我想创建一个调度程序脚本来按顺序多次运行同一个蜘蛛。
到目前为止,我得到了以下信息:
#!/usr/bin/python3
"""Scheduler for spiders."""
import time
from scrapy.crawler import CrawlerProcess
from scrapy.utils.project import get_project_settings
from my_project.spiders.deals import DealsSpider
def crawl_job():
"""Job to start spiders."""
settings = get_project_settings()
process = CrawlerProcess(settings)
process.crawl(DealsSpider)
process.start() # the script will block here until the end of the crawl
if __name__ == '__main__':
while True:
crawl_job()
time.sleep(30) # wait 30 seconds then crawl again
现在蜘蛛第一次正确执行,然后在时间延迟后,蜘蛛再次启动,但就在它开始抓取之前,我收到以下错误消息:
Traceback (most recent call last):
File "scheduler.py", line 27, in <module>
crawl_job()
File "scheduler.py", line 17, in crawl_job
process.start() # the script will block here until the end of the crawl
File "/usr/local/lib/python3.5/dist-packages/scrapy/crawler.py", line 285, in start
reactor.run(installSignalHandlers=False) # blocking call
File "/usr/local/lib/python3.5/dist-packages/twisted/internet/base.py", line 1193, in run
self.startRunning(installSignalHandlers=installSignalHandlers)
File "/usr/local/lib/python3.5/dist-packages/twisted/internet/base.py", line 1173, in startRunning
ReactorBase.startRunning(self)
File "/usr/local/lib/python3.5/dist-packages/twisted/internet/base.py", line 684, in startRunning
raise error.ReactorNotRestartable()
twisted.internet.error.ReactorNotRestartable
不幸的是,我不熟悉
Twisted
框架及其 Reactor
s,所以任何帮助将不胜感激! 最佳答案
您收到 ReactorNotRestartable
错误,因为无法在 Twisted 中多次启动 Reactor
。基本上,每次调用 process.start()
时,它都会尝试启动 react 器。网上有很多关于这方面的信息。这是一个简单的解决方案:
from twisted.internet import reactor
from scrapy.crawler import CrawlerRunner
from scrapy.utils.project import get_project_settings
from my_project.spiders.deals import DealsSpider
def crawl_job():
"""
Job to start spiders.
Return Deferred, which will execute after crawl has completed.
"""
settings = get_project_settings()
runner = CrawlerRunner(settings)
return runner.crawl(DealsSpider)
def schedule_next_crawl(null, sleep_time):
"""
Schedule the next crawl
"""
reactor.callLater(sleep_time, crawl)
def crawl():
"""
A "recursive" function that schedules a crawl 30 seconds after
each successful crawl.
"""
# crawl_job() returns a Deferred
d = crawl_job()
# call schedule_next_crawl(<scrapy response>, n) after crawl job is complete
d.addCallback(schedule_next_crawl, 30)
d.addErrback(catch_error)
def catch_error(failure):
print(failure.value)
if __name__=="__main__":
crawl()
reactor.run()
与您的代码段有一些明显的差异。
reactor
被直接调用,用 CrawlerProcess
替换 CrawlerRunner
, time.sleep
已被移除,因此 react 器不会阻塞, while
循环已被替换为通过 crawl
对 callLater
函数的连续调用。它很短,应该做你想做的。如果有任何部分让您感到困惑,请告诉我,我会详细说明。更新 - 在特定时间抓取
import datetime as dt
def schedule_next_crawl(null, hour, minute):
tomorrow = (
dt.datetime.now() + dt.timedelta(days=1)
).replace(hour=hour, minute=minute, second=0, microsecond=0)
sleep_time = (tomorrow - dt.datetime.now()).total_seconds()
reactor.callLater(sleep_time, crawl)
def crawl():
d = crawl_job()
# crawl everyday at 1pm
d.addCallback(schedule_next_crawl, hour=13, minute=30)
关于python-3.x - 如何以编程方式安排 Scrapy 爬网执行,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/47552507/