notifications-admin/app/proxy_fix.py

from werkzeug.contrib.fixers import ProxyFix


class CustomProxyFix(object):
    def __init__(self, app, forwarded_proto):
        self.app = ProxyFix(app)
        self.forwarded_proto = forwarded_proto

    def __call__(self, environ, start_response):
        environ.update({
            "HTTP_X_FORWARDED_PROTO": self.forwarded_proto
        })
        return self.app(environ, start_response)


def init_app(app):
    app.wsgi_app = CustomProxyFix(app.wsgi_app, app.config.get('HTTP_PROTOCOL', 'http'))