Skeleton flask server with QT interface

qt_flask.py

'''
qtflask.py: Run a flask server as a subordinate thread to a Qt GUI application
'''
import sys
import threading
from PyQt6.QtWidgets import QApplication, QWidget, QPushButton, QMessageBox
from flask import Flask, jsonify


class App(QWidget):

    def __init__(self):
        super().__init__()
        self.initUI()

    def initUI(self):
        self.setWindowTitle('Hello World')
        self.setGeometry(100, 100, 300, 200)

        button = QPushButton('Click me', self)
        button.setToolTip('Click me to say Hello')
        button.move(100, 70)
        button.clicked.connect(self.say_hello)

        self.show()

    def say_hello(self):
        QMessageBox.information(self, 'Message', 'Hello, World!')


def flask_server():
    app = Flask(__name__)

    @app.route('/api/greeting')
    def greeting():
        return jsonify({'message': 'Hello, World!'})

    app.run()


if __name__ == '__main__':
    threading.Thread(target=flask_server, daemon=True).start()

    app = QApplication(sys.argv)
    ex = App()
    sys.exit(app.exec())

requirements.txt

click==8.1.3
Flask==2.2.3
itsdangerous==2.1.2
Jinja2==3.1.2
MarkupSafe==2.1.2
PyQt6==6.5.0
PyQt6-Qt6==6.5.0
PyQt6-sip==13.5.0
Werkzeug==2.2.3