Features

• Ability to resize and serve any picture supported by PIL
• HTTP caching support (If-Modified-since / Last-Modified header, + Apache mod_headers)
• Supports all databases supported by SQL Alchemy
• can be deployed standalone (for development purposes) as well as behind Apache using mod_wsgi
• RESTful interface, URLs, and returns HTTP Error codes (see error codes below)
• Is supposed to handle locking correctly in case of pending requests for the same not-yet-processed derived image

Install Dependencies $ sudo apt-get install python-imaging python-sqlalchemy python-psycopg2 python-zope.interface python-cherrypy3 python-setuptools python-pkg-resources python-migrate

Additional dependencies for developers : $ sudo apt-get install python-setuptools python-nose python-mox

Run unit tests to make sure everything's fine $ python setup.py test

Run the service in standalone mode $ python pymager-standalone.py

HTTP Error Codes that are returned

• 304 : (resource not modified)
• 400
  • {original} Unsupported Format (POST)
  • DEV: {original} Invalid Multipart request (POST) : only for dev, should never happen if client is coded properly
  • DEV: {derived} Invalid requested format (GET) : only for dev, should never happen if client does not allow requesting unknown image formats
  • DEPRECATED: {original} Supplied ID does not use the correct ID format (POST) (FIXME: should disappear) : should never happen if client API checks ID format before submitting
• 403
  • Resize characteristics not allowed (GET)
• 404
  • {original, derived} Resource does not exist (GET, DELETE)
  • DEV: {derived} URL decoding error (GET) : should never happen if client generates URLs correctly
• 405
  • DEV: {original, derived}: the supported method is not authorized (e.g. DELETE issues on derived/) should never happen as clients are not supposed to expose more than is currently available
• 409
  • Image ID already exists (POST)
• 500
  • various, unexpected errors (IO exceptions, etc..)

Returned headers

• Allowed methods (when 405)
• Last-Modified
• Content-Type (FIXME: is it returned ?)

= Interface = /original/ /derived/-x.

• ID should match ([w_-]+)-(d+)x(d+).([a-zA-Z]+)
• width and height should be integers (allowed sizes are configurable in pymager configuration file)

Examples: http://localhost:8000/derived/sample-100x100.jpg http://localhost:8000/derived/sample-800x600.jpg

What is not tested automatically (using integration or unit tests)

• everything that is in Apache WSGi configuration (Authentication, Caching, etc..)
• The image resize algorithm (whether it expands the image correctly, shrinks it correctly, etc..)
• content type header of served file

FIXME:

• ASCII / Unicode / ID constraints should be re-checked and enforced.. for now, things are crashing at myscellaneous levels. what kind of constraints do we want to enforce exactly ? Do we want unicode IDs ?

Create release

git tag v0.5 git push origin --tags python setup sdist re-create debian package (see http://www.vis.ethz.ch/de/visionen/pdfs/2010/visionen_2010_4.pdf?end=28&start=22 for a list of dependencies to install)

IDE Setup

Pydev

• Install eclipse
• Install Pydev
• Activate Python interpreter
• Setup test runner to 'nose'

= Backlog =

• Upgrade to python-distribute
• Upload to Pypi
• Fix exception handling to include complete stack traces
• Complete Debian package that configures apache2 + Database
• Fix Multi-Thread issue
• DB data should be reset in dev mode, in addition to deleting the files
• Extract caching code and plug other caching engines (memcache, ..)
• Create Scala API to access Pymager (and other languages ?)
• Better logging
• Pythonize the *Templates, ...
• Create website
• Push to Pypi
• Cleanup debian package (add samples, default configuration files, apache scripts, ..) and (try to) push it to the main repositories (Ubuntu PPA)
• Add additional NoSQL Backends
• Better Advertisement on MFU's website