calibre-web/cps/redirect.py

# -*- coding: utf-8 -*-

# Flask License
#
# Copyright © 2010 by the Pallets team.
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# Some rights reserved.

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# documentation, with or without modification, are permitted provided that the
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# and the following disclaimer.
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# https://web.archive.org/web/20120517003641/http://flask.pocoo.org/snippets/62/

from urllib.parse import urlparse, urljoin

from flask import request, url_for, redirect, current_app


def is_safe_url(target):
    ref_url = urlparse(request.host_url)
    test_url = urlparse(urljoin(request.host_url, target))
    return test_url.scheme in ('http', 'https') and ref_url.netloc == test_url.netloc


def remove_prefix(text, prefix):
    if text.startswith(prefix):
        return text[len(prefix):]
    return ""


def redirect_back(endpoint, **values):
    target = request.form.get('next', None) or url_for(endpoint, **values)
    adapter = current_app.url_map.bind(urlparse(request.host_url).netloc)
    if not len(adapter.allowed_methods(remove_prefix(target, request.environ.get('HTTP_X_SCRIPT_NAME',"")))):
        target = url_for(endpoint, **values)
    return redirect(target)