Question

由于我们开始在jenkins中运行selenium UI测试，我们注意到在测试期间出现了一些小但令人讨厌的错误。我们在看似随机的硒动作（点击，退出，访问等）上得到BadStatusLine和CannotSendRequest错误。

他们通常看起来像：

  File "/usr/lib/python2.7/unittest/case.py", line 327, in run
    testMethod()
  File "/home/jenkins/workspace/Create and Upload Functional Testing/shapeways/test_suite/Portal/CreateAndUpload/TestUploadWhenNotLoggedIn_ExpectLoginModal.py", line 22, in runTest
    self.dw.visit(ShapewaysUrlBuilder.build_model_upload_url())
  File "/home/jenkins/workspace/Create and Upload Functional Testing/webdriver/webdriverwrapper/WebDriverWrapper.py", line 212, in visit
    return self.execute_and_handle_webdriver_exceptions(lambda: _visit(url))
  File "/home/jenkins/workspace/Create and Upload Functional Testing/webdriver/webdriverwrapper/WebDriverWrapper.py", line 887, in execute_and_handle_webdriver_exceptions
    return function_to_execute()
  File "/home/jenkins/workspace/Create and Upload Functional Testing/webdriver/webdriverwrapper/WebDriverWrapper.py", line 212, in <lambda>
    return self.execute_and_handle_webdriver_exceptions(lambda: _visit(url))
  File "/home/jenkins/workspace/Create and Upload Functional Testing/webdriver/webdriverwrapper/WebDriverWrapper.py", line 205, in _visit
    return self.driver.get(url)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 185, in get
    self.execute(Command.GET, {'url': url})
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/webdriver.py", line 171, in execute
    response = self.command_executor.execute(driver_command, params)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/remote_connection.py", line 349, in execute
    return self._request(command_info[0], url, body=data)
  File "/usr/local/lib/python2.7/dist-packages/selenium/webdriver/remote/remote_connection.py", line 380, in _request
    resp = self._conn.getresponse()
  File "/usr/lib/python2.7/httplib.py", line 1030, in getresponse
    response.begin()
  File "/usr/lib/python2.7/httplib.py", line 407, in begin
    version, status, reason = self._read_status()
  File "/usr/lib/python2.7/httplib.py", line 371, in _read_status
    raise BadStatusLine(line)

这个特例来自以下堆栈：

硒== 2.44.0
python == 2.7.3
firefox == 34.0
jenkins
xvfb（使用jenkins插件进行无头显示）

虽然我们已经看到这些错误一直出现在firefox / selenium的许多不同版本的排列中。

我运行了一个tcpdump来捕获在BadStatusLine错误出现之前发送的实际请求并得到以下内容。

    POST /hub/session/ab64574a-4a17-447a-b2e8-5b0f5ed5e923/url HTTP/1.1 
    Host: 127.0.0.1:41246
    Accept-Encoding: identity Content-Length: 102
    Connection: keep-alive
    Content-type: application/json;charset="UTF-8"
    POST: /hub/session/ab64574a-4a17-447a-b2e8-5b0f5ed5e923/url
    Accept: application/json
    User-Agent: Python http auth

    {"url": "http://example.com/login", "sessionId": "ab64574a-4a17-447a-b2e8-5b0f5ed5e923"}

响应以0字节返回。所以BadStatusLine是由空响应引起的，这是有道理的。

问题是，为什么selenium的服务器会返回一个空响应。如果服务器死了，我们不会在这些行上得到ConnectionError吗？

Answer 1

有一段时间，我没有责备，也不知道原因是什么。我终于能够通过运行来重现：

import requests
import json

while True:

  requests.post('http://127.0.0.1/hub/session/', data=json.dumps({"url": "http://example.com/login", "sessionId": "ab64574a-4a17-447a-b2e8-5b0f5ed5e923"}))

当它运行时，我退出浏览器并收到BadStatusLine错误！当我再次尝试发出请求时，当我得到预期的＆＃34; ConnectionError＆＃34;你可以从任何死机上看到它。

所以，我怀疑发生的是当浏览器发送kill信号时，在关闭期间有一个短窗口，其中仍然会返回任何响应但是有0个字节。这就是为什么你为基本相同的问题得到不同类型的例外（浏览器死机）。原来我们有一个cron在后台杀了我们的浏览器。

如何在python WebDriver中处理偶发的BadStatusLine，CannotSendRequest错误

1 个答案: