""" Test of OpenId Connect & OAuth2 with FastAPI """ from typing import Annotated from pathlib import Path from datetime import datetime import logging import logging.config import importlib.resources from yaml import safe_load from urllib.parse import urlencode from contextlib import asynccontextmanager from httpx import HTTPError from fastapi import Depends, FastAPI, HTTPException, Request, status from fastapi.staticfiles import StaticFiles from fastapi.responses import HTMLResponse, RedirectResponse from fastapi.templating import Jinja2Templates from fastapi.middleware.cors import CORSMiddleware from jwt import PyJWTError from starlette.middleware.sessions import SessionMiddleware from authlib.integrations.starlette_client.apps import StarletteOAuth2App from authlib.integrations.base_client import OAuthError from authlib.oauth2.rfc6749 import OAuth2Token # TODO: PKCE # from authlib.integrations.httpx_client import AsyncOAuth2Client # from fastapi.security import OpenIdConnect # from pkce import generate_code_verifier, generate_pkce_pair from oidc_test.registry import registry from oidc_test.auth.provider import NoPublicKey, Provider from oidc_test.auth.utils import ( get_auth_provider, get_auth_provider_or_none, get_current_user_or_none, authlib_oauth, get_token_from_session_or_none, get_token_from_session, update_token, ) from oidc_test.auth.utils import init_providers from oidc_test.settings import settings from oidc_test.auth_providers import providers from oidc_test.models import User from oidc_test.database import TokenNotInDb, db from oidc_test.resource_server import resource_server logger = logging.getLogger("oidc-test") if settings.log: assert __package__ is not None with ( importlib.resources.path(__package__) as package_path, open(package_path / settings.log_config_file) as f, ): logging_config = safe_load(f) logging.config.dictConfig(logging_config) templates = Jinja2Templates(Path(__file__).parent / "templates") @asynccontextmanager async def lifespan(app: FastAPI): assert app is not None init_providers() registry.make_registry() for provider in list(providers.values()): if provider.disabled: continue try: await provider.get_info() except NoPublicKey: logger.warning(f"Disable {provider.id}: public key not found") del providers[provider.id] yield app = FastAPI(title="OIDC auth test", lifespan=lifespan) app.add_middleware( CORSMiddleware, allow_origins=settings.cors_origins, allow_credentials=True, allow_methods=["*"], allow_headers=["*"], ) # SessionMiddleware is required by authlib app.add_middleware( SessionMiddleware, secret_key=settings.secret_key, ) app.mount("/static", StaticFiles(directory=Path(__file__).parent / "static"), name="static") app.mount("/resource", resource_server, name="resource_server") @app.get("/") async def home( request: Request, user: Annotated[User | None, Depends(get_current_user_or_none)], provider: Annotated[Provider | None, Depends(get_auth_provider_or_none)], token: Annotated[OAuth2Token | None, Depends(get_token_from_session_or_none)], ) -> HTMLResponse: context = { "show_token": settings.show_token, "user": user, "now": datetime.now(), "auth_provider": provider, } if provider is None or token is None: context["providers"] = providers context["access_token"] = None context["id_token_parsed"] = None context["access_token_parsed"] = None context["refresh_token_parsed"] = None context["resources"] = None else: context["access_token"] = token["access_token"] try: access_token_parsed = provider.decode(token["access_token"], verify_signature=False) except PyJWTError as err: access_token_parsed = {"Cannot parse": err.__class__.__name__} try: context["access_token_scope"] = access_token_parsed["scope"] except KeyError: context["access_token_scope"] = None context["id_token_parsed"] = provider.decode(token["id_token"], verify_signature=False) context["access_token_parsed"] = access_token_parsed context["resources"] = registry.resources context["resource_providers"] = provider.resource_providers try: context["refresh_token_parsed"] = provider.decode( token["refresh_token"], verify_signature=False ) except PyJWTError as err: context["refresh_token_parsed"] = {"Cannot parse": err.__class__.__name__} return templates.TemplateResponse(name="home.html", request=request, context=context) # Endpoints for the login / authorization process @app.get("/login/{auth_provider_id}") async def login(request: Request, auth_provider_id: str) -> RedirectResponse: """Login with the provider id, giving the browser a redirect to its authorize page. The provider is expected to send the browser back to our own /auth/{auth_provider_id} url with the token. """ redirect_uri = request.url_for("auth", auth_provider_id=auth_provider_id) try: provider: StarletteOAuth2App = getattr(authlib_oauth, auth_provider_id) except AttributeError: raise HTTPException(status.HTTP_401_UNAUTHORIZED, "No such provider") # if ( # code_challenge_method := providers[ # auth_provider_id # ].code_challenge_method # ) is not None: # #client = AsyncOAuth2Client(..., code_challenge_method=code_challenge_method) # code_verifier = generate_code_verifier() # logger.debug("TODO: PKCE") # else: # code_verifier = None try: response = await provider.authorize_redirect( request, redirect_uri, access_type="offline", code_verifier=None, ) return response except HTTPError: raise HTTPException(status.HTTP_401_UNAUTHORIZED, "Cannot reach provider") @app.get("/auth/{auth_provider_id}") async def auth( request: Request, auth_provider_id: str, ) -> RedirectResponse: """Decrypt the auth token, store it to the session (cookie based) and response to the browser with a redirect to a "welcome user" page. """ try: provider = providers[auth_provider_id] except KeyError: raise HTTPException(status.HTTP_401_UNAUTHORIZED, "No such provider") try: token: OAuth2Token = await provider.authlib_client.authorize_access_token(request) except OAuthError as error: raise HTTPException(status.HTTP_401_UNAUTHORIZED, detail=error.error) # Remember the authlib_client in the session # logger.info(f"Scope: {token['scope']}") request.session["auth_provider_id"] = auth_provider_id # # One could process the full decoded token which contains extra information # eg for updates. Here we are only interested in roles # if userinfo := token.get("userinfo"): # Remember the authlib_client in the session request.session["auth_provider_id"] = auth_provider_id # User id (sub) given by auth provider sub = userinfo["sub"] ## Get additional data from userinfo endpoint # try: # user_info_from_endpoint = await authlib_client.userinfo( # token=token, follow_redirects=True # ) # except Exception as err: # logger.warn(f"Cannot get userinfo from endpoint: {err}") # user_info_from_endpoint = {} # Build and remember the user in the session request.session["user_sub"] = sub # Store the user in the database, which also verifies the token validity and signature try: user = await db.add_user( sub, user_info=userinfo, auth_provider=providers[auth_provider_id], access_token=token["access_token"], ) except PyJWTError as err: raise HTTPException( status.HTTP_401_UNAUTHORIZED, detail=f"Token invalid: {err.__class__.__name__}", ) assert isinstance(user, User) # Add the provider session id to the session request.session["sid"] = provider.get_session_key(userinfo) # Add the token to the db because it is used for logout await db.add_token(provider, token) # Send the user to the home: (s)he is authenticated return RedirectResponse(url=request.url_for("home")) else: # Not sure if it's correct to redirect to plain login # if no userinfo is provided return RedirectResponse(url=request.url_for("login", auth_provider_id=auth_provider_id)) @app.get("/account") async def account( provider: Annotated[Provider, Depends(get_auth_provider)], ) -> RedirectResponse: """Redirect to the auth provider account management, if account_url_template is in the provider's settings""" return RedirectResponse(f"{provider.account_url_template}") @app.get("/logout") async def logout( request: Request, provider: Annotated[Provider, Depends(get_auth_provider)], ) -> RedirectResponse: # Get provider's endpoint if ( provider_logout_uri := provider.authlib_client.server_metadata.get("end_session_endpoint") ) is None: logger.warning(f"Cannot find end_session_endpoint for provider {provider.id}") return RedirectResponse(request.url_for("non_compliant_logout")) post_logout_uri = request.url_for("home") # Clear session request.session.pop("user_sub", None) request.session.pop("auth_provider_id", None) try: token = await db.get_token(provider, request.session.pop("sid", None)) except TokenNotInDb: logger.warning("No session in db for the token or no token") return RedirectResponse(request.url_for("home")) url_query = { "post_logout_redirect_uri": post_logout_uri, "client_id": provider.client_id, } if provider.logout_with_id_token_hint: url_query["id_token_hint"] = token["id_token"] logout_url = f"{provider_logout_uri}?{urlencode(url_query)}" return RedirectResponse(logout_url) @app.get("/non-compliant-logout") async def non_compliant_logout( request: Request, provider: Annotated[Provider, Depends(get_auth_provider)], ): """A page for non-compliant OAuth2 servers that we cannot log out.""" # Clear session request.session.pop("user_sub", None) request.session.pop("auth_provider_id", None) return templates.TemplateResponse( name="non_compliant_logout.html", request=request, context={"auth_provider": provider, "home_url": request.url_for("home")}, ) @app.get("/refresh") async def refresh( request: Request, provider: Annotated[Provider, Depends(get_auth_provider)], token: Annotated[OAuth2Token, Depends(get_token_from_session)], ) -> RedirectResponse: """Manually refresh token""" new_token = await provider.authlib_client.fetch_access_token( refresh_token=token["refresh_token"], grant_type="refresh_token", ) try: await update_token(provider.id, new_token) except PyJWTError as err: logger.info(f"Cannot refresh token: {err.__class__.__name__}") raise HTTPException( status.HTTP_510_NOT_EXTENDED, f"Token refresh error: {err.__class__.__name__}" ) return RedirectResponse(url=request.url_for("home")) # Snippet for running standalone # Mostly useful for the --version option, # as running with uvicorn is easy and provides better flexibility, eg. # uvicorn --host foo oidc_test.main:app --reload def main(): from uvicorn import run from argparse import ArgumentParser parser = ArgumentParser(description=__doc__) parser.add_argument( "-l", "--host", type=str, default="0.0.0.0", help="Address to listen to (default: 0.0.0.0)", ) parser.add_argument( "-p", "--port", type=int, default=80, help="Port to listen to (default: 80)" ) parser.add_argument("-v", "--version", action="store_true", help="Print version and exit") args = parser.parse_args() if args.version: import sys from importlib.metadata import version print(version("oidc-fastapi-test")) sys.exit(0) run(app, host=args.host, port=args.port)