53 lines
2.1 KiB
Python
53 lines
2.1 KiB
Python
import re
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from django.utils.text import compress_sequence, compress_string
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from django.utils.cache import patch_vary_headers
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re_accepts_gzip = re.compile(r'\bgzip\b')
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class GZipMiddleware(object):
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"""
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This middleware compresses content if the browser allows gzip compression.
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It sets the Vary header accordingly, so that caches will base their storage
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on the Accept-Encoding header.
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"""
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def process_response(self, request, response):
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# It's not worth attempting to compress really short responses.
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if not response.streaming and len(response.content) < 200:
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return response
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patch_vary_headers(response, ('Accept-Encoding',))
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# Avoid gzipping if we've already got a content-encoding.
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if response.has_header('Content-Encoding'):
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return response
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# MSIE have issues with gzipped response of various content types.
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if "msie" in request.META.get('HTTP_USER_AGENT', '').lower():
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ctype = response.get('Content-Type', '').lower()
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if not ctype.startswith("text/") or "javascript" in ctype:
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return response
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ae = request.META.get('HTTP_ACCEPT_ENCODING', '')
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if not re_accepts_gzip.search(ae):
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return response
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if response.streaming:
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# Delete the `Content-Length` header for streaming content, because
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# we won't know the compressed size until we stream it.
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response.streaming_content = compress_sequence(response.streaming_content)
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del response['Content-Length']
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else:
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# Return the compressed content only if it's actually shorter.
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compressed_content = compress_string(response.content)
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if len(compressed_content) >= len(response.content):
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return response
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response.content = compressed_content
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response['Content-Length'] = str(len(response.content))
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if response.has_header('ETag'):
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response['ETag'] = re.sub('"$', ';gzip"', response['ETag'])
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response['Content-Encoding'] = 'gzip'
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return response
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