c0ntribut0r/django-mptt-urls

Creating hierarchical URLs in Django associated with django-MPTT models

Overview

This reusable app helps to create arbitrary-depth Clean URLs which correspond to MPTT tree hierarchy of model instances, like these:

http://best-photographer.com/gallery/weddings/Dexter-and-Rita/

http://best-photographer.com/gallery/my-pets/dogs/husky/

As you can see, the links are quite different - they have different depth of hierarchy. When users see these URLs they can easily discover where they are located. They can either delete some part of the URL and thus move up in the hierarchy.

Django-mptt-urls is just a simple view that knows how to resolve hierarchical urls.

Example

The simpliest way to understand how django_mptt_urls works is to clone this GitHub project, create virtual environment and run test_project (no extra settings required, except sqlite3 database support):

git clone https://github.com/c0ntribut0r/django-mptt-urls.git
pyvenv django-mptt-urls
source django-mptt-urls/bin/activate
pip install django-mptt-urls/
python django-mptt-urls/test_project/manage.py runserver

And visit 127.0.0.1:8000 in your browser.

Requirements

django-mptt-urls uses django-mptt. It will be automatically installed as a requirement.

Installation

First of all, you should already be using django-mptt, something like this:

from mptt.models import MPTTModel, TreeForeignKey

class Category(MPTTModel):
    ...
    parent = TreeForeignKey('self', null=True, blank=True)
    slug = models.SlugField()
    class Meta:
        unique_together = ('slug', 'parent')

Install django-mptt-urls:

pip install django-mptt-urls

Then, in your urls.py, replace one or more views with special mptt_urls.view:

# urls.py
...
import mptt_urls

urlpatterns = patterns('',
    ...
    url(r'^gallery/(?P<path>.*)', mptt_urls.view(model='gallery.models.Category', view='gallery.views.category', slug_field='slug', trailing_slash=True), {'extra': 'You may also pass extra options as usual!'}, name='gallery'),
    ...
)

Here is what we've done:

• We are capturing (?P<path>.*), which will be passed to mptt_urls.view when url resolution is fired. You can define path whatever you like (for example (?P<path>[\d/]+)), but don't forget to include '/' in the regex.
• Replace your view with special mptt_urls.view.

mptt-urls.view works like a decorator to a view: it gets fired when url resolution is performed, calculates an instance the path is poining to, and passes it to original view.

So, if you write

url(r'^gallery/(?P<path>.*)', 'gallery.views.category', name='gallery'),

the gallery.views.category view will receive path variable and will have to make object resolution. With mptt_urls.view, you will get the resolved object automatically - gallery.views.category view will receive path and instance variables:

url(r'^gallery/(?P<path>.*)', mptt_urls.view(model='gallery.models.Category', view='gallery.views.category', slug_field='slug'), name='gallery'),

mptt_urls.view options are:

• model - your model derived from MPTTModel.
• view - a view which will process the request. Don't forget to capture path and instance (def category(request, path, instance):). If resolution fails, instance will be None.
• slug_field - the field where model instance's slug is stored

get_absolute_url()

Well, url(...) defines direct url resolution. To define reverse url resolution, add to your model:

class Category(MPTTModel):
    ...
    def get_absolute_url(self):
        return reverse('gallery', kwargs={'path': self.get_path()})

Here, we use Category.get_path() which is available since using mptt_urls.view.

If you use namespaced url routing, don't forget to add namespace specifier like this:

return reverse('namespace:gallery', kwargs={'path': self.get_path()})

License

MIT. Do whatever you like. View license file for details.