An extension of TastyPie's ModelResource to easily support nested resources, and more.
The ExtendedModelResource is an extension for TastyPie’s ModelResource that adds some interesting features:
- Supports easily using resources as nested of another resource, with proper authorization checks for each case.
- [This feature has already been included in the official TastyPie] Supports using a custom identifier attribute for resources in uris (not only the object’s pk!)
- Latest django-tastypie from repository (0.9.12-alpha or hopefully greater) and its requirements.
- Django 1.4.1 for the sample project.
Clone repository and do:
python setup.py install
Or just do
pip install django-tastypie-extendedmodelresource
to get the latest version from pypi.
Here we explain what we mean by nested resources and what a simple use case would be.
Imagine you have a simple application which has users, each of which can write any number of entries. Every entry is associated to a user. For example
from django.contrib.auth.models import User from django.db import models class Entry(models.Model): user = models.ForeignKey(User, related_name='entries') # ... more fields
The ‘standard’ TastyPie models for this would be
from django.contrib.auth.models import User from tastypie.resources import ModelResource from myapp.models import Entry class UserResource(ModelResource): class Meta: queryset = User.objects.all() class EntryResource(ModelResource): class Meta: queryset = Entry.objects.all()
This gives you full CRUD ability over users and entries, with uris such as /api/user/ and /api/entry/.
Now imagine you want to be able to easily list all the entries authored by a given user, with a uri such as /api/user/<pk>/entries. Additionally, you would like to be able to POST to this uri and create an entry automatically associated to this user. This is why nested resources are for.
If a resource such as the EntryResource is to be accessed as /api/user/<pk>/<something> where <something> is custom-defined (for example entries), then we say the EntryResource is being used as nested of the UserResource. We also say that UserResource is the parent of EntryResource.
The standard TastyPie’s ModelResource would force you to write a function overriding the urls of the UserResource and adding a method to handle the entry resource (see Nested Resources). Using ExtendedModelResource it is as easy as
from django.contrib.auth.models import User from tastypie import fields from extendedmodelresource import ExtendedModelResource from myapp.models import Entry class UserResource(ExtendedModelResource): class Meta: queryset = User.objects.all() class Nested: entries = fields.ToManyField('api.resources.EntryResource', 'entries') class EntryResource(ExtendedModelResource): user = fields.ForeignKey(UserResource, 'user') class Meta: queryset = Entry.objects.all()
And that’s it!
- ExtendedModelResource only supports one level nesting.
- Resources used as nested can also be registered in an Api instance, but need not to. That is, there can be resources used only as nested and not exposed otherwise in the urls.
Changing object’s identifier attribute in urls
Using the latest TastyPie you can define a detail_uri_name attribute in the Meta class, to use a different attribute than the object’s pk
class UserResource(ExtendedModelResource): class Meta: queryset = User.objects.all() detail_uri_name = 'username'
With ExtendedModelResource you can change the regular expression used for your identifier attribute in the urls, you can override the method get_url_id_attribute_regex and return it, like the following example
def get_detail_uri_name_regex(self): return r'[aA-zZ][\w-]*'