Working around an issue with Nuitka-commercial's handling of embedded file and it's incompatibility with anyio/asyncio async file IO, which is used by Starlette's FileResponse class.

nuikta_fastapi_workaround.py

import os
import stat

from fastapi.responses import FileResponse
from starlette.types import Receive, Scope, Send


class FileResponseSynchronous(FileResponse):
    """
    This works around an issue building with `Nuitka-commercial` and embedding files
    (so they are not present on disk), since that doesn't work with anyio/asyncio.

    See issue: https://github.com/Nuitka/Nuitka-commercial/issues/159
    """

    async def __call__(self, scope: Scope, receive: Receive, send: Send) -> None:
        """This is identical to FileResponse's `__call__()` method, but with a conversion to synchronous file IO."""
        if self.stat_result is None:
            try:
                stat_result = os.stat(self.path)
                self.set_stat_headers(stat_result)
            except FileNotFoundError:
                raise RuntimeError(f"File at path {self.path} does not exist.")
            else:
                mode = stat_result.st_mode
                if not stat.S_ISREG(mode):
                    raise RuntimeError(f"File at path {self.path} is not a file.")
        await send(
            {
                "type": "http.response.start",
                "status": self.status_code,
                "headers": self.raw_headers,
            }
        )
        if scope["method"].upper() == "HEAD":
            await send({"type": "http.response.body", "body": b"", "more_body": False})
        elif "extensions" in scope and "http.response.pathsend" in scope["extensions"]:
            await send({"type": "http.response.pathsend", "path": str(self.path)})
        else:
            with open(self.path, mode="rb") as file:
                more_body = True
                while more_body:
                    chunk = file.read(self.chunk_size)
                    more_body = len(chunk) == self.chunk_size
                    await send(
                        {
                            "type": "http.response.body",
                            "body": chunk,
                            "more_body": more_body,
                        }
                    )
        if self.background is not None:
            await self.background()