利用信号在指定的位置注册指定操作
from scrapy import signals class MyExtension(object): def __init__(self, value): self.value = value @classmethod def from_crawler(cls, crawler): val = crawler.settings.getint(‘MMMM‘) ext = cls(val) crawler.signals.connect(ext.spider_opened, signal=signals.spider_opened) crawler.signals.connect(ext.spider_closed, signal=signals.spider_closed) return ext def spider_opened(self, spider): print(‘open‘) def spider_closed(self, spider): print(‘close‘)
#在scrapy中注册信号，spider_opend
crawler.signals.connect(ext.spider_opened, signal=signals.spider_opened)
#在scrapy中注册信号，spider_closed
crawler.signals.connect(ext.spider_closed, signal=signals.spider_closed)
#出发信号时，执行的函数
ext.spider_opened, ext.spider_closed
def opend(self,spider):
print(‘open‘)
def closed(self,spider):
print(‘close‘)
setting中注册类的路径
# EXTENSIONS = {
# # ‘step8_king.extensions.MyExtension‘: 500,
# }