如何计算烧瓶中已连接客户端的数量

Question

我需要在使用flask-socketio的网页上显示已连接客户端的数量，并且编写此代码来检查connected和disconnected的连接。

app = Flask(__name__)
socketio = SocketIO(app)
clients = []

@socketio.on('connect', namespace='/')
def connect():
    clients.append(request.namespace)

@socketio.on('disconnect', namespace='/')
def disconnect():
    clients.remove(request.namespace)

然后我渲染这样的模板

return render_template_string(TABLE_TEMPLATE, data=data, clients=len(clients))

在html部分中，我这样称呼

<h1>{{ clients }} </h1>

但是在网页上，即使客户端已连接，它也会持续显示0，我从客户端获得输出并且连接了它，它应该显示1 2取决于连接的客户端数。即使我打印此 print(len(clients))返回0。

这是我的完整应用代码。

from flask import Flask, request, render_template_string
from flask_socketio import SocketIO


app = Flask(__name__)
socketio = SocketIO(app)
clients = []

@socketio.on('connect', namespace='/')
def connect():
    clients.append(request.namespace)

@socketio.on('disconnect', namespace='/')
def disconnect():
    clients.remove(request.namespace)

TABLE_TEMPLATE = """
<h1>{{ clients }} </h1>
<style>
   table, th, td {
   border: 1px solid black;
   }
</style>
<table style="width: 100%">
   <thead>
      <th>Client</th>
      <th>IP</th>
      <th>Status</th>
   </thead>
   <tbody>
      {% for row in data %}
      <tr>
         <td><center>{{ row.client }}</td></center>
         <td><center>{{ row.ip }}</td></center>
         <td><center>{{ row.status }}</td></center>
      </tr>
      {% endfor %}
   </tbody>
</table>
"""


@app.route("/device_add", methods=['POST'])
def device_add():
    name = request.args.get('name')
    with open('logs.log', 'a') as f:
        f.write(f'{name} Connected USB from IP: {request.remote_addr} \n')
    return 'ok'


@app.route("/device_remove", methods=['POST'])
def device_remove():
    name = request.args.get('name')
    with open('logs.log', 'a') as f:
        f.write(f'{name} Disconnected USB from IP: {request.remote_addr}\n')

    return 'ok'


@app.route("/", methods=['GET'])
def device_list():
    keys = ['client', 'ip', 'status']
    data = []
    with open('logs.log', 'r') as f:
        for line in f:
            row = line.split()
            data.append(dict(zip(keys, [row[0], row[-1], row[1]])))
            

    return render_template_string(TABLE_TEMPLATE, data=data, clients=len(clients))


if __name__ == "__main__":
  app.run(threaded=True)