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我想做的是在打开一个scrapy蜘蛛时触发一个函数（abc），这应该由scrapys'信号'触发。

（稍后我想将其更改为“关闭”以将每个蜘蛛的统计信息保存到数据库中以进行日常监控。）所以现在我尝试了这个简单的解决方案只是为了打印一些东西，我希望在控制台中看到什么当我在打开蜘蛛的那一刻运行爬虫进程时。

发生的情况是爬虫运行良好，但在蜘蛛打开时不打印“abc”的输出，这应该触发输出。最后，我发布了在控制台中看到的内容，这只是蜘蛛运行得非常好。

为什么在日志中看到“INFO：Spider 打开”时（或根本没有）的信号没有触发 abc 函数？

MyCrawlerProcess.py：

from twisted.internet import reactor
from scrapy import signals
from scrapy.crawler import CrawlerProcess
from scrapy.utils.project import get_project_settings

process = CrawlerProcess(get_project_settings())

def abc():
    print '######################works!######################'

def from_crawler(crawler):
    crawler.signals.connect(abc, signal=signals.spider_opened)

process.crawl('Dissident')
process.start() # the script will block here until the crawling is finished

控制台输出：

2016-03-17 13:00:14 [scrapy] INFO: Scrapy 1.0.4 started (bot: Chrome 41.0.2227.1. Mozilla/5.0 (Macintosh; Intel Mac Osource)
2016-03-17 13:00:14 [scrapy] INFO: Optional features available: ssl, http11
2016-03-17 13:00:14 [scrapy] INFO: Overridden settings: {'NEWSPIDER_MODULE': 'scrapytry.spiders', 'SPIDER_MODULES': ['scrapytry.spiders'], 'DOWNLOAD_DELAY': 5, 'BOT_NAME': 'Chrome 41.0.2227.1. Mozilla/5.0 (Macintosh; Intel Mac Osource'}
2016-03-17 13:00:14 [scrapy] INFO: Enabled extensions: CloseSpider, TelnetConsole, LogStats, CoreStats, SpiderState
2016-03-17 13:00:14 [scrapy] INFO: Enabled downloader middlewares: HttpAuthMiddleware, DownloadTimeoutMiddleware, UserAgentMiddleware, RetryMiddleware, DefaultHeadersMiddleware, MetaRefreshMiddleware, HttpCompressionMiddleware, RedirectMiddleware, CookiesMiddleware, ChunkedTransferMiddleware, DownloaderStats
2016-03-17 13:00:14 [scrapy] INFO: Enabled spider middlewares: HttpErrorMiddleware, OffsiteMiddleware, RefererMiddleware, UrlLengthMiddleware, DepthMiddleware
2016-03-17 13:00:14 [scrapy] INFO: Enabled item pipelines: ImagesPipeline, FilesPipeline, ScrapytryPipeline
2016-03-17 13:00:14 [scrapy] INFO: Spider opened
2016-03-17 13:00:14 [scrapy] INFO: Crawled 0 pages (at 0 pages/min), scraped 0 items (at 0 items/min)
2016-03-17 13:00:14 [scrapy] DEBUG: Telnet console listening on 127.0.0.1:6023
2016-03-17 13:00:14 [scrapy] DEBUG: Crawled (200) <GET http://www.xyz.zzm/> (referer: None)
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1 回答 1

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简单地定义from_crawler是不够的，因为它没有与 scrapy 框架挂钩。看看这里的文档，它展示了如何创建一个完全符合您想要做的事情的扩展。请务必按照说明通过MYEXT_ENABLED设置启用扩展程序。

于 2016-03-17T13:46:04.853 回答