from urllib import quote

class SSLRedirect(object):
    def __init__(self,app):
        self.app=app

    def __call__(self,environ,start_response):
        proto = environ.get('HTTP_X_FORWARDED_PROTO') or environ.get('wsgi.url_scheme', 'http')

        if proto=='https':
            return self.app(environ,start_response)

        else:
            url = 'https://'

            if environ.get('HTTP_HOST'):
                url += environ['HTTP_HOST']
            else:
                url += environ['SERVER_NAME']

            url += quote(environ.get('SCRIPT_NAME', ''))
            url += quote(environ.get('PATH_INFO', ''))
            if environ.get('QUERY_STRING'):
                url += '?' + environ['QUERY_STRING']

            status = "301 Moved Permanently"
            headers = [('Location',url),('Content-Length','0')]

            start_response(status,headers)

            return ['']