我能够使用CrawlerRunner或CrawlerProcess从另一个Python脚本调用一个抓爬虫。但是,当我尝试从pywikibot机器人调用同一蜘蛛调用类时,出现ReactorNotRestartable错误。为什么会这样,我该如何解决?
这里是错误:
File ".\scripts\userscripts\ReplicationWiki\RWLoad.py", line 161, in format_new_page
aea = AEAMetadata(url=DOI_url)
File ".\scripts\userscripts\ReplicationWiki\GetAEAMetadata.py", line 39, in __init__
reactor.run() # the script will block here until all crawling jobs are finished
File "C:\Users\lextr\.conda\envs\py37\lib\site-packages\twisted\internet\base.py", line 1282, in run
self.startRunning(installSignalHandlers=installSignalHandlers)
File "C:\Users\lextr\.conda\envs\py37\lib\site-packages\twisted\internet\base.py", line 1262, in startRunning
ReactorBase.startRunning(self)
File "C:\Users\lextr\.conda\envs\py37\lib\site-packages\twisted\internet\base.py", line 765, in startRunning
raise error.ReactorNotRestartable()
twisted.internet.error.ReactorNotRestartable
CRITICAL: Exiting due to uncaught exception <class 'twisted.internet.error.ReactorNotRestartable'>
这里是一个叫我沙皮蜘蛛的脚本。如果我只是从main调用类,它将运行正常。
from twisted.internet import reactor, defer
from scrapy import signals
from scrapy.crawler import Crawler, CrawlerProcess, CrawlerRunner
from scrapy.settings import Settings
from scrapy.utils.project import get_project_settings
from Scrapers.spiders.ScrapeAEA import ScrapeaeaSpider
class AEAMetadata:
"""
Helper to run ScrapeAEA spider and return JEL codes and data links
for a given AEA article link.
"""
def __init__(self, *args, **kwargs):
"""Initializer"""
url = kwargs.get('url')
if not url:
raise ValueError('No article url given')
self.items = []
def collect_items(item, response, spider):
self.items.append(item)
settings = get_project_settings()
crawler = Crawler(ScrapeaeaSpider, settings)
crawler.signals.connect(collect_items, signals.item_scraped)
runner = CrawlerRunner(settings)
d = runner.crawl(crawler, url=url)
d.addBoth(lambda _: reactor.stop())
reactor.run() # the script will block here until all crawling jobs are finished
#process = CrawlerProcess(settings)
#process.crawl(crawler, url=url)
#process.start() # the script will block here until the crawling is finished
def get_jelcodes(self):
jelcodes = self.items[0]['jelcodes']
return jelcodes
def main():
aea = AEAMetadata(url='https://doi.org/10.1257/app.20180286')
jelcodes = aea.get_jelcodes()
print(jelcodes)
if __name__ == '__main__':
main()
已更新的简单测试,该实例将AEAMetadata类实例化两次。这是我的pywikibot机器人失败的调用代码:
from GetAEAMetadata import AEAMetadata
def main(*args):
for _ in [1,2]:
print('Top')
url = 'https://doi.org/10.1257/app.20170442'
aea = AEAMetadata(url=url)
print('After AEAMetadata')
jelcodes = aea.get_jelcodes()
print(jelcodes)
if __name__ == '__main__':
main()
我对AEAMetadata的调用被嵌入到一个更大的脚本中,这使我误以为AEAMetadata类仅在失败前实例化了一次。实际上,AEAMetadata被调用了两次。
而且,我还认为该脚本会在react..run()之后阻塞,因为所有草率示例中的注释均是如此。但是,第二个延迟的回调是反应堆.stop(),它会解除阻塞反应堆.run()。
一个更基本的错误假设是,每次迭代都删除并重新创建了反应堆。实际上,<< first >>导入时,将实例化和初始化反应堆。并且,它是一个全局对象,其生存时间与基础进程一样长,并且不旨在重新启动。此处描述了删除和重新启动反应堆实际需要的极端操作:http://www.blog.pythonlibrary.org/2016/09/14/restarting-a-twisted-reactor/所以,我想我已经回答了我自己的问题。而且,我正在重写脚本,因此它不会尝试以从未使用过的方式使用反应堆。
而且,感谢Gallaecio使我朝着正确的方向思考。