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，我在代码 sn-p 下运行：

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()

执行时出现以下错误：

$ 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 service argument 并使用Explicit Waits 使它对我有用：

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。

请注意，如果没有--ssl-protocol=any，PhantomJS 甚至还没有加载页面，并且当前 url 保持为about:blank。

Answer 2

我认为发生在你身上的事情是你试图在页面上找到一个尚未加载的元素。所以我可以推荐的是在您尝试输入搜索字段之前插入WaitForElementDisplayed(by.ID("search_form_input_homepage"));。因此，在尝试与之交互之前，您将确定该元素存在。

我不能真正给你一个代码示例，因为我并不真正熟悉 Python 绑定。