52 lines
2.1 KiB
Python
52 lines
2.1 KiB
Python
from django.utils.cache import patch_vary_headers
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from django.utils.deprecation import MiddlewareMixin
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from django.utils.regex_helper import _lazy_re_compile
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from django.utils.text import compress_sequence, compress_string
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re_accepts_gzip = _lazy_re_compile(r'\bgzip\b')
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class GZipMiddleware(MiddlewareMixin):
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"""
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Compress content if the browser allows gzip compression.
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Set 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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# 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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patch_vary_headers(response, ('Accept-Encoding',))
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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 there is a strong ETag, make it weak to fulfill the requirements
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# of RFC 7232 section-2.1 while also allowing conditional request
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# matches on ETags.
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etag = response.get('ETag')
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if etag and etag.startswith('"'):
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response['ETag'] = 'W/' + etag
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response['Content-Encoding'] = 'gzip'
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return response
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