Scrapy (1.0) - 未收到信号

Question

我要做的是在打开一个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，当我在蜘蛛打开的那一刻运行爬虫进程时，我希望在控制台中看到什么。

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，这只是蜘蛛运行得很好。

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

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)

Answer 1

仅仅定义from_crawler 是不够的，因为它没有与scrapy 框架挂钩。看看the docs here，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。