Python简单实现WebSocket

实现一个简单的聊天室程序,代码如下:

#-*- coding:utf8 -*-

import threading
import hashlib
import socket
import base64

global clients
clients = {}

#通知客户端
def notify(message):
    for connection in clients.values():
        connection.send('%c%c%s' % (0x81, len(message), message))

#客户端处理线程
class websocket_thread(threading.Thread):
    def __init__(self, connection, username):
        super(websocket_thread, self).__init__()
        self.connection = connection
        self.username = username
    
    def run(self):
        print 'new websocket client joined!'
        data = self.connection.recv(1024)
        headers = self.parse_headers(data)
        token = self.generate_token(headers['Sec-WebSocket-Key'])
        self.connection.send('\
HTTP/1.1 101 WebSocket Protocol Hybi-10\r\n\
Upgrade: WebSocket\r\n\
Connection: Upgrade\r\n\
Sec-WebSocket-Accept: %s\r\n\r\n' % token)
        while True:
            try:
                data = self.connection.recv(1024)
            except socket.error, e:
                print "unexpected error: ", e
                clients.pop(self.username)
                break
            data = self.parse_data(data)
            if len(data) == 0:
                continue
            message = self.username + ": " + data
            notify(message)
            
    def parse_data(self, msg):
        v = ord(msg[1]) & 0x7f
        if v == 0x7e:
            p = 4
        elif v == 0x7f:
            p = 10
        else:
            p = 2
        mask = msg[p:p+4]
        data = msg[p+4:]
        return ''.join([chr(ord(v) ^ ord(mask[k%4])) for k, v in enumerate(data)])
        
    def parse_headers(self, msg):
        headers = {}
        header, data = msg.split('\r\n\r\n', 1)
        for line in header.split('\r\n')[1:]:
            key, value = line.split(': ', 1)
            headers[key] = value
        headers['data'] = data
        return headers

    def generate_token(self, msg):
        key = msg + '258EAFA5-E914-47DA-95CA-C5AB0DC85B11'
        ser_key = hashlib.sha1(key).digest()
        return base64.b64encode(ser_key)

#服务端
class websocket_server(threading.Thread):
    def __init__(self, port):
        super(websocket_server, self).__init__()
        self.port = port

    def run(self):
        sock = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
        sock.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
        sock.bind(('127.0.0.1', self.port))
        sock.listen(5)
        print 'websocket server started!'
        while True:
            connection, address = sock.accept()
            try:
                username = "ID" + str(address[1])
                thread = websocket_thread(connection, username)
                thread.start()
                clients[username] = connection
            except socket.timeout:
                print 'websocket connection timeout!'

if __name__ == '__main__':
    server = websocket_server(9000)
    server.start()

测试页面:

<!--
@http://www.cnblogs.com/zhuweisky/p/3930780.html
-->
<!DOCTYPE html>
</html>
    <head>
        <meta charset="utf-8">
    </head>
    <body>
        <h3>WebSocketTest</h3>
        <div id="login">
            <div>
                <input id="serverIP" type="text" placeholder="服务器IP" value="127.0.0.1" autofocus="autofocus" />
                <input id="serverPort" type="text" placeholder="服务器端口" value="9000" />
                <input id="btnConnect" type="button" value="连接" onclick="connect()" />
            </div>
            <div>
                <input id="sendText" type="text" placeholder="发送文本" value="I'm WebSocket Client!" />
                <input id="btnSend" type="button" value="发送" onclick="send()" />
            </div>
            <div>
                <div>
                    来自服务端的消息
                </div>
                <textarea id="txtContent" cols="50" rows="10" readonly="readonly"></textarea>
            </div>
        </div>
    </body>
    <script>
        var socket;

        function connect() {
            var host = "ws://" + $("serverIP").value + ":" + $("serverPort").value + "/"
            socket = new WebSocket(host);
            try {

                socket.onopen = function (msg) {
                    $("btnConnect").disabled = true;
                    alert("连接成功!");
                };

                socket.onmessage = function (msg) {
                    if (typeof msg.data == "string") {
                        displayContent(msg.data);
                    }
                    else {
                        alert("非文本消息");
                    }
                };

                socket.onclose = function (msg) { alert("socket closed!") };
            }
            catch (ex) {
                log(ex);
            }
        }

        function send() {
            var msg = $("sendText").value
            socket.send(msg);
        }

        window.onbeforeunload = function () {
            try {
                socket.close();
                socket = null;
            }
            catch (ex) {
            }
        };

        function $(id) { return document.getElementById(id); }

        Date.prototype.Format = function (fmt) { //author: meizz 
            var o = {
                "M+": this.getMonth() + 1, //月份 
                "d+": this.getDate(), //日 
                "h+": this.getHours(), //小时 
                "m+": this.getMinutes(), //分 
                "s+": this.getSeconds(), //秒 
                "q+": Math.floor((this.getMonth() + 3) / 3), //季度 
                "S": this.getMilliseconds() //毫秒 
            };
            if (/(y+)/.test(fmt)) fmt = fmt.replace(RegExp.$1, (this.getFullYear() + "").substr(4 - RegExp.$1.length));
            for (var k in o)
                if (new RegExp("(" + k + ")").test(fmt)) fmt = fmt.replace(RegExp.$1, (RegExp.$1.length == 1) ? (o[k]) : (("00" + o[k]).substr(("" + o[k]).length)));
            return fmt;
        }

        function displayContent(msg) {
            $("txtContent").value += "\r\n" +new Date().Format("yyyy/MM/dd hh:mm:ss")+ ":  " + msg;
        }
        function onkey(event) { if (event.keyCode == 13) { send(); } }
    </script>
</html>

参考链接


python简单实现websocket

原生JS写Ajax的请求函数

一般我们写网页的时候,如果用到Ajax请求服务器,都是使用JQuery等已经封装好的库来调用,比较简单。

但是一般这些库的功能很多,引入了太多我们用不到的东西,如果我们需要写一个功能单一,简单的页面,完全用不到引用如此庞大的库文件。

我们可以简单实现一个自己的Ajax请求功能,具体的代码如下:

var ajax = {};
ajax.x = function () {
	if (typeof XMLHttpRequest !== 'undefined') {
		return new XMLHttpRequest();
	}
	var versions = [
	"MSXML2.XmlHttp.6.0",
	"MSXML2.XmlHttp.5.0",
	"MSXML2.XmlHttp.4.0",
	"MSXML2.XmlHttp.3.0",
	"MSXML2.XmlHttp.2.0",
	"Microsoft.XmlHttp"
	];

	var xhr;
	for (var i = 0; i < versions.length; i++) {
		try {
			xhr = new ActiveXObject(versions[i]);
			break;
		} catch (e) {
		}
	}
	return xhr;
};

ajax.send = function (url, method, data, success,fail,async) {
	if (async === undefined) {
		async = true;
	}
	var x = ajax.x();
	x.open(method, url, async);
	x.onreadystatechange = function () {
		if (x.readyState == 4) {
			var status = x.status;
			if (status >= 200 && status < 300) {
				success && success(x.responseText,x.responseXML)
			} else {
				fail && fail(status);
			}
			
		}
	};
	if (method == 'POST') {
		x.setRequestHeader('Content-type', 'application/x-www-form-urlencoded');
	}
	x.send(data)
};

ajax.get = function (url, data, callback, fail, async) {
	var query = [];
	for (var key in data) {
		query.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
	}
	ajax.send(url + (query.length ? '?' + query.join('&') : ''), 'GET', null, callback, fail, async)
};

ajax.post = function (url, data, callback, fail, async) {
	var query = [];
	for (var key in data) {
		query.push(encodeURIComponent(key) + '=' + encodeURIComponent(data[key]));
	}
	ajax.send(url,'POST', query.join('&'), callback, fail, async)
};

使用方法:GET

ajax.get('/test.php', {foo: 'bar'}, function(response,xml) {
	//success
},
function(status){
	//fail
});

POST

ajax.post('/test.php', {foo: 'bar'}, function(response,xml) {
	//succcess

},function(status){
	//fail
	
});

这里需要注意一个问题,如果我们想要发送类似

http://www.mobibrw.com/control?op_code=code&op_cmd=cmd

URL,是不能通过上面的发送方式(字段填写在data参数中)发送的,上面的发送方式是属于表单的上传方式。

我们需要用下面的方式进行处理(自己拼凑URL

var sendCmd = "?op_code=" + code + "&op_cmd=" + cmd;
ajax.post('/control' + sendCmd,'',function(response,xml) {
   console.log('success');
},
function(status){
   console.log('failed:' + status);
});

参考链接


树莓派2 B+任务栏(LXPanel)不断闪烁消失(RASPBIAN STRETCH WITH DESKTOP)

长时间不用的一个树莓派2 B+,使用的系统为RASPBIAN STRETCH WITH DESKTOP。在重新加电后,任务栏(LXPanel)不断闪烁消失,貌似启动的时候发生了异常,然后崩溃,重启,循环往复(并不是一直消失不见,而是不断闪烁)。但是查看系统日志,却找不到相关的异常日志。

这种现象,可以通过如下方法解决:

$ sudo apt-get remove --purge lxpanel

$ sudo apt-get install lxpanel

$ sudo apt-get autoremove

$ rm -rf ~/.config/lxpanel/LXDE-pi 

$ sudo reboot

参考链接


树莓派3 B+下次启动强制检查系统分区

树莓派使用的过程中,难免会由于突然断电等原因导致SD卡发生错误。这个时候我们就需要强制让树莓派在下次启动的时候进行磁盘检查。

如果是普通分区,可以卸载后执行fsck命令,但是如果是系统分区,由于一直被占用,因此是没有办法进行磁盘检查的。

网上找了一下,找到了解决办法,可以强制让树莓派在下次系统启动的时候,强制检查系统分区。具体的方式如下:

$ sudo touch /forcefsck

$ sudo reboot

参考链接


Checking sdcard for errors, unmount problem

树莓派3 B+设置静态IP

最近需要为一台`树莓派3 B+`设置静态`IP`地址,结果尝试了半天总是不成功。

网上搜索了一下,找到解决方法。

修改`/etc/dhcpcd.conf`文件

$ sudo vim /etc/dhcpcd.conf

在文件的尾部增加如下内容:

interface eth0

static ip_address=192.168.0.10/24
static routers=192.168.0.1
static domain_name_servers=192.168.0.1

interface wlan0

static ip_address=192.168.0.200/24
static routers=192.168.0.1
static domain_name_servers=192.168.0.1

上面的配置文件中,`eth0`是有线的配置, `wlan0`是无线配置
`ip_address`就是静态`IP`, 后面要接`/24`
`routers`是网关
`domain_name_servers`是`DNS`

参考链接


设置树莓派3 B+的静态IP