• 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")>]
    View Code

    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()

    可了解更多可以查看: http://selenium-python.readthedocs.io/api.html#module-selenium.webdriver.remote.webelement

    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()

    更多操作: http://selenium-python.readthedocs.io/api.html#module-selenium.webdriver.common.action_chains

    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': '1', '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': '51854390', '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': '1', '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': '1', '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': '1', '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': '51854390', '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': '1', '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': '1', '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'}]
    []
    View Code

    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

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  • 原文地址:https://www.cnblogs.com/tangkaishou/p/9541553.html
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