file_manager/file_manager.py

# Copy from https://github.com/silentsokolov/flask-thumbnails/blob/master/flask_thumbnails/thumbnail.py
import os
from datetime import datetime

import cv2
import time
from io import BytesIO
from pathlib import Path
import numpy as np
from watchdog.events import FileSystemEventHandler
from watchdog.observers import Observer

from PIL import Image, ImageOps, PngImagePlugin
from loguru import logger

LARGE_ENOUGH_NUMBER = 100
PngImagePlugin.MAX_TEXT_CHUNK = LARGE_ENOUGH_NUMBER * (1024**2)
from .storage_backends import FilesystemStorageBackend
from .utils import aspect_to_string, generate_filename, glob_img


class FileManager(FileSystemEventHandler):
    def __init__(self, app=None):
        self.app = app
        self._default_root_directory = "media"
        self._default_thumbnail_directory = "media"
        self._default_root_url = "/"
        self._default_thumbnail_root_url = "/"
        self._default_format = "JPEG"
        self.output_dir: Path = None

        if app is not None:
            self.init_app(app)

        self.image_dir_filenames = []
        self.output_dir_filenames = []

        self.image_dir_observer = None
        self.output_dir_observer = None

        self.modified_time = {
            "image": datetime.utcnow(),
            "output": datetime.utcnow(),
        }

    def start(self):
        self.image_dir_filenames = self._media_names(self.root_directory)
        self.output_dir_filenames = self._media_names(self.output_dir)

        logger.info(f"Start watching image directory: {self.root_directory}")
        self.image_dir_observer = Observer()
        self.image_dir_observer.schedule(self, self.root_directory, recursive=False)
        self.image_dir_observer.start()

        logger.info(f"Start watching output directory: {self.output_dir}")
        self.output_dir_observer = Observer()
        self.output_dir_observer.schedule(self, self.output_dir, recursive=False)
        self.output_dir_observer.start()

    def on_modified(self, event):
        if not os.path.isdir(event.src_path):
            return
        if event.src_path == str(self.root_directory):
            logger.info(f"Image directory {event.src_path} modified")
            self.image_dir_filenames = self._media_names(self.root_directory)
            self.modified_time["image"] = datetime.utcnow()
        elif event.src_path == str(self.output_dir):
            logger.info(f"Output directory {event.src_path} modified")
            self.output_dir_filenames = self._media_names(self.output_dir)
            self.modified_time["output"] = datetime.utcnow()

    def init_app(self, app):
        if self.app is None:
            self.app = app
        app.thumbnail_instance = self

        if not hasattr(app, "extensions"):
            app.extensions = {}

        if "thumbnail" in app.extensions:
            raise RuntimeError("Flask-thumbnail extension already initialized")

        app.extensions["thumbnail"] = self

        app.config.setdefault("THUMBNAIL_MEDIA_ROOT", self._default_root_directory)
        app.config.setdefault(
            "THUMBNAIL_MEDIA_THUMBNAIL_ROOT", self._default_thumbnail_directory
        )
        app.config.setdefault("THUMBNAIL_MEDIA_URL", self._default_root_url)
        app.config.setdefault(
            "THUMBNAIL_MEDIA_THUMBNAIL_URL", self._default_thumbnail_root_url
        )
        app.config.setdefault("THUMBNAIL_DEFAULT_FORMAT", self._default_format)

    @property
    def root_directory(self):
        path = self.app.config["THUMBNAIL_MEDIA_ROOT"]

        if os.path.isabs(path):
            return path
        else:
            return os.path.join(self.app.root_path, path)

    @property
    def thumbnail_directory(self):
        path = self.app.config["THUMBNAIL_MEDIA_THUMBNAIL_ROOT"]

        if os.path.isabs(path):
            return path
        else:
            return os.path.join(self.app.root_path, path)

    @property
    def root_url(self):
        return self.app.config["THUMBNAIL_MEDIA_URL"]

    @property
    def media_names(self):
        # return self.image_dir_filenames
        return self._media_names(self.root_directory)

    @property
    def output_media_names(self):
        return self._media_names(self.output_dir)
        # return self.output_dir_filenames

    @staticmethod
    def _media_names(directory: Path):
        names = sorted([it.name for it in glob_img(directory)])
        res = []
        for name in names:
            path = os.path.join(directory, name)
            img = Image.open(path)
            res.append(
                {
                    "name": name,
                    "height": img.height,
                    "width": img.width,
                    "ctime": os.path.getctime(path),
                }
            )
        return res

    @property
    def thumbnail_url(self):
        return self.app.config["THUMBNAIL_MEDIA_THUMBNAIL_URL"]

    def get_thumbnail(
        self, directory: Path, original_filename: str, width, height, **options
    ):
        storage = FilesystemStorageBackend(self.app)
        crop = options.get("crop", "fit")
        background = options.get("background")
        quality = options.get("quality", 90)

        original_path, original_filename = os.path.split(original_filename)
        original_filepath = os.path.join(directory, original_path, original_filename)
        image = Image.open(BytesIO(storage.read(original_filepath)))

        # keep ratio resize
        if width is not None:
            height = int(image.height * width / image.width)
        else:
            width = int(image.width * height / image.height)

        thumbnail_size = (width, height)

        thumbnail_filename = generate_filename(
            original_filename,
            aspect_to_string(thumbnail_size),
            crop,
            background,
            quality,
        )

        thumbnail_filepath = os.path.join(
            self.thumbnail_directory, original_path, thumbnail_filename
        )
        thumbnail_url = os.path.join(
            self.thumbnail_url, original_path, thumbnail_filename
        )

        if storage.exists(thumbnail_filepath):
            return thumbnail_url, (width, height)

        try:
            image.load()
        except (IOError, OSError):
            self.app.logger.warning("Thumbnail not load image: %s", original_filepath)
            return thumbnail_url, (width, height)

        # get original image format
        options["format"] = options.get("format", image.format)

        image = self._create_thumbnail(
            image, thumbnail_size, crop, background=background
        )

        raw_data = self.get_raw_data(image, **options)
        storage.save(thumbnail_filepath, raw_data)

        return thumbnail_url, (width, height)

    def get_raw_data(self, image, **options):
        data = {
            "format": self._get_format(image, **options),
            "quality": options.get("quality", 90),
        }

        _file = BytesIO()
        image.save(_file, **data)
        return _file.getvalue()

    @staticmethod
    def colormode(image, colormode="RGB"):
        if colormode == "RGB" or colormode == "RGBA":
            if image.mode == "RGBA":
                return image
            if image.mode == "LA":
                return image.convert("RGBA")
            return image.convert(colormode)

        if colormode == "GRAY":
            return image.convert("L")

        return image.convert(colormode)

    @staticmethod
    def background(original_image, color=0xFF):
        size = (max(original_image.size),) * 2
        image = Image.new("L", size, color)
        image.paste(
            original_image,
            tuple(map(lambda x: (x[0] - x[1]) / 2, zip(size, original_image.size))),
        )

        return image

    def _get_format(self, image, **options):
        if options.get("format"):
            return options.get("format")
        if image.format:
            return image.format

        return self.app.config["THUMBNAIL_DEFAULT_FORMAT"]

    def _create_thumbnail(self, image, size, crop="fit", background=None):
        try:
            resample = Image.Resampling.LANCZOS
        except AttributeError:  # pylint: disable=raise-missing-from
            resample = Image.ANTIALIAS

        if crop == "fit":
            image = ImageOps.fit(image, size, resample)
        else:
            image = image.copy()
            image.thumbnail(size, resample=resample)

        if background is not None:
            image = self.background(image)

        image = self.colormode(image)

        return image