django-restlayer 0.9.0

HTTP REST toolkit for Django

Introduction

Django Restlayer is a very simple to use toolkit to create RESTful APIs for your Django projects or apps.

Features

• Allows you to respect HTTP methods and headers within your application.

• Class based resources.

• Simple to code.

• Form validation in case you need it.

Installation

• For Django 1.4: pip install django-restlayer==0.8.5

• For Django 1.5+: pip install django-restlayer

Configuration

Django Restlayer doesn’t need any configuration nor any app in INSTALLED_APPS settings.

Simple example

urls.py:

from django.conf.urls import patterns, url

urlpatterns = patterns('',
    url(r'^$', 'myapp.resources.simple', name='simple'),
)

myapp/resources.py:

from restlayer import Resource, Response

# Our resource class
class SimpleResponse(Response):
    def response_get(self, request):
        return ['foo', 'bar']

# Resource (a callable object or a view if you prefer)
simple = Resource(SimpleResponse)

That’s it. Now, query your development server

curl -s -v -H "accept:application/json" http://localhost:8000/

> GET /api/ HTTP/1.1
> User-Agent: curl/7.33.0
> Host: localhost
> accept:application/json
>
< HTTP/1.1 200 OK
< Server: nginx/1.4.3
< Date: Thu, 28 Nov 2013 14:34:15 GMT
< Content-Type: application/json; charset=UTF-8
< Transfer-Encoding: chunked
< Connection: keep-alive
< Vary: Accept-Language, Cookie
< Content-Language: en
<
[
 "foo",
 "bar"
]

Usage

Response class

All your responses should inherit restlayer.Response class. Then, add methods named response_VERB where VERB is an HTTP verb. To handle GET responses, you need to create a response_get method, for POST, response_post. Each response_VERB method acts as a view with needed arguments. A basic example:

from restlayer import Response

class SimpleResponse(Response):
    def response_get(self, request, my_id):
        # This method will match a URL pattern with "my_id"
        return "foo"

Predefined response methods

There are two predefined response methods:

• response_options returns an empty 204 response with Allow header.

• response_head calls response_get if any and returns it without body.

Serializers

You can set serializers and deserializers properties. They set how data are going to be serialized (out) or unserialized (in). In this example, we add a silly serializer for text/plain:

class SimpleResponse(Response):
    serializers = Response.serializers + (
      ('text/plain', lambda x: return str(x))
    )

Well, that won’t work very well but you have the idea. serializers is a list of tuples of mime types and callables getting data as only parameter. deserializers is the same thing for accepted data types (callable takes request as only argument).

Default formats are:

• serializers

  • application/json

  • application/xml

  • application/python-pickle

• deserializers

  • application/x-www-form-urlencoded

  • multipart/form-data

  • application/json

Responses are valid HttpResponse objects

restlayer.Response instances are valid django.http.HttpResponse objects. Thus you can:

• Add any header you want to your response setting self['my-header'] before returning data;

• Change status code with self.status_code;

• Return self if you need to set a specific response content without using serializers.

Resource

Your response class should be wrapped within a restlayer.Resource class. The resulting instance is a callable acting like a classic view. You can extend this class to create your own resource. Simply override __call__ method.

from restlayer import Resource

class SillyResource(Resource):
    def __call__(self, request, *args, **kwargs):
        rsp = super(SillyResource, self).__call__(request, *args, **kwargs)
        rsp.status_code = 401
        rsp['Content-Type'] = 'text/plain'
        return rsp

Responses for Django models

If you are working with Django models, you can use restlayer.ModelResponse. Using this parent class for your responses, you can return model instance or queryset. Here is a simple example:

from django.contrib.auth.models import User
from restlayer import ModelResponse

class SimpleResponse(ModelResponse):
    fields = ('id', 'name', 'firstname', 'email')

    def response_get(self, request):
        return User.objects.all()

That’s it! Using the fields property, you set the fields you want to return in the response.

You can add custom methods to create a specific response field. This method takes two parameters: ìnstance and request. Example:

from django.contrib.auth.models import User
from restlayer import ModelResponse

class SimpleResponse(ModelResponse):
    fields = ('id', 'name', 'firstname', 'email', 'other_field')

    def other_field(self, instance, request):
        return instance.name.capitalize()

    def response_get(self, request):
        return User.objects.all()

URLs

You’ll often need to create a resource_uri field to point to another resource in your API. Response class provides two methods to create absolute (with FQDN) URLs:

• _build_absolute_uri(self, request, [location]) only calling request.build_absolute_uri(location) but you can override it if you need.

• reverse(self, request, view, [args, kwargs]) acts as django.core.urlresolvers.reverse but returns an absolute URL.

Pagination

You might want to paginate your responses. Restlayer Response class provides a simple method for this task: paginate(self, request, object_list, [limit]) which is a simple wrapper around django.core.paginator.Paginator. Resulting response will contain the following headers:

• X-Pages-Objects

• X-Pages-Count

• X-Pages-Current

• X-Pages-Next (if next page exists)

• X-Pages-Next-URI (if next page exists)

• X-Pages-Prev (if previous page exists)

• X-Pages-Prev-URI (if previous page exists)

Use the source

I admit this documentation is a bit rough. Don’t hesitate to read the source code, there’s no hidden rocket science, only some basic python code :)

License

Django Restlayer is released under the MIT license. See the LICENSE file for the complete license.