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# -*- encoding: utf-8 -*-
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or
# implied. See the License for the specific language governing permissions and
# limitations under the License.
from oslo_config import cfg
from oslo_middleware import base
OPTS = [
cfg.BoolOpt('enable_proxy_headers_parsing',
default=False,
help="Whether the application is behind a proxy or not. "
"This determines if the middleware should parse the "
"headers or not.")
]
class HTTPProxyToWSGI(base.ConfigurableMiddleware):
"""HTTP proxy to WSGI termination middleware.
This middleware overloads WSGI environment variables with the one provided
by the remote HTTP reverse proxy.
"""
def __init__(self, application, *args, **kwargs):
super(HTTPProxyToWSGI, self).__init__(application, *args, **kwargs)
self.oslo_conf.register_opts(OPTS, group='oslo_middleware')
@staticmethod
def _parse_rfc7239_header(header):
"""Parses RFC7239 Forward headers.
e.g. for=192.0.2.60;proto=http, for=192.0.2.60;by=203.0.113.43
"""
result = []
for proxy in header.split(","):
entry = {}
for d in proxy.split(";"):
key, _, value = d.partition("=")
entry[key.lower().strip()] = value.strip()
result.append(entry)
return result
def process_request(self, req):
if not self._conf_get('enable_proxy_headers_parsing'):
return
fwd_hdr = req.environ.get("HTTP_FORWARDED")
if fwd_hdr:
proxies = self._parse_rfc7239_header(fwd_hdr)
# Let's use the value from the first proxy
if proxies:
proxy = proxies[0]
forwarded_proto = proxy.get("proto")
if forwarded_proto:
req.environ['wsgi.url_scheme'] = forwarded_proto
forwarded_host = proxy.get("host")
if forwarded_host:
req.environ['HTTP_HOST'] = forwarded_host
forwarded_for = proxy.get("for")
if forwarded_for:
req.environ['REMOTE_ADDR'] = forwarded_for
else:
# World before RFC7239
forwarded_proto = req.environ.get("HTTP_X_FORWARDED_PROTO")
if forwarded_proto:
req.environ['wsgi.url_scheme'] = forwarded_proto
forwarded_host = req.environ.get("HTTP_X_FORWARDED_HOST")
if forwarded_host:
req.environ['HTTP_HOST'] = forwarded_host
forwarded_for = req.environ.get("HTTP_X_FORWARDED_FOR")
if forwarded_for:
req.environ['REMOTE_ADDR'] = forwarded_for
v = req.environ.get("HTTP_X_FORWARDED_PREFIX")
if v:
req.environ['SCRIPT_NAME'] = v + req.environ['SCRIPT_NAME']
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