75 lines
2.9 KiB
Python
75 lines
2.9 KiB
Python
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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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max_random_bytes = 100
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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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if response.is_async:
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# pull to lexical scope to capture fixed reference in case
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# streaming_content is set again later.
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orignal_iterator = response.streaming_content
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async def gzip_wrapper():
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async for chunk in orignal_iterator:
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yield compress_string(
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chunk,
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max_random_bytes=self.max_random_bytes,
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)
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response.streaming_content = gzip_wrapper()
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else:
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response.streaming_content = compress_sequence(
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response.streaming_content,
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max_random_bytes=self.max_random_bytes,
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)
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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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del response.headers["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(
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response.content,
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max_random_bytes=self.max_random_bytes,
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)
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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.headers["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 9110 Section 8.8.1 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.headers["ETag"] = "W/" + etag
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response.headers["Content-Encoding"] = "gzip"
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return response
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