mirror of https://github.com/scrapy/scrapy.git
139 lines
4.4 KiB
Python
139 lines
4.4 KiB
Python
"""
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Base class for Scrapy spiders
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See documentation in docs/topics/spiders.rst
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"""
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import logging
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import warnings
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from scrapy import signals
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from scrapy.http import Request
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from scrapy.utils.trackref import object_ref
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from scrapy.utils.url import url_is_from_spider
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from scrapy.utils.deprecate import create_deprecated_class
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from scrapy.exceptions import ScrapyDeprecationWarning
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from scrapy.utils.deprecate import method_is_overridden
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class Spider(object_ref):
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"""Base class for scrapy spiders. All spiders must inherit from this
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class.
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"""
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name = None
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custom_settings = None
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def __init__(self, name=None, **kwargs):
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if name is not None:
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self.name = name
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elif not getattr(self, 'name', None):
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raise ValueError("%s must have a name" % type(self).__name__)
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self.__dict__.update(kwargs)
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if not hasattr(self, 'start_urls'):
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self.start_urls = []
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@property
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def logger(self):
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logger = logging.getLogger(self.name)
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return logging.LoggerAdapter(logger, {'spider': self})
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def log(self, message, level=logging.DEBUG, **kw):
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"""Log the given message at the given log level
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This helper wraps a log call to the logger within the spider, but you
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can use it directly (e.g. Spider.logger.info('msg')) or use any other
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Python logger too.
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"""
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self.logger.log(level, message, **kw)
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@classmethod
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def from_crawler(cls, crawler, *args, **kwargs):
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spider = cls(*args, **kwargs)
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spider._set_crawler(crawler)
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return spider
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def set_crawler(self, crawler):
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warnings.warn("set_crawler is deprecated, instantiate and bound the "
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"spider to this crawler with from_crawler method "
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"instead.",
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category=ScrapyDeprecationWarning, stacklevel=2)
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assert not hasattr(self, 'crawler'), "Spider already bounded to a " \
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"crawler"
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self._set_crawler(crawler)
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def _set_crawler(self, crawler):
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self.crawler = crawler
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self.settings = crawler.settings
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crawler.signals.connect(self.close, signals.spider_closed)
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def start_requests(self):
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cls = self.__class__
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if method_is_overridden(cls, Spider, 'make_requests_from_url'):
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warnings.warn(
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"Spider.make_requests_from_url method is deprecated; it "
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"won't be called in future Scrapy releases. Please "
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"override Spider.start_requests method instead (see %s.%s)." % (
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cls.__module__, cls.__name__
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),
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)
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for url in self.start_urls:
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yield self.make_requests_from_url(url)
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else:
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for url in self.start_urls:
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yield Request(url, dont_filter=True)
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def start_requests_with_control(self):
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for r in self.start_requests():
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yield r
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if r is not None:
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yield None
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def make_requests_from_url(self, url):
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""" This method is deprecated. """
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return Request(url, dont_filter=True)
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def parse(self, response):
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raise NotImplementedError('{}.parse callback is not defined'.format(self.__class__.__name__))
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@classmethod
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def update_settings(cls, settings):
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settings.setdict(cls.custom_settings or {}, priority='spider')
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@classmethod
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def handles_request(cls, request):
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return url_is_from_spider(request.url, cls)
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@staticmethod
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def close(spider, reason):
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closed = getattr(spider, 'closed', None)
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if callable(closed):
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return closed(reason)
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def __str__(self):
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return "<%s %r at 0x%0x>" % (type(self).__name__, self.name, id(self))
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__repr__ = __str__
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BaseSpider = create_deprecated_class('BaseSpider', Spider)
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class ObsoleteClass(object):
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def __init__(self, message):
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self.message = message
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def __getattr__(self, name):
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raise AttributeError(self.message)
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spiders = ObsoleteClass(
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'"from scrapy.spider import spiders" no longer works - use '
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'"from scrapy.spiderloader import SpiderLoader" and instantiate '
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'it with your project settings"'
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)
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# Top-level imports
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from scrapy.spiders.crawl import CrawlSpider, Rule
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from scrapy.spiders.feed import XMLFeedSpider, CSVFeedSpider
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from scrapy.spiders.sitemap import SitemapSpider
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