fastapi-cache 0.1.4: TypeError: Unicode-objects must be encoded before hashing

[diegocgaona]

Hi,

I updated fastapi-cache using Github to solve the problem of "not JSON serializable", but now I have a new error:

  File "/lib/python3.9/site-packages/fastapi_cache/decorator.py", line 40, in inner
    cache_key = key_builder(
  File "/lib/python3.9/site-packages/fastapi_cache/key_builder.py", line 21, in default_key_builder
    + hashlib.md5(  # nosec:B303
TypeError: Unicode-objects must be encoded before hashing

Before (with version 1.3.4) I was using something like this bellow, but with the two lines commented and returning the json_updated_user:

@router.get("/me/items/", response_model=List[schemas.User_Pydantic])
@cache(namespace="test", expire=60, coder=JsonCoder)
async def read_current_user_items(user: UserDB = Depends(fastapi_users.get_current_active_user)):
    user_cards = await schemas.Card_Pydantic.from_queryset(
        Card.filter(owner_id=user.id).all())
    for city in user_cards:
        await weather_api.get_api_info_by_id(city.id)
    # user_with_items = await schemas.User_Pydantic.from_queryset(UserModel.filter(id=user.id).all())
    # json_updated_user = jsonable_encoder(user_with_items)
    return await schemas.User_Pydantic.from_queryset(UserModel.filter(id=user.id).all())

Without jsonable_encoder I get the error "not JSON serializable", but now I have the hash error.
If I comment the @cache decorator, it works fine (and I don't need the jsonable_encoder).

Thanks in advance!

[long2ice]

You need write you custom key_builder

[diegocgaona]

Ok, after some tries I had modified the default key_builder, putting an .encode('utf-8'). It works, I don't know if it is the best way.

def my_key_builder(
        func,
        namespace: Optional[str] = "",
        request: Optional[Request] = None,
        response: Optional[Response] = None,
        args: Optional[tuple] = None,
        kwargs: Optional[dict] = None,
):
    from fastapi_cache import FastAPICache

    prefix = f"{FastAPICache.get_prefix()}:{namespace}:"
    cache_key = (
            prefix
            + hashlib.md5(f"{func.__module__}:{func.__name__}:{args}:{kwargs}".encode('utf-8'))
            .hexdigest()
    )
    return cache_key

@long2ice , this is correct? This could be the default to handle cases like mine or would cause problems with others?

Thanks!!

[long2ice]

Fixed