django-permission 0.3.0

A enhanced permission system which enable object permission

**********************************
djagno-permission
**********************************

django-permission is an enhanced permission system which support object permission and role based permission system.

**This is under development. The codes below may not works in the future**

Install
==============
django-permission is in PyPI_ so::

$ pip install django-permission

or

$ pip install git+git://github.com/lambdalisue/django-permission.git#egg=django-permission

Quick tutorial
============================

1. Add ``'permission'`` to ``INSTALLED_APPS`` of your ``settings.py`` and confirm
''django.contrib.auth' and 'django.contrib.contenttypes' is in ``INSTALLED_APPS``

.. Note::
django-permission can use `django-fenicms <https://github.com/matiasb/fenics>`_ to improve
the visual design of change_list page in django admin if available. Add 'fenicms' to
your ``INSTALLED_APPS`` to enable AJAX sorting, adding, expanding features.

2. Add ``'permission.backends.PermissionBackend'`` to ``AUTHENTICATION_BACKENDS``
of your ``settings.py``. If you cannot existing settings, simply add
following code::

AUTHENTICATION_BACKENDS = (
'django.contrib.auth.backends.ModelBackend',
'permission.backends.PermissionBackend',
'permission.backends.RoleBackend',
)

3. Add ``permissions.py`` to the directory which contains ``models.py``. And
write following codes for starting::

from permission import registry
from permission import PermissionHandler

from models import YourModel

class YourModelPermissionHandler(PermissionHandler):
"""Permission handler class for ``YourModel``. Similar with AdminSite"""
def has_perm(self, user_obj, perm, obj=None):
"""this is called for checking permission of the model."""
if user_obj.is_authenticated():
if perm == 'yourapp.add_yourmodel':
# Authenticated user has add permissions of this model
return True
elif obj and obj.author == user_obj:
# Otherwise (change/delete) user must be an author
return True
# User doesn't have permission of ``perm``
return False

# register this ``YourModelPermissionHandler`` with ``YourModel``
registry.register(YourModel, YourModelPermissionHandler)

4. ``has`` and ``of`` keyword is added to ``if`` in template. You can check permission
as::

{% if user has 'blog.add_entry' %}
<p>You can add entry</p>
{% endif %}
{% if object and user has 'blog.change_entry' of object or user has 'blog.delete_entry' of object %}
<!-- object is exist and user can change or delete this object. -->
<div class="control-panel">
{% if user has 'blog.change_entry' of object %}
<p>You can change this entry.</p>
{% endif %}
{% if user has 'blog.delete_entry' of object %}
<p>You can delete this entry.</p>
{% endif %}
</div>
{% endif %}

.. Note::
If you don't want django-permission to replace builtin ``if`` tag, set
``PERMISSION_REPLATE_BUILTIN_IF`` to ``False`` in your ``settings.py``.
Then you have to use ``{% permission %}`` templatetag as::

{% permission user has 'blog.add_entry' %}
<p>You can add entry</p>
{% endpermission %}

``{% permission %}`` tag is exactuly same as ``{% if %}`` thus you can use
``{% elpermission %}`` for ``{% elif %}`` and ``{% else %}``.


Role?
==========

django-permission has role based permission system. visit your django admin page to create/modify roles (See the screenshots below).
The role permissions are handled with ``permission.backends.RoleBackend``.

.. image:: http://s1-01.twitpicproxy.com/photos/full/528601159.png?key=943727
:align: center

.. image:: http://s1-04.twitpicproxy.com/photos/full/528601385.png?key=9431458
:align: center

This role system is under development. This system might not work correctly yet.

.. Note::
Role based permission system does not support object permission and anonymous permission.
However these permissions are handled with Individual handler based permission backend
(``permission.backends.PermissionBackend``)


How to regulate permissions used in the handler
==============================================================================================

``PermissionHandler`` care permissions related with registered model only in default. To change
this behavior, you must define ``permissions`` attribute or ``get_permissions`` methods which
return a permission string (like 'auth.add_user') list.

``get_permissions`` return the value of ``permissions`` if the attribute is defined. Otherwise it
return all permissions related to the model in default used ``get_model_permissions`` method.

The sample code below show how to handle all permissions of the app of the model in one
``PermissionHandler``::

from permission import registry
from permission import PermissionHandler

from models import YourModel
from models import HisModel
from models import HerModel

class AppPermissionHandler(PermissionHandler):
def get_permissions(self):
# ``get_app_permissions()`` method return all permissions related
# to the app of the model.
return self.get_app_permissions()

def has_perm(self, user_obj, perm, obj=None):
if perm.endswith('_yourmodel'):
# All user has all permissions for ``YourModel``
return True
elif perm.endswith('_hismodel'):
if user_obj.is_authenticated():
# only authenticated user has all permissions for ``HisModel``
return True
elif perm.endswith('_hermodel'):
if user_obj.is_staff:
# only staff user has all permissions for ``HerModel``
return True
return False

# you have to register the handler with the model
# even AppPermissionHandler doesn't care about model
registry.register(YourModel, AppPermissionHandler)
# registry.register(HisModel, AppPermissionHandler) # or you can register with HisModel
# registry.register(HerModel, AppPermissionHandler) # or you can register with HerModel


.. Note::
DO NOT call ``user.has_perm()`` in ``has_perm()`` method unless the checking permissions are
excluded by ``permissions`` attribute or ``get_permissions()`` method.