[Python] "AttributeError: 'property' object has no attribute 'get'" when using Depends in...

To implement authentication for a FastAPI endpoint, I want to make use of the Depends functionality offered in the latest versions (>=0.95) of FastAPI. I have tried several ways to implement it but I am facing an error "AttributeError: 'property' object has no attribute 'get'". This implies that the starlette Request object is not recognised as such when using Depends.

Endpoint implementation:

@app.get("/")
async def home(user: Annotated[User, Depends(authenticate_request(Request))]):
"""
status _summary_
Returns status message if service is running
"""
if isinstance(user, User):
return {"Welcome, service is running ok!"}
raise HTTPException(
status_code=401,
detail="User not authorized!",
)


Function authenticate_request checks validity of cookies based on provided Request:

def authenticate_request(request: Request) -> User:
cookie1 = request.cookies.get("x")
cookie2 = request.cookies.get("y")
if cookie1 is not None and cookie2 is not None:
tenant = get_tenant(request)
if user := authenticate_cookies(cookie1, cookie2, tenant):
if not tenant.startswith(user.tenant):
print("Unauthorized: Token hostname mismatch")
raise Exception("Token hostname mismatch")
return user
print("Unauthorized: please login")
raise HTTPException(status_code=401, detail="Unauthorized: please login")


This results in error "AttributeError: 'property' object has no attribute 'get'". This implies that the Request object is not passed correctly or is not recognised as such.

I then tried to solve this without using Depends:

@app.get("/")
async def home(request: Request):
"""
status _summary_
Returns status message if service is running
"""
user = authenticate_request(request=request)
if isinstance(user, User):
return {"Welcome, service is running ok!"}
raise HTTPException(
status_code=401,
detail="User not authorized!",
)


This is working correctly. If no valid cookie is provided a 401 is returned. Based on this I come to the conclusion that my authenticate_request() function is working correctly.

Does anybody know why there is a difference in behaviour between Depends() and the alternative solution?

Help is much appreciated!

Regards, Laurens

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