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/<ID>
/derived/<ID>-<width>x<height>.<extension>

- 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