django-sliver

Lightweight REST API for Django built on top of generic views

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Why django-sliver?

Sliver was designed for sites that just need a simple API for their front-end (backbone, etc), without all the bells and whistles (and headaches :) of a solution like django-tastypie.

Some things to note:

• It's built on top of Django's generic views, so a lot of the methods you are used to overriding are here.
• It only works with Django's ORM, and there are no plans to expand on that.
• It provides no authentication/authorization systems, instead relying on whatever auth backend you have to do the heavy lifting.
• Like the generic views, it relies heavily on mixins to provide additional functionality.

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Requirements

There are no dependencies beyond having Django >= 1.11

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Installation

pip install -e git+git@github.com:jarcoal/django-sliver.git#egg=django-sliver

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What's it look like?

views.py

# sliver objects
from sliver.views import ModelResource, CollectionResource
from sliver.mixins import JSONMixin

# your data
from products.models import Product


class ProductCollectionResource(JSONMixin, CollectionResource):
	model = Product

class ProductResource(JSONMixin, ModelResource):
	model = Product

urls.py:

from django.conf.urls import patterns, url
from views import ProductCollectionResource, ProductResource

urlpatterns = patterns('',
	url(r'^products/$', ProductCollectionResource.as_view(), name='api-products-collection'),
	url(r'^products/(?P<pk>\d+)/$', ProductResource.as_view(), name='api-products-model'),
)

That's all you need for a basic JSON API.

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Views

There are two main views that will be important to you. Remember, they both inherit from Django's View class, so you can override dispatch(), get(), post(), etc, whenever you want.

sliver.views.ModelResource

ModelResource is designed to handle requests relating to a single model object. It's mixed with Django's SingleObjectMixin, so methods like get_object() and get_queryset() can easily be overrided.

sliver.views.CollectionResource

CollectionResource is designed to handle requests relating to a collection of model objects. Similar to ModelResource, it mixes with Django's MultipleObjectMixin, so those methods are available.

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Limiting incoming/outgoing fields

Handling which fields are shown / updateable is just like using Django's form views. Continuing our example:

class ProductCollectionResource(JSONMixin, CollectionResource):
	#this will limit the output to these three fields.  it will restrict updates to just them as well.
	fields = ['id', 'name', 'description']

	#like form views, exclude also works
	exclude = ['secret_key']

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Serializing / Deserializing

Serializing is really up to you; the bare resources don't implement anything in particular. There is a JSONMixin provided that you can add to your resource that will aide in parsing/rendering your resource in JSON.

When a request comes in, the parse() method on your resource will be called with request.body passed to it. Here is an example for JSON:

def parse(self, raw_data):
	return json.loads(raw_data)

NOTE: If request.body isn't all you need to parse a request, remember this is just a generic view, the request object is available at self.request.

When a response is ready to go out, the render() method is called on your resource. Again, a JSON example:

def render(self, data):
	return json.dumps(data)

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Filtering

Filtering can easily be applied by overriding get_queryset() and applying your own logic. However, if you need a simple solution, you can add the FiltersMixin to your resource (usually on collection). Continuing our basic example from above:

from sliver.mixins import FiltersMixin

class ProductCollectionResource(FiltersMixin, JSONMixin, CollectionResource):
	filters = ['name__contains', 'date_added__gt']

All filters must be specified in the filters attribute, otherwise they are ignored.

If you need more advanced filtering, you can override get_filters() which should return a dictionary of filters that will be applied to the queryset. You can go one step further than that by overriding the get_queryset() method and doing exactly what you want with the queryset.

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Relationships

Relationships are always a trick in APIs, so I've tried to make them as simple as possible. Both to-one and to-many relationships are possible. Example:

class ProductResource(JSONMixin, CollectionResource):
	model = Product

	relationships = {
		'vendor': {},			#to-one
		'feature_set': {}		#to-many
	}

If you need to exclude some fields from your related models, that can easily be done:

relationships = {
	'vendor': {
		'exclude': ['private_notes']
	},
	'feature_set': {
		'fields': ['id', 'name']
	}
}

Deeper relationships are denoted by double underscores:

relationships = {
	'vendor': {},
	'vendor__parent_company': {}
}

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URIs

By default, the resources will not insert any URIs into the responses. For many, this is fine, but not all. Sliver ships with a URIMixin that provides this functionality. Example:

class ProductCollectionResource(URIMixin, JSONMixin, CollectionResource):
	#this should be the 'name' parameter you used in your URL patterns
	model_resource_name = 'api-product-model'

	#this is the name of the attribute you want serialized into your responses
	uri_attribute_name = '_uri'

This is nice, but it won't insert URIs into related objects. This will:

relationships = {
	'vendor': {
		'model_resource_name': 'api-vendor-model'
	}
}