fetch and save full-size covers from bookwalker

bwcover.py

#!/bin/python
import sys
import re
import requests


# https://github.com/qsniyg/maxurl/issues/17
# https://github.com/qsniyg/maxurl/commit/5d5a77c08f9461c5d7c4ceac209fca240b776d7b#diff-1bc842c9e7dda2f26048e68021e82a3c290fb38639d0acf259392b26f4664fc8R21594-R21613
def get_real_url(url):
    if "rimg.bookwalker.jp" in url:
        url = re.sub(
            r":\/\/[^/]*\/([0-9]+)\/[0-9a-zA-Z_]+(\.[^/.]*)$",
            r"://c.bookwalker.jp/\1/t_700x780\2",
            url,
        )

    if "c.bookwalker.jp" in url:
        match = re.search(r":\/\/[^/]*\/([0-9]+)\/[^/]*(?:[?#].*)?$", url)
        if match:
            number = match[1]
            reversed_number = int(number[::-1]) - 1
            url = (
                "https://c.bookwalker.jp/coverImage_"
                + str(reversed_number)
                + re.sub(r".*(\.[^/.?#]*)(?:[?#].*)?$", r"\1", url)
            )

    return url


def save_img(url, name):
    ext = url.rsplit(".", maxsplit=1)[1]

    with requests.get(url) as response:
        response.raise_for_status()
        img = response.content

    with open(f"{name}.{ext}", "wb") as f:
        f.write(img)


if __name__ == "__main__":
    arg_count = len(sys.argv)

    if arg_count == 1:
        sys.exit("no url supplied")

    input_url = sys.argv[1] if arg_count > 1 else None
    file_name = sys.argv[2] if arg_count > 2 else None

    if "rimg.bookwalker.jp" in input_url or "c.bookwalker.jp" in input_url:
        cover_url = get_real_url(input_url)
    else:
        sys.exit("invalid url supplied")

    if file_name:
        save_img(cover_url, file_name)
    else:
        print(cover_url)

right click -> copy image link -> bwcover.py <url> <filename>
bwcover.py <url> cool-cover -> saves cool-cover.<ext>
bwcover.py <url> -> prints full-size url