爬虫爬取拉勾招聘信息（selenium+Chromedriver）

之前使用requests库爬取拉勾网站招聘信息时，老是出现访问频繁或者因检测到存在爬虫行为被禁止访问。从开始学习爬虫到工作，爬取过一些网站。拉勾算是反爬虫措施做的最变态的，没有之一。

为了获取获取更加完整的数据信息，今天介绍使用selenium+chromdriver，借助工具进行爬取，以招聘python岗位为关键字。

爬取思路可分为以下几个步骤：

1. 爬取第一页页面中所有职位的链接：每个职位有个id。
2. 然后根据每个职位的链接，获取职位的详细信息。

   

3. 右键——检查，根据html,选取元素。见代码。
4. 第一页职位信息爬取完成后，让浏览器跳转到第二页，继续爬取每一个职位的详细信息，以此类推，直到最后一页。
5. 爬取过程如下：

    

6. 完整代码如下：

   # project:  seleniumChromedriver
   # author:  liulei
   # time:  2019/8/6 9:39   
   # file:  lagouSpider.py
   import random
   
   from selenium import webdriver
   from lxml import etree
   import time
   import re
   from selenium.webdriver.support.ui import WebDriverWait
   from selenium.webdriver.support import expected_conditions as EC
   from selenium.webdriver.common.by import By
   
   
   class LagouSpider(object):
       driver_path = r'C:\chromedriver\chromedriver.exe'
   
       def __init__(self):
           self.driver = webdriver.Chrome(executable_path=LagouSpider.driver_path)
           self.url = 'https://www.lagou.com/jobs/list_python?px=default&city=%E5%8C%97%E4%BA%AC#filterBox'
           self.positions = []
   
       def run(self):
           page_num = 1
           self.driver.get(self.url)
           while True:
               source = self.driver.page_source
               WebDriverWait(driver=self.driver, timeout=300).until(
                   EC.presence_of_element_located((By.XPATH, "//div[@class='pager_container']/span[last()]"))
               )
               self.parse_list_page(source, page_num) 
               next_btn = self.driver.find_element_by_xpath("//div[@class='pager_container']/span[last()]")            
               if 'pager_next pager_next_disabled' in next_btn.get_attribute('class'):
                   print("已是最后一页了")
                   break
               else:
                   next_btn.click()
                   page_num += 1
               time.sleep(random.randint(1, 3))
   
       def parse_list_page(self, source, page_num):
           html = etree.HTML(source)
           links = html.xpath("//a[@class='position_link']/@href")
           postion_num = 1
           for link in links:
               print("正在解析第% s页的第%s条数据" % (page_num, postion_num))
               self.request_detail_page(link)
               time.sleep(random.randint(1, 3))
               postion_num += 1
   
       def request_detail_page(self, url):
           self.driver.execute_script("window.open('%s')" % url)
           self.driver.switch_to.window(self.driver.window_handles[1])
           WebDriverWait(self.driver, timeout=300).until(
               EC.presence_of_element_located((By.XPATH, "//h2[@class='name']"))
           )
           source = self.driver.page_source
           self.parse_detail_page(source)
           self.driver.close()
           self.driver.switch_to.window(self.driver.window_handles[0])
   
       def parse_detail_page(self, source):
           html = etree.HTML(source)
           postion_name = html.xpath("//h2[@class = 'name']/text()")[0]
           job_request_spans = html.xpath("//h3/span")
           salary = job_request_spans[0].xpath(".//text()")[0]
           city = job_request_spans[1].xpath(".//text()")[0]
           city = re.sub(r"[\s/]", "", city)
           work_years = job_request_spans[2].xpath(".//text()")[0]
           work_years = re.sub(r"[\s/]", "", work_years)
           education = job_request_spans[3].xpath(".//text()")[0]
           education = re.sub(r"[\s/]", "", education)
           job_desc = "".join(html.xpath("//dd[@class='job_bt']//text()")).strip()
           job_desc = re.sub(r"\n", "", job_desc)
           company = html.xpath("//em[@class='fl-cn']/text()")[0].strip()
           postion = {
               "company": company,
               "postion_name": postion_name,
               "salary":salary,
               "city": city,
               "work_years": work_years,
               "education": education,
               "job_desc": job_desc
           }
           print(postion)
           print('-' * 50)
           self.positions.append(postion)
   
   
   def main():
       lagou = LagouSpider()
       lagou.run()
   
   
   if __name__ == '__main__':
       main()