flask_app.py

from flask import Flask, redirect, request, session, jsonify
from google_auth_oauthlib.flow import Flow
from google.oauth2 import id_token
from google.auth.transport import requests
import os

app = Flask(__name__)
app.secret_key = 'YOUR_FLASK_SECRET_KEY'

# Google OAuth Configuration
CLIENT_ID = '931024815427-72meiq3uivuuolfukb3jvikvhhqlr574.apps.googleusercontent.com'
CLIENT_SECRET = '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'
REDIRECT_URI = 'http://localhost:5001/oauth2callback'
SCOPES = ['openid', 'https://www.googleapis.com/auth/userinfo.email', 'https://www.googleapis.com/auth/userinfo.profile']

@app.route('/login')
def login():
    flow = Flow.from_client_config(
        client_config={
            "web": {
                "client_id": CLIENT_ID,
                "client_secret": CLIENT_SECRET,
                "auth_uri": "https://accounts.google.com/o/oauth2/auth",
                "token_uri": "https://oauth2.googleapis.com/token"
            }
        },
        scopes=SCOPES,
        redirect_uri=REDIRECT_URI
    )
    authorization_url, state = flow.authorization_url(access_type='offline', include_granted_scopes='true')
    session['state'] = state
    return redirect(authorization_url)

@app.route('/oauth2callback')
def oauth2callback():
    state = session['state']
    flow = Flow.from_client_config(
        client_config={
            "web": {
                "client_id": CLIENT_ID,
                "client_secret": CLIENT_SECRET,
                "auth_uri": "https://accounts.google.com/o/oauth2/auth",
                "token_uri": "https://oauth2.googleapis.com/token"
            }
        },
        scopes=SCOPES,
        state=state,
        redirect_uri=REDIRECT_URI
    )
    flow.fetch_token(authorization_response=request.url)
    credentials = flow.credentials
    session['credentials'] = credentials.to_json()
    
    idinfo = id_token.verify_oauth2_token(
        id_token=credentials.id_token,
        request=requests.Request(),
        audience=CLIENT_ID
    )
    
    session['user_info'] = {"name": idinfo.get("name")}
    return redirect("http://localhost:7860")  # Redirect back to the Shiny app

@app.route('/user_info')
def user_info():
    return jsonify(session.get('user_info', {}))

if __name__ == '__main__':
    app.run(port=5001)