使用Python+Appium做移动端浏览器自动化时遇URI与Package参数必填错误

问题详情 #

执行Python+Appium移动端浏览器自动化测试时，出现以下错误：

selenium.common.exceptions.WebDriverException: Message: An unknown server-side error occurred while processing the command. Original error: URI and package arguments are required Stacktrace:UnknownError: An unknown server-side error occurred while processing the command. Original error: URI and package arguments are required
at getResponseForW3CError (C:\Program Files\Appium Server GUI\resources\app\node_modules\appium\node_modules\appium-base-driver\lib\protocol\errors.js:804:9)
at asyncHandler (C:\Program Files\Appium Server GUI\resources\app\node_modules\appium\node_modules\appium-base-driver\lib\protocol\protocol.js:380:37)

用户源代码：

from appium import webdriver
import time
from selenium import webdriver
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as ec
from selenium.webdriver.support.wait import WebDriverWait

desired_caps = {
'platformName': 'Android',
'deviceName': 'AQE6MVWWAEVOZLTO-r1HMVZ',
'udid': '22e051b70d1783d3',
'appPackage': 'com.android.chrome',
'appActivity': 'com.google.android.apps.chrome.Main',
'showChromedriverLog': True,
 'automationName': 'UiAutomator2',
'noReset': False
}
web_driver = webdriver.Remote('http://localhost:4723/wd/hub', desired_caps)
# Open a website
web_driver.get('https://www.google.com')

web_driver.find_element(By.XPATH, '//*[@id="js-search-autocomplete"]').send_keys("USA")
wait = WebDriverWait(web_driver, 10)
date = wait.until(ec.element_to_be_clickable((By.XPATH, '//*[@id="js-date-range-display"]')))
date.click()
time.sleep(125)
web_driver.execute_script('mobile: shell', {'command': 'pm', 'args': ['clear', 'https://www.rentbyowner.com']})
# Close the browser
web_driver.quit()

用户疑问：是否是Desired Capabilities中遗漏了配置项？

问题原因与解决方法 #

核心错误原因 #

报错和Desired Capabilities无关，问题出在mobile: shell执行的pm clear命令参数错误：

• pm clear的正确语法是pm clear <应用包名>，你传入的是网址https://www.rentbyowner.com，不是合法的包名，导致命令执行失败
• 若要清除Chrome浏览器缓存，需传入Chrome的包名com.android.chrome

其他代码问题修正 #

1. 重复导入冲突：同时从appium和selenium导入webdriver，会覆盖对象导致异常，保留from appium import webdriver即可
2. XPath转义字符错误：代码中的"是HTML转义双引号，需改为正常双引号"，否则元素定位会失败
3. 元素定位与页面不匹配：原代码里的元素ID是针对rentbyowner.com的，但你先打开的是google.com，这会导致定位失败，需根据实际访问页面调整定位表达式

修正后的完整代码 #

from appium import webdriver
import time
from selenium.webdriver.common.by import By
from selenium.webdriver.support import expected_conditions as ec
from selenium.webdriver.support.wait import WebDriverWait

desired_caps = {
    'platformName': 'Android',
    'deviceName': 'AQE6MVWWAEVOZLTO-r1HMVZ',
    'udid': '22e051b70d1783d3',
    'appPackage': 'com.android.chrome',
    'appActivity': 'com.google.android.apps.chrome.Main',
    'showChromedriverLog': True,
    'automationName': 'UiAutomator2',
    'noReset': False
}
web_driver = webdriver.Remote('http://localhost:4723/wd/hub', desired_caps)
# 直接访问目标网站，匹配后续元素定位
web_driver.get('https://www.rentbyowner.com')

# 搜索框定位
web_driver.find_element(By.XPATH, '//*[@id="js-search-autocomplete"]').send_keys("USA")
wait = WebDriverWait(web_driver, 10)
# 等待日期选择元素可点击
date = wait.until(ec.element_to_be_clickable((By.XPATH, '//*[@id="js-date-range-display"]')))
date.click()
time.sleep(5)
# 修正pm clear命令，传入Chrome包名
web_driver.execute_script('mobile: shell', {'command': 'pm', 'args': ['clear', 'com.android.chrome']})
# 关闭浏览器
web_driver.quit()

内容的提问来源于stack exchange，提问作者Mahboob Nur