Source code for glance.api.middleware.gzip
# Copyright 2013 Red Hat, Inc.
# All Rights Reserved.
#
# 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.
"""
Use gzip compression if the client accepts it.
"""
import re
from oslo_log import log as logging
from glance.common import wsgi
from glance.i18n import _LI
LOG = logging.getLogger(__name__)
[docs]
class GzipMiddleware(wsgi.Middleware):
re_zip = re.compile(r'\bgzip\b')
def __init__(self, app):
LOG.info(_LI("Initialized gzip middleware"))
super(GzipMiddleware, self).__init__(app)
[docs]
def process_response(self, response):
request = response.request
accept_encoding = request.headers.get('Accept-Encoding', '')
if self.re_zip.search(accept_encoding):
# NOTE(flaper87): Webob removes the content-md5 when
# app_iter is called. We'll keep it and reset it later
checksum = response.headers.get("Content-MD5")
# NOTE(flaper87): We'll use lazy for images so
# that they can be compressed without reading
# the whole content in memory. Notice that using
# lazy will set response's content-length to 0.
content_type = response.headers.get("Content-Type", "")
lazy = content_type == "application/octet-stream"
# NOTE(flaper87): Webob takes care of the compression
# process, it will replace the body either with a
# compressed body or a generator - used for lazy com
# pression - depending on the lazy value.
#
# Webob itself will set the Content-Encoding header.
response.encode_content(lazy=lazy)
if checksum:
response.headers['Content-MD5'] = checksum
return response