标签：stop 异步网络 configure 基于 sage 需要 ide 相同 帮助
1. 可以使用API从脚本运行Scrapy，而不是运行Scrapy的典型方法scrapy crawl；Scrapy是基于Twisted异步网络库构建的，因此需要在Twisted容器内运行它，可以通过两个API来运行单个或多个爬虫scrapy.crawler.CrawlerProcess、scrapy.crawler.CrawlerRunner。
2. 启动爬虫的的第一个实用程序是scrapy.crawler.CrawlerProcess 。该类将为您启动Twisted reactor，配置日志记录并设置关闭处理程序，此类是所有Scrapy命令使用的类。
示例运行单个爬虫：
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import scrapy from scrapy.crawler import CrawlerProcess class MySpider(scrapy.Spider): # Your spider definition ... process = CrawlerProcess({ ‘USER_AGENT‘: ‘Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 5.1)‘ }) process.crawl(MySpider) process.start() # the script will block here until the crawling is finished
通过CrawlerProcess传入参数，并使用get_project_settings获取Settings 项目设置的实例。
from scrapy.crawler import CrawlerProcess from scrapy.utils.project import get_project_settings process = CrawlerProcess(get_project_settings()) # ‘followall‘ is the name of one of the spiders of the project. process.crawl(‘followall‘, domain=‘scrapinghub.com‘) process.start() # the script will block here until the crawling is finished
注意，爬虫结束后需要手动关闭Twisted reactor，通过向CrawlerRunner.crawl方法返回的延迟添加回调来实现。
下面是它的用法示例，在MySpider完成运行后手动停止容器的回调。
from twisted.internet import reactor import scrapy from scrapy.crawler import CrawlerRunner from scrapy.utils.log import configure_logging class MySpider(scrapy.Spider): # Your spider definition ... configure_logging({‘LOG_FORMAT‘: ‘%(levelname)s: %(message)s‘}) runner = CrawlerRunner() d = runner.crawl(MySpider) d.addBoth(lambda _: reactor.stop()) reactor.run() # the script will block here until the crawling is finished
默认情况下，Scrapy在您运行时为每个进程运行一个蜘蛛。但是，Scrapy支持使用内部API为每个进程运行多个蜘蛛。
这是一个同时运行多个蜘蛛的示例：
import scrapy from scrapy.crawler import CrawlerProcess 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 finished
使用CrawlerRunner示例：
import scrapy from twisted.internet import reactor from scrapy.crawler import CrawlerRunner from scrapy.utils.log import configure_logging class MySpider1(scrapy.Spider): # Your first spider definition ... class MySpider2(scrapy.Spider): # Your second spider definition ... configure_logging() runner = CrawlerRunner() runner.crawl(MySpider1) runner.crawl(MySpider2) d = runner.join() d.addBoth(lambda _: reactor.stop()) reactor.run() # the script will block here until all crawling jobs are finished
相同的示例，但通过异步运行爬虫蛛：
from twisted.internet import reactor, defer from scrapy.crawler import CrawlerRunner from scrapy.utils.log import configure_logging class MySpider1(scrapy.Spider): # Your first spider definition ... class MySpider2(scrapy.Spider): # Your second spider definition ... configure_logging() runner = CrawlerRunner() @defer.inlineCallbacks def crawl(): yield runner.crawl(MySpider1) yield runner.crawl(MySpider2) reactor.stop() crawl() reactor.run() # the script will block here until the last crawl call is finished
标签：stop 异步网络 configure 基于 sage 需要 ide 相同 帮助
原文地址：https://www.cnblogs.com/pypypy/p/12207716.html
