django-markupfield 1.0.0a

Custom Django field for easy use of markup in text fields

An implementation of a custom MarkupField for Django. A MarkupField is in essence a TextField with an associated markup type. The field also caches its rendered value on the assumption that disk space is cheaper than CPU cycles in a web application.

Installation

You can obtain the latest release of django-markupfield via PyPI or check out the latest source

To install a source distribution:

python setup.py install

It is also possible to install django-markupfield with pip or easy_install.

It is not necessary to add 'markupfield' to your INSTALLED_APPS, it merely needs to be on your PYTHONPATH.

Requirements

django-markupfield depends on django 1.0+ (tested with 1.0-1.2) and libraries for whichever markup options you wish to include.

Settings

To best make use of MarkupField you should define the MARKUP_FIELD_TYPES setting, a dictionary of strings to callables that ‘render’ a markup type:

import markdown
from docutils.core import publish_parts

def render_rest(markup):
    parts = publish_parts(source=markup, writer_name="html4css1")
    return parts["fragment"]

MARKUP_FIELD_TYPES = {
    'markdown': markdown.markdown,
    'ReST': render_rest,
}

If you do not define a MARKUP_FIELD_TYPES then one is provided with the following markup types available:

html:

allows HTML, potentially unsafe

plain:

plain text markup, calls urlize and replaces text with linebreaks

markdown:

default markdown renderer (only if python-markdown is installed)

restructuredtext:

default ReST renderer (only if docutils is installed)

textile:

default textile renderer (only if textile is installed)

Usage

Using MarkupField is relatively easy, it can be used in any model definition:

from django.db import models
from markupfield.fields import MarkupField

class Article(models.Model):
    title = models.CharField(max_length=100)
    slug = models.SlugField(max_length=100)
    body = MarkupField()

Article objects can then be created with any markup type defined in MARKUP_FIELD_TYPES:

Article.objects.create(title='some article', slug='some-article',
                       body='*fancy*', body_markup_type='markdown')

You will notice that a field named body_markup_type exists that you did not declare, MarkupField actually creates two extra fields here body_markup_type and _body_rendered. These fields are always named according to the name of the declared MarkupField.

Arguments

MarkupField also takes two optional arguments default_markup_type and markup_type. Either of these arguments may be specified but not both.

default_markup_type:

Set a markup_type that the field will default to if one is not specified. It is still possible to edit the markup type attribute and it will appear by default in ModelForms.

markup_type:

Set markup type that the field will always use, editable=False is set on the hidden field so it is not shown in ModelForms.

Accessing a MarkupField on a model

When accessing an attribute of a model that was declared as a MarkupField a special Markup object is returned. The Markup object has three parameters:

raw:

The unrendered markup.

markup_type:

The markup type.

rendered:

The rendered HTML version of raw, this attribute is read-only.

This object has a __unicode__ method that calls django.utils.safestring.mark_safe on rendered allowing MarkupField objects to appear in templates as their rendered selfs without any template tag or having to access rendered directly.

Assuming the Article model above:

>>> a = Article.objects.all()[0]
>>> a.body.raw
u'*fancy*'
>>> a.body.markup_type
u'markdown'
>>> a.body.rendered
u'<p><em>fancy</em></p>'
>>> print unicode(a.body)
<p><em>fancy</em></p>

Assignment to a.body is equivalent to assignment to a.body.raw and assignment to a.body_markup_type is equivalent to assignment to a.body.markup_type.

Note

a.body.rendered is only updated when a.save() is called

Origin

For those coming here via django snippets or the tracker, my original implementation is at https://gist.github.com/67724/3b7497713897fa0021d58e46380e4d80626b6da2

Jacob Kaplan-Moss commented on twitter that he’d possibly like to see a MarkupField in core and I filed a ticket on the Django trac http://code.djangoproject.com/ticket/10317

The resulting django-dev discussion drastically changed the purpose of the field. While I initially intended to write a version that seemed more acceptable for Django core I wound up feeling that the ‘acceptable’ version had so little functionality and so much complexity it wasn’t worth using.