Class FastAPIResponseAdapter

dash/backends/_fastapi.py:59–92

A custom Response class that wraps FastAPI's JSONResponse and provides a set_response() method for compatibility with Dash's callback system.

class FastAPIResponseAdapter(ResponseAdapter):
    """
    A custom Response class that wraps FastAPI's JSONResponse
    and provides a set_response() method for compatibility with Dash's callback system.
    """

    @property
    def callback_response(self):
        """Get the response object to be returned from a callback."""
        print(
            "Cannot access callback_response directly on FastAPIResponseAdapter. Use set_response() to create a response with data."
        )
        raise NotImplementedError()

    def set_response(self, **kwargs):
        """
        Set the response data. This method provides compatibility with Flask's Response.set_data().
        """
        data = kwargs.get("data")
        if isinstance(data, (str, bytes, bytearray)):
            resp = Response(content=data)
        else:
            resp = JSONResponse(content=data)
        if self._headers:
            for key, value in self._headers.items():
                if isinstance(value, list):
                    for v in value:
                        resp.headers.append(key, v)
                else:
                    resp.headers[key] = value
        if self._cookies:
            for key, (value, cookie_kwargs) in self._cookies.items():
                resp.set_cookie(key, value, **cookie_kwargs)
        return resp


_current_request_var = ContextVar("dash_current_request", default=None)