"""
Base class for Scrapy spiders
See documentation in docs/topics/spiders.rst
"""
import logging
import warnings
from scrapy import signals
from scrapy.http import Request
from scrapy.utils.trackref import object_ref
from scrapy.utils.url import url_is_from_spider
from scrapy.utils.deprecate import method_is_overridden
[docs]class Spider(object_ref):
"""Base class for scrapy spiders. All spiders must inherit from this
class.
"""
name = None
custom_settings = None
def __init__(self, name=None, **kwargs):
if name is not None:
self.name = name
elif not getattr(self, 'name', None):
raise ValueError("%s must have a name" % type(self).__name__)
self.__dict__.update(kwargs)
if not hasattr(self, 'start_urls'):
self.start_urls = []
@property
def logger(self):
logger = logging.getLogger(self.name)
return logging.LoggerAdapter(logger, {'spider': self})
[docs] def log(self, message, level=logging.DEBUG, **kw):
"""Log the given message at the given log level
This helper wraps a log call to the logger within the spider, but you
can use it directly (e.g. Spider.logger.info('msg')) or use any other
Python logger too.
"""
self.logger.log(level, message, **kw)
[docs] @classmethod
def from_crawler(cls, crawler, *args, **kwargs):
spider = cls(*args, **kwargs)
spider._set_crawler(crawler)
return spider
def _set_crawler(self, crawler):
self.crawler = crawler
self.settings = crawler.settings
crawler.signals.connect(self.close, signals.spider_closed)
[docs] def start_requests(self):
cls = self.__class__
if not self.start_urls and hasattr(self, 'start_url'):
raise AttributeError(
"Crawling could not start: 'start_urls' not found "
"or empty (but found 'start_url' attribute instead, "
"did you miss an 's'?)")
if method_is_overridden(cls, Spider, 'make_requests_from_url'):
warnings.warn(
"Spider.make_requests_from_url method is deprecated; it "
"won't be called in future Scrapy releases. Please "
"override Spider.start_requests method instead (see %s.%s)." % (
cls.__module__, cls.__name__
),
)
for url in self.start_urls:
yield self.make_requests_from_url(url)
else:
for url in self.start_urls:
yield Request(url, dont_filter=True)
def make_requests_from_url(self, url):
""" This method is deprecated. """
warnings.warn(
"Spider.make_requests_from_url method is deprecated: "
"it will be removed and not be called by the default "
"Spider.start_requests method in future Scrapy releases. "
"Please override Spider.start_requests method instead."
)
return Request(url, dont_filter=True)
def _parse(self, response, **kwargs):
return self.parse(response, **kwargs)
[docs] def parse(self, response, **kwargs):
raise NotImplementedError('{}.parse callback is not defined'.format(self.__class__.__name__))
@classmethod
def update_settings(cls, settings):
settings.setdict(cls.custom_settings or {}, priority='spider')
@classmethod
def handles_request(cls, request):
return url_is_from_spider(request.url, cls)
@staticmethod
def close(spider, reason):
closed = getattr(spider, 'closed', None)
if callable(closed):
return closed(reason)
def __str__(self):
return "<%s %r at 0x%0x>" % (type(self).__name__, self.name, id(self))
__repr__ = __str__
# Top-level imports
from scrapy.spiders.crawl import CrawlSpider, Rule
from scrapy.spiders.feed import XMLFeedSpider, CSVFeedSpider
from scrapy.spiders.sitemap import SitemapSpider