app.py

import gradio as gr
from typing import Optional


def hello(profile: Optional[gr.OAuthProfile]) -> str:
    if profile is None:
        return "I don't know you."
    return f"Hello {profile.name}"


with gr.Blocks() as demo:
    gr.LoginButton()
    gr.LogoutButton()
    gr.Markdown().attach_load_event(hello, None)

demo.launch()