flask-socketio精简版

flask-socketio

flask-socketio 是基于flask的提供websocket的一个模块

客户端收发信息

var websocker_url = 'ws://192.168.137.1:5000' + '/cate'
// 这里的/cata 就是namespace命名空间 
var socket = io.connect(websocker_url);

得到这个socket对象之后，我们可以用这个对象进行消息的收发。简单的前端消息收发如下:

// 发送消息
socket.emit('request',{'param':'value'});

// 监听回复的消息
socket.on('response',function(data){
    if (data.code == '200'){
        alert(data.msg);
    }else{
        alert('ERROR' + data.msg)
    }
})

其中的request和response这两个名字都是我自己取得, 这两个名字应该和后端相关的名字协同一致才能保证通信的成功。另外刚才的namespace是在socket创建的时候就决定的，也就是说这些消息的收发都是在‘cate’这个命名空间中进行的，所以在后端上这个空间也要和前端一致

后端socket编写（flask-socketio）

from flask import Flask
from flask-socketio import SocketIO, emit

app = Flask(__name__)

socketio = SocketIO()
socketio.init_app(app)
"""
对app进行一些路由设置
"""

"""
对socketio进行一些监听设置
"""
if __name__ = "__main__":
    socketio.run(app,debug=True,host='0.0.0.0',port=5000)
	# 这里就不再用app.run 而是用socketio.run了 socketio.run的参数可app.run的参数差不多

上面的，对app的路由设置就不再说了，想说的是对socketio的监听设置，这才是真正关系到前后端websocket通信过程的。结合前面的前端代码，socketio的监听设置可以这样做 :

@socketio.on('request',namespace='/cate')
def give_response(data):
    value = data.get('param')
    
    # 进行一些对value的处理或者其他操作, 在此期间可以随时会调用emit方法向前台发送消息
    emit('response',{'code':'200','msg':'start to process..'})
    time.sleep(5)
    emit('response',{'code':'200','msg':'processed'})

socketio也用了和app.route类似的装饰器的形式进行监听设置。主要参数中有namespace这一项，也就是这项指定了这个监听的范围。在前端，只有注册在‘cate’上的socket，emit向request的消息才会被这个函数接收并处理。

处理函数自带一个参数用来接收前端emit来消息中的那个object，在处理函数中可以对其解析处理。随后后端向前端发送了start to process的消息。也使用了emit这个方法，然后指明了监听是response。也就是说前端on在response上的监听处理函数会处理这个消息（当然还是在testnamespace的框架内）。发出消息后后端不会被阻塞而是继续向下执行，在处理了5秒钟之后发出了结束处理的消息，前端自然隔了五秒之后就得到了这个消息了。

socket监听响应函数本身不需要返回什么值，只需要在处理过程中适当的位置emit出消息即可。

网上其他一些教程中会提到send方法来取代emit方法的位置（无论是前端还是后端），其实send方法就是把上文中的'request_for_response','response'这两个标识都默认成'message'。如此在写的时候就不用写事件名，直接写要传递的参数即可。反过来看，用emit方法实际上是做了一个自定义事件的工作，可以说更加灵活多变一点。

案例:

后端代码:

#!/usr/bin/env python
from threading import Lock
from flask import Flask, render_template, session, request, \
    copy_current_request_context
from flask_socketio import SocketIO, emit, join_room, leave_room, \
    close_room, rooms, disconnect
 
# Set this variable to "threading", "eventlet" or "gevent" to test the
# different async modes, or leave it set to None for the application to choose
# the best option based on installed packages.
async_mode = None
 
app = Flask(__name__)
app.config['SECRET_KEY'] = 'secret!'
socketio = SocketIO(app, async_mode=async_mode)
thread = None
thread_lock = Lock()
 
 
def background_thread():
    """Example of how to send server generated events to clients."""
    count = 0
    while True:
        socketio.sleep(100)
        count += 1
        socketio.emit('my_response',
                      {'data': 'Server generated event', 'count': count},
                      namespace='/test')
 
 
@app.route('/')
def index():
    return render_template('index.html', async_mode=socketio.async_mode)
 
'''
1.后端如何得到前端数据
1）如果前端提交的方法为POST：
后端接收时要写methods=[‘GET’,‘POST’]
xx=request.form.get(xx);
xx=request.form[’‘xx’]
2）如果是GET
xx=request.args.get(xx)
2.后端向前端传数据
1) 传单个数据`
return render_template(‘需要传参网址’,xx=u’ xx’)；
前端接收：
{{xx}}
2) 传多个数据
先把数据写进字典，字典整体传
return render_template(‘需要传参网址’,**字典名’)；
前端接收：
{{字典名.变量名}}
'''
 
 
@socketio.on('my_event', namespace='/test')
def mtest_message(message):
    session['receive_count'] = session.get('receive_count', 0) + 1
    # print(message)
    # print(message['data'])
    emit('my_response',
         {'data': message['data'], 'count': session['receive_count']})
 
 
@socketio.on('my_broadcast_event', namespace='/test')
def mtest_broadcast_message(message):
    session['receive_count'] = session.get('receive_count', 0) + 1
    emit('my_response',
         {'data': message['data'], 'count': session['receive_count']},
         broadcast=True)
 
 
@socketio.on('join', namespace='/test')
def join(message):
    join_room(message['room'])
    session['receive_count'] = session.get('receive_count', 0) + 1
    emit('my_response',
         {'data': 'In rooms: ' + ', '.join(rooms()),
          'count': session['receive_count']})
 
 
@socketio.on('leave', namespace='/test')
def leave(message):
    leave_room(message['room'])
    session['receive_count'] = session.get('receive_count', 0) + 1
    emit('my_response',
         {'data': 'In rooms: ' + ', '.join(rooms()),
          'count': session['receive_count']})
 
 
@socketio.on('close_room', namespace='/test')
def close(message):
    session['receive_count'] = session.get('receive_count', 0) + 1
    emit('my_response', {'data': 'Room ' + message['room'] + ' is closing.',
                         'count': session['receive_count']},
         room=message['room'])
    close_room(message['room'])
 
 
@socketio.on('my_room_event', namespace='/test')
def send_room_message(message):
    session['receive_count'] = session.get('receive_count', 0) + 1
    emit('my_response',
         {'data': message['data'], 'count': session['receive_count']},
         room=message['room'])
 
 
@socketio.on('disconnect_request', namespace='/test')
def disconnect_request():
    @copy_current_request_context
    def can_disconnect():
        disconnect()
 
    session['receive_count'] = session.get('receive_count', 0) + 1
    # for this emit we use a callback function
    # when the callback function is invoked we know that the message has been
    # received and it is safe to disconnect
    emit('my_response',
         {'data': 'Disconnected!', 'count': session['receive_count']},
         callback=can_disconnect)
 
 
@socketio.on('my_ping', namespace='/test')
def ping_pong():
    emit('my_pong')
 
 
@socketio.on('connect', namespace='/test')
def mtest_connect():
    global thread
    with thread_lock:
        if thread is None:
            thread = socketio.start_background_task(background_thread)
    emit('my_response', {'data': 'Connected', 'count': 0})
 
 
@socketio.on('disconnect', namespace='/test')
def mtest_disconnect():
    print('Client disconnected', request.sid)
 
 
if __name__ == '__main__':
    socketio.run(app, debug=True)

前端代码:

<!DOCTYPE HTML>
<html>
<head>
    <title>Flask-SocketIO Test</title>
    <script src="//code.jquery.com/jquery-1.12.4.min.js" integrity="sha256-ZosEbRLbNQzLpnKIkEdrPv7lOy9C27hHQ+Xp8a4MxAQ=" crossorigin="anonymous"></script>
    <script src="//cdnjs.cloudflare.com/ajax/libs/socket.io/2.2.0/socket.io.js" integrity="sha256-yr4fRk/GU1ehYJPAs8P4JlTgu0Hdsp4ZKrx8bDEDC3I=" crossorigin="anonymous"></script>
    <script type="text/javascript" charset="utf-8">
        $(document).ready(function() {
            // Use a "/test" namespace.
            // An application can open a connection on multiple namespaces, and
            // Socket.IO will multiplex all those connections on a single
            // physical channel. If you don't care about multiple channels, you
            // can set the namespace to an empty string.
            namespace = '/test';
 
            // Connect to the Socket.IO server.
            // The connection URL has the following format, relative to the current page:
            //     http[s]://<domain>:<port>[/<namespace>]
            var socket = io(namespace);
 
            // Event handler for new connections.
            // The callback function is invoked when a connection with the
            // server is established.
            socket.on('connect', function() {
                socket.emit('my_event', {data: 'I\'m connected!'});
            });
 
            // Event handler for server sent data.
            // The callback function is invoked whenever the server emits data
            // to the client. The data is then displayed in the "Received"
            // section of the page.
            socket.on('my_response', function(msg, cb) {
                $('#log').append('<br>' + $('<div/>').text('Received #' + msg.count + ': ' + msg.data).html());
 
                if (cb)
                    cb();
            });
 
            // Interval function that tests message latency by sending a "ping"
            // message. The server then responds with a "pong" message and the
            // round trip time is measured.
            var ping_pong_times = [];
            var start_time;
            window.setInterval(function() {
                start_time = (new Date).getTime();
                socket.emit('my_ping');
            }, 10000);
 
            // Handler for the "pong" message. When the pong is received, the
            // time from the ping is stored, and the average of the last 30
            // samples is average and displayed.
            socket.on('my_pong', function() {
                var latency = (new Date).getTime() - start_time;
                ping_pong_times.push(latency);
                ping_pong_times = ping_pong_times.slice(-30); // keep last 30 samples
                var sum = 0;
                for (var i = 0; i < ping_pong_times.length; i++)
                    sum += ping_pong_times[i];
                $('#ping-pong').text(Math.round(10 * sum / ping_pong_times.length) / 10);
            });
 
            // Handlers for the different forms in the page.
            // These accept data from the user and send it to the server in a
            // variety of ways
            $('form#emit').submit(function(event) {
                socket.emit('my_event', {data: $('#emit_data').val()});
                return false;
            });
            $('form#broadcast').submit(function(event) {
                socket.emit('my_broadcast_event', {data: $('#broadcast_data').val()});
                return false;
            });
            $('form#join').submit(function(event) {
                socket.emit('join', {room: $('#join_room').val()});
                return false;
            });
            $('form#leave').submit(function(event) {
                socket.emit('leave', {room: $('#leave_room').val()});
                return false;
            });
            $('form#send_room').submit(function(event) {
                socket.emit('my_room_event', {room: $('#room_name').val(), data: $('#room_data').val()});
                return false;
            });
            $('form#close').submit(function(event) {
                socket.emit('close_room', {room: $('#close_room').val()});
                return false;
            });
            $('form#disconnect').submit(function(event) {
                socket.emit('disconnect_request');
                return false;
            });
        });
    </script>
</head>
<body>
    <h1>Flask-SocketIO Test</h1>
    <p>Async mode is: <b>{{ async_mode }}</b></p>
    <p>Average ping/pong latency: <b><span id="ping-pong"></span>ms</b></p>
    <h2>Send:</h2>
    <form id="emit" method="POST" action='#'>
        <input type="text" name="emit_data" id="emit_data" placeholder="Message">
        <input type="submit" value="Echo">
    </form>
    <form id="broadcast" method="POST" action='#'>
        <input type="text" name="broadcast_data" id="broadcast_data" placeholder="Message">
        <input type="submit" value="Broadcast">
    </form>
    <form id="join" method="POST" action='#'>
        <input type="text" name="join_room" id="join_room" placeholder="Room Name">
        <input type="submit" value="Join Room">
    </form>
    <form id="leave" method="POST" action='#'>
        <input type="text" name="leave_room" id="leave_room" placeholder="Room Name">
        <input type="submit" value="Leave Room">
    </form>
    <form id="send_room" method="POST" action='#'>
        <input type="text" name="room_name" id="room_name" placeholder="Room Name">
        <input type="text" name="room_data" id="room_data" placeholder="Message">
        <input type="submit" value="Send to Room">
    </form>
    <form id="close" method="POST" action="#">
        <input type="text" name="close_room" id="close_room" placeholder="Room Name">
        <input type="submit" value="Close Room">
    </form>
    <form id="disconnect" method="POST" action="#">
        <input type="submit" value="Disconnect">
    </form>
    <h2>Receive:</h2>
    <div id="log"></div>
</body>
</html>

原文链接：https://blog.csdn.net/qq_37193537/article/details/90901171

posted @ 2021-03-30 10:42 死里学阅读(1083) 评论(0) 收藏举报

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GRLend

flask-socketio精简版

flask-socketio

客户端收发信息

后端socket编写（flask-socketio）

公告

GRLend

flask-socketio精简版

flask-socketio

客户端 收发信息

后端socket编写（flask-socketio）

公告

客户端收发信息