python Scrapy框架原理解析

# -*- coding: utf-8 -*-
import scrapy
from scrapy.linkextractors import LinkExtractor
from scrapy.spiders import CrawlSpider, Rule
from example.items import CountryOrDistrictItem


class CountryOrDistrictSpider(CrawlSpider):
  name = 'country_or_district'
  allowed_domains = ['example.python-scraping.com']
  start_urls = ['http://example.python-scraping.com/']

  rules = (
    Rule(LinkExtractor(allow=r'/index/', deny=r'/user/'),
       follow=True),
    Rule(LinkExtractor(allow=r'/view/', deny=r'/user/'),
       callback='parse_item'),
  )

  def parse_item(self, response):
    item = CountryOrDistrictItem()
    name_css = 'tr#places_country_or_district__row td.w2p_fw::text'
    item['name'] = response.css(name_css).extract()
    pop_xpath = '//tr[@id="places_population__row"]/td[@class="w2p_fw"]/text()'
    item['population'] = response.xpath(pop_xpath).extract()
    return item