隨堂筆記

scrapy框架使用基本流程

• 建立專案: scrapy startproject dushu

• 建立爬蟲: cd /dushu; scrapy genspider guoxue ““www.dushu.com””

• 開啟guoxue.py,開始寫程式碼.

  class GuoxueSpider(scrapy.Spider):
      name = 'guoxue'
      allowed_domains = ['www.dushu.com']
      # 起始地址,一般需要修改.
      start_urls = ['https://www.dushu.com/book/1617.html']
  
      def parse(self, response):
          # 找到詳情頁的超連結
          detail_url_list = response.xpath('//div[@class="book-info"]//h3/a/@href')
          for detail_url in detail_url_list.getall():
              detail = 'https://www.dushu.com' + detail_url
              yield scrapy.Request(url=detail, callback=self.detail_parse)
  		
          # 下一頁地址.
          for i in range(2, 11):
              next_page = 'https://www.dushu.com/book/1617_%d.html' % i
              yield scrapy.Request(url=next_page, callback=self.parse)
  	
      # 解析詳情頁的內容
      def detail_parse(self, response):
          book_title = response.xpath('string(//div[@class="book-title"])').extract_first()
          book_img = response.xpath('//div[@class="book-pic"]//img/@src').extract_first()
          price = response.xpath('//p[@class="price"]/span/text()').extract_first()
          author = response.xpath('string(//div[@class="book-details-left"]//table/tbody/tr[1]/td[2])').extract_first()
          book_brief, author_brief = response.xpath('//div[contains(@class, "txtsummary")]/text()')[:2].extract()
          book_brief, author_brief = book_brief.strip(), author_brief.strip()
          item = DushuItem()
          item['book_title'] = book_title
          item['book_img'] = book_img
          item['price'] = price
          item['author'] = author
          item['book_brief'] = book_brief
          item['author_brief'] = author_brief
          yield item
  

• scrapy shell,利用這個shell可以進行程式碼除錯.

em

- scrapy shell,利用這個shell可以進行程式碼除錯.

- crawler spider