app/django/middleware/gzip.py
author Todd Larsen <tlarsen@google.com>
Wed, 21 Jan 2009 00:27:39 +0000
changeset 858 e79e7a22326f
parent 54 03e267d67478
permissions -rw-r--r--
Add an export() view, and implement it as text/text for Document. For every Model except Document, the public() view is displayed for any attempts to access the export() view. Currently, the permissions for export() are the same as for public(). This seems reasonable for Document, since anyone could extract the raw HTML from the page source anyway. The permissions should probably be different for other types of exports, such as vCard or iCard exports of profiles, CSV exports of lists, etc. Patch by: Todd Larsen Review by: to-be-reviewed

import re

from django.utils.text import compress_string
from django.utils.cache import patch_vary_headers

re_accepts_gzip = re.compile(r'\bgzip\b')

class GZipMiddleware(object):
    """
    This middleware compresses content if the browser allows gzip compression.
    It sets the Vary header accordingly, so that caches will base their storage
    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:
            return response

        patch_vary_headers(response, ('Accept-Encoding',))

        # Avoid gzipping if we've already got a content-encoding.
        if response.has_header('Content-Encoding'):
            return response

        # Older versions of IE have issues with gzipped pages containing either
        # Javascript and PDF.
        if "msie" in request.META.get('HTTP_USER_AGENT', '').lower():
            ctype = response.get('Content-Type', '').lower()
            if "javascript" in ctype or ctype == "application/pdf":
                return response

        ae = request.META.get('HTTP_ACCEPT_ENCODING', '')
        if not re_accepts_gzip.search(ae):
            return response

        response.content = compress_string(response.content)
        response['Content-Encoding'] = 'gzip'
        response['Content-Length'] = str(len(response.content))
        return response