爬虫之scrapy框架应用selenium

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在scrapy中使用selenium的编码流程:
    1.在spider的构造方法中创建一个浏览器对象(作为当前spider的一个属性)
    2.重写spider的一个方法closed(self,spider),在该方法中执行浏览器关闭的操作
    3.在下载中间件的process_response方法中,通过spider参数获取浏览器对象
    4.在中间件的process_response中定制基于浏览器自动化的操作代码(获取动态加载出来的页面源码数据)
    5.实例化一个响应对象,且将page_source返回的页面源码封装到该对象中
    6.返回该新的响应对象
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from scrapy.html import HtmlResponse

    def process_response(self, request, response, spider):
        # Called with the response returned from the downloader.

        # Must either;
        # - return a Response object
        # - return a Request object
        # - or raise IgnoreRequest

        # 获取动态加载出来的数据
        print("即将返回一个新的响应对象")
        bw = spider.bw
        bw.get(url = request.url)
        import time
        # 防止数据加载过慢
        time.sleep(3)
        # 包含了动态加载的数据
        page_text = bw.page_source
        time.sleep(3)
        return HtmlResponse(url = spider.bw.current_url,body=page_text,encoding="utf8",request=request)

# -*- coding: utf-8 -*-
import scrapy
from selenium import webdriver

class ScrapySeleniumSpider(scrapy.Spider):
    name = ‘scrapy_selenium‘
    # allowed_domains = [‘www.xxx.com‘]
    start_urls = [‘http://war.163.com/‘]
    def __init__(self):
        self.bw = webdriver.Chrome(executable_path="F:\爬虫+数据\chromedriver.exe")

    def parse(self, response):
        div_list = response.xpath(‘//div[@class="data_row news_article clearfix "]‘)
        for div in div_list:
            title = div.xpath(‘.//div[@class="news_title"]/h3/a/text()‘).extract_first()
            print(title)

    def closed(self, spider):
        print(‘关闭浏览器对象!‘)
        self.bw.quit()