searxng/searx/flaskfix.py
Markus Heiser a0dd416e8a
[fix] use X-Forwarded-Proto header if the URL scheme is unknown (#5106)
The HTTP X-Forwarded-Proto (XFP) request header is a de-facto standard header
for identifying the protocol (HTTP or HTTPS) that a client used to connect to a
proxy or load balancer.[1]

In our documentation[2] we recommend to set the `X-Scheme` header. This header
is not required if the `server.base_url` is set correctly.[3]

If none of these URL scheme details exist, then the header X-Forwarded-Proto is
evaluated as a third alternative.

[1] https://developer.mozilla.org/en-US/docs/Web/HTTP/Reference/Headers/X-Forwarded-Proto
[2] https://docs.searxng.org/admin/installation-apache.html#apache-s-searxng-site
[3] https://docs.searxng.org/admin/settings/settings_server.html

Closes: https://github.com/searxng/searxng/issues/5105
2025-08-10 11:08:57 +02:00

76 lines
2.6 KiB
Python

# SPDX-License-Identifier: AGPL-3.0-or-later
# pylint: disable=missing-module-docstring
from urllib.parse import urlparse
from werkzeug.serving import WSGIRequestHandler
from searx import settings
class ReverseProxyPathFix:
'''Wrap the application in this middleware and configure the
front-end server to add these headers, to let you quietly bind
this to a URL other than / and to an HTTP scheme that is
different than what is used locally.
http://flask.pocoo.org/snippets/35/
In nginx:
location /myprefix {
proxy_pass http://127.0.0.1:8000;
proxy_set_header Host $host;
proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
proxy_set_header X-Scheme $scheme;
proxy_set_header X-Script-Name /myprefix;
}
:param wsgi_app: the WSGI application
'''
# pylint: disable=too-few-public-methods
def __init__(self, wsgi_app):
self.wsgi_app = wsgi_app
self.script_name = None
self.scheme = None
self.server = None
if settings['server']['base_url']:
# If base_url is specified, then these values from are given
# preference over any Flask's generics.
base_url = urlparse(settings['server']['base_url'])
self.script_name = base_url.path
if self.script_name.endswith('/'):
# remove trailing slash to avoid infinite redirect on the index
# see https://github.com/searx/searx/issues/2729
self.script_name = self.script_name[:-1]
self.scheme = base_url.scheme
self.server = base_url.netloc
def __call__(self, environ, start_response):
script_name = self.script_name or environ.get('HTTP_X_SCRIPT_NAME', '')
if script_name:
environ['SCRIPT_NAME'] = script_name
path_info = environ['PATH_INFO']
if path_info.startswith(script_name):
environ['PATH_INFO'] = path_info[len(script_name) :]
scheme = self.scheme or environ.get('HTTP_X_SCHEME') or environ.get('HTTP_X_FORWARDED_PROTO')
if scheme:
environ['wsgi.url_scheme'] = scheme
server = self.server or environ.get('HTTP_X_FORWARDED_HOST', '')
if server:
environ['HTTP_HOST'] = server
return self.wsgi_app(environ, start_response)
def patch_application(app):
# serve pages with HTTP/1.1
WSGIRequestHandler.protocol_version = "HTTP/{}".format(settings['server']['http_protocol_version'])
# patch app to handle non root url-s behind proxy
app.wsgi_app = ReverseProxyPathFix(app.wsgi_app)