python爬虫scrapy图书分类实例讲解

# -*- coding: utf-8 -*-
import scrapy
import requests
from scrapy import Selector
from lxml import etree
from ..items import DangdangItem
from scrapy_redis.spiders import RedisSpider
 
class DangdangSpider(RedisSpider):
  name = 'dangdangspider'
  redis_key = 'dangdangspider:urls'
  allowed_domains = ["dangdang.com"]
  start_urls = 'http://category.dangdang.com/cp01.00.00.00.00.00.html'
  def start_requests(self):
    user_agent = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.22 \
           Safari/537.36 SE 2.X MetaSr 1.0'
    headers = {'User-Agent': user_agent}
    yield scrapy.Request(url=self.start_urls, headers=headers, method='GET', callback=self.parse)

def parse(self, response):
    user_agent = 'Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/49.0.2623.22 \
           Safari/537.36 SE 2.X MetaSr 1.0'
    headers = {'User-Agent': user_agent}
    lists = response.body.decode('gbk')
    selector = etree.HTML(lists)
    goodslist = selector.xpath('//*[@id="leftCate"]/ul/li')
    for goods in goodslist:
      try:
        category_big = goods.xpath('a/text()').pop().replace('  ','') # 大种类
        category_big_id = goods.xpath('a/@href').pop().split('.')[1]  # id
        category_big_url = "http://category.dangdang.com/pg1-cp01.{}.00.00.00.00.html".\
                 format(str(category_big_id))
        # print("{}:{}".format(category_big_url,category_big))
        yield scrapy.Request(url=category_big_url, headers=headers,callback=self.detail_parse,
                   meta={"ID1":category_big_id,"ID2":category_big})
      except Exception:
        Pass

def detail_parse(self, response):
    ID1:大种类ID  ID2:大种类名称  ID3:小种类ID ID4:小种类名称
    url = 'http://category.dangdang.com/pg1-cp01.{}.00.00.00.00.html'.format(response.meta["ID1"])
    category_small = requests.get(url)
    contents = etree.HTML(category_small.content.decode('gbk'))
    goodslist = contents.xpath('//*[@class="sort_box"]/ul/li[1]/div/span')
    for goods in goodslist:
      try:
        category_small_name = goods.xpath('a/text()').pop().replace(" ","").split('(')[0]
        category_small_id = goods.xpath('a/@href').pop().split('.')[2]
        category_small_url = "http://category.dangdang.com/pg1-cp01.{}.{}.00.00.00.html".\
                 format(str(response.meta["ID1"]),str(category_small_id))
        yield scrapy.Request(url=category_small_url, callback=self.third_parse, meta={"ID1":response.meta["ID1"],\
            "ID2":response.meta["ID2"],"ID3":category_small_id,"ID4":category_small_name})
 
        # print("============================ {}".format(response.meta["ID2"])) # 大种类名称
        # print(goods.xpath('a/text()').pop().replace(" ","").split('(')[0])  # 小种类名称
        # print(goods.xpath('a/@href').pop().split('.')[2])  # 小种类ID
      except Exception:
        Pass

def third_parse(self,response):
    for i in range(1,101):
      url = 'http://category.dangdang.com/pg{}-cp01.{}.{}.00.00.00.html'.format(str(i),response.meta["ID1"],\
                                           response.meta["ID3"])
      try:
        contents = requests.get(url)
        contents = etree.HTML(contents.content.decode('gbk'))
        goodslist = contents.xpath('//*[@class="list_aa listimg"]/li')
        for goods in goodslist:
          item = DangdangItem()
          try:
            item['comments'] = goods.xpath('div/p[2]/a/text()').pop()
            item['title'] = goods.xpath('div/p[1]/a/text()').pop()
            item['time'] = goods.xpath('div/div/p[2]/text()').pop().replace("/", "")
            item['price'] = goods.xpath('div/p[6]/span[1]/text()').pop()
            item['discount'] = goods.xpath('div/p[6]/span[3]/text()').pop()
            item['category1'] = response.meta["ID4"]    # 种类(小)
            item['category2'] = response.meta["ID2"]    # 种类(大)
          except Exception:
            pass
          yield item
      except Exception:
        pass