爬虫之selenium模块

selenium模块

  • 介绍
selenium最初是一个自动化测试工具,而爬虫中使用它主要是为了解决requests无法直接执行JavaScript代码的问题

selenium本质是通过驱动浏览器,完全模拟浏览器的操作,比如跳转、输入、点击、下拉等,来拿到网页渲染之后的结果,可支持多种浏览器

from selenium import webdriver
browser=webdriver.Chrome()
browser=webdriver.Firefox()
browser=webdriver.PhantomJS()
browser=webdriver.Safari()
browser=webdriver.Edge()

安装

#安装:selenium+chromedriver
pip3 install selenium
下载chromdriver.exe放到python安装路径的scripts目录中即可,注意最新版本是2.29,并非2.9
国内镜像网站地址:http://npm.taobao.org/mirrors/chromedriver/2.29/
最新的版本去官网找:https://sites.google.com/a/chromium.org/chromedriver/downloads

#验证安装
C:\Users\Administrator>python3
Python 3.6.1 (v3.6.1:69c0db5, Mar 21 2017, 18:41:36) [MSC v.1900 64 bit (AMD64)] on win32
Type "help", "copyright", "credits" or "license" for more information.
>>> from selenium import webdriver
>>> driver=webdriver.Chrome() #弹出浏览器
>>> driver.get('https://www.baidu.com')
>>> driver.page_source

#注意:
selenium3默认支持的webdriver是Firfox,而Firefox需要安装geckodriver
下载链接:https://github.com/mozilla/geckodriver/releases

基本使用

from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素

browser=webdriver.Chrome()
try:
    browser.get('https://www.baidu.com')

    input_tag=browser.find_element_by_id('kw')
    input_tag.send_keys('美女') #python2中输入中文错误,字符串前加个u
    input_tag.send_keys(Keys.ENTER) #输入回车

    wait=WebDriverWait(browser,10)
    wait.until(EC.presence_of_element_located((By.ID,'content_left'))) #等到id为content_left的元素加载完毕,最多等10秒

    print(browser.page_source)
    print(browser.current_url)
    print(browser.get_cookies())

finally:
    browser.close()

选择器

  • 基本用法
#官网链接:http://selenium-python.readthedocs.io/locating-elements.html
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素
import time

driver=webdriver.Chrome()
driver.get('https://www.baidu.com')
wait=WebDriverWait(driver,10)

try:
   #===============所有方法===================
   # 1、find_element_by_id
   # 2、find_element_by_link_text
   # 3、find_element_by_partial_link_text
   # 4、find_element_by_tag_name
   # 5、find_element_by_class_name
   # 6、find_element_by_name
   # 7、find_element_by_css_selector
   # 8、find_element_by_xpath
   # 强调:
   # 1、上述均可以改写成find_element(By.ID,'kw')的形式
   # 2、find_elements_by_xxx的形式是查找到多个元素,结果为列表

   #===============示范用法===================
   # 1、find_element_by_id
   print(driver.find_element_by_id('kw'))

   # 2、find_element_by_link_text
   # login=driver.find_element_by_link_text('登录')
   # login.click()

   # 3、find_element_by_partial_link_text
   login=driver.find_elements_by_partial_link_text('录')[0]
   login.click()

   # 4、find_element_by_tag_name
   print(driver.find_element_by_tag_name('a'))

   # 5、find_element_by_class_name
   button=wait.until(EC.element_to_be_clickable((By.CLASS_NAME,'tang-pass-footerBarULogin')))
   button.click()

   # 6、find_element_by_name
   input_user=wait.until(EC.presence_of_element_located((By.NAME,'userName')))
   input_pwd=wait.until(EC.presence_of_element_located((By.NAME,'password')))
   commit=wait.until(EC.element_to_be_clickable((By.ID,'TANGRAM__PSP_10__submit')))

   input_user.send_keys('18611453110')
   input_pwd.send_keys('lhf@094573')
   commit.click()

   # 7、find_element_by_css_selector
   driver.find_element_by_css_selector('#kw')

   # 8、find_element_by_xpath

   time.sleep(5)

finally:
   driver.close()
  • xpath
#官网链接:http://selenium-python.readthedocs.io/locating-elements.html
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素
import time

driver=webdriver.PhantomJS()
driver.get('https://doc.scrapy.org/en/latest/_static/selectors-sample1.html')
# wait=WebDriverWait(driver,3)
driver.implicitly_wait(3) #使用隐式等待

try:
    # find_element_by_xpath
    #//与/
    # driver.find_element_by_xpath('//body/a')  # 开头的//代表从整篇文档中寻找,body之后的/代表body的儿子,这一行找不到就会报错了

    driver.find_element_by_xpath('//body//a')  # 开头的//代表从整篇文档中寻找,body之后的//代表body的子子孙孙
    driver.find_element_by_css_selector('body a')

    #取第n个
    res1=driver.find_elements_by_xpath('//body//a[1]') #取第一个a标签
    print(res1[0].text)

    #按照属性查找,下述三者查找效果一样
    res1=driver.find_element_by_xpath('//a[5]')
    res2=driver.find_element_by_xpath('//a[@href="image5.html"]')
    res3=driver.find_element_by_xpath('//a[contains(@href,"image5")]') #模糊查找
    print('==>', res1.text)
    print('==>',res2.text)
    print('==>',res3.text)


    #其他
    res1=driver.find_element_by_xpath('/html/body/div/a')
    print(res1.text)

    res2=driver.find_element_by_xpath('//a[img/@src="image3_thumb.jpg"]') #找到子标签img的src属性为image3_thumb.jpg的a标签
    print(res2.tag_name,res2.text)

    res3 = driver.find_element_by_xpath("//input[@name='continue'][@type='button']") #查看属性name为continue且属性type为button的input标签
    res4 = driver.find_element_by_xpath("//*[@name='continue'][@type='button']") #查看属性name为continue且属性type为button的所有标签
    
    
    time.sleep(5)

finally:
    driver.close()
  • 获取标签属性
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素

browser=webdriver.Chrome()

browser.get('https://www.amazon.cn/')

wait=WebDriverWait(browser,10)
wait.until(EC.presence_of_element_located((By.ID,'cc-lm-tcgShowImgContainer')))

tag=browser.find_element(By.CSS_SELECTOR,'#cc-lm-tcgShowImgContainer img')

#获取标签属性,
print(tag.get_attribute('src'))


#获取标签ID,位置,名称,大小(了解)
print(tag.id)
print(tag.location)
print(tag.tag_name)
print(tag.size)


browser.close()

等待元素被加载

#1、selenium只是模拟浏览器的行为,而浏览器解析页面是需要时间的(执行css,js),一些元素可能需要过一段时间才能加载出来,为了保证能查找到元素,必须等待
#2、等待的方式分   两种: 隐式等待:在    browser.get('xxx')前就设置,针对所有元素有效 显式等待:在browser.get('xxx')之后设置,只针对某个元素有效
  • 隐式等待
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素

browser=webdriver.Chrome()

#隐式等待:在查找所有元素时,如果尚未被加载,则等10秒
browser.implicitly_wait(10)

browser.get('https://www.baidu.com')


input_tag=browser.find_element_by_id('kw')
input_tag.send_keys('美女')
input_tag.send_keys(Keys.ENTER)

contents=browser.find_element_by_id('content_left') #没有等待环节而直接查找,找不到则会报错
print(contents)

browser.close()
  • 显示等待
rom selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素

browser=webdriver.Chrome()
browser.get('https://www.baidu.com')


input_tag=browser.find_element_by_id('kw')
input_tag.send_keys('美女')
input_tag.send_keys(Keys.ENTER)


#显式等待:显式地等待某个元素被加载
wait=WebDriverWait(browser,10)
wait.until(EC.presence_of_element_located((By.ID,'content_left')))

contents=browser.find_element(By.CSS_SELECTOR,'#content_left')
print(contents)


browser.close()

元素交互操作

  • 点击清空
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素

browser=webdriver.Chrome()
browser.get('https://www.amazon.cn/')
wait=WebDriverWait(browser,10)


input_tag=wait.until(EC.presence_of_element_located((By.ID,'twotabsearchtextbox')))
input_tag.send_keys('iphone 8')
button=browser.find_element_by_css_selector('#nav-search > form > div.nav-right > div > input')
button.click()


import time
time.sleep(3)

input_tag=browser.find_element_by_id('twotabsearchtextbox')
input_tag.clear() #清空输入框
input_tag.send_keys('iphone7plus')
button=browser.find_element_by_css_selector('#nav-search > form > div.nav-right > div > input')
button.click()



# browser.close()
  • Action Chains
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By  # 按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys  # 键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait  # 等待页面加载某些元素
import time

driver = webdriver.Chrome()
driver.get('http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable')
wait=WebDriverWait(driver,3)
# driver.implicitly_wait(3)  # 使用隐式等待

try:
    driver.switch_to.frame('iframeResult') ##切换到iframeResult
    sourse=driver.find_element_by_id('draggable')
    target=driver.find_element_by_id('droppable')

    #方式一:基于同一个动作链串行执行
    # actions=ActionChains(driver) #拿到动作链对象
    # actions.drag_and_drop(sourse,target) #把动作放到动作链中,准备串行执行
    # actions.perform()

    #方式二:不同的动作链,每次移动的位移都不同
    ActionChains(driver).click_and_hold(sourse).perform()
    distance=target.location['x']-sourse.location['x']

    track=0
    while track < distance:
        ActionChains(driver).move_by_offset(xoffset=2,yoffset=0).perform()
        track+=2

    ActionChains(driver).release().perform()

    time.sleep(10)

finally:
    driver.close()
  • 在交互动作比较难实现的时候可以自己写js(万能方法)

from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素


try:
    browser=webdriver.Chrome()
    browser.get('https://www.baidu.com')
    browser.execute_script('alert("hello world")') #打印警告
finally:
    browser.close()

  • 补充frame的切换
#frame相当于一个单独的网页,在父frame里是无法直接查看到子frame的元素的,必须switch_to_frame切到该frame下,才能进一步查找

from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素


try:
    browser=webdriver.Chrome()
    browser.get('http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable')

    browser.switch_to.frame('iframeResult') #切换到id为iframeResult的frame

    tag1=browser.find_element_by_id('droppable')
    print(tag1)

    # tag2=browser.find_element_by_id('textareaCode') #报错,在子frame里无法查看到父frame的元素
    browser.switch_to.parent_frame() #切回父frame,就可以查找到了
    tag2=browser.find_element_by_id('textareaCode')
    print(tag2)

finally:
    browser.close()

其他

  • 模拟浏览器的前进后退
#模拟浏览器的前进后退
import time
from selenium import webdriver

browser=webdriver.Chrome()
browser.get('https://www.baidu.com')
browser.get('https://www.taobao.com')
browser.get('http://www.sina.com.cn/')

browser.back()
time.sleep(10)
browser.forward()
browser.close()
  • cookies
#cookies
from selenium import webdriver

browser=webdriver.Chrome()
browser.get('https://www.zhihu.com/explore')
print(browser.get_cookies())
browser.add_cookie({'k1':'xxx','k2':'yyy'})
print(browser.get_cookies())

# browser.delete_all_cookies()
  • 选项卡管理
#选项卡管理:切换选项卡,有js的方式windows.open,有windows快捷键:ctrl+t等,最通用的就是js的方式
import time
from selenium import webdriver

browser=webdriver.Chrome()
browser.get('https://www.baidu.com')
browser.execute_script('window.open()')

print(browser.window_handles) #获取所有的选项卡
browser.switch_to_window(browser.window_handles[1])
browser.get('https://www.taobao.com')
time.sleep(10)
browser.switch_to_window(browser.window_handles[0])
browser.get('https://www.sina.com.cn')
browser.close()
  • 异常处理
from selenium import webdriver
from selenium.common.exceptions import TimeoutException,NoSuchElementException,NoSuchFrameException

try:
    browser=webdriver.Chrome()
    browser.get('http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable')
    browser.switch_to.frame('iframssseResult')

except TimeoutException as e:
    print(e)
except NoSuchFrameException as e:
    print(e)
finally:
    browser.close()

小程序

  • 自动登录163邮箱并发送邮件
#注意:网站都策略都是在不断变化的,精髓在于学习流程。下述代码生效与2018-01-15,不能保证永久有效
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By
from selenium.webdriver.common.keys import Keys
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait

browser=webdriver.Chrome()

try:
    browser.get('http://mail.163.com/')

    wait=WebDriverWait(browser,5)

    frame=wait.until(EC.presence_of_element_located((By.ID,'x-URS-iframe')))
    browser.switch_to.frame(frame)

    wait.until(EC.presence_of_element_located((By.CSS_SELECTOR,'.m-container')))

    inp_user=browser.find_element_by_name('email')
    inp_pwd=browser.find_element_by_name('password')
    button=browser.find_element_by_id('dologin')
    inp_user.send_keys('18611453110')
    inp_pwd.send_keys('xxxx')
    button.click()

    #如果遇到验证码,可以把下面一小段打开注释
    # import time
    # time.sleep(10)
    # button = browser.find_element_by_id('dologin')
    # button.click()

    wait.until(EC.presence_of_element_located((By.ID,'dvNavTop')))
    write_msg=browser.find_elements_by_css_selector('#dvNavTop li')[1] #获取第二个li标签就是“写信”了
    write_msg.click()


    wait.until(EC.presence_of_element_located((By.CLASS_NAME,'tH0')))
    recv_man=browser.find_element_by_class_name('nui-editableAddr-ipt')
    title=browser.find_element_by_css_selector('.dG0 .nui-ipt-input')
    recv_man.send_keys('378533872@qq.com')
    title.send_keys('圣旨')
    print(title.tag_name)


    frame=wait.until(EC.presence_of_element_located((By.CLASS_NAME,'APP-editor-iframe')))
    browser.switch_to.frame(frame)
    body=browser.find_element(By.CSS_SELECTOR,'body')
    body.send_keys('egon很帅,可以加工资了')

    browser.switch_to.parent_frame() #切回他爹
    send_button=browser.find_element_by_class_name('nui-toolbar-item')
    send_button.click()

    #可以睡时间久一点别让浏览器关掉,看看发送成功没有
    import time
    time.sleep(10000)

except Exception as e:
    print(e)
finally:
    browser.close()
  • 爬取京东商城商品信息
from selenium import webdriver
from selenium.webdriver import ActionChains
from selenium.webdriver.common.by import By #按照什么方式查找,By.ID,By.CSS_SELECTOR
from selenium.webdriver.common.keys import Keys #键盘按键操作
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.support.wait import WebDriverWait #等待页面加载某些元素
import time


def get_goods(driver):
    try:
        goods=driver.find_elements_by_class_name('gl-item')

        for good in goods:
            detail_url=good.find_element_by_tag_name('a').get_attribute('href')

            p_name=good.find_element_by_css_selector('.p-name em').text.replace('\n','')
            price=good.find_element_by_css_selector('.p-price i').text
            p_commit=good.find_element_by_css_selector('.p-commit a').text

            msg = '''
            商品 : %s
            链接 : %s
            价钱 :%s
            评论 :%s
            ''' % (p_name,detail_url,price,p_commit)

            print(msg,end='\n\n')


        button=driver.find_element_by_partial_link_text('下一页')
        button.click()
        time.sleep(1)
        get_goods(driver)
    except Exception:
        pass

def spider(url,keyword):
    driver = webdriver.Chrome()
    driver.get(url)
    driver.implicitly_wait(3)  # 使用隐式等待
    try:
        input_tag=driver.find_element_by_id('key')
        input_tag.send_keys(keyword)
        input_tag.send_keys(Keys.ENTER)
        get_goods(driver)
    finally:
        driver.close()


if __name__ == '__main__':
    spider('https://www.jd.com/',keyword='iPhone8手机')
posted @ 2018-01-16 11:13  DaMoWang  阅读(220)  评论(0编辑  收藏  举报