执行PhantomJS + Selenium Webdriver + Python程序时出现异常

Question

在我的Ubuntu机器上安装了PhantomJS和Selenium的所有先决条件后，我运行下面的代码片段:

from selenium import webdriver
driver = webdriver.PhantomJS()
driver.set_window_size(1120, 550)
driver.get("https://duckduckgo.com/")
driver.find_element_by_id('search_form_input_homepage').send_keys("realpython")
driver.find_element_by_id("search_button_homepage").click()
print driver.current_url
driver.quit()

在执行时，我得到以下错误:

$ python duck.py 
Traceback (most recent call last):
  File "duck.py", line 5, in <module>
    driver.find_element_by_id('search_form_input_homepage').send_keys("realpython")
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 208, in find_element_by_id
    return self.find_element(by=By.ID, value=id_)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 664, in find_element
    {'using': by, 'value': value})['value']
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 175, in execute
    self.error_handler.check_response(response)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/errorhandler.py", line 166, in check_response
    raise exception_class(message, screen, stacktrace)
selenium.common.exceptions.NoSuchElementException: Message: Error Message => 'Unable to find element with id 'search_form_input_homepage''
 caused by Request => {"headers":{"Accept":"application/json","Accept-Encoding":"identity","Connection":"close","Content-Length":"107","Content-Type":"application/json;charset=UTF-8","Host":"127.0.0.1:50789","User-Agent":"Python-urllib/2.7"},"httpVersion":"1.1","method":"POST","post":"{"using": "id", "sessionId": "26560250-fec9-11e4-b2ee-2dada5838664", "value": "search_form_input_homepage"}","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/26560250-fec9-11e4-b2ee-2dada5838664/element"}
Screenshot: available via screen

Answer 1

设置--ssl-protocol=any服务参数并使用显式等待使其为我工作:

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.PhantomJS(service_args=['--ssl-protocol=any'])
driver.maximize_window()
driver.get("https://duckduckgo.com/")
wait = WebDriverWait(driver, 10)
search = wait.until(EC.presence_of_element_located((By.ID, "search_form_input_homepage")))
search.send_keys("realpython")
driver.find_element_by_id("search_button_homepage").click()
print driver.current_url
driver.quit()

打印https://duckduckgo.com/?q=realpython。

注意，如果没有--ssl-protocol=any, PhantomJS甚至没有加载页面，当前的url保持为about:blank。

Answer 2

我认为发生在你身上的是你试图找到一个尚未加载在页面上的元素。所以我可以建议的是，在你尝试键入搜索字段之前插入一个WaitForElementDisplayed(by.ID("search_form_input_homepage"));。因此，在尝试与元素交互之前，您将确保元素在那里。

我真的不能给你一个代码示例，因为我不是很熟悉Python绑定。