get #13121 to work without restart

import functools

import os.path

import urllib.parse

from pathlib import Path

extra_pages = []

allowed_dirs = set()

allowed_preview_extensions = ["png", "jpg", "jpeg", "webp", "gif"]

if shared.opts.samples_format not in allowed_preview_extensions:

    allowed_preview_extensions.append(shared.opts.samples_format)

allowed_preview_extensions_dot = ['.' + extension for extension in allowed_preview_extensions]

default_allowed_preview_extensions = ["png", "jpg", "jpeg", "webp", "gif"]

@functools.cache

def allowed_preview_extensions_with_extra(extra_extensions=None):

    return set(default_allowed_preview_extensions) | set(extra_extensions or [])

def allowed_preview_extensions():

    return allowed_preview_extensions_with_extra((shared.opts.samples_format, ))

def register_page(page):

    if not any(Path(x).absolute() in Path(filename).absolute().parents for x in allowed_dirs):

        raise ValueError(f"File cannot be fetched: {filename}. Must be in one of directories registered by extra pages.")

    ext = os.path.splitext(filename)[1].lower()

    if ext not in allowed_preview_extensions_dot:

        raise ValueError(f"File cannot be fetched: {filename}. Only png, jpg, webp, and gif.")

    ext = os.path.splitext(filename)[1].lower()[1:]

    if ext not in allowed_preview_extensions():

        raise ValueError(f"File cannot be fetched: {filename}. Extensions allowed: {allowed_preview_extensions()}.")

    # would profit from returning 304

    return FileResponse(filename, headers={"Accept-Ranges": "bytes"})

        Find a preview PNG for a given path (without extension) and call link_preview on it.

        """

        potential_files = sum([[path + "." + ext, path + ".preview." + ext] for ext in allowed_preview_extensions], [])

        potential_files = sum([[path + "." + ext, path + ".preview." + ext] for ext in allowed_preview_extensions()], [])

        for file in potential_files:

            if os.path.isfile(file):