Source code for scrapy.robotstxt

from __future__ import annotations

import logging
import sys
from abc import ABCMeta, abstractmethod
from typing import TYPE_CHECKING

from scrapy.utils.python import to_unicode

if TYPE_CHECKING:
    # typing.Self requires Python 3.11
    from typing_extensions import Self

    from scrapy import Spider
    from scrapy.crawler import Crawler


logger = logging.getLogger(__name__)


def decode_robotstxt(
    robotstxt_body: bytes, spider: Spider | None, to_native_str_type: bool = False
) -> str:
    try:
        if to_native_str_type:
            body_decoded = to_unicode(robotstxt_body)
        else:
            body_decoded = robotstxt_body.decode("utf-8", errors="ignore")
    except UnicodeDecodeError:
        # If we found garbage or robots.txt in an encoding other than UTF-8, disregard it.
        # Switch to 'allow all' state.
        logger.warning(
            "Failure while parsing robots.txt. File either contains garbage or "
            "is in an encoding other than UTF-8, treating it as an empty file.",
            exc_info=sys.exc_info(),
            extra={"spider": spider},
        )
        body_decoded = ""
    return body_decoded


[docs]class RobotParser(metaclass=ABCMeta):
[docs] @classmethod @abstractmethod def from_crawler(cls, crawler: Crawler, robotstxt_body: bytes) -> Self: """Parse the content of a robots.txt_ file as bytes. This must be a class method. It must return a new instance of the parser backend. :param crawler: crawler which made the request :type crawler: :class:`~scrapy.crawler.Crawler` instance :param robotstxt_body: content of a robots.txt_ file. :type robotstxt_body: bytes """ pass
[docs] @abstractmethod def allowed(self, url: str | bytes, user_agent: str | bytes) -> bool: """Return ``True`` if ``user_agent`` is allowed to crawl ``url``, otherwise return ``False``. :param url: Absolute URL :type url: str or bytes :param user_agent: User agent :type user_agent: str or bytes """ pass
class PythonRobotParser(RobotParser): def __init__(self, robotstxt_body: bytes, spider: Spider | None): from urllib.robotparser import RobotFileParser self.spider: Spider | None = spider body_decoded = decode_robotstxt(robotstxt_body, spider, to_native_str_type=True) self.rp: RobotFileParser = RobotFileParser() self.rp.parse(body_decoded.splitlines()) @classmethod def from_crawler(cls, crawler: Crawler, robotstxt_body: bytes) -> Self: spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url: str | bytes, user_agent: str | bytes) -> bool: user_agent = to_unicode(user_agent) url = to_unicode(url) return self.rp.can_fetch(user_agent, url) class RerpRobotParser(RobotParser): def __init__(self, robotstxt_body: bytes, spider: Spider | None): from robotexclusionrulesparser import RobotExclusionRulesParser self.spider: Spider | None = spider self.rp: RobotExclusionRulesParser = RobotExclusionRulesParser() body_decoded = decode_robotstxt(robotstxt_body, spider) self.rp.parse(body_decoded) @classmethod def from_crawler(cls, crawler: Crawler, robotstxt_body: bytes) -> Self: spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url: str | bytes, user_agent: str | bytes) -> bool: user_agent = to_unicode(user_agent) url = to_unicode(url) return self.rp.is_allowed(user_agent, url) class ProtegoRobotParser(RobotParser): def __init__(self, robotstxt_body: bytes, spider: Spider | None): from protego import Protego self.spider: Spider | None = spider body_decoded = decode_robotstxt(robotstxt_body, spider) self.rp = Protego.parse(body_decoded) @classmethod def from_crawler(cls, crawler: Crawler, robotstxt_body: bytes) -> Self: spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url: str | bytes, user_agent: str | bytes) -> bool: user_agent = to_unicode(user_agent) url = to_unicode(url) return self.rp.can_fetch(url, user_agent)