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Re: HTTP/2 Header Encoding Status Update

From: James M Snell <jasnell@gmail.com>
Date: Wed, 27 Feb 2013 15:00:08 -0800
Message-ID: <CABP7RbfaSLUCw+sns8Av2i2EDOioRxSx0RxuaSozKNJtO9YeBQ@mail.gmail.com>
To: Mark Nottingham <mnot@mnot.net>
Cc: "ietf-http-wg@w3.org" <ietf-http-wg@w3.org>
On Wed, Feb 27, 2013 at 2:45 PM, Mark Nottingham <mnot@mnot.net> wrote:
> Hi James,
>
>[snip]
> So, the biggest concern here, I think, is that the conversion of a UTF-8 value to ASCII/Latin-1 -- to be able to forward the header on a HTTP/1.x hop -- requires knowledge of the header.
>
> Would you want to define a standard way to encode UTF-8 in Latin-1 (e.g., percent-encoding) for headers that use this? It would constrain the headers (and likely rule out any existing headers from using UTF-8), but I don't see how this is going to be viable otherwise.
>

Yes, I think that is reasonable. One key thing is that existing
headers would need to be explicitly redefined to take advantage of the
new encoding options so it would be technically invalid to take any of
the existing headers and encode them as UTF-8 unless their definition
has been changed in spec. That said, a standard mapping like you
suggest would be good in the cases we do have to drop down from http/2
to /1. Percent-encoding seems to be perfectly reasonable.

>[snip]
>>
>>  For example, the byte sequence 01 02 03 is encoded as:
>>    20 03 01 02 03
>
> Similar problem as with UTF-8, unless you define a single transformation between binary and ASCII (base64?).
>

Yes, I had imagined that the transform here would be base64.

- James
Received on Wednesday, 27 February 2013 23:00:58 GMT

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