Making the Switch from
PHP to Python
The Grass Is Always Greener
Alex Ezell
July 21, 2009

the on e on t he left.
Hi, I’m

The bloodiest wars in history
have been religious wars.
-Richard M. Nixon

Why did we change?
How did we change (so far)?
Would I do it all again?

Why did we change?

Change Is What We Do

Opportunity
Major push from the business for new features more
often and the freedom to make that happen
Team growth
Stability in other areas: infrastructure, strategic
planning, etc.
Necessity with regards to current codebase

Background Scripting
Lots of background, server processes managing parts
of our application
Desire for code in daemon processes to more closely
resemble application code
Threading, threading, threading.

Web Frameworks
Rapid development
Reuse of code
Easy, powerful templating
Modern database access layer with an ORM
Python: Django, Pylons, TurboGears, web2py, Zope,
etc.
PHP: CakePHP, Solar, Symfony, Zend, etc.

Internationalization
PHP and Python can use gettext
Framework support is easy
Unicode?
Python’s strict typing and encoding helps avoid
confusion and mistakes
f life. But I believe
“Glo balization is a fact o
ated its fragility.”
we have underestim
- Kofi Annan

Developer Buy-In
Stagnation with current codebase
Familiarity with new tools
Developer interest in a new language
Shorter uptake for new hires

Why Python/Django?
Maturity and capability
Ease of use / Low learning curve
Rapid development
Future of the technology
Ecosystem of tools

How did we change?

Let’s Try To Avoid Armageddon
Stop for a full rewrite and not have something
compelling when you reboot
No new features while the rewrite occurs
Inability to really beta test new stuff
Incremental transition

Session Handling
Let PHP continue to handle session authentication
Teach Python how to read/write PHP serialization using
Scott Hurring’s code: http://hurring.com/scott/code/
python/serialize/
Django has built-in memcache support, so we make
PHP save sessions in memcache

Database Access
Moving to multi-database model
Handle different types of encoding
How does the speed compare?
How does writing queries in Django/sqlalchemy
compare to straight SQL?

The Campaign Edit Example
2600 lines of code to 700
Exact same functionality including some additional stuff
Number of database queries stayed close to the same
Very Javascript heavy, so changes might not be as
extensive as other sections

Audience Main Code

Get Mailings

Would I do it all again?

Learning a New Language
Porting is bad
Bad habits are easy to break in Python, though not
unavoidable
Python’s interactive interpreter makes tinkering easy
Every developer learns in unique ways and at different
rates
One way to do something

Framework Evaluation
Who is using it and what are they doing?
How does it handle legacy data?
Do something with a few of them and see what fits
your culture and needs
What direction is the framework moving?

Hindsight is 20/20
PHP frameworks (CakePHP and Symfony) have come
a long way and are on par with Django
The shift to sqlalchemy from the Django ORM has been
problematic
Django template parsing can be slow in certain
situations
Hiring Python developers can be tough, especially in
Nashville

Positives
Codebase is becoming more standardized
Developer energy is high
Features we have implemented have turned out well
and been easy to add functionality to
Python’s standard library offers powerful, quality add-
on modules for free
Developers we have hired have been able to contribute
quickly and be impactful

www.wordle.net

Many of us crucify ourselves
between two thieves - regret for
the past and fear of the future.
- Fulton Oursler

Contact Me
Email: aezell@gmail.com
Twitter: @aezell

Photo Credits
Nixon - BusinessWeek: http://images.businessweek.com/ss/07/04/0426_dow/
source/5.htm
Change - http://www.flickr.com/photos/spursfan_ace/2328879637/
Kofi Annan - http://www.gambianow.com/news/Open-Forum/Have-Your-Say/
Many_Give_Annan_High_Marks_as_UN_Chief_Despite_Flaws.html
Butterflies - http://21stcenturylearning.typepad.com/blog/2009/01/why-
change.html
Winehouse - http://jezebel.com/5247714/amys-comeback-gig-is-a-total-disaster
Sad boy - http://www.psychologytoday.com/blog/ulterior-motives/200806/will-i-
regret-it-in-the-morning-how-about-when-im-64

Resources
Doug Hellman’s PyMOTW: http://
www.doughellmann.com/PyMOTW/
effbot.org’s articles: http://effbot.org/zone/
PythonVsPHP: http://wiki.python.org/moin/
PythonVsPhp
Mark Pilgrim’s Dive into Python
Python’s own tutorial: http://docs.python.org/tutorial/