python - 停止 Scrapy 抓取相同的 URL

Question

我写了一个基本的 Scrapy 蜘蛛来抓取一个似乎运行良好的网站，除了它不想停止的事实，即它不断重新访问相同的 url 并返回相同的内容 - 我总是最终得到阻止它。我怀疑它一遍又一遍地访问相同的网址。有没有规则可以阻止这种情况？或者还有什么我必须做的吗？也许是中间件？

蜘蛛如下:

class LsbuSpider(CrawlSpider):
name = "lsbu6"
allowed_domains = ["lsbu.ac.uk"]
start_urls = [
    "http://www.lsbu.ac.uk"
]
rules = [
    Rule(SgmlLinkExtractor(allow=['lsbu.ac.uk/business-and-partners/.+']), callback='parse_item', follow=True),
]

def parse_item(self, response):
    join = Join()
    sel = Selector(response)
    bits = sel.xpath('//*')
    scraped_bits = []            
    for bit in bits:
        scraped_bit = LsbuItem()
        scraped_bit['title'] = scraped_bit.xpath('//title/text()').extract()
        scraped_bit['desc'] = join(bit.xpath('//*[@id="main_content_main_column"]//text()').extract()).strip()
        scraped_bits.append(scraped_bit)

    return scraped_bits

我的 settings.py 文件如下所示

BOT_NAME = 'lsbu6'
DUPEFILTER_CLASS = 'scrapy.dupefilter.RFPDupeFilter'
DUPEFILTER_DEBUG = True
SPIDER_MODULES = ['lsbu.spiders']
NEWSPIDER_MODULE = 'lsbu.spiders'

任何关于停止它连续运行的帮助/指导/说明将不胜感激......

因为我是新手；任何关于整理代码的评论也会有所帮助(或良好指导的链接)。

谢谢...

Answer 1

DupeFilter 默认启用:http://doc.scrapy.org/en/latest/topics/settings.html#dupefilter-class它基于请求 url。

我在没有任何自定义配置的新 Vanilla scrapy 项目上尝试了您的蜘蛛的简化版本。 dupefilter 起作用了，在几次请求后爬网停止了。我会说你的设置或你的 scrapy 版本有问题。我建议你升级到 scrapy 1.0，以确保:)

$ pip install scrapy --pre

我测试的简化蜘蛛:

from scrapy.spiders import CrawlSpider
from scrapy.linkextractors import LinkExtractor
from scrapy import Item, Field
from scrapy.spiders import Rule 

class LsbuItem(Item):
    title = Field()
    url = Field()

class LsbuSpider(CrawlSpider):
    name = "lsbu6"
    allowed_domains = ["lsbu.ac.uk"]

    start_urls = [
        "http://www.lsbu.ac.uk"
    ]    

    rules = [
        Rule(LinkExtractor(allow=['lsbu.ac.uk/business-and-partners/.+']), callback='parse_item', follow=True),
    ]    

    def parse_item(self, response):
        scraped_bit = LsbuItem()
        scraped_bit['url'] = response.url
        yield scraped_bit