How to add CORS support to a Flask app in 9 lines of code

flask_cors.py

def add_cors_headers(response):
    response.headers['Access-Control-Allow-Origin'] = '*'
    if request.method == 'OPTIONS':
        response.headers['Access-Control-Allow-Methods'] = 'DELETE, GET, POST, PUT'
        headers = request.headers.get('Access-Control-Request-Headers')
        if headers:
            response.headers['Access-Control-Allow-Headers'] = headers
    return response
app.after_request(add_cors_headers)

can you please explain what is that request is having?

can some one tell me what does that request does?

It adds CORS headers in every response

Great for me. Now I don't need to add "Flask-CORS" package. Thanks.