anyit.djattributes 0.3.1
Attributes and a persistend dict type for django models in a JQuery inspired syntax.
License: BSD
Keywords: django attributes persistent dict generic

==============
attributes ...
==============
... is a *django app* which aims to provide *arbitrary attributes* for any model without touching it. The *flexibility won* is paid with the *speed lost*, which will become obvious in large scaled applications with dense data.

Changes in 0.3.1
================
- Added batch processing for (o)bjects if passed as list argument.
- Added batch processing for (n)ames if which will assign (if passed as dict argument) or retreive (list) multiple attributes.
- Added namespace like retreivel of nested dict elements using dots (.).

Installation
============
- Just copy the attributes folder to your current django project and include 'attributes' in your settings.
- Or install it using *sudo easy_install anyit.djattributes* and include 'anyit.djattributes.attributes'.

Usage
=====
A javascript / JQuery like notation is implemented and provided by a simple interface class called *attr*. No capital letter like in usual classnames trying to make it feel like JQuery.

Mind the gap
------------

I am a bit concerned about this being *not compliant to django philosophy*. Make sure you do not use this for large scale non sparse data stuff. I was just bothered with a tree structure containing arbitrary, path dependent attributes. This is why I did it. If I could have avoided this I had my models more nailed down :)

Type interfaces
---------------
::

  # Creates a type. Look at the __doc__ for further info on types and 
  # how they are represented. By now the internal_types int, float, 
  # string, text, unicode, class (any pickleable object) and contenttype, 
  # using a django gereric key, are supported.
  attr.create_type(name, description , type) 

  # Careful! The cascade will destroy any values of the given type.
  attr.delete_type(name) 

Carrier interfaces
------------------
::

  # returns all attribute objects
  attr()               

  # returns a list of attributes for the given owner.
  attr(owner)               

  # returns the owners attribute with a given name or None.
  attr(owner, name)         

  # ... set its value or raise if the type is not koscher.
  attr(owner, name, value)  

  # create_attributetype chooses between creating an attributetype 
  # with the given name, type determined by the given value and the 
  # description set to the given name if a description is not 
  # explicitely provided. create_attribute will associate a given 
  # attribute with a carrier which is not yet attached with an 
  # attribute type like given or raise a NameError. klass chooses 
  # to enforce the attribute being attached to a model, even if an 
  # instance is given. as_attribute will return the attribute, not
  # it's value.
  #
  # special cases:
  #   o is a list: batch processing for multiple objects
  #   n is a dict: batch processing setting multiple attributes
  #   n is a list: batch processing getting multiple attributes
  #   n (items) contain dots (.): namespace like retreival for subkeys
  #   o and n are lists, or n a dict: a nested dict will be returned 
  #
  # naming conventions for attribute keys
  #   try using unicode
  #   do not use the .

  attr(
      owner=None,
      name=None,
      value=None, 
      create_attributetype=True, 
      create_attribute=True, 
      klass=False,
      description=None, 
      as_attribute=False
  ) 


Attribute interfaces
--------------------
::

  # returns the owner of a given attribute
  attr.find(attribute) 

  # returns a list of attributes for the attribute type of the given name
  attr.find(name) 

  # returns a list of attributes for the attribute type of the given name matching the value
  attr.find(name, value) 

Destructive interfaces
----------------------
::

  # deletes all attributes
  attr.delete() 
  
  # deletes all attributes having the given type.
  attr.delete(n=name) 

  # deletes all attributes being attached to the given object or class.
  attr.delete(o=object) 

  # deletes the attribute named n attached to o, the given object or class.
  attr.delete(o=object, n=name) 

Tests
=====
To get started you might also want to run the ./manage.py test attributes command and have a look at the second half of the *tests.py* file.

Credits
=======
The *PickledObjectField* and their tests (found in the first half of tests.py) taken from  http://djangosnippets.org/snippets/1694/ and slightly modified so the __in lookup would work, too. Thanks for the snippet. Later I realized, this one might have worked, too: https://github.com/shrubberysoft/django-picklefield/blob/master/src/picklefield/fields.py.

Have fun and feel free to contact me if you are having trouble, suggestions, ...