Satisfying the type checker when accessing request.sid

[Kalilamodow]

Type checkers give an error message (eg. Cannot access attribute "sid" for class "Request") when accessing request.sid. Is there any type-safe workaround, or do I have to define a function like

def getSioSid() -> str:
    sid: str = request.sid  # type: ignore
    return sid # type: ignore

?

[miguelgrinberg]

Unfortunately the request.sid attribute was added long before Flask had typing annotations.

You can trick type checkers with a subclass of the request that declares the sid attribute, done inside a TYPE_CHECKING block. Something like this:

from typing import TYPE_CHECKING

if TYPE_CHECKING:
    from flask import Request as _Request

    class Request(_Request):
        sid: str

    request: Request