Handle pagination

[eight04]

It is often that we have to grab multiple pages to get all images. With the current hook get_chapter_files, we have to implement something like this:

page_url = chapter.url
count = 0
while True:
  content = self.request.get(page_url)
  # parse content and find image links
  for url in urls:
    yield Image(...)
    count += 1
  # parse content and find next page
  if not next_page_url:
    break
  page_url = next_page_url

The problem is that you always have to start from the first page. I want to allow users to pause the download process, save the process to the disk, restart the application, load the process and continue.