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Fixed #10762, #17514 -- Prevented the GZip middleware from returning …

…a response longer than the original content, allowed compression of non-200 responses, and added tests (there were none). Thanks cannona for the initial patch.

git-svn-id: http://code.djangoproject.com/svn/django/trunk@17365 bcc190cf-cafb-0310-a4f2-bffc1f526a37
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commit 4288c8831bde86f1be581d65c13e2f878a02c7ff 1 parent 62766f4
@aaugustin aaugustin authored
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11 django/middleware/gzip.py
@@ -12,8 +12,8 @@ class GZipMiddleware(object):
on the Accept-Encoding header.
"""
def process_response(self, request, response):
- # It's not worth compressing non-OK or really short responses.
- if response.status_code != 200 or len(response.content) < 200:
+ # It's not worth attempting to compress really short responses.
+ if len(response.content) < 200:
return response
patch_vary_headers(response, ('Accept-Encoding',))
@@ -32,7 +32,12 @@ def process_response(self, request, response):
if not re_accepts_gzip.search(ae):
return response
- response.content = compress_string(response.content)
+ # Return the compressed content only if it's actually shorter.
+ compressed_content = compress_string(response.content)
+ if len(compressed_content) >= len(response.content):
+ return response
+
+ response.content = compressed_content
response['Content-Encoding'] = 'gzip'
response['Content-Length'] = str(len(response.content))
return response
View
21 docs/ref/middleware.txt
@@ -82,22 +82,29 @@ addresses defined in the :setting:`INTERNAL_IPS` setting. This is used by
Django's :doc:`automatic documentation system </ref/contrib/admin/admindocs>`.
Depends on :class:`~django.contrib.auth.middleware.AuthenticationMiddleware`.
-GZIP middleware
+GZip middleware
---------------
.. module:: django.middleware.gzip
- :synopsis: Middleware to serve gziped content for performance.
+ :synopsis: Middleware to serve GZipped content for performance.
.. class:: GZipMiddleware
-Compresses content for browsers that understand gzip compression (all modern
+Compresses content for browsers that understand GZip compression (all modern
browsers).
It is suggested to place this first in the middleware list, so that the
-compression of the response content is the last thing that happens. Will not
-compress content bodies less than 200 bytes long, when the response code is
-something other than 200, JavaScript files (for IE compatibility), or
-responses that have the ``Content-Encoding`` header already specified.
+compression of the response content is the last thing that happens.
+
+It will not compress content bodies less than 200 bytes long, when the
+``Content-Encoding`` header is already set, or when the browser does not send
+an ``Accept-Encoding`` header containing ``gzip``.
+
+Content will also not be compressed when the browser is Internet Explorer and
+the ``Content-Type`` header contains ``javascript`` or starts with anything
+other than ``text/``. This is done to overcome a bug present in early versions
+of Internet Explorer which caused decompression not to be performed on certain
+content types.
GZip compression can be applied to individual views using the
:func:`~django.views.decorators.http.gzip_page()` decorator.
View
87 tests/regressiontests/middleware/tests.py
@@ -1,6 +1,9 @@
# -*- coding: utf-8 -*-
+import gzip
import re
+import random
+import StringIO
from django.conf import settings
from django.core import mail
@@ -9,6 +12,7 @@
from django.middleware.clickjacking import XFrameOptionsMiddleware
from django.middleware.common import CommonMiddleware
from django.middleware.http import ConditionalGetMiddleware
+from django.middleware.gzip import GZipMiddleware
from django.test import TestCase
@@ -495,3 +499,86 @@ def get_xframe_options_value(self, request, response):
r = OtherXFrameOptionsMiddleware().process_response(HttpRequest(),
HttpResponse())
self.assertEqual(r['X-Frame-Options'], 'DENY')
+
+
+class GZipMiddlewareTest(TestCase):
+ """
+ Tests the GZip middleware.
+ """
+ short_string = "This string is too short to be worth compressing."
+ compressible_string = 'a' * 500
+ uncompressible_string = ''.join(chr(random.randint(0, 255)) for _ in xrange(500))
+
+ def setUp(self):
+ self.req = HttpRequest()
+ self.req.META = {
+ 'SERVER_NAME': 'testserver',
+ 'SERVER_PORT': 80,
+ }
+ self.req.path = self.req.path_info = "/"
+ self.req.META['HTTP_ACCEPT_ENCODING'] = 'gzip, deflate'
+ self.req.META['HTTP_USER_AGENT'] = 'Mozilla/5.0 (Windows NT 5.1; rv:9.0.1) Gecko/20100101 Firefox/9.0.1'
+ self.resp = HttpResponse()
+ self.resp.status_code = 200
+ self.resp.content = self.compressible_string
+ self.resp['Content-Type'] = 'text/html; charset=UTF-8'
+
+ @staticmethod
+ def decompress(gzipped_string):
+ return gzip.GzipFile(mode='rb', fileobj=StringIO.StringIO(gzipped_string)).read()
+
+ def test_compress_response(self):
+ """
+ Tests that compression is performed on responses with compressible content.
+ """
+ r = GZipMiddleware().process_response(self.req, self.resp)
+ self.assertEqual(self.decompress(r.content), self.compressible_string)
+ self.assertEqual(r.get('Content-Encoding'), 'gzip')
+ self.assertEqual(r.get('Content-Length'), str(len(r.content)))
+
+ def test_compress_non_200_response(self):
+ """
+ Tests that compression is performed on responses with a status other than 200.
+ See #10762.
+ """
+ self.resp.status_code = 404
+ r = GZipMiddleware().process_response(self.req, self.resp)
+ self.assertEqual(self.decompress(r.content), self.compressible_string)
+ self.assertEqual(r.get('Content-Encoding'), 'gzip')
+
+ def test_no_compress_short_response(self):
+ """
+ Tests that compression isn't performed on responses with short content.
+ """
+ self.resp.content = self.short_string
+ r = GZipMiddleware().process_response(self.req, self.resp)
+ self.assertEqual(r.content, self.short_string)
+ self.assertEqual(r.get('Content-Encoding'), None)
+
+ def test_no_compress_compressed_response(self):
+ """
+ Tests that compression isn't performed on responses that are already compressed.
+ """
+ self.resp['Content-Encoding'] = 'deflate'
+ r = GZipMiddleware().process_response(self.req, self.resp)
+ self.assertEqual(r.content, self.compressible_string)
+ self.assertEqual(r.get('Content-Encoding'), 'deflate')
+
+ def test_no_compress_ie_js_requests(self):
+ """
+ Tests that compression isn't performed on JavaScript requests from Internet Explorer.
+ """
+ self.req.META['HTTP_USER_AGENT'] = 'Mozilla/4.0 (compatible; MSIE 5.00; Windows 98)'
+ self.resp['Content-Type'] = 'application/javascript; charset=UTF-8'
+ r = GZipMiddleware().process_response(self.req, self.resp)
+ self.assertEqual(r.content, self.compressible_string)
+ self.assertEqual(r.get('Content-Encoding'), None)
+
+ def test_no_compress_uncompressible_response(self):
+ """
+ Tests that compression isn't performed on responses with uncompressible content.
+ """
+ self.resp.content = self.uncompressible_string
+ r = GZipMiddleware().process_response(self.req, self.resp)
+ self.assertEqual(r.content, self.uncompressible_string)
+ self.assertEqual(r.get('Content-Encoding'), None)
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