url option is not working if there are no url available

[wankio]

"url": "{sample_url}", it work well if there are sample_url, but it will :
gelbooru: An unexpected error occurred: IndexError - string index out of range. Please run gallery-dl again with the --verbose flag, copy its output and report this issue on https://github.com/mikf/gallery-dl/issues .
if sample_url is not found, which i think it can fallback to second or third url option available if the first one is not found, to prevent this error

[mikf]

IndexError is fixed (bf44add) and you can now have more than one url field to have a fallback in case the first one doesn't work (6940ad0).

[wankio]

oh i noticed it only affected booru, not included sankaku

[mikf]

This works for sankaku as well. What makes you think it doesn't?

[wankio]

because i just tested and it won't work, booru.py have change but sankaku.py is not, it still fixed file_url

                for post in posts:
                    if not expires:
                        url = post["file_url"]

currently i just hard code it into sample_url > preview_url > file_url