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+==============
+Django Tagging
+==============
+
+A generic tagging application for `Django`_ projects, which allows
+association of a number of tags with any ``Model`` instance and makes
+retrieval of tags simple.
+
+.. _`Django`: http://www.djangoproject.com
+
+
+Installation
+============
+
+Downloading django-tagging
+--------------------------
+
+There are two options for downloading; one is to download the latest
+packaged version from http://code.google.com/p/django-tagging/ and
+unpack it; inside is a script called setup.py. Type this command::
+
+    python setup.py install
+
+...and the package will install automatically.
+
+The other method is to perform a Subversion checkout from somewhere on
+your Python path:
+
+    svn checkout http://django-tagging.googlecode.com/svn/trunk/tagging/
+
+Keep in mind that the current code in SVN may be different from the
+packaged release, and may contain bugs and backwards-incompatible
+changes.
+
+Using django-tagging in your projects
+-------------------------------------
+
+Once you've downloaded django-tagging and want to use it in your
+projects, do the following::
+
+    1. Put ``'tagging'`` in your ``INSTALLED_APPS`` setting.
+    2. Run the command ``manage.py syncdb``.
+
+The ``syncdb`` command creates the necessary database tables and
+creates permission objects for all installed apps that need them.
+
+That's it!
+
+
+Settings
+========
+
+Some of django-tagging's behaviour may be configured by adding the
+appropriate settings to your project's settings file.
+
+The following settings are available:
+
+FORCE_LOWERCASE_TAGS
+--------------------
+
+Default: ``False``
+
+A boolean that turns on/off forcing of tags to lowercase before they
+are saved to the database.
+
+
+Tags
+====
+
+Tags are represented by the ``Tag`` model, which lives in the
+``tagging.models`` module.
+
+API reference
+-------------
+
+Fields
+~~~~~~
+
+``Tag`` objects have the following fields:
+
+    * ``name`` -- The name of the tag. This is a unique value
+      consisting only of unicode alphanumeric characters, numbers,
+      underscores and hyphens.
+
+Manager functions
+~~~~~~~~~~~~~~~~~
+
+The ``Tag`` model has a custom manager which has the following helper
+functions:
+
+    * ``update_tags(obj, tag_names)`` -- Updates tags associated with
+      an object.
+
+      ``tag_names`` is a string containing tag names with which
+      ``obj`` should be tagged. Valid tag names may contain unicode
+      alphanumeric characters, numbers, underscores or hyphens.
+      Multiple tag names may be specified, separated by any number of
+      commas and spaces.
+
+      If ``tag_names`` is ``None`` or ``''``, the object's tags will
+      be cleared.
+
+    * ``add_tag(obj, tag_name)`` -- Associates a tag with an an object.
+
+      ``tag_name`` is a string containing a tag name with which
+      ``obj`` should be tagged. Valid tag names may contain unicode
+      alphanumeric characters, numbers, underscores or hyphens.
+
+    * ``get_for_object(obj)`` -- Returns a ``QuerySet`` containing all
+      ``Tag`` objects associated with ``obj``.
+
+    * ``usage_for_model(Model, counts=False, min_count=None, filters=None)``
+      -- Returns a list of ``Tag`` objects associated with instances
+      of ``Model``.
+
+      If ``counts`` is ``True``, a ``count`` attribute will be added
+      to each tag, indicating how many times it has been associated
+      with instances of ``Model``.
+
+      If ``min_count`` is given, only tags which have a ``count``
+      greater than or equal to ``min_count`` will be returned. Passing
+      a value for ``min_count`` implies ``counts=True``.
+
+      To limit the tags (and counts, if specified) returned to those
+      used by a subset of the model's instances, pass a dictionary of
+      field lookups to be applied to ``Model`` as the ``filters``
+      argument.
+
+    * ``related_for_model(tags, Model, counts=False, min_count=None)``
+      -- Returns a list of tags related to a given list of tags - that
+      is, other tags used by items which have all the given tags.
+
+      If ``counts`` is ``True``, a ``count`` attribute will be added
+      to each tag, indicating the number of items which have it in
+      addition to the given list of tags.
+
+      If ``min_count`` is given, only tags which have a ``count``
+      greater than or equal to ``min_count`` will be returned. Passing
+      a value for ``min_count`` implies ``counts=True``.
+
+    * ``cloud_for_model(Model, steps=4, distribution=LOGARITHMIC,
+      filters=None, min_count=None)`` -- Returns a list of the
+      distinct ``Tag`` objects associated with instances of ``Model``,
+      each having a ``count`` attribute as above and an additional
+      ``font_size`` attribute, for use in creation of a tag cloud (a
+      type of weighted list).
+
+      ``steps`` defines the number of font sizes available -
+      ``font_size`` may be an integer between ``1`` and ``steps``,
+      inclusive.
+
+      ``distribution`` defines the type of font size distribution
+      algorithm which will be used - logarithmic or linear. It must
+      be either ``tagging.utils.LOGARITHMIC`` or
+      ``tagging.utils.LINEAR``.
+
+      To limit the tags displayed in the cloud to those associated
+      with a subset of the Model's instances, pass a dictionary of
+      field lookups to be applied to the given Model as the
+      ``filters`` argument.
+
+      To limit the tags displayed in the cloud to those with a
+      ``count`` greater than or equal to ``min_count``, pass a value
+      for the ``min_count`` argument.
+
+Basic usage
+-----------
+
+Tagging objects and retrieving an object's tags
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Objects may be tagged using the ``update_tags`` helper function::
+
+    >>> from shop.apps.products.models import Widget
+    >>> from tagging.models import Tag
+    >>> widget = Widget.objects.get(pk=1)
+    >>> Tag.objects.update_tags(widget, 'house thing')
+
+Retrieve tags for an object using the ``get_for_object`` helper
+function::
+
+    >>> Tag.objects.get_for_object(widget)
+    [<Tag: house>, <Tag: thing>]
+
+Tags are created, associated and unassociated accordingly when you use
+``update_tags`` and ``add_tags``::
+
+    >>> Tag.objects.update_tags(widget, 'house monkey')
+    >>> Tag.objects.get_for_object(widget)
+    [<Tag: house>, <Tag: monkey>]
+    >>> Tag.objects.add_tag(widget, 'tiles')
+    >>> Tag.objects.get_for_object(widget)
+    [<Tag: house>, <Tag: monkey>, <Tag: tiles>]
+
+Clear an object's tags by passing ``None`` or ``''`` to
+``update_tags``::
+
+    >>> Tag.objects.update_tags(widget, None)
+    >>> Tag.objects.get_for_object(widget)
+    []
+
+Retrieving tags used by a particular model
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To retrieve all tags used for a particular model, use the
+``get_for_model`` helper function::
+
+    >>> widget1 = Widget.objects.get(pk=1)
+    >>> Tag.objects.update_tags(widget1, 'house thing')
+    >>> widget2 = Widget.objects.get(pk=2)
+    >>> Tag.objects.update_tags(widget2, 'cheese toast house')
+    >>> Tag.objects.usage_for_model(Widget)
+    [<Tag: cheese>, <Tag: house>, <Tag: thing>, <Tag: toast>]
+
+To get a count of how many times each tag was used for a particular
+model, pass in ``True`` for the ``counts`` argument::
+
+    >>> tags = Tag.objects.usage_for_model(Widget, counts=True)
+    >>> [(tag.name, tag.count) for tag in tags]
+    [('cheese', 1), ('house', 2), ('thing', 1), ('toast', 1)]
+
+To get counts and limit the tags returned to those with counts above a
+certain size, pass in a ``min_count`` argument::
+
+    >>> tags = Tag.objects.usage_for_model(Widget, min_count=2)
+    >>> [(tag.name, tag.count) for tag in tags]
+    [('house', 2)]
+
+You can also specify a dictionary of `field lookups`_ to be used to
+restrict the tags and counts returned based on a subset of the
+model's instances. For example, the following would retrieve all tags
+used on Widgets created by a user named Alan which have a size
+greater than 99::
+
+    >>> Tag.objects.usage_for_model(Widget, filters=dict(size__gt=99, user__username='Alan'))
+
+.. _`field lookups`: http://www.djangoproject.com/documentation/db-api/#field-lookups
+
+
+Tagged Items
+============
+
+The relationship between a ``Tag`` and an object is represented by
+the ``TaggedItem`` model, which lives in the ``tagging.models``
+module.
+
+API reference
+-------------
+
+Fields
+~~~~~~
+
+``TaggedItem`` objects have the following fields:
+
+    * ``tag`` -- The ``Tag`` an object is associated with.
+    * ``content_type`` -- The ContentType of the associated object.
+    * ``object_id`` -- The id of the associated object.
+    * ``object`` -- The associated object.
+
+Manager functions
+~~~~~~~~~~~~~~~~~
+
+The ``TaggedItem`` model has a custom manager which has the following
+helper functions:
+
+    * ``get_by_model(Model, tag)`` -- If ``tag`` is an instance of a
+      ``Tag``, returns a ``QuerySet`` containing all instances of
+      ``Model`` which are tagged with it.
+
+      If ``tag`` is a list of tags, returns a ``QuerySet`` containing
+      all instances of ``Model`` which are tagged with every tag in
+      the list.
+
+    * ``get_intersection_by_model(Model, tags)`` -- Returns a
+      ``QuerySet`` containing all instances of ``Model`` which are
+      tagged with every tag in the list.
+
+      ``get_by_model`` will call this function behind the scenes when
+      you pass it a list, so it's recommended that you use
+      ``get_by_model`` instead of calling this function directly.
+
+    * ``get_related(obj, Model, num=None)`` - Returns instances of
+       ``Model`` which share tags with the model instance ``obj``,
+       ordered by the number of shared tags in descending order.
+
+       If ``num`` is given, a maximum of ``num`` instances will be
+       returned.
+
+Basic usage
+-----------
+
+Retrieving tagged objects
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+Objects may be retrieved based on their tags using the ``get_by_model``
+helper function::
+
+    >>> from shop.apps.products.models import Widget
+    >>> from tagging.models import Tag
+    >>> house_tag = Tag.objects.get(name='house')
+    >>> TaggedItem.objects.get_by_model(Widget, house_tag)
+    [<Widget: pk=1>, <Widget: pk=2>]
+
+Passing a list of tags to ``get_by_model`` returns an intersection of
+objects which have those tags, i.e. tag1 AND tag2 ... AND tagN::
+
+    >>> thing_tag = Tag.objects.get(name='thing')
+    >>> TaggedItem.objects.get_by_model(Widget, [house_tag, thing_tag])
+    [<Widget: pk=1>]
+
+Functions which take tags are flexible when it comes to tag input::
+
+    >>> TaggedItem.objects.get_by_model(Widget, Tag.objects.filter(name__in=['house', 'thing']))
+    [<Widget: pk=1>]
+    >>> TaggedItem.objects.get_by_model(Widget, 'house thing')
+    [<Widget: pk=1>]
+    >>> TaggedItem.objects.get_by_model(Widget, ['house', 'thing'])
+    [<Widget: pk=1>]
+
+
+Utilities
+=========
+
+Tag-related utility functions are defined in the ``tagging.utils``
+module:
+
+get_tag_name_list(tags_names)
+-----------------------------
+
+Finds tag names in the given string and return them in a list.
+
+get_tag_list(tags)
+------------------
+
+Utility function for accepting tag input in a flexible manner.
+
+If a ``Tag`` object is given, it will be returned in a list as its
+single occupant.
+
+If given, the tag names in the following will be used to create a
+``Tag`` ``QuerySet``:
+
+    * A string, which may contain multiple tag names.
+    * A list or tuple of strings corresponding to tag names.
+    * A list or tuple of integers corresponding to tag ids.
+
+If given, the following will be returned as-is:
+
+    * A list or tuple of ``Tag`` objects.
+    * A ``Tag`` ``QuerySet``.
+
+calculate_cloud(tags, steps=4, distribution=tagging.utils.LOGARITHMIC)
+----------------------------------------------------------------------
+
+Adds a ``font_size`` attribute to each tag given according to the
+frequency of its use, as indicated by its ``count`` attribute.
+
+``steps`` defines the range of font sizes - ``font_size`` will be an
+integer between 1 and ``steps`` (inclusive).
+
+``distribution`` defines the type of font size distribution algorithm
+which will be used - logarithmic or linear. It must be either
+``tagging.utils.LOGARITHMIC`` (default) or ``tagging.utils.LINEAR``.
+
+The algorithm to scale the tags logarithmically is from a blog post by
+Anders Pearson, `Scaling tag clouds`_.
+
+.. _`Scaling tag clouds`: http://thraxil.com/users/anders/posts/2005/12/13/scaling-tag-clouds/
+
+
+Model Fields
+============
+
+The ``tagging.fields`` module contains fields which make it easy to
+integrate tagging into your models and into the
+``django.contrib.admin`` application.
+
+Field types
+-----------
+
+``TagField``
+~~~~~~~~~~~~
+
+A ``CharField`` that actually works as a relationship to tags "under
+the hood".
+
+Using this example model::
+
+    class Link(models.Model):
+        ...
+        tags = TagField()
+
+Setting tags::
+
+    >>> l = Link.objects.get(...)
+    >>> l.tags = 'tag1 tag2 tag3'
+
+Getting tags for an instance::
+
+    >>> l.tags
+    'tag1 tag2 tag3'
+
+Getting tags for a model - i.e. all tags used by all instances of the
+model::
+
+    >>> Link.tags
+    'tag1 tag2 tag3 tag4 tag5'
+
+This field will also validate that it has been given a valid list of
+tag names, separated by a single comma, a single space or a comma
+followed by a space, using the ``isTagList`` validator from
+``tagging.validators``.
+
+
+Form Fields
+===========
+
+The ``tagging.forms`` module contains a ``Field`` for use with
+Django's `newforms library`_ which takes care of validating tag name
+input when used in your forms.
+
+.. _`newforms library`: http://www.djangoproject.com/documentation/newforms/
+
+Field types
+-----------
+
+``TagField``
+~~~~~~~~~~~~
+
+A form ``Field`` which is displayed as a single-line text input, which
+validates that the input it receives is a valid list of tag names,
+separated by a single comma, a single space or a comma followed by a
+space.
+
+When you generate a form for one of your models automatically, using
+the ``form_for_model`` or ``form_for_instance`` functions provided by
+the newforms library, any ``tagging.fields.TagField`` fields in your
+model will automatically be represented by a
+``tagging.forms.TagField`` in the generated form.
+
+
+Simplified tagging and retrieval of tags with properties
+========================================================
+
+If you're not using ``TagField``, a useful method for simplifying
+tagging and retrieval of tags for your models is to set up a
+property::
+
+    from django.db import models
+    from tagging.models import Tag
+
+    class MyModel(models.Model):
+        name = models.CharField(maxlength=100)
+        tag_list = models.CharField(maxlength=255)
+
+        def save(self):
+            super(MyModel, self).save()
+            self.tags = self.tag_list
+
+        def _get_tags(self):
+            return Tag.objects.get_for_object(self)
+
+        def _set_tags(self, tag_list):
+            Tag.objects.update_tags(self, tag_list)
+
+        tags = property(_get_tags, _set_tags)
+
+        def __str__(self):
+            return self.name
+
+Once you've set this up, you can access and set tags in a fairly
+natural way::
+
+    >>> obj = MyModel.objects.get(pk=1)
+    >>> obj.tags = 'foo bar'
+    >>> obj.tags
+    [<Tag: bar>, <Tag: foo>]
+
+Remember that ``obj.tags`` will return a ``QuerySet``, so you can
+perform further filtering on it, should you need to.
+
+
+Generic Views
+=============
+
+**New in django-tagging development version**
+
+The ``tagging.views`` module contains views to handle common display
+ogic related to tagging.
+
+The following sample URLconf demonstrates using a generic view to list
+items of a particular model which have a given tag::
+
+    from django.conf.urls.defaults import *
+    from tagging.views import tagged_object_list
+    from shop.apps.products.models import Widget
+
+    urlpatterns = patterns('',
+        (r'^widgets/tag/(?P<tag>[^/]+(?u))/$', tagged_object_list,
+            dict(model=Widget, paginate_by=10, allow_empty=True,
+                 template_object_name='widget')),
+    )
+
+``tagging.views.tagged_object_list``
+------------------------------------
+
+**Description:**
+
+A view that displays a list of objects for a given model which have a
+given tag. This is a thin wrapper around the
+``django.views.generic.list_detail.object_list`` view, which takes a
+model and a tag as its arguments (in addition to the other optional
+arguments supported by ``object_list``), building the appropriate
+``QuerySet`` for you instead of expecting one to be passed in.
+
+**Required arguments:**
+
+    * ``model``: The Django model class of the object that will be
+      listed.
+
+    * ``tag``: The tag which objects of the given model must have in
+      order to be listed.
+
+**Optional arguments:**
+
+Please refer to the `object_list documentation`_ for additional optional
+arguments which may be given.
+
+    * ``related_tags``: If ``True``, a ``related_tags`` context variable
+      will also contain tags related to the given tag for the given
+      model.
+
+    * ``related_tag_counts``: If ``True`` and ``related_tags`` is
+      ``True``, each related tag will have a ``count`` attribute
+      indicating the number of items which have it in addition to the
+      given tag.
+
+**Template context:**
+
+    * ``tag``: The ``Tag`` instance for the given tag.
+
+Please refer to the `object_list documentation`_ for  additional
+template context variables which may be provided.
+
+.. _`object_list documentation`: http://www.djangoproject.com/documentation/generic_views/#django-views-generic-list-detail-object-list
+
+Template tags
+=============
+
+The ``tagging.templatetags.tagging_tags`` module defines a number of
+template tags which may be used to work with tags.
+
+Tag reference
+-------------
+
+tags_for_model
+~~~~~~~~~~~~~~
+
+Retrieves a list of tags associated with the given model and stores
+them in a context variable.
+
+The model is specified in ``[appname].[modelname]`` format.
+
+If specified - by providing extra ``with counts`` arguments - adds a
+``count`` attribute to each tag containing the number of instances of
+the given model which have been tagged with it.
+
+Example usage::
+
+    {% tags_for_model products.Widget as widget_tags %}
+
+    {% tags_for_model products.Widget as widget_tags with counts %}
+
+tags_for_object
+~~~~~~~~~~~~~~~
+
+Retrieves a list of tags associated with an object and stores them in
+a context variable.
+
+Example usage::
+
+    {% tags_for_object widget as tag_list %}
+
+tagged_objects
+~~~~~~~~~~~~~~
+
+Retrieves a list of objects for a given model which are tagged with
+a given tag and stores them in a context variable.
+
+The tag must be an instance of a ``Tag``, not the name of a tag.
+
+The model is specified in ``[appname].[modelname]`` format.
+
+Example usage::
+
+    {% tagged_objects house_tag in products.Widget as widgets %}
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