Question

$pip install selenium
$sudo apt-get install firefox xvfb


from selenium import webdriver
from selenium.common.exceptions import NoSuchElementException
from selenium.webdriver.common.keys import Keys

browser = webdriver.Firefox() 
browser.get("http://www.yahoo.com") 

This is what I have so far, for Selenium. It seems to work, except it says, “Error: no display specified“

My question is: Do I need to run the selenium jar? It doesn’t seem to matter whether I run it or not…

Answer 1

First let me define for you client mode and server mode:

• Client mode: where the language
  bindings connect to the remote
  instance. This is the way that the
  FirefoxDriver and the RemoteWebDriver
  client normally work.
• Server mode:
  where the language bindings are
  responsible for setting up the
  server, which the driver running in
  the browser can connect to. The
  ChromeDriver works in this way

In the current trunk all of the browsers can run in client mode although you must specify the ChromeDriver.exe path. Server mode can be used to do the same thing. You can set up the jar to run to act as a server for a particular browser. You then connect to that server. If you do this you’ll see a Jetty server being set up and it handling requests. If this is not happening then you are not using server mode. As I can see from your code you are currently using client mode so there is no need to run the jar unless you want the extra remote functionality of it.

Running the jar is useful if you want to run tests on a remote machine in which case you run the jar there then connect to it from your local machine. The jar will then deal with launching browsers on the machine it is running on and forwarding actions to it.

I believe in the past with the Selenium RC API, it was necessary to always run the jar but with WebDriver this is not the case.