Xvfb + Firefox
Posted Sat, 08 Apr 2006
Combine something simple like Firefox and Xvfb (X Virtual Frame Buffer), and you've got a simple way to run Firefox without a visible display.
Let's start Xvfb:
startx -- `which Xvfb` :1 -screen 0 1024x768x24 # Or with Xvnc (also headless) startx -- `which Xvnc` :1 -geometry 1024x768x24 # Or with Xephyr (nested X server, requires X) startx -- `which Xephyr` :1 -screen 1024x768x24This starts Xvfb running on :1 with a screen size of 1024x768 and 24bits/pixel color depth. Now, let's run firefox:
DISPLAY=:1 firefox # Or, if you run csh or tcsh env DISPLAY=:1 firefoxSeems simple enough. What now? We want to tell firefox to go to google.com, perhaps.
DISPLAY=:1 firefox-remote http://www.google.com/Now, let's take a screenshot (requires ImageMagick's import command):
DISPLAY=:1 import -window root googledotcom.pngLets see what that looks like: googledotcom.png
While this isn't complicated, we could very easily automate lots of magic using something like the Selenium extension, all without requiring the use of a visual display (Monitor). Hopefully I'll find time to work on something cool using this soon.
Problems with screen scraping and other website interaction automation is that it almost always needs to be done without a browser. For instance, all of my screen scraping adventures have been using Perl. Browsers already know how to speak to the web, so why reinvent the wheel?
Tie this back to unit tests. Instead of simply displaying results of unit tests, have the page also report the results to a cgi script on the webserver. This will let you automatically test websites using a web browser and have it automatically report the results back to a server.