用来测试端口 work 的Demo app

Python 自带就能 run，方便测试端口和映射是否能 work。

import http.server
import socketserver
import argparse

class DemoHandler(http.server.SimpleHTTPRequestHandler):
    def do_GET(self):
        if self.path == '/':
            self.send_response(200)
            self.send_header('Content-type', 'text/html')
            self.end_headers()
            self.wfile.write(b'Hello, World! This is a demo app.')
        elif self.path == '/about':
            self.send_response(200)
            self.send_header('Content-type', 'text/html')
            self.end_headers()
            self.wfile.write(b'This is a simple demo application.')
        else:
            super().do_GET()

def run(port):
    with socketserver.TCPServer(("", port), DemoHandler) as httpd:
        print(f"Serving at port {port}")
        httpd.serve_forever()

def main():
    parser = argparse.ArgumentParser(description='Run the demo app on a specified port.')
    parser.add_argument('--port', type=int, default=8000, help='Port to run the server on')
    args = parser.parse_args()
    run(args.port)

if __name__ == '__main__':
    main()