陈旧异常web抓取selenium python

Question

我正在尝试从tripadvisor获取信息。我有时会得到

消息:陈旧元素引用:元素未附加到页面文档(会话信息: chrome=47.0.2526.73) (驱动程序信息: chromedriver=2.20.353124 (035346203162d32c80f1dce587c8154a1efa0c3b)，platform=Mac OS X 10.10.4 x86_64)

然后元素就是我分配给它的任何东西。我如何修复我的代码来处理这个问题，然后找出解决方案，而不是重新运行代码？

  def getElements(driver):
        elements = []
        for dd in driver.find_elements_by_xpath("//*[contains(@class, 'ui_button original')]"):
            try:
                if dd.text == "Book Now":
                    elements.append(dd)
            except Exception as ee:
                print ee
        return elements 

def getBookingPartner(driver, ibInfo):
    data = []
    i = 0 
    elements = []
    time.sleep(2)
    elements = getElements(driver)
    elementCounter = 0
    while(elements == [] or elementCounter >5):
        elements = getElements(driver)
        elementCounter+=1

    print "Length of elements should be > 0 : " + str(len(elements))
    for ii in ibInfo:
        if ii[0] == "Yes":
            driver.implicitly_wait(3)
            bookingPartner = "Error"    
            print ii    
            driver.implicitly_wait(3)
            try:
                elements[i].click()
                driver.implicitly_wait(3)
                driver.switch_to_window(driver.window_handles[-1])
            except Exception as ee:
                try:
                    driver.refresh()
                    getElements(driver)[i].click()
                    time.sleep(1)
                    driver.switch_to_window(driver.window_handles[-1])
                except Exception as ee:
                    print "Stale Exception...."
                    print ee    
            try:
                driver.implicitly_wait(3)
                driver.find_elements_by_xpath("//*[contains(@class, 'book_now')]")[1].click()
                driver.implicitly_wait(1)
                page = etree.HTML(driver.page_source)
                bookingPartner = page.xpath("//div[contains(@class, 'custServiceMsg')]//text()")[0].split("will")[0].strip()                    
            except:
                try:
                    time.sleep(3)
                    driver.find_elements_by_xpath("//*[contains(@class, 'book_now')]")[1].click()
                    time.sleep(2)
                    page = etree.HTML(driver.page_source)
                    bookingPartner = page.xpath("//div[contains(@class, 'custServiceMsg')]//text()")[0].split("will")[0].strip()                    
                except:
                    try:
                        bookingPartner = page.xpath("//div[contains(@class, 'custServiceMsg')]//text()")[1].split("will")[0].strip()
                    except Exception as ee:
                        bookingPartner = "Error"
                        print "error"
            i+=1

            if bookingPartner == "The remainder":
                bookingPartner = page.xpath("//div[contains(@class, 'custServiceMsg')]//text()")[1].split("will")[0].strip()

            if len(driver.window_handles) > 1:
                driver.close()
                driver.switch_to_window(driver.window_handles[0])

            print bookingPartner

            data.append([ii[0], ii[1], bookingPartner])
        else:
            data.append([ii[0], ii[1], "N/A"])
            ii.extend(["N/A"])

        print data
    return data

Answer 1

当以下元素出现时，将出现Stale Element Reference Exception：

1. 已被删除
2. 已不再附加到DOM (与您的情况相同)
3. 已更改

从文档中：

您应该丢弃当前持有的引用并替换它，可能的方法是在元素附加到DOM后再次定位它。

即:再次“查找”该元素。

您需要修改代码，以便在适当的步骤中捕获此错误。

from selenium.common.exceptions import StaleElementReferenceException

elem = driver.find_element_by_xpath('something leaves dom')
# ... do other actions which change the page and then later...
try:
    elem.click()
except StaleElementReferenceException:
    elem = driver.find_element_by_xpath('something leaves dom')
    elem.click()

如果你对几个元素有广泛的需求，那就做一个可重用的版本。

顺便说一句，你不应该在你的代码中捕获 Exception。具体说明你想要处理的是哪些。