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From bugzi...@apache.org
Subject DO NOT REPLY [Bug 42987] - Weak Etags in Apache are useless and violate RFC 2616, 13.3.3
Date Sun, 30 Dec 2007 05:42:25 GMT
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http://issues.apache.org/bugzilla/show_bug.cgi?id=42987





------- Additional Comments From hno@squid-cache.org  2007-12-29 21:42 -------
It's not true that the meaning of a weak etag sent by Apache is useless and the
object will be dropped on the next request. Only on the next cache validation
after the object has expired.

For as long as the object has not expired the weak etag is sufficient for
client<->cache validations.

There is no real problem in that Apache never matches these weak etags in
If-None-Match.

Yes, it's true that to comply with the RFC the ETag should guarantee within
reasonable doubt that the representations is equal (semantically in case of a
weak etag, octet equal in case of a strong). The only way of guaranteeing this
is by knowing why the object gets updatated and how. This can not be guaranteed
while using a fs backend as direct filesystem access may modify the object and
object timestamps in any manner it likes.

But direct filesystem modifications not modifying mtime, or significant
modifications within the same second where results matter within that same
second is both relatively unlikely to be seen in real life.

But you should probably modify the weak ETag a little more than only making it
weak. In the RFC a strong and weak ETag with the same value compares true for
If-None-Match.

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