Python爬虫 selenium

库的安装

pip3 install selenium

声明浏览器对象

from selenium import webdriver

browser = webdriver.Chrome()

browser = webdriver.Firefox()

browser = webdriver.Edge()

browser = webdriver.PhantomJS()

browser = webdriver.Safari()

访问页面

from selenium import webdriver

browser = webdriver.Chrome()

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

print(browser.page_source)

browser.close()

查找元素

查找单个元素的 element

* find_element_by_name

* find_element_by_xpath

* find_element_by_link_text

* find_element_by_partial_link_text

* find_element_by_tag_name

* find_element_by_class_name

* find_element_by_css_selector

查找多个元素的 elements

* find_elements_by_name

* find_elements_by_xpath

* find_elements_by_link_text

* find_elements_by_partial_link_text

* find_elements_by_tag_name

* find_elements_by_class_name

* find_elements_by_css_selector

单个元素

第一种方式直接指定通过某种方式查找 find_element_by...

from selenium import webdriver

browser = webdriver.Chrome()

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

input_first = browser.find_element_by_id('q')

input_second = browser.find_element_by_css_selector('#q')

input_third = browser.find_element_by_xpath('//*[@id="q"]')

print(input_first, input_second, input_third)

browser.close()

第二种方式通过 find_element(By.xx , ' ....')

from selenium import webdriver

from selenium.webdriver.common.by import By

browser = webdriver.Chrome()

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

input_first = browser.find_element(By.ID, 'q')

print(input_first)

browser.close()

"""

<selenium.webdriver.remote.webelement.WebElement (session="1f209c0d11551c40d9d20ad964fef244", element="0.07914603542731591-1")>

"""

多个元素

第一种

from selenium import webdriver

browser = webdriver.Chrome()

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

lis = browser.find_elements_by_css_selector('.service-bd li')

print(lis)

browser.close()

打印的结果如下

print(lis)

browser.close()

[<selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-1")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-2")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-3")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-4")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-5")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-6")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-7")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-8")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-9")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-10")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-11")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-12")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-13")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-14")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-15")>, <selenium.webdriver.remote.webelement.WebElement (session="c26290835d4457ebf7d96bfab3740d19", element="0.09221044033125603-16")>]

第二种

from selenium import webdriver

from selenium.webdriver.common.by import By

browser = webdriver.Chrome()

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

lis = browser.find_elements(By.CSS_SELECTOR, '.service-bd li')

print(lis)

browser.close()

元素交互操作

以下操作往淘宝输入框中输入 iPhone 然后清空再输入 iPad 在点击搜索

from selenium import webdriver

import time

browser = webdriver.Chrome()

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

input = browser.find_element_by_id('q')

input.send_keys('iPhone')

time.sleep(1)

input.clear()

input.send_keys('iPad')

button = browser.find_element_by_class_name('btn-search')

button.click()

交互动作

from selenium import webdriver

from selenium.webdriver import ActionChains

browser = webdriver.Chrome()

url = 'http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable'

browser.get(url)

browser.switch_to.frame('iframeResult') # 选择iframe

source = browser.find_element_by_css_selector('#draggable')

target = browser.find_element_by_css_selector('#droppable')

actions = ActionChains(browser) # 动作链

actions.drag_and_drop(source, target)

actions.perform()

执行JavaScript

通过函数 execute_script()

from selenium import webdriver

browser = webdriver.Chrome()

browser.get('https://www.zhihu.com/explore')

browser.execute_script('window.scrollTo(0, document.body.scrollHeight)')

browser.execute_script('alert("To Bottom")')

获取元素信息

1.获取属性 get_attribute()

from selenium import webdriver

from selenium.webdriver import ActionChains

browser = webdriver.Chrome()

url = 'https://www.zhihu.com/explore'

browser.get(url)

logo = browser.find_element_by_id('zh-top-link-logo')

print(logo)

print(logo.get_attribute('class'))

"""

<selenium.webdriver.remote.webelement.WebElement (session="e08c0f28d7f44d75ccd50df6bb676104", element="0.7236390660048155-1")>

zu-top-link-logo

"""

2.获取文本值 text

from selenium import webdriver

browser = webdriver.Chrome()

url = 'https://www.zhihu.com/explore'

browser.get(url)

input = browser.find_element_by_class_name('zu-top-add-question')

print(input.text)

打印结果:

提问

获取ID、位置、标签名、大小等

from selenium import webdriver

browser = webdriver.Chrome()

url = 'https://www.zhihu.com/explore'

browser.get(url)

input = browser.find_element_by_class_name('zu-top-add-question')

print(input.id)

print(input.location)

print(input.tag_name)

print(input.size)

"""

0.6822924344980397-1

{'y': 7, 'x': 774}

button

{'height': 32, 'width': 66}

"""

Frame

切换子Iframe switch_to.frame("iframe的id值")

切换回来 switch_to.parent_frame()

import time

from selenium import webdriver

from selenium.common.exceptions import NoSuchElementException

browser = webdriver.Chrome()

url = 'http://www.runoob.com/try/try.php?filename=jqueryui-api-droppable'

browser.get(url)

browser.switch_to.frame('iframeResult')

source = browser.find_element_by_css_selector('#draggable')

print(source)

try:

    logo = browser.find_element_by_class_name('logo')

except NoSuchElementException:

    print('NO LOGO')

browser.switch_to.parent_frame()

logo = browser.find_element_by_class_name('logo')

print(logo)

print(logo.text)

"""

<selenium.webdriver.remote.webelement.WebElement (session="4bb8ac03ced4ecbdefef03ffdc0e4ccd", element="0.44746093888932004-1")>

NO LOGO

<selenium.webdriver.remote.webelement.WebElement (session="4bb8ac03ced4ecbdefef03ffdc0e4ccd", element="0.13792611320464965-2")>

RUNOOB.COM

"""

等待

由于页面需要时间刷新，防止某些元素未刷新出来就访问导致出错，可设置等待时间

隐式等待

当使用了隐式等待执行测试的时候，如果 WebDriver没有在 DOM中找到元素，将继续等待，超出设定时间后则抛出找不到元素的异常, 换句话说，当查找元素或元素并没有立即出现的时候，隐式等待将等待一段时间再查找 DOM，默认的时间是0

from selenium import webdriver

browser = webdriver.Chrome()

browser.implicitly_wait(10) # 等待时间

browser.get('https://www.zhihu.com/explore')

input = browser.find_element_by_class_name('zu-top-add-question')

print(input)

打印结果:

<selenium.webdriver.remote.webelement.WebElement (session="b29214772d59e912f1ac52e96ed29abe", element="0.12886805191194894-1")>

显示等待

from selenium import webdriver

from selenium.webdriver.common.by import By

from selenium.webdriver.support.ui import WebDriverWait

from selenium.webdriver.support import expected_conditions as EC

browser = webdriver.Chrome()

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

wait = WebDriverWait(browser, 10) # 最长的等待时间

input = wait.until(EC.presence_of_element_located((By.ID, 'q')))

button = wait.until(EC.element_to_be_clickable((By.CSS_SELECTOR, '.btn-search')))

print(input, button)

打印结果:

<selenium.webdriver.remote.webelement.WebElement (session="07dd2fbc2d5b1ce40e82b9754aba8fa8", element="0.5642646294074107-1")> <selenium.webdriver.remote.webelement.WebElement (session="07dd2fbc2d5b1ce40e82b9754aba8fa8", element="0.5642646294074107-2")>

元素动作判断

title_is 标题是某内容

title_contains 标题包含某内容

presence_of_element_located 元素加载出，传入定位元组，如(By.ID, 'p')

visibility_of_element_located 元素可见，传入定位元组

visibility_of 可见，传入元素对象

presence_of_all_elements_located 所有元素加载出

text_to_be_present_in_element 某个元素文本包含某文字

text_to_be_present_in_element_value 某个元素值包含某文字

frame_to_be_available_and_switch_to_it frame加载并切换

invisibility_of_element_located 元素不可见

element_to_be_clickable 元素可点击

staleness_of 判断一个元素是否仍在DOM，可判断页面是否已经刷新

element_to_be_selected 元素可选择，传元素对象

element_located_to_be_selected 元素可选择，传入定位元组

element_selection_state_to_be 传入元素对象以及状态，相等返回True，否则返回False

element_located_selection_state_to_be 传入定位元组以及状态，相等返回True，否则返回False

alert_is_present 是否出现Alert

详细内容：http://selenium-python.readthedocs.io/api.html#module-selenium.webdriver.support.expected_conditions

前进与后退

与浏览器的交互 back() 后退 froward() 前进

import time

from selenium import webdriver

browser = webdriver.Chrome()

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

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

browser.get('https://www.python.org/')

browser.back()

time.sleep(1)

browser.forward()

browser.close()

获取Cookies 以及添加Cookies

from selenium import webdriver

browser = webdriver.Chrome()

browser.get('https://www.zhihu.com/explore')

print(browser.get_cookies())

browser.add_cookie({'name': 'name', 'domain': 'www.zhihu.com', 'value': 'germey'})

print(browser.get_cookies())

browser.delete_all_cookies()

print(browser.get_cookies())

打印结果:

[{'secure': False, 'value': '"NGM0ZTM5NDAwMWEyNDQwNDk5ODlkZWY3OTkxY2I0NDY=|1491604091|236e34290a6f407bfbb517888849ea509ac366d0"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_cap_id', 'expiry': 1494196091.403418}, {'secure': False, 'value': '"YWEyOGY4MmI1MzQ2NGY5MmFiMjgzZGUzZWJjYTgwYjY=|1491604091|ff946847ddb5881245bdb7a5e6401b70dc61013f"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'cap_id', 'expiry': 1494196091.402855}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_n_c'}, {'secure': False, 'value': '"MjcxMDE3YzU1YjI4NDljZjljNTQ4ZDIyOWJjZTBhNmY=|1491604091|8da4722b56a1545c2020dba97394a220c0eca8d9"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'r_cap_id', 'expiry': 1494196091.402525}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmc'}, {'secure': False, 'value': '"AADCo7e1kguPTqvEOMieRUzwkA7ZUBhV-VY=|1491604091"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'd_c0', 'expiry': 1586212091.344773}, {'secure': False, 'value': '51854390.1491604091.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmz', 'expiry': 1507372091}, {'secure': False, 'value': '3cc99fc5-8706-43fc-90ac-3ad991bd1a25', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '_zap', 'expiry': 1554676091}, {'secure': False, 'value': '97cb00128ccb46659728f7c69cc191b0|1491604091000|1491604091000', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'q_c1', 'expiry': 1586212091.401644}, {'secure': False, 'value': '51854390.2.10.1491604091', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmb', 'expiry': 1491605891}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'n_c'}, {'secure': False, 'value': '51854390.000--|3=entry_date=20170408=1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmv', 'expiry': 1554676091}, {'secure': False, 'value': '51854390.669300758.1491604091.1491604091.1491604091.1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utma', 'expiry': 1554676091}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmt', 'expiry': 1491604691}, {'secure': False, 'value': 'AQAAALCZuwh+dgIAeu3PPHA+csDPnXvT', 'domain': 'www.zhihu.com', 'path': '/', 'httpOnly': True, 'name': 'aliyungf_tc'}]

[{'secure': False, 'value': 'germey', 'domain': '.www.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'name'}, {'secure': False, 'value': '"NGM0ZTM5NDAwMWEyNDQwNDk5ODlkZWY3OTkxY2I0NDY=|1491604091|236e34290a6f407bfbb517888849ea509ac366d0"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_cap_id', 'expiry': 1494196091.403418}, {'secure': False, 'value': '"YWEyOGY4MmI1MzQ2NGY5MmFiMjgzZGUzZWJjYTgwYjY=|1491604091|ff946847ddb5881245bdb7a5e6401b70dc61013f"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'cap_id', 'expiry': 1494196091.402855}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'l_n_c'}, {'secure': False, 'value': '"MjcxMDE3YzU1YjI4NDljZjljNTQ4ZDIyOWJjZTBhNmY=|1491604091|8da4722b56a1545c2020dba97394a220c0eca8d9"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'r_cap_id', 'expiry': 1494196091.402525}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmc'}, {'secure': False, 'value': '"AADCo7e1kguPTqvEOMieRUzwkA7ZUBhV-VY=|1491604091"', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'd_c0', 'expiry': 1586212091.344773}, {'secure': False, 'value': '51854390.1491604091.1.1.utmcsr=(direct)|utmccn=(direct)|utmcmd=(none)', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmz', 'expiry': 1507372091}, {'secure': False, 'value': '3cc99fc5-8706-43fc-90ac-3ad991bd1a25', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '_zap', 'expiry': 1554676091}, {'secure': False, 'value': '97cb00128ccb46659728f7c69cc191b0|1491604091000|1491604091000', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'q_c1', 'expiry': 1586212091.401644}, {'secure': False, 'value': '51854390.2.10.1491604091', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmb', 'expiry': 1491605891}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': 'n_c'}, {'secure': False, 'value': '51854390.000--|3=entry_date=20170408=1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmv', 'expiry': 1554676091}, {'secure': False, 'value': '51854390.669300758.1491604091.1491604091.1491604091.1', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utma', 'expiry': 1554676091}, {'secure': False, 'value': '', 'domain': '.zhihu.com', 'path': '/', 'httpOnly': False, 'name': '__utmt', 'expiry': 1491604691}, {'secure': False, 'value': 'AQAAALCZuwh+dgIAeu3PPHA+csDPnXvT', 'domain': 'www.zhihu.com', 'path': '/', 'httpOnly': True, 'name': 'aliyungf_tc'}]

[]

浏览器选项卡的管理

通过switch_to_window(browser.window_handles[])

import time

from selenium import webdriver

browser = webdriver.Chrome()

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

browser.execute_script('window.open()')

print(browser.window_handles)

browser.switch_to_window(browser.window_handles[1])

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

time.sleep(1)

browser.switch_to_window(browser.window_handles[0])

browser.get('https://python.org')

打印结果:

['CDwindow-4f58e3a7-7167-4587-bedf-9cd8c867f435', 'CDwindow-6e05f076-6d77-453a-a36c-32baacc447df']

异常处理

比如下面的元素不存在的处理打印肯定会报错的啦

from selenium import webdriver

browser = webdriver.Chrome()

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

browser.find_element_by_id('hello')

处理方式:

from selenium import webdriver

from selenium.common.exceptions import TimeoutException, NoSuchElementException

browser = webdriver.Chrome()

try:

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

except TimeoutException:

    print('Time Out')

try:

    browser.find_element_by_id('hello')

except NoSuchElementException:

    print('No Element')

finally:

    browser.close()

打印结果:

No Element

详细文档：http://selenium-python.readthedocs.io/api.html#module-selenium.common.exceptions