What is @permalink and get_absolute_url in Django?

Question

What is @permalink and get_absolute_url in Django? When and why to use it?

Please a very simple example (a real practical example). Thanks

Answer 1

As of 2013, the Django documentation discouraged use of the permalink decorator and encouraged use of reverse() in the body of the get_absolute_url method. By 2015, the permalink decorator seemed to have vanished without a trace from the Django documentation, and it was finally removed in Django version 2.1 in 2018.

So, for a standard DRY way to create a permanent link to a single object view, use get_absolute_url() in your model like this:

from django.db import models from django.urls import reverse #  NOTE: pre Django 1.10+ this is "from django.core.urlresolvers import reverse"   class MyModel(models.Model):     slug = models.SlugField()      def get_absolute_url(self):         return reverse('mymodel_detail', args=(self.slug,)) 

and then have an entry in urls.py that points to your view:

url(r'^(?P<slug>[-\w\d\_]+)/$',     MyModelDetailView.as_view(),     name='mymodel_detail'), 

Answer 2

@permalink is a python decorator, while get_absolute_url is a method on a django model.

Both are concerned with allowing you to reverse the URL for a particular object and should be used together. They are used anytime you need to provide a link to a particular object or want to display that object's specific URL (if it has one) to the user

You could simply write your get_absolute_url method to return a hard coded string, but this wouldn't adhere to Django's philosophy of DRY (don't repeat yourself). Instead, there is the @permalink to make things more flexible.

If you read the docs on the subject you will see how they relate to each other. the @permalink decorator hooks into django's URLconf's backend, allowing you to write much more portable code by using named url patterns. This is preferable to just using get_absolute_url on it's own: your code becomes much DRYer as you don't have to specify paths.

class BlogPost(models.Model):     name = modelsCharField()     slug = models.SlugField(...)      @permalink     def get_absolute_url(self):         return ("blog-detail", [self.slug,]) 

and in urls.py

    ...     url(r'/blog/(?P<slug>[-w]+)/$', blog.views.blog_detail, name="blog-detail")