app/django/middleware/gzip.py
author Lennard de Rijk <ljvderijk@gmail.com>
Sat, 21 Feb 2009 10:53:52 +0000
changeset 1421 7602d41f0ed8
parent 54 03e267d67478
permissions -rw-r--r--
Made some changes to StudentProposal. Abstract is now required and content field has been added. New is now the default status. This will be used to easily distinguish between applications that didn't have their initial ranking/scoring yet. Patch by: Lennard de Rijk Reviewed 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