CODEWITHSUNDEEP
djangohttpgzip
pjbeardsley
pjbeardsley

Reputation: 1531

Serving gzipped content from django

I'm trying to serve a gzipped version of a text/html page in Django, but Firefox is telling me there's a content encoding error.

NOTES:

Here's my code:

rendered_page =  zlib.compress(template.render(context).encode('utf-8'))

response = HttpResponse(rendered_page)
response['Content-Encoding'] = 'gzip'
response['Content-Length'] = len(rendered_page)
return response

Am I missing something here? Is it possible that the content length is wrong? Are there additional headers I'm missing?

Thanks.

Upvotes: 50

Views: 43001

Answers (6)

Andres
Andres

Reputation: 2900

You could also simply use Django's GZip Middleware:

Either by enabling the middleware in settings.py by adding:

MIDDLEWARE_CLASSES = (
    "django.middleware.gzip.GZipMiddleware",
    ...
)

Or do it before you return a particular response. In your views.py, dec would be the handler for a certain url

from django.middleware.gzip import GZipMiddleware

gzip_middleware = GZipMiddleware()

 def dec(request, *args, **kwargs):
        response = func(request, *args, **kwargs)
        return gzip_middleware.process_response(request, response)
        return dec

NOTE: You should be certain you are not subject to side-channel attacks before using GZip middleware.

Warning

Security researchers recently revealed that when compression techniques (including GZipMiddleware) are used on a website, the site may become exposed to a number of possible attacks. Before using GZipMiddleware on your site, you should consider very carefully whether you are subject to these attacks. If you’re in any doubt about whether you’re affected, you should avoid using GZipMiddleware. For more details, see the the BREACH paper (PDF) and breachattack.com.

Also:

Changed in Django 1.10: In older versions, Django’s CSRF protection mechanism was vulnerable to BREACH attacks when compression was used. This is no longer the case, but you should still take care not to compromise your own secrets this way.

Upvotes: 98

el.pescado - нет войне
el.pescado - нет войне

Reputation: 19214

If you compress your data with zlib, you have to set Content-Encoding to deflate, not gzip.

rendered_page =  zlib.compress(template.render(context).encode('utf-8'))

response = HttpResponse(rendered_page)
response['Content-Encoding'] = 'deflate'
response['Content-Length'] = len(rendered_page)
return response

Content-Encoding

(...)

deflate

Using the zlib structure (defined in RFC 1950) with the deflate compression algorithm (defined in RFC 1951).

Upvotes: 1

Kritz
Kritz

Reputation: 7301

If you need it for a single page and you are using class based views, use this:

gzip_middleware = GZipMiddleware()

class GZipMixin(object):

    def dispatch(self, request, *args, **kwargs):
        response = super(GZipMixin, self).dispatch(request, *args, **kwargs)
        return gzip_middleware.process_response(request, response)

Then in your actual view:

class MyView(GZipMixin, View):
    def get(self, request, *args, **kwargs):
         #return your response

Upvotes: 1

aero
aero

Reputation: 1724

For the sake of others finding this question and who are using nginx, this SO worked for me:

https://stackoverflow.com/a/41820704/4533488

Basically turning gzip on in the /etc/nginx/nginx.conf file did all the compression handling for me. On the client-side, most modern browsers automatically handle extracting (uncompressing) the data when receiving it - sweet!

Here is the nginx.conf file settings:

    http {

        #... other settings ...#

        ##
        # Gzip Settings
        ##

        gzip on;
        gzip_disable "msie6";

        gzip_vary on;
        gzip_proxied any;
        gzip_comp_level 6;
        gzip_buffers 16 8k;
        gzip_http_version 1.1;
        gzip_types text/plain text/css application/json application/x-javascript text/xml application/xml application/xml+rss text/javascript;
    }

Upvotes: 2

feifan.overflow
feifan.overflow

Reputation: 565

If you're gzipping single page, not for all pages, you can use gzip_page decorator instead of GzipMiddleware.

from django.views.decorators.gzip import gzip_page

@gzip_page
def viewFunc(request):
  return HttpResponse("hello"*100)

Reference here: https://docs.djangoproject.com/en/1.4/topics/http/decorators/#module-django.views.decorators.gzip

Upvotes: 30

Jarret Hardie
Jarret Hardie

Reputation: 97912

zlib is a bit too low-level for this purpose. Here's how the GZip middleware itself does it (see compress_string in django.utils.text.py):

import cStringIO, gzip
zbuf = cStringIO.StringIO()
zfile = gzip.GzipFile(mode='wb', compresslevel=6, fileobj=zbuf)
zfile.write(template.render(context).encode('utf-8'))
zfile.close()

compressed_content = zbuf.getvalue()
response = HttpResponse(compressed_content)
response['Content-Encoding'] = 'gzip'
response['Content-Length'] = str(len(compressed_content))
return response

GZip uses zlib, but on its own zlib produces content that's improperly encoded for a browser seeing 'gzip' as the content encoding. Hope that helps!

Upvotes: 27

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