从脚本中运行Scrapy

文档： https://www.osgeo.cn/scrapy/topics/practices.html

1、scrapy.crawler.CrawlerProcess

　　Scrapy构建于Twisted异步网络框架基础之上，因此你需要在Twisted reactor里面运行。

　　可以使用scrapy.crawler.CrawlerProcess这个类来运行你的spider，这个类会为你启动一个Twisted reactor，并能配置你的日志和shutdown处理器。所有的scrapy命令都使用这个类。

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

　　使用 get_project_settings 得到一个 Settings 具有项目设置的实例。

2、scrapy.crawler.CrawlerRunner

　　使用这个类，在调度spider之后应该显式地运行reactor。建议您使用 CrawlerRunner 而不是 CrawlerProcess 如果您的应用程序已经在使用Twisted，并且您希望在同一个反应器中运行Scrapy。

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

3、在同一进程中运行多个spider

　　默认情况下，当您运行时，scrapy为每个进程运行一个spider scrapy crawl . 但是，Scrapy支持使用 internal API .

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

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

通过链接延迟来按顺序运行spider

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