advent22/api/advent22_api/core/image_helpers.py

import re
from io import BytesIO

from fastapi.responses import StreamingResponse
from PIL import Image

from .webdav import WebDAV


async def list_images_auto() -> list[str]:
    """
    Finde alle Bilddateien im "automatisch"-Verzeichnis
    """

    return await WebDAV.list_files(
        directory="/images_auto",
        regex=re.compile(r"\.(gif|jpe?g|tiff?|png|bmp)$", flags=re.IGNORECASE),
    )


async def load_image(file_name: str) -> Image.Image:
    """
    Versuche, Bild aus Datei zu laden
    """

    if not await WebDAV.file_exists(file_name):
        raise RuntimeError(f"DAV-File {file_name} does not exist!")

    return Image.open(BytesIO(await WebDAV.read_bytes(file_name)))


async def api_return_image(img: Image.Image) -> StreamingResponse:
    """
    Bild mit API zurückgeben
    """

    # JPEG-Daten in Puffer speichern
    img_buffer = BytesIO()
    img.save(img_buffer, format="JPEG", quality=85)
    img_buffer.seek(0)

    # zurückgeben
    return StreamingResponse(
        media_type="image/jpeg",
        content=img_buffer,
    )