unable to call firefox from selenium in python on AWS machine

Question

I am trying to use selenium from python to scrape some dynamics pages with javascript. However, I cannot call firefox after I followed the instruction of selenium on the pypi page(http://pypi.python.org/pypi/selenium). I installed firefox on AWS ubuntu 12.04. The error message I got is:

In [1]: from selenium import webdriver  In [2]: br = webdriver.Firefox() --------------------------------------------------------------------------- WebDriverException                        Traceback (most recent call last) /home/ubuntu/<ipython-input-2-d6a5d754ea44> in <module>() ----> 1 br = webdriver.Firefox()  /usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/webdriver.pyc in __init__(self, firefox_profile, firefox_binary, timeout)      49         RemoteWebDriver.__init__(self,      50             command_executor=ExtensionConnection("127.0.0.1", self.profile, ---> 51             self.binary, timeout),      52             desired_capabilities=DesiredCapabilities.FIREFOX)      53  /usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/extension_connection.pyc in __init__(self, host, firefox_profile, firefox_binary, timeout)      45         self.profile.add_extension()      46 ---> 47         self.binary.launch_browser(self.profile)      48         _URL = "http://%s:%d/hub" % (HOST, PORT)      49         RemoteConnection.__init__(  /usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/firefox_binary.pyc in launch_browser(self, profile)      42      43         self._start_from_profile_path(self.profile.path) ---> 44         self._wait_until_connectable()      45      46     def kill(self):  /usr/local/lib/python2.7/dist-packages/selenium/webdriver/firefox/firefox_binary.pyc in _wait_until_connectable(self)      79                 raise WebDriverException("The browser appears to have exited "      80                       "before we could connect. The output was: %s" % ---> 81                       self._get_firefox_output())      82             if count == 30:      83                 self.kill()  WebDriverException: Message: 'The browser appears to have exited before we could connect. The output was: Error: no display specified\n' 

I did search on the web and found that this problem happened with other people (https://groups.google.com/forum/?fromgroups=#!topic/selenium-users/21sJrOJULZY). But I don't understand the solution, if it is.

Can anyone help me please? Thanks!

Answer 1

The problem is Firefox requires a display. I've used pyvirtualdisplay in my example to simulate a display. The solution is:

from pyvirtualdisplay import Display from selenium import webdriver  display = Display(visible=0, size=(1024, 768)) display.start()  driver= webdriver.Firefox() driver.get("http://www.somewebsite.com/")  <---some code--->  #driver.close() # Close the current window. driver.quit() # Quit the driver and close every associated window. display.stop() 

Please note that pyvirtualdisplay requires one of the following back-ends: Xvfb, Xephyr, Xvnc.

This should resolve your issue.