A Flask extension for handling Cross Origin Resource Sharing (CORS), making cross-origin AJAX possible.

Install the extension with using pip, or easy_install.

$ pip install -U flask-cors

This extension enables CORS support either via a decorator, or a Flask extension. There are three examples shown in the examples directory, showing the major use cases. The suggested configuration is the simple_example.py, or the app_example.py. A full list of options can be found in the documentation.

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 CRSF protection before doing so!

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

app = Flask(__name__)
cors = CORS(app)

@app.route("/")
def helloWorld():
  return "Hello, cross-origin-world!"

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

@app.route("/api/v1/users")
def list_users():
  return "user example"

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

@app.route("/")
@cross_origin()
def helloWorld():
  return "Hello, cross-origin-world!"

Flask-Cors uses standard Python logging, using the logger name 'app.logger_name.cors'. The app's logger name attribute is usually the same as the name of the app. You can read more about logging from Flask's documentation.

import logging
# make your awesome app
logging.basicConfig(level=logging.INFO)

For a full list of options, please see the full documentation

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.

Questions, comments or improvements? Please create an issue on Github, tweet at @corydolphin or send me an email. I do my best to include every contribution proposed in any way that I can.

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