CrawlerProcess与CrawlerRunner

CrawlerProcess与CrawlerRunner

Scrapy的文档在给出两者的实际应用示例方面做得非常糟糕。

CrawlerProcess

假设scrapy是唯一使用twisted反应堆的东西。如果你在python中使用线程来运行其他代码，则并非总是如此。让我们以此为例。

from scrapy.crawler import CrawlerProcessimport scrapydef notThreadSafe(x):    """do something that isn't thread-safe"""    # ...class MySpider1(scrapy.Spider):    # Your first spider definition    ...class MySpider2(scrapy.Spider):    # Your second spider definition    ...process = CrawlerProcess()process.crawl(MySpider1)process.crawl(MySpider2)process.start() # the script will block here until all crawling jobs are finishednotThreadSafe(3) # it will get executed when the crawlers stop

现在，你可以看到，该函数仅在搜寻器停止时才执行，如果我希望在搜寻器在同一反应堆中爬行时执行该函数，该怎么办？

from twisted.internet import reactorfrom scrapy.crawler import CrawlerRunnerimport scrapydef notThreadSafe(x):    """do something that isn't thread-safe"""    # ...class MySpider1(scrapy.Spider):    # Your first spider definition    ...class MySpider2(scrapy.Spider):    # Your second spider definition    ...runner = CrawlerRunner()runner.crawl(MySpider1)runner.crawl(MySpider2)d = runner.join()d.addBoth(lambda _: reactor.stop())reactor.callFromThread(notThreadSafe, 3)reactor.run() #it will run both crawlers and pre inside the function

Runner类不限于此功能