如何在线程中使用 python-socketio 每秒向客户端发送数据

Question

我有 Python 服务器代码 fserver.py，在连接时我正在尝试创建线程，一旦创建并运行线程，我试图将计数器值增加 1，每秒后将事件发回以将客户端连接到显示从服务器到客户端的增量计数器值

import sys
from threading import Thread, Event
import time
from flask import Flask, jsonify, request, json
from flask_socketio import SocketIO, emit
from flask_cors import CORS
from gevent.pywsgi import WSGIServer
from geventwebsocket.handler import WebSocketHandler

app = Flask(__name__)
app.config["SECRET_KEY"] = "secret!"
socketio = SocketIO(app, cors_allowed_origins="*")
CORS(app)

thread = Thread()
thread_stop_event = Event()


class CounterThread(Thread):
    def __init__(self):
        self.delay = 0.5
        super(CounterThread, self).__init__()

    def start_counterthread(self):
        print("Initializing Thread==")
        try:
            counter = 0
            while not thread_stop_event.isSet():
                counter = counter + 1
                time.sleep(1)
                print(counter, " counter ")
                jsonResp = {"counter": counter}
                emit("counter", jsonResp)
                time.sleep(self.delay)
        except KeyboardInterrupt:
            print("Keyboard  Interrupt")

    def run(self):
        self.start_counterthread()

@socketio.on("connect")
def test_connect():
    print("Client connected")

    global thread
    if not thread.isAlive():
        print("Starting Thread")
        thread = CounterThread()
        thread.start()

if __name__ == "__main__":
    print("main === 1")
    http_server = WSGIServer(('127.0.0.1', 5000), app, handler_class=WebSocketHandler)
    print("main === 2")
    http_server.serve_forever()
    print("main === 3")

和客户端代码

import React, { Component } from 'react'
import socketIOClient from "socket.io-client";
const ENDPOINT = "http://127.0.0.1:5000/";

export default class Toggle extends Component {
    componentDidMount = () => {
        // Create WebSocket connection.
        const socket = socketIOClient.connect(ENDPOINT, { transports: ['websocket'] });
        // socket.on('connect', () => console.log('Test connected!!'));

        socket.on("responseMessage", data => {
            console.log(data);
        });

     }
}

我正在尝试在客户端中获取每秒增加 1 的计数数据。

错误如下：

C:\work\Flask> python fserver.py
main === 1
main === 2
Client connected
Starting Thread
Initializing Thread==
1  counter
Exception in thread Thread-2:
Traceback (most recent call last):
  File "C:\tools\python3\lib\threading.py", line 926, in _bootstrap_inner
    self.run()
  File "fserver.py", line 39, in run
    self.start_counterthread()
  File "fserver.py", line 33, in start_counterthread
    emit("counter", jsonResp)
  File "C:\tools\python3\lib\site-packages\flask_socketio\__init__.py", line 772, in emit
    namespace = flask.request.namespace
  File "C:\tools\python3\lib\site-packages\werkzeug\local.py", line 347, in __getattr__
    return getattr(self._get_current_object(), name)
  File "C:\tools\python3\lib\site-packages\werkzeug\local.py", line 306, in _get_current_object
    return self.__local()
  File "C:\tools\python3\lib\site-packages\flask\globals.py", line 38, in _lookup_req_object
    raise RuntimeError(_request_ctx_err_msg)
RuntimeError: Working outside of request context.

This typically means that you attempted to use functionality that needed
an active HTTP request.  Consult the documentation on testing for
information about how to avoid this problem.