Selenium Firefox WebDriver and proxies.

Selenium is an functional web application testing system. It really helps developing test cases for apps that have a lot of logic implemented in the frontend layer. Selenium provides WebDrivers for most popular browsers, like IE, Chrome and last buy not least: Firefox. Of course Selenium has python bindings, which makes it even better. 

Suppose you need to use proxy servers for some of your scenarios (unique visitors). Since each test case may use many proxies, changing the global system proxy settings is a rather bad idea. Fortunately HTTP proxies may be configured in a web browser. If you inspect the Firefox about:config panel, you will notice many properties that configure how your browser really acts. We'll be interested in the network.proxy.* settings.

from selenium import webdriver
from selenium.common.exceptions import TimeoutException

try:
    proxy = "192.168.1.3"
    port = 8080

    fp = webdriver.FirefoxProfile()
    fp.set_preference('network.proxy.ssl_port', int(port))
    fp.set_preference('network.proxy.ssl', proxy)
    fp.set_preference('network.proxy.http_port', int(port))
    fp.set_preference('network.proxy.http', proxy)
    fp.set_preference('network.proxy.type', 1)

    browser = webdriver.Firefox(firefox_profile=fp)
    browser.set_page_load_timeout(15)
    browser.get('http://192.168.1.1/test')
    print browser.find_element_by_id('my_div').text

except TimeoutException as te: 
    print "timeout"
except Exception as ex: 
    print ex.message
finally:
    browser.quit()

First we need to configure our profile by setting the HTTP, and HTTPS proxies. Secondly we have to tell Firefox to start using them: network.proxy.type -> 1. Finally we create an instance of Firefox with our proxy settings and execute out test routine.

Have fun!

~KR

A quick peek into new django 1.4 feature

Its been a few months since a stable release of django 1.4 has been published. Many of my projects were based on django 1.3, and some even on 1.1. Since they worked there was no sense migrating to the latest version, but recently I started a new project and decided to try out the latest stable version.

The first visible difference is the directory structure, if you for example execute:

~ $ django-admin.py startproject test

a following project directory will be created:

test/

  manage.py

  test/

     settings.py

     urls.py

     wsgi.py

You may now add you apps under the test/test or test directories, this affects the package namespace, this is a nice improvement since it allows you to share your modules not only between your applications but other django projects.

Now lets go to some other major improvements, that have a greater impact on process of building/managing web applications.

The first feature that significantly improves the quality of your code is the ability to implement in-browser test cases. In the previous editions you had to setup curl or write dedicated scripts that simulate user behavior. Django 1.4 is integrated with selenium - one of the most popular browser automation systems, designed for website testing. Yeah, no more situations when somebody actually forgot to commit a template to the production repository.

Another important feature improves the ORM, as from django 1.4 QuerySet's  have a method select_for_update(). Now what does it do? I'm speaking rhetorically, of course it  implements the SQL: SELECT ... FOR UPDATE  which locks the selected rows to prevent other threads modifying  them. Now this greatly improves transactional processing.

More features can be found on the official release page https://docs.djangoproject.com/en/dev/releases/1.4/.

As for requirements, the first thing I need to mention is that django 1.4 drops support for python 2.4. Most projects nowadays run on python 2.6 or 2.7, so this shouldn't be a problem. Support for python 3.X is not included, and it probably won't be in the next release aswell.  So for now I guess python 2.7 and django 1.4 is the strongest choice.

~KR