如何在Python中的单独线程中启动Flask API服务器

编程问答 2022-10-27

问题描述

我正在研究一个Python项目，该项目包括基于pyqt5和flask的API。在用户界面中，有start和stop按钮，当它们按下时将启动flask api服务器，并在单击停止按钮时停止。

from server import start_local_server
from multiprocessing import Process

"""
SOME CODE
"""

def start_server_btn_event(self):
    p1 = Process(target=start_local_server())
    p1.start()
    

def stop_server_btn_event(self):
    # Code to stop the api server

但是，执行上述操作会使整个UI失去响应，并且我无法单击UI上的任何其他对象。如何在单独的线程或进程中单击按钮时运行api服务器，以便其他UI对象处于活动状态并可以执行其功能。谢谢

最小可复制示例：

app.py：其中包含pyqt5按钮，用于启动本地服务器 

import sys
from PyQt5.QtWidgets import QApplication,QWidget,QPushButton
from server import start_local_server
from PyQt5.QtCore import pyqtSlot
from multiprocessing import Process


class App(QWidget):

    def __init__(self):
        super().__init__()
        self.title = 'PyQt5 button - pythonspot.com'
        self.left = 10
        self.top = 10
        self.width = 320
        self.height = 200
        self.initUI()

    def initUI(self):
        self.setwindowTitle(self.title)
        self.setGeometry(self.left,self.top,self.width,self.height)

        start_btn = QPushButton('Start Server',self)
        start_btn.move(100,70)
        start_btn.clicked.connect(self.on_click_start_btn)

        stop_btn = QPushButton('Stop Server',self)
        stop_btn.move(200,70)
        stop_btn.clicked.connect(self.on_click_stop_btn)

        fun_btn = QPushButton('Click to check responsiveness',self)
        fun_btn.move(150,100)
        fun_btn.clicked.connect(self.on_click_fun_btn)

        self.show()

    @pyqtSlot()
    def on_click_start_btn(self):
        # Start server here
        p1 = Process(target=start_local_server())
        p1.start()


    @pyqtSlot()
    def on_click_stop_btn(self):
        print("Stop server ")

    @pyqtSlot()
    def on_click_fun_btn(self):
        print('If it is working,this means UI is responsive')


if __name__ == '__main__':
    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec_())

server.py：这是Flask API服务器代码 

import os
import datetime
from flask import Flask,jsonify
from flask_cors import CORS

app = Flask(__name__)
CORS(app)
wsgi_app = app.wsgi_app


@app.route('/api/status')
def check_status():
    return jsonify({'status': 'ok','date': datetime.datetime.Now().isoformat()}),200


def start_local_server():

    HOST = os.environ.get('SERVER_HOST','localhost')
    try:
        PORT = int(os.environ.get('SERVER_PORT','5555'))
    except ValueError:
        PORT = 5555
    app.run(HOST,80)

解决方法

我通过启动一个单独的线程来运行API服务器来解决该问题：

run = True


def start_api_server():
    while run:
        start_local_server()
        
    time.sleep(1)
    print("SERVER HAS STOPPED")

@pyqtSlot()
def on_click_start_btn(self):
    Thread(target=start_api_server).start()
flaskmultithreadingprocesspyqt5python