I want to implement the login with google inside my streamlit app. The user should see directly the screen to select their google account even before being able to see the main screen app. Here is an example of implementation you can use.

import asyncio
from typing import Optional
import jwt
import streamlit as st
from httpx_oauth.clients.google import GoogleOAuth2
import os

client_id = os.environ['CLIENT_ID']
client_secret = os.environ['CLIENT_SECRET']
redirect_url = os.environ['REDIRECT_URL']

client = GoogleOAuth2(client_id=client_id, client_secret=client_secret)

def decode_user(token: str):
    decoded_data = jwt.decode(jwt=token, options={"verify_signature": False})
    return decoded_data

async def get_authorization_url(client: GoogleOAuth2, redirect_url: str) -> str:
    authorization_url = await client.get_authorization_url(
        redirect_url,
        scope=["email"],
        extras_params={"access_type": "offline"},
    )
    return authorization_url

def show_login_button(text: Optional[str] = "Login with Google", sidebar: bool = True):
    button_location = st.sidebar if sidebar else st
    authorization_url = asyncio.run(get_authorization_url(client=client, redirect_url=redirect_url))
    if button_location.button(text, key="google_login", type="primary"):
        st.markdown(f'<meta http-equiv="refresh" content="0;url={authorization_url}">', unsafe_allow_html=True)

async def get_access_token(client: GoogleOAuth2, redirect_url: str, code: str):
    token = await client.get_access_token(code, redirect_url)
    return token

def get_access_token_from_query_params(client: GoogleOAuth2, redirect_url: str):
    if 'code' in st.query_params:
        code = st.query_params['code']
        token = asyncio.run(get_access_token(client=client, redirect_url=redirect_url, code=code))
        # Clear the query parameters
        st.query_params.clear()
        return token
    return None

def get_logged_in_user_email() -> Optional[str]:
    if "email" in st.session_state:
        return st.session_state.email

    token = get_access_token_from_query_params(client, redirect_url)
    if token:
        user_info = decode_user(token=token["id_token"])
        st.session_state["email"] = user_info["email"]
        return user_info["email"]

    return None