gistfile1.py

class AllowOriginMiddleware(object):
    """
      Sets 'Access-Control-Allow-Origin'
    """
    def __init__(self, app):
        self.app = app

    def __call__(self, environ, start_response):
        def custom_start_response(status, headers, exc_info = None):
            origin_header   = ["Access-Control-Allow-Origin", "*"]
            req_with_header = ["Access-Control-Allow-Headers", "X-Requested-With"]
            headers.append(origin_header)
            headers.append(req_with_header)
            return start_response(status, headers, exc_info)
        return self.app(environ, custom_start_response)