grue / django-api

Django API

django_api lets you specify and validate your Django APIs in a single block of code.

It does this with an @api decorator that wraps Django views. This keeps the API documentation consistent, localized and declarative.

from django import forms
from django_api.decorators import api
from django_api.json_helpers import JsonResponse
from django_api.json_helpers import JsonResponseForbidden


@api({
    'accepts': {
        'x': forms.IntegerField(min_value=0),
        'y': forms.IntegerField(max_value=10),
    },
    'returns': {
        200: 'Addition successful',
    }
})
def add(request, *args, **kwargs):
    # `x` and `y` have been validated, and are integers
    # so we can safely perform arithmetic operations on them
    return JsonResponse({
        'sum': request.GET['x'] + request.GET['y']
    })

Based on the above example, the following API responses are automatically available (assuming you wire up the /add route to the view above:

GET /add

"failed to validate: {'y': [u'This field is required.'], 'x': [u'This field is required.']}"


GET /add?x=10

"failed to validate: {'y': [u'This field is required.']}"


GET /add?x=10&y=100

"failed to validate: {'y': [u'Ensure this value is less than or equal to 10.']}"


GET /add?x=10&y=10

{sum: 20}

Dependencies

None

Installation

To use django_api in your Django project it needs to be accessible by your Python installation:

$ pip install django-api

(or simply place the django_api directory in your $PYTHON_PATH)

Django Setup

Add django_api to INSTALLED_APPS in your project's settings.py.

Example:

INSTALLED_APPS = (
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.sites',
    'django.contrib.admin',
    'django_api',
)

Usage

Specify your API by using the @api decorator. The @api decorator takes a dictionary with two keys: accepts and returns.

from django_api.decorators import api
@api({
    'accepts': {
    },
    'returns': {
    }
})
def add(request, *args, **kwargs):

accepts

Describe the query parameters your API accepts by listing them out in the accepts dictionary. Each entry in the accepts section maps a name to a Django form field type. Received query parameters are automatically converted to the specified type. If the parameter does not conform to the specification the query fails to validate (see below). Once validated, the variables will be placed in the request dictionary for use within the view.

'accepts': {
    'x': forms.IntegerField(min_value=0),
    'y': forms.IntegerField(max_value=10, required=False),
    'u': User(),
}

Since each parameter is specified using a Django form field, any argument that its class constructor takes can be used. Examples include

• required
• initial
• max_length for CharField
• min_value for IntegerField

For a full reference, please see here.

returns

By default, the @api decorator checks that the returned response is of JSON type.

Specify the valid returned HTTP codes by listing them out in the returns dictionary. Each entry in the dictionary maps a HTTP response code to a helpful message, explaining the outcome of the action. The helpful message is for documentation purposes only. If the response does not conform to the specification, the query will fail to validate (see below).

'returns': {
    200: 'Addition successful',
    403: 'User does not have permission',
    404: 'Resource not found',
    404: 'User not found',
}

Validation

If validation fails, a HTTP 400 - Bad request is returned to the client. For safety, django_api will perform validation only if settings.DEBUG = True. This ensures that production code always remains unaffected.

Testing

Run the tests with the folllowing command

python manage.py test django_api

Advanced usage

Django Models

@accepts can be used to also accept your Django models through the object's id. For a Model Model, Django expects the query parameter to be name model-id.

'accepts': {
    'x': forms.IntegerField(min_value=0),
    'y': forms.IntegerField(max_value=10, required=False),
    'u': User(),
}

You can also simply choose to validate either only the parameters the API accepts, or the return values of the API.

Example:

from django import forms
from django_api.decorators import api_accepts
from django_api.json_helpers import JsonResponse
from django_api.json_helpers import JsonResponseForbidden


@api_accepts({
    'x': forms.IntegerField(min_value=0),
    'y': forms.IntegerField(min_value=0),
})
def add(request, *args, **kwargs):
    return JsonResponse({
        'sum': request.GET['x'] + request.GET['y']
    })




from django import forms
from django_api.decorators import api_returns
from django_api.json_helpers import JsonResponse
from django_api.json_helpers import JsonResponseForbidden


@api_returns({
    200: 'Operation successful',
    403: 'User does not have permission',
    404: 'Resource not found',
    404: 'User not found',
})
def add(request, *args, **kwargs):
    return JsonResponse({
        'sum': request.GET['x'] + request.GET['y']
    })