我可以在Python脚本中按照维基百科上的以下步骤来运行爬虫:
如果我只打印
from twisted.internet import reactor
from scrapy.crawler import Crawler
from scrapy import log, signals
from testspiders.spiders.followall import FollowAllSpider
from scrapy.utils.project import get_project_settings
spider = FollowAllSpider(domain='scrapinghub.com')
settings = get_project_settings()
crawler = Crawler(settings)
crawler.signals.connect(reactor.stop, signal=signals.spider_closed)
crawler.configure()
crawler.crawl(spider)
crawler.start()
log.start()
reactor.run()
正如您所见,我可以将domain
传递给FollowAllSpider
,但我的问题是如何使用上面的代码将start_urls
(实际上是将添加到固定URL的date
)传递给我的蜘蛛类?
这是我的蜘蛛类:
class MySpider(CrawlSpider):
name = 'tw'
def __init__(self,date):
y,m,d=date.split('-') #this is a test , it could split with regex!
try:
y,m,d=int(y),int(m),int(d)
except ValueError:
raise 'Enter a valid date'
self.allowed_domains = ['mydomin.com']
self.start_urls = ['my_start_urls{}-{}-{}'.format(y,m,d)]
def parse(self, response):
questions = Selector(response).xpath('//div[@class="result-link"]/span/a/@href')
for question in questions:
item = PoptopItem()
item['url'] = question.extract()
yield item['url']
这是我的脚本:
from pdfcreator import convertor
from twisted.internet import reactor
from scrapy.crawler import Crawler
from scrapy import log, signals
#from testspiders.spiders.followall import FollowAllSpider
from scrapy.utils.project import get_project_settings
from poptop.spiders.stackoverflow_spider import MySpider
from poptop.items import PoptopItem
settings = get_project_settings()
crawler = Crawler(settings)
crawler.signals.connect(reactor.stop, signal=signals.spider_closed)
crawler.configure()
date=raw_input('Enter the date with this format (d-m-Y) : ')
print date
spider=MySpider(date=date)
crawler.crawl(spider)
crawler.start()
log.start()
item=PoptopItem()
for url in item['url']:
convertor(url)
reactor.run() # the script will block here until the spider_closed signal was sent
如果我只打印
item
,将会得到以下错误:2015-02-25 17:13:47+0330 [tw] ERROR: Spider must return Request, BaseItem or None, got 'unicode' in <GET test-link2015-1-17>
项目:
import scrapy
class PoptopItem(scrapy.Item):
titles= scrapy.Field()
content= scrapy.Field()
url=scrapy.Field()
KeyError
,似乎没有运行爬取!for url in item['url']:
- Mazdakyield item
而不是yield item['url']
。如果有帮助,请告诉我。 - alecxeyield item
,但出现了错误!我会编辑问题!我添加了我的脚本!希望这能有所帮助! - MazdakPoptopItem
类的定义。谢谢。 - alecxequestion.extract()
! - Mazdak