scrapy.robotstxt 源代码

import sys
import logging
from abc import ABCMeta, abstractmethod

from scrapy.utils.python import to_unicode


logger = logging.getLogger(__name__)


def decode_robotstxt(robotstxt_body, spider, to_native_str_type=False):
    try:
        if to_native_str_type:
            robotstxt_body = to_unicode(robotstxt_body)
        else:
            robotstxt_body = robotstxt_body.decode('utf-8')
    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},
        )
        robotstxt_body = ''
    return robotstxt_body


[文档]class RobotParser(metaclass=ABCMeta):
[文档] @classmethod @abstractmethod def from_crawler(cls, crawler, robotstxt_body): """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
[文档] @abstractmethod def allowed(self, url, user_agent): """Return ``True`` if ``user_agent`` is allowed to crawl ``url``, otherwise return ``False``. :param url: Absolute URL :type url: str :param user_agent: User agent :type user_agent: str """ pass
class PythonRobotParser(RobotParser): def __init__(self, robotstxt_body, spider): from urllib.robotparser import RobotFileParser self.spider = spider robotstxt_body = decode_robotstxt(robotstxt_body, spider, to_native_str_type=True) self.rp = RobotFileParser() self.rp.parse(robotstxt_body.splitlines()) @classmethod def from_crawler(cls, crawler, robotstxt_body): spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url, user_agent): user_agent = to_unicode(user_agent) url = to_unicode(url) return self.rp.can_fetch(user_agent, url) class ReppyRobotParser(RobotParser): def __init__(self, robotstxt_body, spider): from reppy.robots import Robots self.spider = spider self.rp = Robots.parse('', robotstxt_body) @classmethod def from_crawler(cls, crawler, robotstxt_body): spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url, user_agent): return self.rp.allowed(url, user_agent) class RerpRobotParser(RobotParser): def __init__(self, robotstxt_body, spider): from robotexclusionrulesparser import RobotExclusionRulesParser self.spider = spider self.rp = RobotExclusionRulesParser() robotstxt_body = decode_robotstxt(robotstxt_body, spider) self.rp.parse(robotstxt_body) @classmethod def from_crawler(cls, crawler, robotstxt_body): spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url, user_agent): 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, spider): from protego import Protego self.spider = spider robotstxt_body = decode_robotstxt(robotstxt_body, spider) self.rp = Protego.parse(robotstxt_body) @classmethod def from_crawler(cls, crawler, robotstxt_body): spider = None if not crawler else crawler.spider o = cls(robotstxt_body, spider) return o def allowed(self, url, user_agent): user_agent = to_unicode(user_agent) url = to_unicode(url) return self.rp.can_fetch(url, user_agent)