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Range requests and content encoding

From: Martin Thomson <martin.thomson@gmail.com>
Date: Tue, 22 Dec 2015 13:28:32 +1100
Message-ID: <CABkgnnUm3T4J1x0PqV_ofiv41znne9c8G0shg3+K6fxP2Qm0zQ@mail.gmail.com>
To: HTTP Working Group <ietf-http-wg@w3.org>
RFC 7233 does not mention content encoding at all.  Same for transfer
encoding.  I assume that is because this is completely unspecified and
therefore completely unreliable, however, for my sanity...

My reading is that a 206 response includes ranges of the encoded
message, and that the content-encoding applies to the complete message
body prior to being split into ranges.  Thus, if I had a "x2" content
encoding that turned "Hello World!" into "HHeelllloo  WWoorrlldd!!",
asking for bytes 3-5 would get you "eel" and not "llo".

The text in Section 4.1 suggests that you would not include a
Content-Encoding header field if the client used If-Range on the
expectation that they already know.  That seems pretty dangerous, but
it's consistent with the idea that you are repairing a larger message.

On the other hand, I have to assume that a Transfer-Encoding applies
*after* the range request.

p.s., I've opened https://github.com/httpwg/http11bis/issues/11 for this.
Received on Tuesday, 22 December 2015 02:29:00 UTC

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