8chan.py

# -*- coding: utf-8 -*-

# Copyright 2022-2026 Mike Fährmann
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License version 2 as
# published by the Free Software Foundation.

"""Extractors for https://8chan.moe/"""

from .common import Extractor, Message
from .. import text, dt
from ..cache import memcache
import itertools

BASE_PATTERN = r"(?:https?://)?8chan\.(moe|se|cc)"


class _8chanExtractor(Extractor):
    """Base class for 8chan extractors"""
    category = "8chan"
    root = "https://8chan.moe"

    def __init__(self, match):
        self.root = "https://8chan." + match[1]
        Extractor.__init__(self, match)

    @memcache()
    def cookies_tos_name(self):
        domain = "8chan." + self.groups[0]
        for cookie in self.cookies:
            if cookie.domain == domain and \
                    cookie.name.lower().startswith("tos"):
                self.log.debug("TOS cookie name: %s", cookie.name)
                return cookie.name

        url = self.root + "/.static/pages/confirmed.html"
        headers = {"Referer": self.root + "/.static/pages/disclaimer.html"}
        response = self.request(url, headers=headers, allow_redirects=False)

        for cookie in response.cookies:
            if cookie.name.lower().startswith("tos"):
                self.log.debug("TOS cookie name: %s", cookie.name)
                return cookie.name

        self.log.error("Unable to determin TOS cookie name")
        return "TOS20250418"

    @memcache()
    def cookies_prepare(self):
        # fetch captcha cookies
        # (necessary to download without getting interrupted)
        now = dt.now()
        url = self.root + "/captcha.js"
        params = {"d": now.strftime("%a %b %d %Y %H:%M:%S GMT+0000 (UTC)")}
        self.request(url, params=params).content

        # adjust cookies
        # - remove 'expires' timestamp
        # - move 'captchaexpiration' value forward by 1 month
        domain = self.root.rpartition("/")[2]
        for cookie in self.cookies:
            if cookie.domain.endswith(domain):
                cookie.expires = None
                if cookie.name == "captchaexpiration":
                    cookie.value = (now + dt.timedelta(30, 300)).strftime(
                        "%a, %d %b %Y %H:%M:%S GMT")

        return self.cookies


class _8chanThreadExtractor(_8chanExtractor):
    """Extractor for 8chan threads"""
    subcategory = "thread"
    directory_fmt = ("{category}", "{boardUri}",
                     "{threadId} {subject[:50]}")
    filename_fmt = "{postId}{num:?-//} {filename[:200]}.{extension}"
    archive_fmt = "{boardUri}_{postId}_{num}"
    pattern = BASE_PATTERN + r"/([^/?#]+)/(?:res|last)/(\d+)"
    example = "https://8chan.moe/a/res/12345.html"

    def items(self):
        _, board, thread = self.groups
        self.cookies.set(self.cookies_tos_name(), "1", domain=self.root[8:])

        # fetch thread data
        url = f"{self.root}/{board}/res/{thread}."
        self.session.headers["Referer"] = url + "html"
        thread = self.request_json(url + "json")
        thread["postId"] = thread["threadId"]
        thread["_http_headers"] = {"Referer": url + "html"}

        try:
            self.cookies = self.cookies_prepare()
        except Exception as exc:
            self.log.debug("Failed to fetch captcha cookies:  %s: %s",
                           exc.__class__.__name__, exc, exc_info=exc)

        # download files
        posts = thread.pop("posts", ())
        yield Message.Directory, "", thread
        for post in itertools.chain((thread,), posts):
            files = post.pop("files", ())
            if not files:
                continue
            thread.update(post)
            for num, file in enumerate(files):
                file.update(thread)
                file["num"] = num
                file["_http_validate"] = _validate
                text.nameext_from_url(file["originalName"], file)
                yield Message.Url, self.root + file["path"], file


class _8chanBoardExtractor(_8chanExtractor):
    """Extractor for 8chan boards"""
    subcategory = "board"
    pattern = BASE_PATTERN + r"/([^/?#]+)/(?:(\d+)\.html)?$"
    example = "https://8chan.moe/a/"

    def items(self):
        _, board, pnum = self.groups
        self.cookies.set(self.cookies_tos_name(), "1", domain=self.root[8:])

        pnum = text.parse_int(pnum, 1)
        url = f"{self.root}/{board}/{pnum}.json"
        data = self.request_json(url)
        threads = data["threads"]

        while True:
            for thread in threads:
                thread["_extractor"] = _8chanThreadExtractor
                url = f"{self.root}/{board}/res/{thread['threadId']}.html"
                yield Message.Queue, url, thread

            pnum += 1
            if pnum > data["pageCount"]:
                return
            url = f"{self.root}/{board}/{pnum}.json"
            threads = self.request_json(url)["threads"]


def _validate(response):
    hget = response.headers.get
    return not (
        hget("expires") == "0" and
        hget("content-length") == "166" and
        hget("content-type") == "image/png"
    )