【问题标题】:Python Selenium can't go through links. Pastebin CrawlingPython Selenium 无法通过链接。巴斯宾爬行
【发布时间】:2016-08-03 07:20:32
【问题描述】:

您好,我正在尝试提取所有链接,超过 10 页,用于搜索 ssh

我可以从第一页提取前 10 个链接,在加载 JavaScript 后,我​​可以单击一次,第一页,然后提取接下来的 10 个链接,但是,当尝试转到第三页时,我得到一个错误。

这是我的代码:

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
import requests
import re

links = []
driver = webdriver.Firefox()
driver.get("http://pastebin.com/search?q=ssh")

# wait for the search results to be loaded
wait = WebDriverWait(driver, 10)
wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, ".gsc-result-info")))
for link in driver.find_elements_by_xpath("//div[@class='gs-title']/a[@class='gs-title']"):
        if link.get_attribute("href") != None:
            print link.get_attribute("href")
# get all search results links
for page in driver.find_elements_by_xpath("//div[@class='gsc-cursor-page']"):
    driver.implicitly_wait(10) # seconds
    page.click()

    for link in driver.find_elements_by_xpath("//div[@class='gs-title']/a[@class='gs-title']"):
        if link.get_attribute("href") != None:
            print link.get_attribute("href")

这是我能够得到的,以及我犯的错误:

python pastebinselenium.py 
http://pastebin.com/u/ssh
http://pastebin.com/gsQWBEZP
http://pastebin.com/gfA12TWk
http://pastebin.com/udWMWdPR
http://pastebin.com/J55238CB
http://pastebin.com/DN2aHvRr
http://pastebin.com/f0rh66kU
http://pastebin.com/3zvY3DSm
http://pastebin.com/fqHVJGEm
http://pastebin.com/3aB7h0fm
http://pastebin.com/3uBAxXu3
http://pastebin.com/cxjRqeSh
http://pastebin.com/5nJPNr3Q
http://pastebin.com/qV0rPNfP
http://pastebin.com/zubt2Yc7
http://pastebin.com/jFrjWYpE
http://pastebin.com/DU7yqjQ1
http://pastebin.com/AFtWHmtE
http://pastebin.com/UVP5behK
http://pastebin.com/hP7XTyv1
Traceback (most recent call last):
  File "pastebinselenium.py", line 21, in <module>
    page.click()
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webelement.py", line 74, in click
    self._execute(Command.CLICK_ELEMENT)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webelement.py", line 457, in _execute
    return self._parent.execute(command, params)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 233, in execute
    self.error_handler.check_response(response)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/errorhandler.py", line 194, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.StaleElementReferenceException: Message: Element not found in the cache - perhaps the page has changed since it was looked up
Stacktrace:
    at fxdriver.cache.getElementAt (resource://fxdriver/modules/web-element-cache.js:9454)
    at Utils.getElementAt (file:///tmp/tmpzhZSEC/extensions/fxdriver@googlecode.com/components/command-processor.js:9039)
    at fxdriver.preconditions.visible (file:///tmp/tmpzhZSEC/extensions/fxdriver@googlecode.com/components/command-processor.js:10090)
    at DelayedCommand.prototype.checkPreconditions_ (file:///tmp/tmpzhZSEC/extensions/fxdriver@googlecode.com/components/command-processor.js:12644)
    at DelayedCommand.prototype.executeInternal_/h (file:///tmp/tmpzhZSEC/extensions/fxdriver@googlecode.com/components/command-processor.js:12661)
    at fxdriver.Timer.prototype.setTimeout/<.notify (file:///tmp/tmpzhZSEC/extensions/fxdriver@googlecode.com/components/command-processor.js:625)

我想从 10 个页面中提取 10 个链接(总共 100 个),我只能提取 20 个 =(

我也试过这个:

wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, ".gsc-cursor-box")))

就在click之前,但没有成功。

【问题讨论】:

    标签: javascript python selenium web-crawler pastebin


    【解决方案1】:

    这个想法是在循环中单击分页链接,等待下一个页码成为活动的收集链接。实施:

    from pprint import pprint
    
    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
    
    
    driver = webdriver.Firefox()
    driver.get("http://pastebin.com/search?q=ssh")
    
    # wait for the search results to be loaded
    wait = WebDriverWait(driver, 10)
    wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, ".gsc-result-info")))
    
    links = [link.get_attribute("href") for link in driver.find_elements_by_css_selector(".gsc-results .gs-result > .gsc-thumbnail-inside > .gs-title > a.gs-title")]
    for page_number in range(2, 11):
        driver.find_element_by_xpath("//div[@class='gsc-cursor-page' and . = '%d']" % page_number).click()
    
        wait.until(EC.visibility_of_element_located((By.XPATH, "//div[contains(@class, 'gsc-cursor-current-page') and . = '%d']" % page_number)))
    
        links.extend([link.get_attribute("href") for link in driver.find_elements_by_css_selector(".gsc-results .gs-result > .gsc-thumbnail-inside > .gs-title > a.gs-title")])
    
    print(len(links))
    pprint(links)
    

    打印:

    100
    ['http://pastebin.com/u/ssh',
     'http://pastebin.com/gsQWBEZP',
      ...
     'http://pastebin.com/vtBgrndi',
     'http://pastebin.com/WgXrebLq',
     'http://pastebin.com/Nxui56Gh',
     'http://pastebin.com/Qef0LZPR',
     'http://pastebin.com/yNUh1fRe',
     'http://pastebin.com/2j0d8FzL',
     'http://pastebin.com/g92A2jAq']
    

    【讨论】:

    • 这行得通。非常感谢 !!但我不明白为什么它不适用于这一行:wait.until(EC.visibility_of_element_located((By.CSS_SELECTOR, ".gsc-cursor-box"))),它适用于:wait.until(EC.visibility_of_element_located((By.XPATH, "//div[contains(@class, 'gsc-cursor-current-page') and . = '%d']" % page_number))) 想法是一样的:等到分页准备好再点击下一次
    • @aDoN 这正是这里的诀窍——第一个条件将立即得到满足,因为带有gsc-cursor-box 的元素出现在每个页面上并且立即可用。后者更加集中 - 我们正在等待分页部分中的特定页码链接变为活动状态 - 这意味着我们已经进入下一页......希望有助于理解解决方案。谢谢。
    • 是的,但您似乎在等待当前页面,而不是下一页,不是吗?
    • @aDoN 不,等待下一页。比如说,点击“2”并等待“2”成为活动页面链接..
    • ahhh 激活了,也就是说,您实际上是在第二个链接上,您可以点击第三个链接?
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