console.log('cli_closed', id);
	socket.disconnect();
});