python - sending selenium chrome instance to the background

问题

I am trying to open a simple chrome instance using Python and selenium. Please find my code below:

import time, datetime, sys, os
start_time = time.time()
from datetime import datetime
os.system("cls")
from selenium import webdriver
from selenium.webdriver.common.keys import Keys
from selenium.common.exceptions import TimeoutException
from selenium.webdriver.support.ui import WebDriverWait
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.by import By
from selenium.webdriver.chrome.options import Options

CHROME_PATH = 'C:\\Program Files (x86)\\Google\\Chrome\\Application\\chrome.exe'
CHROMEDRIVER_PATH = 'C:\\Users\\'+userID+'\\'+filename+'\\chromedriver.exe'
WINDOW_SIZE = "1920,1080"

chrome_options = Options()  
chrome_options.add_argument("--window-size=%s" % WINDOW_SIZE)
chrome_options.add_argument("disable-gpu")
chrome_options.add_argument("disable-infobars")
chrome_options.add_argument("--disable-notifications")
chrome_options.binary_location = CHROME_PATH

browser = webdriver.Chrome(executable_path=CHROMEDRIVER_PATH,chrome_options=chrome_options)
time.sleep(1)
browser.get("https://www.google.com")
os.system("cls")
time.sleep(2)

I would like this to open in the background ie when I am typing something else the mouse/cursor focus should not randomly go to this automated chrome instance once it opens.

Limitations: Please note the below limitations:

1. I can not use "--headless"
2. I can not use phantomJS
3. I can not use PyVirtualDisplay as the code(exe file) will eventually be deployed on windows machines for the end-users.

Would there be any other way to push this chrome instance to the background? Thanks

回答1:

There is no programatic way to open in the Browser Client at the background or as a Background Process.

Of coarse the alternative way is to use a Headless Browser and you can find a detailed discussion in Which drivers support “no-browser”/“headless” testing?.

Why not possible?

Software Test Automation is an art. Your Test Framework should be:

• Configured with all the required softwares, libraries and binaries.
• Test Execution must be performed in a controled environment for optimized performance.
• While your @Tests are executing, it should be free from Manual Intervention.

• Particularly when your @Tests are Selenium based, while test execution is InProgress the Test Environment shouldn't be intervened because of the following reasons:

  • At the lowest level, the behavior of actions class is intended to mimic the remote end's behavior with an actual input device as closely as possible, and the implementation strategy may involve e.g. injecting synthesized events into a browser event loop. Therefore the steps to dispatch an action will inevitably end up in implementation-specific territory. However there are certain content observable effects that must be consistent across implementations. To accommodate this, the specification requires that remote ends perform implementation-specific action dispatch steps, along with a list of events and their properties. This list is not comprehensive; in particular the default action of the input source may cause additional events to be generated depending on the implementation and the state of the browser (e.g. input events relating to key actions when the focus is on an editable element, scroll events, etc.).

• Moreover,

  • An activation trigger generated by the WebDriver API user needs to be indistinguishable from those generated by a real user interacting with the browser. In particular, the dispatched events will have the isTrusted attribute set to true. The most robust way to dispatch these events is by creating them in the browser implementation itself. Sending OS-specific input messages to the browser's window has the disadvantage that the browser being automated may not be properly isolated from a user accidentally modifying input source state. Use of an OS-level accessibility API has the disadvantage that the browser's window must be focused, and as a result, multiple WebDriver instances cannot run in parallel.

  • An advantage of an OS-level accessibility API is that it guarantees that inputs correctly mirror user input, and allows interaction with the host OS if necessary. This might, however, have performance penalties from a machine utilisation perspective.

• Additionally,

  • Robot Class is used to generate native system input events for the purposes of test automation, self-running demos, and other applications where control of the mouse and keyboard is needed. The primary purpose of Robot is to facilitate automated testing of Java platform implementations. Using the class to generate input events differs from posting events to the AWT event queue or AWT components in that the events are generated in the platform's native input queue. For example, Robot.mouseMove will actually move the mouse cursor instead of just generating mouse move events.

• Finally, as per Internet Explorer and Native Events:

  • As the InternetExplorerDriver is Windows-only, it attempts to use so-called "native", or OS-level events to perform mouse and keyboard operations in the browser. This is in contrast to using simulated JavaScript events for the same operations. The advantage of using native events is that it does not rely on the JavaScript sandbox, and it ensures proper JavaScript event propagation within the browser. However, there are currently some issues with mouse events when the IE browser window does not have focus, and when attempting to hover over elements.

• Browser Focus:

  • The challenge is that IE itself appears to not fully respect the Windows messages we send the IE browser window (WM_MOUSEDOWN and WM_MOUSEUP) if the window doesn't have the focus. Specifically, the element being clicked on will receive a focus window around it, but the click will not be processed by the element. Arguably, we shouldn't be sending messages at all; rather, we should be using the SendInput() API, but that API explicitly requires the window to have the focus. We have two conflicting goals with the WebDriver project.

  • First, we strive to emulate the user as closely as possible. This means using native events rather than simulating the events using JavaScript.

  • Second, we want to not require focus of the browser window being automated. This means that just forcing the browser window to the foreground is suboptimal.

Conclusion

Always keep the Test Environment seperate from Development Environment and absolutely free from Manual Intervention.

来源：https://stackoverflow.com/questions/52730392/python-sending-selenium-chrome-instance-to-the-background