Serving gzipped content from django

user_6812 0
Viewed 34997

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:

  • I realize this is not a best practice and I'm most likely going to use mod_gzip. This is just a learning exercise to understand what's going on.
  • I know about the Django gzip middleware-- it has problems with binary files.

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.

gzip django http
6 Answers

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!

user_722470

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).

user_2266480
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