added login page and started integrated of security

backend/app/routers/auth.py

@@ -0,0 +1,82 @@
+from fastapi import APIRouter, HTTPException, status, Depends
+from fastapi.security import OAuth2PasswordRequestForm
+from fastapi.security import OAuth2AuthorizationCodeBearer
+from app.schemas import loginToken, loginData
+
+import jwt
+from datetime import datetime, timedelta, timezone
+
+# Define an APIRouter for authentication
+router = APIRouter()
+
+
+mock_users_db = {
+    "testuser": {
+        "username": "testuser",
+        "password": "testpass",  # In a real scenario, store the hash of the password
+        "pgroups": [20000, 20001, 20003],
+    }
+}
+
+
+# https://fastapi.tiangolo.com/tutorial/security/oauth2-jwt/#hash-and-verify-the-passwords
+# SECRET_KEY taken from FastAPI documentation, so not that secret :D
+# openssl rand -hex 32
+SECRET_KEY = "09d25e094faa6ca2556c818166b7a9563b93f7099f6f0f4caa6cf63b88e8d3e7"
+ALGORITHM = "HS256"
+ACCESS_TOKEN_EXPIRE_MINUTES = 30
+
+oauth2_scheme = OAuth2AuthorizationCodeBearer(authorizationUrl="/login", tokenUrl="/token/login")
+
+def create_access_token(data: dict) -> str:
+    to_encode = data.copy()
+    expire = datetime.now(timezone.utc) + timedelta(minutes=ACCESS_TOKEN_EXPIRE_MINUTES)
+    to_encode.update({"exp": expire})
+    return jwt.encode(to_encode, SECRET_KEY, algorithm=ALGORITHM)
+
+async def get_current_user(token: str = Depends(oauth2_scheme)) -> loginData:
+    credentials_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Could not validate credentials",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    token_expired_exception = HTTPException(
+        status_code=status.HTTP_401_UNAUTHORIZED,
+        detail="Token expired",
+        headers={"WWW-Authenticate": "Bearer"},
+    )
+    try:
+        payload = jwt.decode(token, SECRET_KEY, algorithms=[ALGORITHM])
+        username: str = payload.get("sub")
+        pgroups = payload.get("pgroups")
+
+        if username is None:
+            raise credentials_exception
+        token_data = loginData(username=username, pgroups=pgroups)
+    except jwt.ExpiredSignatureError:
+        raise token_expired_exception
+    except jwt.InvalidTokenError:
+        raise credentials_exception
+
+    return token_data
+
+@router.post("/token/login", response_model=loginToken)
+async def login(form_data: OAuth2PasswordRequestForm = Depends()):
+    user = mock_users_db.get(form_data.username)
+    if user is None or user["password"] != form_data.password:
+        raise HTTPException(
+            status_code=status.HTTP_401_UNAUTHORIZED,
+            detail="Incorrect username or password",
+            headers={"WWW-Authenticate": "Bearer"},
+        )
+
+    # Create token
+    access_token = create_access_token(
+        data={"sub": user["username"], "pgroups": user["pgroups"]}
+    )
+    return loginToken(access_token=access_token, token_type="bearer")
+
+
+@router.get("/protected-route")
+async def read_protected_data(current_user: loginData = Depends(get_current_user)):
+    return {"username": current_user.username, "pgroups": current_user.pgroups}