safe_redirect.py

from urlparse import urlparse, urljoin
from flask import request, url_for, redirect

from myapp.app import app


def is_safe_url(target):
    ref_url = urlparse(request.host_url)
    test_url = urlparse(urljoin(request.host_url, target))

    if test_url.scheme == 'mobile':
        return True

    return (test_url.scheme in ('http', 'https') and
            ref_url.netloc == test_url.netloc)


def get_redirect_target():
    target = request.values.get('next')

    if target and is_safe_url(target):
        return target


def handle_redirect(target, endpoint=None, **values):
    if not target or not is_safe_url(target):
        if endpoint is None:
            endpoint = app.config.get('INDEX_VIEW')

        target = url_for(endpoint, **values)

    return redirect(target)


def redirect_back(endpoint=None, **values):
    return handle_redirect(request.args.get('next'), endpoint=endpoint, **values)