implement proof-of-concept backend authentication

api/main.py

@@ -1,5 +1,64 @@
+#!/usr/bin/env python3
+from typing import Optional
+from fastapi import FastAPI, Request, Response
+from fastapi.responses import RedirectResponse
+from pydantic import BaseModel
+from contextlib import asynccontextmanager
+from simple_openid_connect.client import OpenidClient
+from simple_openid_connect.data import TokenSuccessResponse, IdToken
+
+
+@asynccontextmanager
+async def lifespan(app: FastAPI):
+    app.extra["oidc_client"] = OpenidClient.from_issuer_url(
+        url="https://id.hamburg.ccc.de/realms/test/",
+        authentication_redirect_uri="http://localhost:8000/auth/login-callback",
+        client_id="dooris",
+        client_secret="dp9HhnvUhAtKm3pRnxfGA7q8Nwrd1td8",
+    )
+    yield
+
+
+app = FastAPI(lifespan=lifespan)
+
+
+class UserInfo(BaseModel):
+    name: str
+
+
+class UserStatus(BaseModel):
+    is_logged_in: bool
+    user_info: Optional[UserInfo]
+
+
+@app.get("/api/user-info/")
+async def get_user_info() -> UserStatus:
+    return { "bla": "blub" }
+
+
+@app.get("/auth/login")
+async def login_init(req: Request):
+    oidc_client = req.app.extra["oidc_client"] # type: OpenidClient
+    return RedirectResponse(oidc_client.authorization_code_flow.start_authentication())
+
+
+@app.get("/auth/login-callback")
+async def login_callback(req: Request, resp: Response):
+    oidc_client = req.app.extra["oidc_client"] # type: OpenidClient
+    auth_result = oidc_client.authorization_code_flow.handle_authentication_result(current_url=req.url)
+    if isinstance(auth_result, TokenSuccessResponse):
+        resp.set_cookie("access_token", auth_result.access_token, httponly=True)
+        resp.set_cookie("id_token", auth_result.id_token)
+        return {"authenticated": True}
+    else:
+        return {"authenticated": False}
+
+
 def main():
-    print("Hello from api!")
+    import uvicorn
+    config = uvicorn.Config(app, port=8000, log_level="info")
+    server = uvicorn.Server(config)
+    server.run()
 
 
 if __name__ == "__main__":