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[whatwg] WebSocket sub protocol name.

From: Ian Hickson <ian@hixie.ch>
Date: Mon, 7 Dec 2009 10:25:09 +0000 (UTC)
Message-ID: <Pine.LNX.4.62.0912071015130.14026@hixie.dreamhostps.com>
On Mon, 7 Dec 2009, Fumitoshi Ukai (??~\????~V~G?~U~O) wrote:
> On Mon, Dec 7, 2009 at 5:05 PM, Ian Hickson <ian at hixie.ch> wrote:
> > On Mon, 7 Dec 2009, Fumitoshi Ukai (???~\??????~V~G???U~O) wrote:
> > > > > >
> > > > > > Control characters are allowed (though using them would be 
> > > > > > silly).
> > > > >
> > > > > Why are control characters (except LF and CR) allowed?
> > > >
> > > > There doesn't seem to be a good reason to exclude them, and 
> > > > excluding them would lead to a more complicated processing model.
> > >
> > > In HTTP, field-content is TEXT or combinations of token, separators, 
> > > and quoted-string. TEXT, or token, separators excludes CTLs. So, we 
> > > must use quoted-string in WebSocket-Protocol: if protocol contains 
> > > CTLs?
> >
> > Oh, I forgot that HTTP had the no-CTL restriction. Good point. I've 
> > updated the spec to be consistent with this.
> 
> In "The Web Sockets API", could you fix the following statement?
>   The second, protocol, if present, specifies a sub-protocol that the server
> must support for the connection to be successful. The sub-protocol name must
> be an ASCII string with no U+000A LINE FEED (LF) or U+000D CARRIAGE RETURN
> (CR) characters in it.

Fixed, thanks.


> IIRC, in old spec draft, protocol should not be an empty string, but 
> current spec draft accepts it?

Man, I'm just incompetent today. Sorry about that. Fixed.


> > > And, why is it limited to ASCII instead of UTF-8?
> >
> > Because the HTTP working group refuse to allow UTF-8 in HTTP headers 
> > for reasons that I don't really understand, and the handshake is 
> > supposed to be valid HTTP.
> 
> Hmm, then it should be mentioned in The Web Socket protocol 1.2 Protocol 
> overview? It looks websocket message accept UTF-8 in handshake message.

There should be no way to _send_ UTF-8 in the handshake at this point, 
given the requirements in the spec, but once you _receive_ the handshake, 
it's no longer HTTP, it's just WebSocket, so you can use UTF-8 fine. (In 
practice it doesn't mean much, since there's nothing in the 
server-to-client handshake other than the client-to-server handshake, so 
if there ever was UTF-8 in the server-to-client handshake, it would either 
be ignored, or the connection would be dropped, depending on where exactly 
the UTF-8 was found.)

HTH,
-- 
Ian Hickson               U+1047E                )\._.,--....,'``.    fL
http://ln.hixie.ch/       U+263A                /,   _.. \   _\  ;`._ ,.
Things that are impossible just take longer.   `._.-(,_..'--(,_..'`-.;.'
Received on Monday, 7 December 2009 02:25:09 UTC

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