Metadata-Version: 1.0
Name: django-model-utils
Version: 0.5.0
Summary: Django model mixins and utilities
Home-page: http://bitbucket.org/carljm/django-model-utils/
Author: Carl Meyer
Author-email: carl@dirtcircle.com
License: UNKNOWN
Description: ==================
        django-model-utils
        ==================
        
        Django model mixins and utilities.
        
        Installation
        ============
        
        Install from PyPI with ``pip``::
        
        pip install django-model-utils
        
        or get the `in-development version`_::
        
        pip install django-model-utils==tip
        
        .. _in-development version: http://bitbucket.org/carljm/django-model-utils/get/tip.gz#egg=django_model_utils-tip
        
        To use ``django-model-utils`` in your Django project, just import and
        use the utility classes described below; there is no need to modify
        your ``INSTALLED_APPS`` setting.
        
        Dependencies
        ------------
        
        ``django-model-utils`` requires `Django`_ 1.0 or later.
        
        .. _Django: http://www.djangoproject.com/
        
        Choices
        =======
        
        ``Choices`` provides some conveniences for setting ``choices`` on a Django model field::
        
        from model_utils import Choices
        
        class Article(models.Model):
        STATUS = Choices('draft', 'published')
        # ...
        status = models.CharField(choices=STATUS, default=STATUS.draft, max_length=20)
        
        A ``Choices`` object is initialized with any number of choices. In the
        simplest case, each choice is a string; that string will be used both
        as the database representation of the choice, and the human-readable
        representation. Note that you can access options as attributes on the
        ``Choices`` object: ``STATUS.draft``.
        
        But you may want your human-readable versions translated, in which
        case you need to separate the human-readable version from the DB
        representation. In this case you can provide choices as two-tuples::
        
        from model_utils import Choices
        
        class Article(models.Model):
        STATUS = Choices(('draft', _('draft')), ('published', _('published')))
        # ...
        status = models.CharField(choices=STATUS, default=STATUS.draft, max_length=20)
        
        But what if your database representation of choices is constrained in
        a way that would hinder readability of your code? For instance, you
        may need to use an ``IntegerField`` rather than a ``CharField``, or
        you may want the database to order the values in your field in some
        specific way. In this case, you can provide your choices as triples,
        where the first element is the database representation, the second is
        a valid Python identifier you will use in your code as a constant, and
        the third is the human-readable version::
        
        from model_utils import Choices
        
        class Article(models.Model):
        STATUS = Choices((0, 'draft', _('draft')), (1, 'published', _('published')))
        # ...
        status = models.IntegerField(choices=STATUS, default=STATUS.draft)
        
        
        StatusField
        ===========
        
        A simple convenience for giving a model a set of "states."
        ``StatusField`` is a ``CharField`` subclass that expects to find a
        ``STATUS`` class attribute on its model, and uses that as its
        ``choices``. Also sets a default ``max_length`` of 100, and sets its
        default value to the first item in the ``STATUS`` choices::
        
        from model_utils.fields import StatusField
        from model_utils import Choices
        
        class Article(models.Model):
        STATUS = Choices('draft', 'published')
        # ...
        status = StatusField()
        
        (The ``STATUS`` class attribute does not have to be a `Choices`_
        instance, it can be an ordinary list of two-tuples).
        
        MonitorField
        ============
        
        A ``DateTimeField`` subclass that monitors another field on the model,
        and updates itself to the current date-time whenever the monitored
        field changes::
        
        from model_utils.fields import MonitorField, StatusField
        
        class Article(models.Model):
        STATUS = Choices('draft', 'published')
        
        status = StatusField()
        status_changed = MonitorField(monitor='status')
        
        (A ``MonitorField`` can monitor any type of field for changes, not only a
        ``StatusField``.)
        
        SplitField
        ==========
        
        A ``TextField`` subclass that automatically pulls an excerpt out of
        its content (based on a "split here" marker or a default number of
        initial paragraphs) and stores both its content and excerpt values in
        the database.
        
        A ``SplitField`` is easy to add to any model definition::
        
        from django.db import models
        from model_utils.fields import SplitField
        
        class Article(models.Model):
        title = models.CharField(max_length=100)
        body = SplitField()
        
        ``SplitField`` automatically creates an extra non-editable field
        ``_body_excerpt`` to store the excerpt. This field doesn't need to be
        accessed directly; see below.
        
        Accessing a SplitField on a model
        ---------------------------------
        
        When accessing an attribute of a model that was declared as a
        ``SplitField``, a ``SplitText`` object is returned.  The ``SplitText``
        object has three attributes:
        
        ``content``:
        The full field contents.
        ``excerpt``:
        The excerpt of ``content`` (read-only).
        ``has_more``:
        True if the excerpt and content are the same, False otherwise.
        
        This object also has a ``__unicode__`` method that returns the full
        content, allowing ``SplitField`` attributes to appear in templates
        without having to access ``content`` directly.
        
        Assuming the ``Article`` model above::
        
        >>> a = Article.objects.all()[0]
        >>> a.body.content
        u'some text\n\n<!-- split -->\n\nmore text'
        >>> a.body.excerpt
        u'some text\n'
        >>> unicode(a.body)
        u'some text\n\n<!-- split -->\n\nmore text'
        
        Assignment to ``a.body`` is equivalent to assignment to
        ``a.body.content``.
        
        .. note::
        a.body.excerpt is only updated when a.save() is called
        
        
        Customized excerpting
        ---------------------
        
        By default, ``SplitField`` looks for the marker ``<!-- split -->``
        alone on a line and takes everything before that marker as the
        excerpt. This marker can be customized by setting the ``SPLIT_MARKER``
        setting.
        
        If no marker is found in the content, the first two paragraphs (where
        paragraphs are blocks of text separated by a blank line) are taken to
        be the excerpt. This number can be customized by setting the
        ``SPLIT_DEFAULT_PARAGRAPHS`` setting.
        
        TimeFramedModel
        ===============
        
        An abstract base class for any model that expresses a time-range. Adds
        ``start`` and ``end`` nullable DateTimeFields, and a ``timeframed``
        manager that returns only objects for whom the current date-time lies
        within their time range.
        
        StatusModel
        ===========
        
        Pulls together `StatusField`_, `MonitorField`_ and `QueryManager`_
        into an abstract base class for any model with a "status."
        
        Just provide a ``STATUS`` class-attribute (a `Choices`_ object or a
        list of two-tuples), and your model will have a ``status`` field with
        those choices, a ``status_changed`` field containing the date-time the
        ``status`` was last changed, and a manager for each status that
        returns objects with that status only::
        
        from model_utils.models import StatusModel
        from model_utils import Choices
        
        class Article(StatusModel):
        STATUS = Choices('draft', 'published')
        
        # ...
        
        a = Article()
        a.status = Article.STATUS.published
        
        # this save will update a.status_changed
        a.save()
        
        # this query will only return published articles:
        Article.published.all()
        
        InheritanceCastModel
        ====================
        
        This abstract base class can be inherited by the root (parent) model
        in a model-inheritance tree.  It allows each model in the tree to
        "know" what type it is (via an automatically-set foreign key to
        ``ContentType``), allowing for automatic casting of a parent instance
        to its proper leaf (child) type.
        
        For instance, if you have a ``Place`` model with subclasses
        ``Restaurant`` and ``Bar``, you may want to query all Places::
        
        nearby_places = Place.objects.filter(location='here')
        
        But when you iterate over ``nearby_places``, you'll get only ``Place``
        instances back, even for objects that are "really" ``Restaurant`` or
        ``Bar``.  If you have ``Place`` inherit from ``InheritanceCastModel``,
        you can just call the ``cast()`` method on each ``Place`` and it will
        return an instance of the proper subtype, ``Restaurant`` or ``Bar``::
        
        from model_utils.models import InheritanceCastModel
        
        class Place(InheritanceCastModel):
        # ...
        
        class Restaurant(Place):
        # ...
        
        nearby_places = Place.objects.filter(location='here')
        for place in nearby_places:
        restaurant_or_bar = place.cast()
        # ...
        
        .. note::
        This is inefficient for large querysets, as it results in n
        queries to the subtype tables.  It would be possible to write a
        QuerySet subclass that could reduce this to k queries, where there
        are k subtypes in the inheritance tree.
        
        TimeStampedModel
        ================
        
        This abstract base class just provides self-updating ``created`` and
        ``modified`` fields on any model that inherits from it.
        
        
        QueryManager
        ============
        
        Many custom model managers do nothing more than return a QuerySet that
        is filtered in some way. ``QueryManager`` allows you to express this
        pattern with a minimum of boilerplate::
        
        from django.db import models
        from model_utils.managers import QueryManager
        
        class Post(models.Model):
        ...
        published = models.BooleanField()
        pub_date = models.DateField()
        ...
        
        objects = models.Manager()
        public = QueryManager(published=True).order_by('-pub_date')
        
        The kwargs passed to ``QueryManager`` will be passed as-is to the
        ``QuerySet.filter()`` method. You can also pass a ``Q`` object to
        ``QueryManager`` to express more complex conditions. Note that you can
        set the ordering of the ``QuerySet`` returned by the ``QueryManager``
        by chaining a call to ``.order_by()`` on the ``QueryManager`` (this is
        not required).
        
        manager_from
        ============
        
        A common "gotcha" when defining methods on a custom manager class is
        that those same methods are not automatically also available on the
        QuerySet used by that model, so are not "chainable". This can be
        counterintuitive, as most of the public QuerySet API is also available
        on managers. It is possible to create a custom Manager that returns
        QuerySets that have the same additional methods, but this requires
        boilerplate code.
        
        The ``manager_from`` function (`created by George Sakkis`_ and
        included here by permission) solves this problem with zero
        boilerplate. It creates and returns a Manager subclass with additional
        behavior defined by mixin subclasses or functions you pass it, and the
        returned Manager will return instances of a custom QuerySet with those
        same additional methods::
        
        from datetime import datetime
        from django.db import models
        
        class AuthorMixin(object):
        def by_author(self, user):
        return self.filter(user=user)
        
        class PublishedMixin(object):
        def published(self):
        return self.filter(published__lte=datetime.now())
        
        def unpublished(self):
        return self.filter(published__gte=datetime.now())
        
        
        class Post(models.Model):
        user = models.ForeignKey(User)
        published = models.DateTimeField()
        
        objects = manager_from(AuthorMixin, PublishedMixin, unpublished)
        
        Post.objects.published()
        Post.objects.by_author(user=request.user).unpublished()
        
        .. _created by George Sakkis: http://djangosnippets.org/snippets/2117/
        CHANGES
        =======
        
        tip (unreleased)
        ----------------
        
        0.5.0 (2010.09.24)
        ------------------
        
        - added manager_from (thanks George Sakkis)
        - added StatusField, MonitorField, TimeFramedModel, and StatusModel
        (thanks Jannis Leidel)
        - deprecated ChoiceEnum and replaced with Choices
        
        0.4.0 (2010.03.16)
        ------------------
        
        - added SplitField
        - added ChoiceEnum
        - added South support for custom model fields
        
        0.3.0
        -----
        
        * Added ``QueryManager``
        
        TODO
        ====
        
        * Custom QuerySet subclass to pair with InheritanceCastModel for more
        efficient querying.
        
Platform: UNKNOWN
Classifier: Development Status :: 4 - Beta
Classifier: Environment :: Web Environment
Classifier: Intended Audience :: Developers
Classifier: License :: OSI Approved :: BSD License
Classifier: Operating System :: OS Independent
Classifier: Programming Language :: Python
Classifier: Framework :: Django
