Secure:always view method decorator for Google App Engine - workaround for issue 7979

secure_view_method.py

import os
import logging
from functools import update_wrapper

def secure(view_method):
    """Decorates view/handler method to redirect to https if requested over http.

    Equivalent to handler setting secure:always in app.yaml.

    Provided as a workaround for App Engine issue 7979.

    Does not decorate the view method if used on a local SDK development server.

    References:

    * https://developers.google.com/appengine/docs/python/config/appconfig#Secure_URLs
    * https://code.google.com/p/googleappengine/issues/detail?id=7979
    * https://groups.google.com/d/topic/google-appengine/w3aKx9KxYoU/discussion
    * http://stackoverflow.com/questions/13064081/how-to-get-major-appengine-issues-fixed

    """
    if os.environ.get('SERVER_SOFTWARE', 'Dev').startswith('Dev'):
        return view_method

    def secure_view_method(view, *args, **kwargs):
        if view.request.scheme == 'http':
            secure_url = view.request.url.replace('http://', 'https://', 1)
            logging.info(u'redirecting to {url}'. format(url=secure_url))
            view.redirect(secure_url, permanent=True)
        else:
            view_method(view, *args, **kwargs)

    update_wrapper(secure_view_method, view_method)
    return secure_view_method