Cherry-picking for Huge Success


  • Doesn’t care about language fights
  • Use the best tool for the job

Consider Twitter

  • 2006: off the shelf Rails application, static HTML, basic XML API
  • Now: The API is the service. Website itself is a JavaScript app. Scala/Erlang backend

Does this mean Ruby sucks?

  • Not it does not
  • Neither does Python
  • Ruby / Python are amazing for prototyping
  • Expect applications to change and grow in implementation over time

Proposed Solution

  • Build smaller apps
  • Combine apps to make bigger apps

Cross boundaries

  • Pygments is awesome

  • Need Pygments in Ruby

    • A: rewrite in Ruby
    • B: Use different syntax highlight
    • C: Use pygments as a service called by Ruby

“It only does Django”

  • You wrote a library that does something useful (thumb-nailing for example)
  • Don’t make it depend on Django if you can help it
  • Try to make it independent
  • Then implement a separate Django app that calls your tool


This also happens with the Zope community. They did “Zope Only Projects” first. ;)

Protocol Examples

Flask Views

  • Wiews can return response objects
  • Respons eobjects are WSGI apps
  • no typecheck
  • Return any WSGI app
  • WSGI server doesn’t care if it

Difflib + Genshi

  • Genshi is valid XML
  • Difflib returns a string
  • Change Difflib to be <ins>/<del> so Genshi can render it
  • Instant pages!


  • pickle, phpserialize, itsdangerous, json
  • Within the compatible types it

Loosely couple all the ways!!!

Many small bits with specific merge points that are loosely coupled

  • WSGI
  • HTTP
  • ZeroMQ
  • Message queues
  • Datastore
  • JavaScript


  • Dictionary passed around

  • Framework independent, but only for Python

  • Tornado and Twisted don’t do it, but everything else does

  • Middlewares are unused and hard to make

    • TODO: Get his middleware example for use as possible sub-domain hack
  • WSGI middleware has issues:

    • Can’t consume dform data
    • Processing response from application is complex
    • Can’t inject HTML
    • TODO - last bullet?
  • Libraries

    • Werkzeug
    • WebOb
    • Paste

Django & WSGI

  • Django used to do WSGI badly
  • Getting documented


  • Pure HTTP is more work than WSGI

  • Easily debugged

  • Language independant

  • Need syntax highlighting with Pygments but your project is Ruby?

    • Write small Flask app that exposes Pygments as a service


  • Python-Requests
  • TODO
  • TODO