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Re: NEW ISSUE: Monitoring Connections text

From: Henrik Nordstrom <henrik@henriknordstrom.net>
Date: Wed, 21 Nov 2007 21:38:58 +0100
To: Bjoern Hoehrmann <derhoermi@gmx.net>
Cc: ietf-http-wg@w3.org
Message-Id: <1195677538.9028.19.camel@henriknordstrom.net>
On ons, 2007-11-21 at 16:50 +0100, Bjoern Hoehrmann wrote:
> Hi,
> 
>   Section "8.2.2 Monitoring Connections for Error Status Messages" has:
> 
>    An HTTP/1.1 (or later) client sending a message-body SHOULD monitor
>    the network connection for an error status while it is transmitting
>    the request. If the client sees an error status, it SHOULD
>    immediately cease transmitting the body. If the body is being sent
>    using a "chunked" encoding (section 3.6), a zero length chunk and
>    empty trailer MAY be used to prematurely mark the end of the message.
>    If the body was preceded by a Content-Length header, the client MUST
>    close the connection.
> 
> This is somewhat confusing, it uses RFC 2119 keywords even though it
> really just makes statements of fact (if you cease transmitting, you
> cannot meaningfully maintain the connection) and it's unclear whether
> clients may still send a non-empty trailer. Better would be e.g.

Personally I find the text quite clear. The way I read it it's a chain
of conditions.

1. client SHOULD monitor
2. If monitoring and seeing an error it SHOULD ..(if not monitoring it
won't see the error, so the rest do not apply then) 
3. If chunked then it MAY terminate the body using chunked encoding
4. Else (Content-Length) it MUST close the connection.

The only change I'd like to do there is in the last part, replacing

  of the message. If the body was.. [to the end] with simply

  else the client MUST close the connection.

to close the blank spot where the client is using chunked encoding but
do not want to use chunked encoding to prematurely mark the end of the
client message.

Extending the text to bind the first two SHOULD together in a chain
isn't needed imho. Should be rather obvious that you can't see things if
you don't monitor. 

>    A client sending a message-body SHOULD monitor the network connection
>    for an error status while it is transmitting the request. If the
>    client sees an error status, it SHOULD cease transmitting the body.
>    Unless the body is being sent using the "chunked" encoding the client
>    MUST close the connection.

This is imho less clear than the original. Especially regarding how to
prematurely end a chunked message which in my experience isn't very
obvious to most people that you can.. (anyone remember the NTLM auth
discussion here some months ago?)

Regards
Henrik

Received on Wednesday, 21 November 2007 20:39:11 GMT

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