Sanic-CORS

A Sanic extension for handling Cross Origin Resource Sharing (CORS), making cross-origin AJAX possible. Based on flask-cors by Cory Dolphin.

This package has a simple philosophy, when you want to enable CORS, you wish to enable it for all use cases on a domain. This means no mucking around with different allowed headers, methods, etc. By default, submission of cookies across domains is disabled due to the security implications, please see the documentation for how to enable credential'ed requests, and please make sure you add some sort of CSRF protection before doing so!

Notice: Please upgrade to Sanic-CORS v0.10.0 if you need compatibility with Sanic v19.12+. See here for more details.

Installation

Install the extension with using pip, or easy_install.

$ pip install -U sanic-cors

Usage

This package exposes a Sanic extension which by default enables CORS support on all routes, for all origins and methods. It allows parameterization of all CORS headers on a per-resource level. The package also contains a decorator, for those who prefer this approach.

Simple Usage

In the simplest case, initialize the Sanic-Cors extension with default arguments in order to allow CORS for all domains on all routes.

from sanic import Sanic
from sanic.response import text
from sanic_cors import CORS, cross_origin

app = Sanic(__name__)
CORS(app)

@app.route("/", methods=['GET', 'OPTIONS'])
def hello_world(request):
  return text("Hello, cross-origin-world!")

Resource specific CORS

Alternatively, you can specify CORS options on a resource and origin level of granularity by passing a dictionary as the resources option, mapping paths to a set of options.

app = Sanic(__name__)
cors = CORS(app, resources={r"/api/*": {"origins": "*"}})

@app.route("/api/v1/users", methods=['GET', 'OPTIONS'])
def list_users(request):
  return text("user example")

Route specific CORS via decorator

This extension also exposes a simple decorator to decorate sanic routes with. Simply add @cross_origin(app) below a call to Sanic's @app.route(..) to allow CORS on a given route.

@app.route("/", methods=['GET', 'OPTIONS'])
@cross_origin(app)
def hello_world(request):
  return text("Hello, cross-origin-world!")

SPF Usage

Sanic-CORS uses Sanic-Plugins-Framework behind the scenes. That means you can use SPF to load the plugin for you if you are orchestrating and application with multiple SPF plugins.

from sanic import Sanic
from sanic.response import text
from spf import SanicPluginsFramework
from sanic_cors.extension import cors
app = Sanic(__name__)
spf = SanicPluginsFramework(app)
spf.register_plugin(cors, automatic_options=True)

@app.route("/", methods=['GET', 'OPTIONS'])
def hello_world(request):
  return text("Hello, cross-origin-world!")

Documentation

For a full list of options, please see the flask-cors documentation.

Preflight Requests

CORS requests have to send pre-flight requests via the options method, Sanic by default only allows the GET method, in order to service your CORS requests you must specify OPTIONS in the methods argument to your routes decorator.

Sanic-CORS includes an automatic_options configuration parameter to allow the plugin handle the OPTIONS response automatically for you. This is enabled by default, but you can turn it off if you wish to do your own OPTIONS response.

CORS(app, automatic_options=True)

@app.delete('/api/auth')
@auth.login_required
async def auth_logout(request):
auth.logout_user(request)
    return json(None, status=OK)

or with the app config key:

app = Sanic(__name__)
app.config['CORS_AUTOMATIC_OPTIONS'] = True

CORS(app)

@app.delete('/api/auth')
@auth.login_required
async def auth_logout(request):
    auth.logout_user(request)
    return json(None, status=OK)

or directly on the route with the cross_origin decorator:

@app.route('/api/auth', methods={'DELETE','OPTIONS'})
@auth.login_required
@cross_origin(app, automatic_options=True)
async def auth_logout(request):
    auth.logout_user(request)
    return json(None, status=OK)

Note: For the third example, you must use @route(), rather than @delete() because you need to enable both DELETE and OPTIONS to work on that route, even though the decorator is handling the OPTIONS response.

Troubleshooting

If things aren't working as you expect, enable logging to help understand what is going on under the hood, and why.

logging.getLogger('sanic_cors').level = logging.DEBUG

Tests

A simple set of tests is included in test/. To run, install nose, and simply invoke nosetests or python setup.py test to exercise the tests.

Contributing

Questions, comments or improvements? Please create an issue on Github. I do my best to include every contribution proposed in any way that I can.

Credits

This Sanic extension is based upon the Decorator for the HTTP Access Control written by Armin Ronacher.