handle receiving an authentication token in a PyQt application after a user has completed a Google authentication

To handle receiving an authentication token in a PyQt application after a user has completed a Google authentication process in a browser, you need to set up a local HTTP server within your PyQt application. This server will listen for the redirect URI call, which will contain the authentication token.

Here's how you can do it step-by-step:

1. **Set up OAuth 2.0 with Google**:

   • Ensure your Google API console project is correctly set up with the appropriate credentials (Client ID, Client Secret) and the redirect URI points to `http://localhost:port/\` (or a similar local address).

2. **Create a PyQt Application with an Embedded Browser**:

   • Use `QWebEngineView` to display the Google login and handle authentication.

3. **Start a Local Server in PyQt**:

   • This local server will listen for the redirect URI. When Google redirects to this URI with the token, the server can parse it.

Here's an example of how you can implement this using PyQt and the built-in http.server:

import sys

from PyQt5.QtWidgets import QApplication, QMainWindow, QVBoxLayout, QWidget

from PyQt5.QtCore import QUrl

from PyQt5.QtWebEngineWidgets import QWebEngineView

from http.server import HTTPServer, BaseHTTPRequestHandler

import threading

import urllib

\# Handler for the HTTP server to capture OAuth callback

class OAuthHandler(BaseHTTPRequestHandler):

    def do_GET(self):

        self.send_response(200)

        self.send_header('Content-type', 'text/html')

        self.end_headers()

        self.wfile.write(b"Authentication complete. Please return to the application.")

        query = urllib.parse.urlparse(self.path).query

        params = urllib.parse.parse_qs(query)

        token = params.get('code', None)  # or 'access_token' depending on your OAuth flow

        if token:

            print("Token received:", token[0])

            # Here you can signal your main app about the token

        else:

            print("No token received")

def start_server():

    server_address = ('', 8080)

    httpd = HTTPServer(server_address, OAuthHandler)

    httpd.serve_forever()

\# PyQt application

class MyApp(QMainWindow):

    def __init\__(self):

        super().__init__()

        self.initUI()

    def initUI(self):

        self.setGeometry(200, 200, 600, 600)

        self.setWindowTitle('OAuth Example')

        

        # Setting up the layout

        layout = QVBoxLayout()

        widget = QWidget(self)

        widget.setLayout(layout)

        self.setCentralWidget(widget)

        # Web view

        self.view = QWebEngineView(self)

        layout.addWidget(self.view)

        # Load the auth URL into the web view

        url = 'https://accounts.google.com/o/oauth2/auth?client_id=YOUR_CLIENT_ID&response_type=code&scope=openid%20email&redirect_uri=http://localhost:8080&access_type=offline'

        self.view.load(QUrl(url))

\# Run the server in a separate thread

server_thread = threading.Thread(target=start_server, daemon=True)

server_thread.start()

\# Start the PyQt application

app = QApplication(sys.argv)

ex = MyApp()

ex.show()

sys.exit(app.exec_())

Important Notes:

• Replace `'YOUR_CLIENT_ID'` and other parameters in the URL with the actual values required by Google's OAuth.

• This example assumes you're using the OAuth authorization code grant type. If you're using implicit grant or another type, you may need to capture a different parameter than 'code'.

• The HTTP server runs on port 8080. Make sure this matches the redirect URI configured in your Google API settings.

• The use of `daemon=True` for the server thread allows the Python application to exit even if the server is still running, which is useful during development.

• This example runs the HTTP server and the PyQt GUI in the same application, which is typically acceptable for small desktop applications.

Adjust the example according to your actual setup and requirements, especially the OAuth parameters and how you handle the token once received.