IPP Mail Archive: Re: IPP> NOT - Agreements on the ISSUES in

IPP Mail Archive: Re: IPP> NOT - Agreements on the ISSUES in

Re: IPP> NOT - Agreements on the ISSUES in the IPPGET spec and IPP base spec

From: mjoel@netreon.com
Date: Fri Jul 20 2001 - 10:18:12 EDT

  • Next message: Mike Bartman: "RE: IPP> NOT - Agreements on the ISSUES in the IPPGET spec and IP P base spec"

    Hi Michael,

    I argued about this for a while in the teleconference call. It seemed to
    me that the client needed to know when it got the end of the bytes of an
    event notification attributes group. It turns out that Get-Notifications
    with waiting requires the use of HTTP 1.1's chunking. Each returned chunk
    will contain 1 or more event notification attributes groups (although I
    expect that for most implementations it will only be 1).

    The nice division between HTTP processing and IPP processing has been
    blurred a little on both client and server. On the server, if the printer
    decides to support a request for Get-Notifications with waiting, it will
    start a chunked HTTP reply. It will then send one chunk containing the
    first part of the IPP reply including any event notification attribute
    groups for events that have already occurred (which is not terminated by
    end-of-attributes-tag). As each event occurs it will send a chunk
    containing only an event notification attributes group. If the printer
    decides to stop sending events when an event occurs, it will send a chunk
    which contains the event notification attributes group containing the event
    that occurred, another group containing just a notify-get-interval
    attribute, and an end-of-attributes-tag. If the printer decides to stop
    sending events when an event has not just occurred, it will send a chunk
    which contains an event notification attributes group containing just a
    notify-get-interval attribute, and an end-of-attributes-tag. Any function
    that does encoding must now be told if it should build a complete reply, a
    first chunk, an intermediate chunk, or a last chunk. On the client, when
    it issues Get-Notifications with waiting, it needs to be prepared to
    receive the HTTP chunks.

    Note to Tom: maybe the ippget spec should explain this.

    Regards,

    Marty

    Michael Sweet <mike@easysw.com>@pwg.org on 07/19/2001 06:55:20 PM

    Sent by: owner-ipp@pwg.org

    To: "Hastings, Tom N" <hastings@cp10.es.xerox.com>
    cc: mjoel@netreon.com, ipp@pwg.org

    Subject: Re: IPP> NOT - Agreements on the ISSUES in the IPPGET spec and
          IPP base spec

    "Hastings, Tom N" wrote:
    > ...
    > TH> Anyone have any thoughts?
    >
    > TH> One possibility would be to add a "notify-status-code"
    > attribute that can be returned in an Event Notification Attributes
    > group along with Event Notification attributes. The value would
    > indicate that this is the last group for now. We've done a similar
    > status code in a Group thing for INDP Send-Notifications Attribute
    > Groups.

    After thinking on this a while, I think we need something like this
    or another special value tag ("end-of-group" tag?) so that the client
    knows that it can go off and process the event data and check back
    later for more info (with the same connection...)

    --
    ______________________________________________________________________
    Michael Sweet, Easy Software Products                  mike@easysw.com
    Printing Software for UNIX                       http://www.easysw.com
    



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