Dave Dash

I went to DjangoCon this past week for work. Django is one of my favorite frameworks. I dropped PHP and the symfony framework to learn python and Django and I haven't looked back. I think for Mozilla's webdev team it would be the framework of choice. We have 100s of sites in many frameworks, but not a lot of resuability. Django apps are built to built to be reusable. If you build correctly you don't have to refactor, it's already done.

Here's a collection of notes I collected through the conference.

Day one

Keynote - Avi Bryant

Frameworks lock us into RDBMS = bad

This keynote mentioned the limits of modern frameworks and modern web development. Essentially frameworks are great for getting started, but as a site grows, the framework gets replaced little by little. Sometimes it can get in the way - such as with limitation of database choices.

UR doing it wrong - James Bennet

James outlined a few key problems that many Django developers run into:

• learning python as you go

  • doesn't work unless you know some programming upfront
  • do the python tutorial
  • read python in a nutshell or dive into python

• Things you should know:

  • subclasses
  • super()
  • slides went too fast... hopefully they'll be posted

All in all RTFM for python and Django :)

Learn about other py packages... like twisted. If Twisted Matrix was implemented in Ruby it would be advertised as the second coming of Christ.

Bennet's Django App review smoketests:

• installable via pip, easy_install or setup.py
  • read distutils-guide
  • stay away from setuptools
• have a README
• INSTALL file list deps
• Write DOCUMENTATION
  • use sphinx.pocoo.org
  • store it in your package and upload package docs
• LICENSE (most Django apps use BSD)
• Write unit tests
• django-lint - to look over code (like pep8.py)

pro-django is a decent book, but not written by Bennet.

Testing - Eric Holscher

• Django 1.1 encourages you to test by auto-creating tests.py.
• Support for:
  • Unittests
  • Doctest
  • Tests done in a db transacation
• Test Driven Documentation (TDD + DDD)
• Doctest
  • easy
  • can't use PDB
  • Hides certain failures
• Unittests via Django TestCase
  • XUnit
  • setup/Teardown
  • adds db fixtures
  • assertions
  • mail testing/inbox testing
  • url testing
• TestCase
  • Browserless Request/Response testing
  • Similar to sfBrowser in symfony
• Google Summer of Code (for Django 1.2)
  • Coverage reports!
• I need to learn PDB

Deploying Django -

Run mod_wsgi in daemon mode.

Day 2

Keynote - Ian Bicking

GNU Manifest:

I consider that the golden rule requires that if I like a program I must share it with other people who like it. Software sellers want to divide the users and conquer them, making each user agree not to share with others. I refuse to break solidarity with other users in this way. I cannot in good conscience sign a nondisclosure agreement or a software license agreement. ...

So that I can continue to use computers without dishonor, I have decided to put together a sufficient body of free software so that I will be able to get along without any software that is not free.

• GNU manifesto was the idea of sharing software amongst friends
• GNU has purpose - BSD, etc is just a rule - free to share
• Free is not just the absense of copyright
• Free is not a reaction to existing rules, but a golden rule
• Not just a fight against MS
• Need to find morality (the why) within the practical (the law, or what you can do)
• Open sourcing closed source code isn't building open source
• This might apply to Mozilla... as webkit has taken off more than Gecko.
• Open source is person to person not company to company - despite sponsorship.

Using Django in Non-standard ways - Eric Florenzano

• Django loosely coupled
• Replace templating with Jinja 2
• Copy Django methods into djangoext to easily customize Django behavior
• Not using django.contrib.auth
  • reasons: writing a fb app - no auth needed
  • no shoehorning needed - saves time - less overhead
• skip the orm?
  • legacy dbs
  • non standard or db (or non-relational database)
  • no database
• wsgi middleware has some cool shit
  • repose.bitblt: autoscales images
  • repose.squeeze: will concat js/css on the fly based on statistical analysis
• non standard Django based apps
  • YARDBird - IRCBot framework
  • djng micro framework
  • Jngo- singlefile cms
• using admin in a nonstandard way is hard/impossible coupled with ORM and auth

Real-time web and other Buzzwords - Chris Wanstrath

• more than just getting your rss feeds faster
• push vs. pull
• 1 persisting connection vs polling
• comet/flash-xml/or html5 web socket
• orbitted - open source python comet server
• zeddicus - does the business logic
• orbitted has its own js libs - its a simple port/socket thing for your server code to deal with - not request/response.
• all connections are persisting browser/orbitted orbitted/zeddicus
• You can even use orbitted to connect straight to IRC and write a client in JS
• Jetty also is good for comet

Also: * see webhooks * see pubsubhubub

Pluggable, Reusable Django Apps: A Use Case and Proposed Solution - Shawn Rider and Nowell Strite

• PBS moved from perl to django - build a lot of reusable apps
• convincing your superiors
  • need a good story -
  • existing base of python helped
  • With Django easy to do things right without doing things slow
  • be really good...
• built a lot of apps to be very reusable, and pluggable based on requirements PBS had

Day 3

Keynote - Ted Leung - Sun

• Django jobs are a growing market
• Preferred by startups
• Bespin/wave - cool
• APIs are big... still
• Physically impossible to create purely server-side interactions that are usable enough - rely on rest/comet/ajax/etc to bridge gap

Scaling Django Mike Malone

• MM from Pownce (now sixapart)
• Slides started out as "Building Scalable Web Applications"
• Django didn't get in the way too much when it came to scaling
• Django had tons of caching support
• Cached objects by hand (memcached) and object ID lists
• Use memache for sessions too
• use signals to signal cache invalidation
• race conditions...
• Queue shit... gearman, rabbit mq, etc.
• Memecached incr/decr operators are awesome
• See gh/mmalone/django-caching
• See gh:.../django-multidb
• to combat slavelag use a memcache key to alternate between master or slave

Gearman - working later - Chris Heisel

• Gearman - a work later alt to rabbit mq
• Makes the most sense for something like cesium, with a bazillion worker bees foxes feeding off a single queue

Also at the con, I talked to someone about rebuilding large apps... and they took a PHP app and used URL rewriting to and a lot of PHP/Python glue code to build a seamless transitory app. The rule is, all new functionality was done up in python while the old app was in maintenance mode.

More talks here!