Generate django-imagekit versions on the fly

generators.py

from imagekit import ImageSpec
from imagekit.processors import ResizeToFill, ResizeToFit
from PIL import Image


class Avatar80x80(ImageSpec):
    processors = [ResizeToFill(80, 80)]
    format = "PNG"

    
VERSIONS = {
    "core:avatar80x80": Avatar80x80,
}

views.py

import json
import base64
import hashlib

from django import forms
from django.http import HttpResponse
from django.shortcuts import redirect
from django.core.cache import cache
from django.core.files.storage import default_storage
from django.utils.translation import gettext

from .generators import VERSIONS

VERSION_CHOICES = [(key, key) for key in VERSIONS.keys()]

PIXEL_GIF_DATA = base64.b64decode(
    "R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7"
)


class ImageVersionForm(forms.Form):
    image_path = forms.CharField(required=True)
    version = forms.ChoiceField(required=True, choices=VERSION_CHOICES)

    def clean_image_path(self):
        image_path = self.cleaned_data["image_path"]
        if image_path.startswith("http") or ".." in image_path:
            raise forms.ValidationError(gettext("Invalid image path"))
        if not default_storage.exists(image_path):
            raise forms.ValidationError(gettext("Image does not exist"))
        if default_storage.size(image_path) > settings.MAX_IMAGE_FILE_SIZE["bytes"]:
            raise forms.ValidationError(
                gettext("Original image is too big. It should be less than {file_size}.").format(file_size=settings.MAX_IMAGE_FILE_SIZE["humanized_size"])
            )
        return image_path

    def get_generator_class(self):
        return VERSIONS[self.cleaned_data["version"]]

    def generate(self):
        from django.core.files import File
        from imagekit.cachefiles import ImageCacheFile

        image_path = self.cleaned_data["image_path"]
        VersionGenerator = self.get_generator_class()
        with default_storage.open(image_path) as source_file:
            image_generator = VersionGenerator(source=File(source_file, name=image_path))
            cached = ImageCacheFile(image_generator)
            cached.generate(force=False)
            cached_url = cached.url
            return cached_url


def show_image_version(request):
    form = ImageVersionForm(data=request.GET)
    if form.is_valid():
        # Create cache key from form data
        cache_key = hashlib.md5(str(sorted(request.GET.items())).encode()).hexdigest()
        cache_key = f"image_url_{cache_key}"

        # Try to get URL from cache
        if not (result_url := cache.get(cache_key)):
            result_url = form.generate()
            cache.set(cache_key, result_url, 60 * 60 * 24)  # 24 hours

        return redirect(result_url)

    # Error fallback
    json_data = json.dumps(form.errors)
    response = HttpResponse(PIXEL_GIF_DATA, content_type="image/gif")
    response["Hints"] = json_data
    return response