app.py

import uvicorn
from fastapi import FastAPI, Depends
from starlette.responses import RedirectResponse
from starlette.middleware.sessions import SessionMiddleware
from authlib.integrations.starlette_client import OAuth, OAuthError
from fastapi import Request
import os
from starlette.config import Config
import gradio as gr

app = FastAPI()

# OAuth settings
GOOGLE_CLIENT_ID = os.environ.get("GOOGLE_CLIENT_ID")
GOOGLE_CLIENT_SECRET = os.environ.get("GOOGLE_CLIENT_SECRET")
SECRET_KEY = os.environ.get("SECRET_KEY")

# Set up OAuth
config_data = {'TWITTER_CLIENT_ID': GOOGLE_CLIENT_ID, 'TWITTER_CLIENT_SECRET': GOOGLE_CLIENT_SECRET}
starlette_config = Config(environ=config_data)
oauth = OAuth(starlette_config)
oauth.register(
    name='twitter',
    api_base_url='https://api.twitter.com/1.1/',
    request_token_url='https://api.twitter.com/oauth/request_token',
    access_token_url='https://api.twitter.com/oauth/access_token',
    authorize_url='https://api.twitter.com/oauth/authenticate',
)

app.add_middleware(SessionMiddleware, secret_key=SECRET_KEY)

# Dependency to get the current user
def get_user(request: Request):
    user = request.session.get('user')
    if user:
        return user['name']
    return None

@app.get('/')
def public(request: Request, user = Depends(get_user)):
    root_url = gr.route_utils.get_root_url(request, "/", None)
    if user:
        return RedirectResponse(url=f'{root_url}/gradio/')
    else:
        return RedirectResponse(url=f'{root_url}/main/')

@app.route('/logout')
async def logout(request: Request):
    request.session.pop('user', None)
    return RedirectResponse(url='/')

@app.route('/login')
async def login(request: Request):
    print("AUTH", request.url_for('auth'))
    return await oauth.twitter.authorize_redirect(request, request.url_for('auth'))


@app.get('/auth')
async def auth(request: Request):
    token = await oauth.twitter.authorize_access_token(request)
    url = 'account/verify_credentials.json'
    resp = await oauth.twitter.get(
        url, params={'skip_status': True}, token=token)
    if resp.status_code != 200:
        return RedirectResponse(url='/')
    else:
        user = resp.json()
        request.session['user'] = dict(user)
        return RedirectResponse(url='/gradio')

with gr.Blocks() as login_demo:
    btn = gr.Button("Login")
    _js_redirect = """
    () => {
        url = '/login' + window.location.search;
        window.open(url, '_blank');
    }
    """
    btn.click(None, js=_js_redirect)

app = gr.mount_gradio_app(app, login_demo, path="/main")

def greet(request: gr.Request):
    return f"Welcome to Gradio, {request.username}"

with gr.Blocks() as main_demo:
    m = gr.Markdown("Welcome to Gradio!")
    gr.Button("Logout", link="/logout")
    main_demo.load(greet, None, m)

app = gr.mount_gradio_app(app, main_demo, path="/gradio", auth_dependency=get_user)


if __name__ == '__main__':
    uvicorn.run(app)