feat: identity provider functions

[Salakar]

Testing:

Deployed the following sample:

from firebase_functions import identity_fn


@identity_fn.before_user_created(
    id_token=True,
    access_token=True,
    refresh_token=True,
)
def beforeusercreated(
    event: identity_fn.AuthBlockingEvent
) -> identity_fn.BeforeCreateResponse | None:
    print(event)
    if not event.data.email:
        return None
    if "@cats.com" in event.data.email:
        return identity_fn.BeforeCreateResponse(display_name="Meow!",)
    if "@dogs.com" in event.data.email:
        return identity_fn.BeforeCreateResponse(display_name="Woof!",)
    return None


@identity_fn.before_user_signed_in(
    id_token=True,
    access_token=True,
    refresh_token=True,
)
def beforeusersignedin(
    event: identity_fn.AuthBlockingEvent
) -> identity_fn.BeforeSignInResponse | None:
    print(event)
    if not event.data.email:
        return None

    if "@cats.com" in event.data.email:
        return identity_fn.BeforeSignInResponse(session_claims={"emoji": "🐈"})

    if "@dogs.com" in event.data.email:
        return identity_fn.BeforeSignInResponse(session_claims={"emoji": "🐕"})

    return None

---

created a user with email "hello123@dogs.com" and function triggered:

---

signed in a user with email "hello123@cats.com" and function triggered:

[taeold]

q: What's the difference between typedict vs dataclass 🤔

should we prefer one style over another here?

[taeold]

answer: typedict allows us to distinguish undefined vs null (in js)

[taeold]

q: is lazy importing intentional? is there a rule of thumb you are using to choose lazy import vs top level import?

[taeold]

answer: to avoid circular imports