网站后端_Flask-第三方库.利用Flask-Socketio扩展构建实时流应用?
模塊簡(jiǎn)介:
說(shuō)明: 此模塊主要用于構(gòu)建支持實(shí)時(shí),雙向基于事件的通信,將Websocket和Polling等其它實(shí)時(shí)通信方式封裝成了通用接口,從而可在各個(gè)平臺(tái)/瀏覽器/設(shè)備上穩(wěn)定工作.
快速安裝:
pip?install?flask-socketio <script?src="https://cdn.socket.io/socket.io-1.4.5.js"></script>應(yīng)用場(chǎng)景:
1. 實(shí)時(shí)分析, 服務(wù)端將數(shù)據(jù)推送到客戶端,客戶端可以為實(shí)時(shí)計(jì)數(shù)器,圖表,日志等
2. 實(shí)時(shí)聊天, 通過(guò)命名空間和房間實(shí)現(xiàn)服務(wù)端Socket多路復(fù)用.
3. 流式傳輸, 已經(jīng)支持任何二進(jìn)制文件的傳輸,包括圖片,視頻,音頻.
4. 文檔合并, 運(yùn)行多個(gè)用戶同時(shí)編輯一個(gè)文檔,并且能夠看到每個(gè)用戶做出的修改.
原理介紹:
客戶端: 利用基于flashsocket/websocket/iframe等封裝的的socket對(duì)象和通用抽象方法(transport接口),包含數(shù)據(jù)編碼/解碼/心跳處理等
服務(wù)端: 利用namespace+room實(shí)現(xiàn)服務(wù)端socket多路復(fù)用,namespace基于客戶端url中path部分區(qū)分應(yīng)用,不同應(yīng)用相互隔離,默認(rèn)為/,room基于客戶端指定namespace和room限制應(yīng)用消息有效范圍,如果沒(méi)有指定,則除了自己外其它屬于此namespace的socket都會(huì)收到消息.
常用事件:
| 服務(wù)端 | |
| connect | 當(dāng)客戶端與服務(wù)端連接成功后被觸發(fā) |
| message | 當(dāng)客戶端使用send發(fā)送數(shù)據(jù)時(shí)被觸發(fā) |
| disconnect | 當(dāng)客戶端與服務(wù)端失去連接時(shí)被觸發(fā),如關(guān)閉瀏覽器,主動(dòng)斷開,掉線等任何斷開連接的情況. |
| 客戶端 | |
| connect | 當(dāng)客戶端與服務(wù)端連接成功后被觸發(fā) |
| message | 當(dāng)服務(wù)端使用send發(fā)送數(shù)據(jù)時(shí)被觸發(fā) |
| disconnect | 當(dāng)客戶端主動(dòng)斷開連接時(shí)被觸發(fā). |
接收消息: [客戶端發(fā)送消息<- 回調(diào)確認(rèn) -> 服務(wù)接收消息]
# 方式一: 客戶端通過(guò)send發(fā)送的未命名事件數(shù)據(jù),服務(wù)端只能使用默認(rèn)message事件接收處理, 客戶端定義的事件回調(diào)函數(shù)接收的數(shù)據(jù)來(lái)自于服務(wù)端message事件處理函數(shù)的返回值
socket.send([data], ...., callback)
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);socket.on('connect',?function(){socket.send({'data':?'hello?word!'},?function(data){console.log('#=>?recive?server?data',?data.data);});}); </script>
@io.on('message') def?message_handler(*args):print?'#=>?recive?{0}?data?from?client'.format(type(args[0])),?argsreturn?args
# 方式二: 客戶端通過(guò)emit發(fā)送的命名事件數(shù)據(jù),服務(wù)端只能使用對(duì)應(yīng)自定義事件接收處理, 客戶端定義的事件回調(diào)函數(shù)接收的數(shù)據(jù)來(lái)自于服務(wù)端對(duì)應(yīng)事件處理函數(shù)的返回值
socket.emit(event_name, [data], ...., callback)
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);socket.on('connect',?function(){socket.emit('connect?event',?{'data':?'hello?word!'},?function(data){console.log('#=>?recive?server?data',?data.data);});}); </script>
@io.on('connect?event') def?connect_event_handler(*args):print?'#=>?recive?{0}?data?from?client'.format(type(args[0])),?argsreturn?args
發(fā)送消息: [服務(wù)端發(fā)送消息 <- 回調(diào)確認(rèn) -> 客戶端接收消息]
# 方式一: 服務(wù)端通過(guò)send發(fā)送的未命名事件數(shù)據(jù),可指定namespace, callback, broadcast, room, include_self額外參數(shù),客戶端只能使用默認(rèn)message事件接收處理,服務(wù)端自定義的回調(diào)函數(shù)接收的數(shù)據(jù)來(lái)自于客戶端對(duì)回調(diào)函數(shù)的調(diào)用,不是return的值.
send(message, namespace, callback, broadcast, room, include_self)
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);socket.on('message',?function(data,?func){console.log('#=>?recive?server?data',?data.data);func();}); </script>
def?message_event_callback(*args):print?'#=>?client?called?{0}'.format(inspect.stack()[0][-4:-2]) @io.on('connect') def?connect_event_handler():io.send({'data':?'hello?word!'},?callback=message_event_callback)
# 方式二: 服務(wù)端通過(guò)emit發(fā)送的命名事件數(shù)據(jù),可指定namespace, callback, broadcast, room, include_self額外參數(shù),客戶端只能使用對(duì)應(yīng)自定義事件接收處理,服務(wù)端自定義的回調(diào)函數(shù)接收的數(shù)據(jù)來(lái)自于客戶端對(duì)回調(diào)函數(shù)的調(diào)用,不是return的值.
emit(event, args, namespace, callback, broadcast, room, include_self)
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);socket.on('connect?event',?function(data,?func){console.log('#=>?recive?server?data',?data.data);func();}); </script>
def?connect_event_callback(*args):print?'#=>?client?called?{0}'.format(inspect.stack()[0][-4:-2]) @io.on('connect') def?connect_event_handler():io.emit('connect?event',{'data':?'hello?word!'},callback=message_event_callback)
廣播消息: [服務(wù)端發(fā)送消息 <- 回調(diào)確認(rèn) -> 客戶端接收消息]
# 方式一: 服務(wù)端通過(guò)send發(fā)送的未命名事件數(shù)據(jù),指定broadcast=True額外參數(shù),可配合namespace/room/include_self額外參數(shù)來(lái)控制消息發(fā)往的應(yīng)用,發(fā)往的房間,是否發(fā)給自己,客戶端只能使用默認(rèn)message事件接收處理
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);var?user?=?{name:?['zmanman',?'qmanman',?'smanman',?'lmanman'][Math.ceil(Math.random()*3)],};console.log('#=>?current?user:?',?user);socket.on('connect',?function(){socket.send(user);});socket.on('message',?function(data){var?$content?=?$('<p>廣播:?'+?data.name?+'上線.</p>');$('#socketio').append($content);}); </script>
@io.on('message',?namespace='/') def?online_notify_handler(*args):print?'#=>?recive?{0}?data?from?client'.format(type(args[0])),?argssend(args[0],?broadcast=True)
# 方式二: 服務(wù)端通過(guò)emit發(fā)送的命名事件數(shù)據(jù),指定broadcast=True額外參數(shù),可配合namespace/room/include_self額外參數(shù)來(lái)控制消息發(fā)往的應(yīng)用,發(fā)往的房間,是否發(fā)給自己,客戶端只能使用對(duì)應(yīng)自定義事件接收處理
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);var?user?=?{name:?['zmanman',?'qmanman',?'smanman',?'lmanman'][Math.ceil(Math.random()*3)],};console.log('#=>?current?user:?',?user);socket.on('connect',?function(){socket.emit('online?notify',?user);});socket.on('online?notify',?function(data){var?$content?=?$('<p>廣播:?'+?data.name?+'上線.</p>');$('#socketio').append($content);}); </script>
@io.on('online?notify',?namespace='/') def?online_notify_handler(*args):print?'#=>?recive?{0}?data?from?client'.format(type(args[0])),?argsemit('online?notify',?args[0],?broadcast=True)
分組廣播: [服務(wù)端發(fā)送消息 <- 回調(diào)確認(rèn) -> 客戶端接收消息]
# 方式一: 服務(wù)端通過(guò)send發(fā)送的未命名事件數(shù)據(jù),指定broadcast=True和room=xxoo額外參數(shù),可配合namespace/include_self額外參數(shù)來(lái)控制消息發(fā)往的應(yīng)用,發(fā)往的房間,是否發(fā)給自己,服務(wù)端提供了join_room和leave_room函數(shù)來(lái)對(duì)請(qǐng)求分組,客戶端只能使用默認(rèn)message事件接收處理
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);var?name?=?['zmanman',?'qmanman',?'smanman',?'lmanman',][Math.ceil(Math.random()*3)];socket.on('connect',?function(){socket.send('user?join',?{'room':?'room1',?'user':?name});});socket.on('message',?function(data){if(data.action=='sys?boradcast'){console.log('公告:?'?+?data.message);};}); </script>
#!/usr/bin/env?python #?-*-?coding:?utf-8?-*- #?@Date????:?2016-12-27?19:22:04 #?@Author??:?李滿滿?(xmdevops@vip.qq.com) #?@Link????:?http://xmdevops.blog.51cto.com/ #?@Version?:?$Id$ from?__future__?import?absolute_import #?說(shuō)明:?導(dǎo)入公共模塊 from?flask?import?request from?datetime?import?datetime from?flask_socketio?import?join_room,?leave_room #?說(shuō)明:?導(dǎo)入其它模塊 from?.?import?io io.room_users?=?{} io.reqid_info?=?{} @io.on('connect') def?connect_event_handler():@io.on('message')def?user_join_handler(action,?data):if?action?==?'user?join':room?=?data['room']user?=?data['user']susr?=?'{0}_{1}'.format(user,?request.sid)io.room_users.setdefault(room,?[]).append(susr)join_room(room)io.reqid_info.setdefault(request.sid,?{}).update({'room':?room,'user':?user,})message?=?'#=>?[{0}]?user:?{1}?action:?{2}?room?{3}.'.format(datetime.now(),?susr,?'join',?room)print?messageprint?'#=>?current?rooms:',?io.room_users.keys()users?=?[]for?item_users?in?io.room_users.itervalues():users.extend(item_users)print?'#=>?current?users:',?usersio.send({'action':?'sys?boradcast',?'message':?message})@io.on('disconnect')def?disconnect_handler():user?=?io.reqid_info[request.sid]['user']susr?=?'{0}_{1}'.format(user,?request.sid)room?=?io.reqid_info[request.sid]['room']io.room_users[room].remove(susr)message?=?'#=>?[{0}]?user:?{1}?action:?{2}?room?{3}.'.format(datetime.now(),?susr,?'leave',?room)print?messageprint?'#=>?current?rooms:',?io.room_users.keys()users?=?[]for?item_users?in?io.room_users.values():users.extend(item_users)print?'#=>?current?users:',?usersio.send({'action':?'sys?boradcast',?'message':?message})leave_room(room)
說(shuō)明: 如上定義io.room_users = {},io.reqid_info = {}分別存儲(chǔ)房間用戶和請(qǐng)求信息,主要是為了存儲(chǔ)在線用戶以及用戶信息,實(shí)際生產(chǎn)中可用Redis等后端替換.
擴(kuò)展: 此插件運(yùn)行時(shí)內(nèi)存中也維護(hù)了一份兒request.sid屬于哪個(gè)namespace哪個(gè)room,但由于connect時(shí)沒(méi)有指定namespace和room而room并沒(méi)有默認(rèn)值,作者使用了None代替,并且為了后續(xù)的雙向回調(diào)跟蹤,所以在room中也包含了request.sid,而且在接口方面也做的不盡人意,所以還是推薦自己手動(dòng)實(shí)現(xiàn)幾個(gè)全局對(duì)象來(lái)存儲(chǔ)這些信息.
# 方式二: 服務(wù)端通過(guò)emit發(fā)送的命名事件數(shù)據(jù),指定broadcast=True和room=xxoo額外參數(shù),可配合namespace/include_self額外參數(shù)來(lái)控制消息發(fā)往的應(yīng)用,發(fā)往的房間,是否發(fā)給自己,服務(wù)端提供了join_room和leave_room函數(shù)來(lái)對(duì)請(qǐng)求分組,客戶端只能使用自定義事件接收處理
<script?type="text/javascript">var?socket?=?io.connect(location.protocol+'//'+document.domain+':'+location.port);var?name?=?['zmanman',?'qmanman',?'smanman',?'lmanman',][Math.ceil(Math.random()*3)];socket.on('connect',?function(){socket.emit('user?join',?{'room':?'room1',?'user':?name});});socket.on('sys?broadcast',?function(data){console.log('公告:?'?+?data.message);}); </script>
#!/usr/bin/env?python #?-*-?coding:?utf-8?-*- #?@Date????:?2016-12-27?19:22:04 #?@Author??:?李滿滿?(xmdevops@vip.qq.com) #?@Link????:?http://xmdevops.blog.51cto.com/ #?@Version?:?$Id$ from?__future__?import?absolute_import #?說(shuō)明:?導(dǎo)入公共模塊 import?inspect from?flask?import?request from?datetime?import?datetime from?flask_socketio?import?join_room,?leave_room #?說(shuō)明:?導(dǎo)入其它模塊 from?.?import?io io.room_users?=?{} io.reqid_info?=?{} @io.on('connect') def?connect_event_handler():@io.on('user?join')def?user_join_handler(data):user?=?data['user']room?=?data['room']susr?=?'{0}_{1}'.format(user,?request.sid)io.room_users.setdefault(room,?[]).append(susr)io.reqid_info.setdefault(request.sid,?{}).update({'room':?room,'user':?user,})join_room(room)message?=?'#=>?[{0}]?user:?{1}?action:?{2}?room:?{3}.'.format(datetime.now(),?susr,?inspect.stack()[0][-4:-2],?room)print?messageusers?=?[]for?item_users?in?io.room_users.itervalues():users.extend(item_users)print?'#=>?current?users:?',?usersio.emit('sys?broadcast',?{'message':?message})@io.on('disconnect')def?disconnect_handler():user?=?io.reqid_info[request.sid]['user']susr?=?'{0}_{1}'.format(user,?request.sid)room?=?io.reqid_info[request.sid]['room']io.room_users[room].remove(susr)message?=?'#=>?[{0}]?user:?{1}?action:?{2}?room:?{3}.'.format(datetime.now(),?susr,?inspect.stack()[0][-4:-2],?room)print?messageio.emit('sys?broadcast',?{'message':?message})leave_room(room)
錯(cuò)誤處理:
#?說(shuō)明:?處理指定NameSpace的異常 @io.on_error() def?error_handler(e):print?request.event['message']print?request.event['args'] #?說(shuō)明:?處理所有NameSpace的異常 @io.on_error_default def?default_error_handler(e):print?request.event['message']print?request.event['args']
說(shuō)明: request.event是在被io.on裝飾的時(shí)候被附加上去的屬性,是一個(gè)字典,默認(rèn)包含message和args,也就是事件名和事件相關(guān)的參數(shù),在出現(xiàn)異常時(shí)可通過(guò)打印它們來(lái)獲取異常請(qǐng)求信息.
異步切換:
說(shuō)明: flask-socketio和客戶端和服務(wù)端的交互是雙向的,當(dāng)你循環(huán)send/emit的時(shí)候會(huì)出現(xiàn)緩沖區(qū)阻塞,可通過(guò)io.sleep(0.1)或import eventlet;eventlet.monkey_patch()打補(bǔ)丁來(lái)實(shí)現(xiàn)異步IO,但是這樣發(fā)送極快,如果使用eventlet或基于eventlet的gevent異步協(xié)程庫(kù)的時(shí)候使用eventlet.sleep(0.1),減慢切換時(shí)間,這樣防止瀏覽器端卡死.
全局對(duì)象:
說(shuō)明: 作為FLASK插件,基于程序上下文可使用current_app, g全局對(duì)象,基于請(qǐng)求上下文可使用request, session全局對(duì)象, 所有的會(huì)話是基于request.sid, 且運(yùn)行時(shí)會(huì)自動(dòng)注冊(cè)event和namespace到request對(duì)象.
用戶驗(yàn)證:
說(shuō)明: flask-socketio默認(rèn)是不支持用戶驗(yàn)證的,可借助flask-login插件通過(guò)login_user()函數(shù)來(lái)將用戶ID信息存儲(chǔ)到本地,然后通過(guò)程序上下文中的current_user對(duì)象來(lái)還原用戶對(duì)象,判斷是否登錄是否有權(quán)限訪問(wèn)等.
消息隊(duì)列:
說(shuō)明: flask-socketio還支持多消費(fèi)者分布式橫向擴(kuò)展,只需在實(shí)例化SocketIO時(shí)指定async_mode和message_queue,message_queue目前只支持redis://和amqp://,接口分別使用的是redis和kombu.由于每個(gè)節(jié)點(diǎn)都維護(hù)著一份兒客戶端連接集,所以如果使用了前端Nginx負(fù)載均衡,需要Session同步或IP_HASH算法負(fù)載,節(jié)點(diǎn)啟動(dòng)時(shí)會(huì)自動(dòng)訂閱flask-socketio頻道,所以我們可以用PY-REDIS客戶端去發(fā)布消息,那么所有節(jié)點(diǎn)都可以獲取到消息然后再分發(fā)給指定的客戶端.
轉(zhuǎn)載于:https://blog.51cto.com/xmdevops/1889053
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