一、什麼是WebSocket
API
GET /chat HTTP/1.1Upgrade: WebSocketConnection: UpgradeHost: www.zendstudio.net:9108Origin: http://www.zendstudio.netCookie: somenterCookie
這很是有些類似於http的頭資訊，同樣每行都是以”\r\n”結尾的，上面這段格式無需我們去構造，WebSocket對象會自動發送，對用戶端這是透明的。此時服務端應該返回的資訊是：
HTTP/1.1 101 Web Socket Protocol HandshakeUpgrade: WebSocketConnection: UpgradeWebSocket-Origin: http://www.zendstudio.netWebSocket-Location: ws://www.zendstudio.net:9108/chat
從這裡我們太容易看出來，websocket協議的握手部分根本就是個類http的協議，所不同的是http每次都會有這樣子的頭資訊互動，這在某些時候不得不顯得很糟糕。而websocket只會執行一次這個過程，之後的傳輸資訊就變得異常簡潔了。
握手協議：request中有三個隨機的key值，頭部有兩個，後面body裡是長度為8位元組的key3（括弧裡的文字是提示，還有字元間的冒號也是為了看上去清晰才加上的，真正傳輸是沒有的），以此向server發送一個challenge，server需要根據這三個key計算出一個token，在響應中發回給client，以證明自己對request的正常解讀。計算方法是這樣的：對於key1，抽取其中的數字字元，形成一個整數num，然後除以他自身的空格數spaces，保留整數部分i1;<html><head><title>WebSocket</title> <style> html,body{font:normal 0.9em arial,helvetica;} #log {width:440px; height:200px; border:1px solid #7F9DB9; overflow:auto;} #msg {width:330px;}</style> <script>var socket; function init(){ var host = "ws://10.3.18.105:19887/"; try{ socket = new WebSocket(host); socket.onopen = function(msg){ ; }; socket.onmessage = function(msg){ log(msg.data); }; socket.onclose = function(msg){ log("Lose Connection!"); }; } catch(ex){ log(ex); } $("msg").focus();} function send(){ var txt,msg; txt = $("msg"); msg = txt.value; if(!msg){ alert("Message can not be empty"); return; } txt.value=""; txt.focus(); try{ socket.send(msg); } catch(ex){ log(ex); }} window.onbeforeunload=function(){ try{ socket.send('quit'); socket.close(); socket=null; } catch(ex){ log(ex); }}; function $(id){ return document.getElementById(id); }function log(msg){ $("log").innerHTML+="<br>"+msg; }function onkey(event){ if(event.keyCode==13){ send(); } }</script> </head><body onload="init()"> <h3>WebSocket</h3> <br><br> <div id="log"></div> <input id="msg" type="textbox" onkeypress="onkey(event)"/> <button onclick="send()">發送</button></body></html>
四、伺服器端server.py
import socketimport structimport hashlibimport threading,randomconnectionlist = {}def sendMessage(message): global connectionlist for connection in connectionlist.values(): connection.send("\x00%s\xFF" %message)def deleteconnection(item): global connectionlist del connectionlist['connection'+item]class WebSocket(threading.Thread): def __init__(self, conn, index, name, remote, path="/"): threading.Thread.__init__(self) self.conn = conn self.index = index self.name = name self.remote = remote self.path = path self.buffer = "" def run(self): print 'Socket %s Start!' %self.index headers = {} self.handshaken = False while True: if self.handshaken == False: print 'Socket %s Start Handshaken with %s!' %(self.index, self.remote) self.buffer += self.conn.recv(1024) if self.buffer.find('\r\n\r\n') != -1: header, data = self.buffer.split('\r\n\r\n', 1) for line in header.split("\r\n")[1:]: key, value = line.split(": ", 1) headers[key] = value headers["Location"] = "ws://%s%s" %(headers["Host"], self.path) print headers key1 = headers["Sec-WebSocket-Key1"] key2 = headers["Sec-WebSocket-Key2"] if len(data) < 8: data += self.conn.recv(8-len(data)) key3 = data[:8] self.buffer = data[8:] token = self.generate_token(key1, key2, key3) handshake = '\HTTP/1.1 101 Web Socket Protocol Handshake\r\n\Upgrade: WebSocket\r\n\Connection: Upgrade\r\n\Sec-WebSocket-Origin: %s\r\n\Sec-WebSocket-Location: %s\r\n\r\n\' %(headers['Origin'], headers['Location']) self.conn.send(handshake + token) self.handshaken = True print 'Socket %s Handshaken with %s success!' %(self.index, self.remote) sendMessage('Welcome, ' + self.name + ' !') else: self.buffer += self.conn.recv(64) if self.buffer.find("\xFF") != -1: s = self.buffer.split("\xFF")[0][1:] if s == 'quit': print 'Socket %s Logout !' %(self.index) sendMessage(self.name + ' Logout') deleteconnection(str(self.index)) self.conn.close() break else: print 'Socket %s Got msg: %s from %s!' %(self.index,s,self.remote) sendMessage(self.name + ':' + s) self.buffer = "" def generate_token(self, key1, key2, key3): num1=int("".join([digit for digit in list(key1) if digit.isdigit()])) spaces1 = len([char for char in list(key1) if char == " "]) num2 = int("".join([digit for digit in list(key2) if digit.isdigit()])) spaces2 = len([char for char in list(key2) if char == " "]) combined = struct.pack(">II", num1/spaces1, num2/spaces2) + key3 return hashlib.md5(combined).digest()class WebSocketServer(object): def __init__(self): self.socket = None def begin(self): print "WebSocketSerber Start!" self.socket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) self.socket.bind(("10.3.18.105", 19887)) self.socket.listen(50) global connectionlist i = 0 while True: connection, address = self.socket.accept() username = address[0] newSocket = WebSocket(connection, i, username, address) newSocket.start() conectionlist['connection'+str(i)] = connection i = i + 1if __name__ == "__main__": server = WebSocketServer() server.begin()Start building with 50+ products and up to 12 months usage for Elastic Compute Service
1 on 1 presale consultation
24/7 Technical Support 6 Free Tickets per Quarter Faster Response
Alibaba Cloud offers highly flexible support services tailored to meet your exact needs.
A comprehensive suite of global cloud computing services to power your business
Payment Methods We Support
