improved auth example

examples/authentication/main.py

@@ -1,46 +1,57 @@
 #!/usr/bin/env python3
+'''This is only a very simple authentication example which stores session ids in memory and does not do any password hashing.
+
+Please see the `OAuth2 example at FastAPI <https://fastapi.tiangolo.com/tutorial/security/simple-oauth2/>`_  or
+use the great `Authlib package <https://docs.authlib.org/en/v0.13/client/starlette.html#using-fastapi>`_ to implement a real authentication system.
+
+Here we just demonstrate the NiceGUI integration.
+'''
+
 import uuid
 from typing import Dict
 
+from fastapi import Request
+from fastapi.responses import RedirectResponse
 from starlette.middleware.sessions import SessionMiddleware
-from starlette.requests import Request
 
 from nicegui import app, ui
 
-app.add_middleware(SessionMiddleware, secret_key='some_random_string')
+app.add_middleware(SessionMiddleware, secret_key='some_random_string')  # use your own secret key here
 
-session_info: Dict[str, Dict] = {}  # in reality in a database
+# in reality users and session_info would be persistent (e.g. database, file, ...) and passwords obviously hashed
+users = [('user1', 'pass1'), ('user2', 'pass2')]
+session_info: Dict[str, Dict] = {}
 
 
 @ui.page('/')
 def main_page(request: Request) -> None:
     if is_authenticated(request):
-        create_welcome_message(session_info[request.session['id']]['username'])
+        session = session_info[request.session['id']]
+        with ui.row().classes('absolute-center'):
+            ui.label(f'Hello {session["username"]}!').classes('text-2xl')
     else:
-        request.session['id'] = str(uuid.uuid4())
-        create_login_form(request.session['id'])
-
-
-def is_authenticated(request: Request) -> bool:
-    return session_info.get(request.session.get('id'), {}).get('authenticated', False)
+        return RedirectResponse('/login')
 
 
-def create_login_form(session_id: str) -> None:
+@ui.page('/login')
+def login(request: Request) -> None:
+    if is_authenticated(request):
+        return RedirectResponse('/')
+    request.session['id'] = str(uuid.uuid4())  # NOTE this stores a new session id in the cookie of the client
     with ui.card().classes('absolute-center'):
         username = ui.input('Username')
         password = ui.input('Password').classes('w-full').props('type=password')
-        ui.button('Log in', on_click=lambda: try_login(session_id, username.value, password.value))
+        ui.button('Log in', on_click=lambda: try_login(request.session['id'], username.value, password.value))
+
+
+def is_authenticated(request: Request) -> bool:
+    return session_info.get(request.session.get('id'), {}).get('authenticated', False)
 
 
 def try_login(session_id: str, username: str, password: str) -> None:
-    if (username, password) in [('user1', 'pass1'), ('user2', 'pass2')]:
+    if (username, password) in users:
         session_info[session_id] = {'username': username, 'authenticated': True}
     ui.open('/')
 
 
-def create_welcome_message(username: str) -> None:
-    with ui.row().classes('absolute-center'):
-        ui.label(f'Hello {username}!').classes('text-2xl')
-
-
 ui.run()