Requiring proxies to process warn-date

Mark Nottingham <> Wed, 08 May 2013 13:16 UTC

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Subject: Requiring proxies to process warn-date
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In #480, Alex brought this text up in p6:

> If an implementation sends a message with one or more Warning header fields to a receiver whose version is HTTP/1.0 or lower, then the sender must include in each warning-value a warn-date that matches the Date header field in the message.
> If a system receives a message with a warning-value that includes a warn-date, and that warn-date is different from the Date value in the response, then that warning-value must be deleted from the message before storing, forwarding, or using it. (preventing the consequences of naive caching of Warning header fields.) If all of the warning-values are deleted for this reason, the Warning header field must be deleted as well.

My inclination here is to change the first paragraph to begin "If a sender generates a message...", and the second to be "If a recipient receives...", also removing "forwarding" later down.

This is because IME proxies do not do any of this for messages that they aren't caching, and moreover there are whole classes of implementations that won't.


Mark Nottingham