pydirs - a simple Python object database
========================================
::

  Guido Wesdorp
  Pragmagik
  http://pragmagik.com/
  guido@pragmagik.com

The first ideas
---------------

 * 'svnodb' - SVN object database
 * SVN turned out to be a nuisance
 * slow
 * can not remove a dir, then create a new one with the same name,
   without committing
 * file-system only

Pydirs
------

 * simple code base (< 500 lines)
 * simple, explorable storage format
 * great for debugging
 * cat, echo, grep, cp
 * uses the Py lib for file-system access

Features
--------

 * stores pydiritems as directories
 * stores basic datatypes as plain text (repr)
 * stores anything else as pickles
 * loads fast, usable for CGI and WSGI
 * transaction support
 * change and delete hooks for logging, caching, etc.

API
---

 * typeregistry

   - .register(pydiritem subclass)

 * database object

   - .initialize(pydiritem instance)
   - .session() -> session instance

 * session object
  
   - .get(path as string) -> pydiritem instance or anything else
   - .commit() -> (changed, removed)
   - .rollback()

 * pydiritem object

   - .__getattr__(name)
   
   - .__setattr__(name, value)

   - .__delattr__(name)

   - some magic attributes (__db__, __relpath__, __path__, etc.)

Example
-------

::

  >>> import pydirs
  >>> class someitem(pydirs.pydiritem):
  ...     pass
  >>> pydirs.typeregistry.register(someitem)

  >>> db = pydirs.pydir('/tmp/testdb')
  >>> db.initialize(someitem())
  True

  >>> sess = db.session()
  >>> root = sess.get('/')
  >>> root.foo = 1
  >>> root.bar = someitem()
  >>> root.baz = [1, 2]
  >>> sess.commit()
  (['/tmp/testdb/baz', '/tmp/testdb/foo', '/tmp/testdb/bar'], [])

  >>> sess2 = db.session()
  >>> sess2.get('/').foo
  1
  >>> sess2.get('/foo')
  1
  >>> sess2.get('/bar')
  <__main__.someitem object at ...>
  >>> sess2.get('/baz')
  [1, 2]

Release
-------

 * still almost...
 * currently quite stable and used in production
 * http://pragmagik.com/
 * guido@pragmagik.com