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"""
Base class for Scrapy spiders
See documentation in docs/topics/spiders.rst
"""
from scrapy import log
from scrapy.settings import SpiderSettings
from scrapy.http import Request
from scrapy.utils.misc import arg_to_iter
from scrapy.utils.trackref import object_ref
from scrapy.utils.url import url_is_from_spider
class BaseSpider(object_ref):
"""Base class for scrapy spiders. All spiders must inherit from this
class.
"""
name = 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 = []
def log(self, message, level=log.DEBUG):
"""Log the given messages at the given log level. Always use this
method to send log messages from your spider
"""
log.msg(message, spider=self, level=level)
def set_crawler(self, crawler):
assert not hasattr(self, '_crawler'), "Spider already bounded to %s" % crawler
self._crawler = crawler
@property
def crawler(self):
assert hasattr(self, '_crawler'), "Spider not bounded to any crawler"
return self._crawler
@property
def settings(self):
if not hasattr(self, '_settings'):
self._settings = SpiderSettings(self, self.crawler.settings)
return self._settings
def start_requests(self):
for url in self.start_urls:
yield self.make_requests_from_url(url)
def make_requests_from_url(self, url):
return Request(url, dont_filter=True)
def parse(self, response):
raise NotImplementedError
@classmethod
def handles_request(cls, request):
return url_is_from_spider(request.url, cls)
def __str__(self):
return "<%s %r at 0x%0x>" % (type(self).__name__, self.name, id(self))
__repr__ = __str__
class ObsoleteClass(object):
def __init__(self, message):
self.message = message
def __getattr__(self, name):
raise AttributeError(self.message)
spiders = ObsoleteClass("""
"from scrapy.spider import spiders" no longer works - use "from scrapy.project import crawler" and then access crawler.spiders attribute"
""")
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