PenParse/penparse/webui/views/thumbnail.py

import os

from loguru import logger

from PIL import Image
from io import BytesIO
from django.core.files.storage import default_storage

from django import conf
from django.http import HttpRequest, HttpResponse
from django.contrib.auth.decorators import login_required

from ..models import ImageMemo


@login_required
def document_thumbnail(request: HttpRequest, pk: str):
    """Given a document uuid, look it up, ensure that it belongs to the current user and respond with a thumbnail"""

    # find document with given ID (pk path param) and current user id
    document = ImageMemo.objects.filter(id=pk, author__id=request.user.id).first()

    if not document:
        logger.debug(f"No memo found for user={request.user.id} and memo_id={pk}")
        return HttpResponse(content="Document not found", status=404)

        # look up the file on disk

    # get thumb directory from django setting
    thumbnail_dir = getattr(conf.settings, "THUMBNAIL_DIR", "thumbnails")

    thumb_max_width = getattr(conf.settings, "THUMBNAIL_MAX_WIDTH", 420)

    thumb_path = os.path.join(thumbnail_dir, str(document.id) + ".jpg")

    if not default_storage.exists(thumb_path):

        if not default_storage.exists(document.image.name):
            logger.warning(
                f"The file associated with memo {document.id} does not exist"
            )
            return HttpResponse(content="Document not found", status=404)

        # Open the image using PIL
        image = Image.open(default_storage.open(document.image.name))

        # get the image width and height
        width = int(image.size[0])
        height = int(image.size[1])

        # find the ratio of the width to height
        ratio = round(width / float(height), 3)

        # max width of thumbnail is 240, calculate height based on ratio
        thumb_height = int(thumb_max_width * ratio)

        # Create a thumbnail
        image.thumbnail((thumb_max_width, thumb_height))  # Adjust size as needed

        # if the image format is not jpeg, convert as needed
        if image.format != "JPEG":
            image = image.convert("RGB")

        # Save the thumbnail to a BytesIO object
        thumb_io = BytesIO()
        image.save(thumb_io, format="JPEG")
        thumb_io.seek(0)

        default_storage.save(thumb_path, thumb_io)

    # Return the thumbnail as an HTTP response
    with open(thumb_path, "rb") as f:
        return HttpResponse(f.read(), content_type="image/jpeg")