通过Xpath循环错误Selenium Python获取元素

Question

我正在尝试为Pinterest制作网络抓取工具。 我几乎可以获取所有数据，但是每个引脚都有一个名为“查看更多”的按钮，该按钮生成：“板名”和“作者名”数据。

逻辑：

1. 将所有按钮元素保存在数组中
2. 遍历它们并单击每个按钮
3. 在页面上获得了总针数
4. 通过增加xpath来针对引脚数进行循环以查找“板名”

按钮单击循环代码：

moreButtons = driver.find_elements_by_xpath('//button[@data-test-id="seemoretoggle"]')
    for moreBtn in moreButtons:
        moreBtn.click()

    source_data = driver.page_source

获取董事会名称代码

# Pin Length - Total Pins
total_pins = []
total_pins = driver.find_elements_by_class_name("Grid__Item")

# Pin Board Names
i = 1
while i <= len(total_pins):
    temp_xpath = "/html/body/div[1]/div[1]/div[1]/div/div/div/div/div[1]/div/div/div/div[" + str(i) + "]/div/div/div[2]/div[2]/h4/a[1]"
    temp = driver.find_element_by_xpath(temp_xpath)
    #pin_Board_Names.append(temp)
    print(temp.text)
    i += 1

部分作品..

Just old
Tiny House interior
SimpleLivingMama.com
Traceback (most recent call last):
  File "scrape.py", line 109, in <module>
    main()
  File "scrape.py", line 106, in main
    grab(args.url, args.fname)
  File "scrape.py", line 91, in grab
    temp = driver.find_element_by_xpath(temp_xpath)
  File "C:\Users\da74\AppData\Roaming\Python\Python36\site-packages\selenium\webdriver\remote\webdriver.py", line 393, in find_element_by_xpath
    return self.find_element(by=By.XPATH, value=xpath)
  File "C:\Users\da74\AppData\Roaming\Python\Python36\site-packages\selenium\webdriver\remote\webdriver.py", line 966, in find_element
    'value': value})['value']
  File "C:\Users\da74\AppData\Roaming\Python\Python36\site-packages\selenium\webdriver\remote\webdriver.py", line 320, in execute
    self.error_handler.check_response(response)
  File "C:\Users\da74\AppData\Roaming\Python\Python36\site-packages\selenium\webdriver\remote\errorhandler.py", line 242, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchElementException: Message: {"errorMessage":"Unable to find element with xpath '/html/body/div[1]/div[1]/div[1]/div/div/div/div/div[1]/div/div/div/div[4]/div/div/div[2]/div[2]/h4/a[1]'","request":{"headers":{"Accept":"application/json","Accept-Encoding":"identity","Connection":"close","Content-Length":"187","Content-Type":"application/json;charset=UTF-8","Host":"127.0.0.1:57743","User-Agent":"selenium/3.13.0 (python windows)"},"httpVersion":"1.1","method":"POST","post":"{\"using\": \"xpath\", \"value\": \"/html/body/div[1]/div[1]/div[1]/div/div/div/div/div[1]/div/div/div/div[4]/div/div/div[2]/div[2]/h4/a[1]\", \"sessionId\": \"a8cdaa10-a2d3-11e8-86db-a3b39599a684\"}","url":"/element","urlParsed":{"anchor":"","query":"","file":"element","directory":"/","path":"/element","relative":"/element","port":"","host":"","password":"","user":"","userInfo":"","authority":"","protocol":"","source":"/element","queryKey":{},"chunks":["element"]},"urlOriginal":"/session/a8cdaa10-a2d3-11e8-86db-a3b39599a684/element"}}
Screenshot: available via screen

它为我找到了3个板名，但以错误结尾。 我尝试编辑循环和按钮单击，但是它们似乎都可以工作。 有谁知道是什么原因引起的，或者也许有建议去探索？

编辑1 ：看到错误，说无法通过xpath找到元素。 但是该元素在网页上。

编辑2 ：添加了try：except进行检查。 这里的代码：

try:
            temp = driver.find_element_by_xpath(temp_xpath)
        except:
            print('no element at pin number: ' + str(i))

输出：

Just old
Tiny House interior
SimpleLivingMama.com
no element at pin number: 4
SimpleLivingMama.com
Books for Pre-Schoolers
Stuff to Try
Baby & Toddler Milestones
Toys For Boys & Girls
House
OT
Make Extra Money
Shoes
Old photos
Crafts
for baby
There's A Book About That
Geek
Real DIY
Recycle & Repurpose
Crafts
Preschool Activities
Wild West Project
#BossMoms
no element at pin number: 24
#BossMoms
Crazy for DIY
Money Saving Tips
Painting Furniture
The home I want
screen door ideas
DIY Home
Little girl rooms
Container Home Desing
Bentley Joseph Adams
some truth bombs
New house!
Advice and Wisdom-Words
no element at pin number: 37
Advice and Wisdom-Words
House ideas
Houses
no element at pin number: 40
Houses
no element at pin number: 41
Houses
Fine Motor Activities for Kids
crafts
decorating ideas
mama
Barn Homes
For the Home
no element at pin number: 48
For the Home

检查了找不到输出的引脚号，但网页上有板名。

编辑3 ：注意，在引脚号47之后，总是说找不到元素。 无论列表多大。 还检查moreButtons中是否存在所有按钮xpath，并且它们是有效的。

预先感谢您的帮助

Answer 1

正如@AnkDasCo在评论中的帮助，找到了解决方案。 这里有两个问题：

1. Pinterest中同一元素有2个不同的xpath。 在某些地方，他们为同一元素创建2个div，而不是1个。
2. 网络驱动程序需要一些时间来提取元素。 尽管驱动程序等待页面使用默认脚本完全加载元素，但在webdriver中添加“ wait ”有助于确保它尝试提取元素然后在一段时间后继续前进。 与“ time.sleep（） ”相同，但是有所不同，因为它与webdriver有关。

xpaths以下是同一项目的2个xpath：

1. / HTML /体/格[1] / DIV [1] / DIV [1] / DIV / DIV / DIV / DIV / DIV [1] / DIV / DIV / DIV / DIV [4] / DIV / DIV / DIV [ 2] / DIV / H4 / A [1]
2. / HTML /体/格[1] / DIV [1] / DIV [1] / DIV / DIV / DIV / DIV / DIV [1] / DIV / DIV / DIV / DIV [1] / DIV / DIV / DIV [ 2] / DIV [2] / H4 / A [1]

我们注意到，两者中的最后一个/ div不同。

工作守则

    driver = webdriver.PhantomJS(executable_path='phantomjs.exe')
    print("Ghost Headless Driver Invoked")
    # driver.implicitly_wait(5) # if element not found, wait for (seconds) before next operation
    driver.get(url) # grab the url

    # Scrolling till the end of page
    print("Started Scrolling ... ")
    match=True # change to 'False' for making this work..
    lenOfPage = driver.execute_script("window.scrollTo(0, document.body.scrollHeight);var lenOfPage=document.body.scrollHeight;return lenOfPage;")
    while(match==False):
        lastCount = lenOfPage
        lenOfPage = driver.execute_script("window.scrollTo(0, document.body.scrollHeight);var lenOfPage=document.body.scrollHeight;return lenOfPage;")
        if lastCount==lenOfPage:
            match=True

    source_data = driver.page_source # page source code as html

    # Get all pins , number of pins collected
    total_pins = []
    try:
        total_pins = driver.find_elements_by_class_name("Grid__Item")
    except:
        print("Unable to load pins")
    print("Total Pins: " + str(len(total_pins)))

    # get number of 'see more' buttons collected - for error checking
    moreButtons = driver.find_elements_by_xpath('//button[@data-test-id="seemoretoggle"]')
    print("Dynamic Elements: " + str(len(moreButtons)))
    print("Display: Dynamic Elements ... ")

    # clicking all 'See More' buttons
    i = 0
    while i <= (len(moreButtons) - 1):
        moreButtons[i].click()
        i += 1

    # Pin Board Names
    print("Extracting Board Names ... ")
    i = 1
    successful = False # for checking success of try | else not working
    while i <= len(total_pins):
        try:
            temp_xpath = "/html/body/div[1]/div[1]/div[1]/div/div/div/div/div[1]/div/div/div/div[" + str(i) + "]/div/div/div[2]/div[2]/h4/a[1]"
            temp = driver.find_element_by_xpath(temp_xpath)
            pin_Board_Names.append(temp.text)
            # print("Board_No: " + str(i) + " > " + temp.text)
            successful = True
        except:
            temp_xpath = "/html/body/div[1]/div[1]/div[1]/div/div/div/div/div[1]/div/div/div/div[" + str(i) + "]/div/div/div[2]/div/h4/a[1]"
            temp = driver.find_element_by_xpath(temp_xpath)
            pin_Board_Names.append(temp.text)
            # print("Board_No: " + str(i) + " > " + temp.text)
            successful = True
        if successful == False:
            print("Board_No: " + str(i) + " not found!")
        i += 1

    # quit driver
    driver.quit()