selenium

selenium

1. selenium简介

官方文档:https://selenium-python.readthedocs.io/

# 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()

2. 安装

2.1 安装selenium

pip3 install selenium

2.2 安装chromedriver

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2.38,并非2.9
国内镜像网站地址:http://npm.taobao.org/mirrors/chromedriver/2.38/
最新的版本去官网找:https://sites.google.com/a/chromium.org/chromedriver/downloads

2.3 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

3. 使用

3.1 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()

3.2 选择器

3.2.1 基本方法

# 官网链接:http://selenium-python.readthedocs.io/locating-elements.html
import time
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

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('xxxxxx')
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()

3.2.3 xpath选择器

# 官网链接:http://selenium-python.readthedocs.io/locating-elements.html
import time
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

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()

3.3 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()

3.4 等待元素加载

  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

3.4.1 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()

3.4.2 显式等待

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()
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()

3.5 元素交互操作

3.5.1 点击,清空

import time
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()

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()

3.5.2 Action Chains

import time
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

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()

3.5.3 自定义js代码(在交互动作比较难实现的时候)

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()

3.6 其他用法

3.6.1 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()

3.6.2 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()

3.6.3 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()

3.6.4 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()
posted @ 2020-01-06 17:17  油饼er  阅读(178)  评论(0编辑  收藏  举报