从脚本进行抓取抓取始终会在抓取后阻止脚本执行

Question

我正在遵循本指南http://doc.scrapy.org/en/0.16/topics/practices.html#run-scrapy-from-
a-script
从我的脚本中运行scrapy。这是我脚本的一部分：

    crawler = Crawler(Settings(settings))
    crawler.configure()
    spider = crawler.spiders.create(spider_name)
    crawler.crawl(spider)
    crawler.start()
    log.start()
    reactor.run()
    print "It can't be printed out!"

它的工作原理应该是：访问页面，抓取所需信息，并将输出json存储在我告诉它的位置（通过FEED_URI）。但是，当蜘蛛完成他的工作（我可以在输出json中通过数字看到它）时，我的脚本将无法恢复执行。也许这不是一个棘手的问题。答案应该在扭曲反应堆的某个地方。如何释放线程执行？

Answer 1

蜘蛛完成后，您将需要停止反应器。您可以通过侦听spider_closed信号来完成此操作：

from twisted.internet import reactor

from scrapy import log, signals
from scrapy.crawler import Crawler
from scrapy.settings import Settings
from scrapy.xlib.pydispatch import dispatcher

from testspiders.spiders.followall import FollowAllSpider

def stop_reactor():
    reactor.stop()

dispatcher.connect(stop_reactor, signal=signals.spider_closed)
spider = FollowAllSpider(domain='scrapinghub.com')
crawler = Crawler(Settings())
crawler.configure()
crawler.crawl(spider)
crawler.start()
log.start()
log.msg('Running reactor...')
reactor.run()  # the script will block here until the spider is closed
log.msg('Reactor stopped.')

命令行日志输出可能类似于：

stav@maia:/srv/scrapy/testspiders$ ./api
2013-02-10 14:49:38-0600 [scrapy] INFO: Running reactor...
2013-02-10 14:49:47-0600 [followall] INFO: Closing spider (finished)
2013-02-10 14:49:47-0600 [followall] INFO: Dumping Scrapy stats:
    {'downloader/request_bytes': 23934,...}
2013-02-10 14:49:47-0600 [followall] INFO: Spider closed (finished)
2013-02-10 14:49:47-0600 [scrapy] INFO: Reactor stopped.
stav@maia:/srv/scrapy/testspiders$