IPP Mail Archive: Re: IPP> Misplaced attributes

IPP Mail Archive: Re: IPP> Misplaced attributes

Re: IPP> Misplaced attributes

From: Carl Kugler (kugler@us.ibm.com)
Date: Wed Mar 14 2001 - 14:36:48 EST

  • Next message: Carl Kugler: "Re: IPP> Misplaced attributes"

    I think choice "C" is the only conforming implementation. Quoting from
    MOD:

       Because of extensibility, any IPP object might receive a request that
         contains new or unknown attributes or values for which it has no
         support. In such cases, the IPP object processes what it can and
         returns the unsupported attributes in the response. The Unsupported
         Attribute group is defined for all operation responses for returning
         unsupported attributes that the client supplied in the request.

    Any request attribute in the Job attributes group is, by definition, a Job
    Template attribute. Support for Job Template attributes by a Printer
    object is OPTIONAL. If the client does not supply a boolean operation
    attribute named "ipp-attribute-fidelity" with value 'true', and a Printer
    does not support a client supplied Job Template attribute, the Printer MUST
    ignore it.

         -Carl

    "Zehler, Peter" <PZehler@c...> wrote:
    > All,
    > I have had some internal discussions around an issue I would like to
    resolve
    > across the IPP WG.
    >
    > ISSUE: An IPP Client sends a print request with the
    > "ipp-attribute-fidelity" attribute containing a value of 'true'. The
    client
    > also supplies the job template attribute "sides" with a value of
    > 'two-sided-long-edge'. The IPP Printer does not support two sided
    printing.
    > The IPP Client software generates the request but put the
    > "ipp-attribute-fidelity" in the job attributes group instead of the
    > operational attributes group. What should the Printer do?
    >
    > A) Reject the request with 'client-error-bad-request' since
    > "ipp-attribute-fidelity" is in the wrong group.
    >
    > B) Reject the job because the printer does not support two sided
    > printing. The IPP Printer would accept "ipp-attribute-fidelity" even
    though
    > it is in the wrong group. The printer would return a
    > "client-error-attributes-or-values-not-supported' error and return the
    > "side" attribute and value in the unsupported attribute group.
    >
    > C) Accept the job and print it substituting 'one-sided'. The IPP
    Printer
    > uses the defaulted value (i.e. 'false' ) for "ipp-attribute-fidelity"
    since
    > it was not an operational attribute. The return code would be
    > 'successful-ok-ignored-or-substituted-attributes' and the "sides" and
    > "ipp-attribute-fidelity" would be returned as unsupported attributes.
    (i.e.
    > "ipp-attribute-fidelity" is not a supported job template attribute)
    >
    >
    > As an IPP Printer implementer I would chose C. The response informs the
    > client that it is in error. The Printer is forgiving and the job is
    > printed. The extensibility of IPP is maintained.
    >
    > The Implementer's guide with need to be updated to provide a
    recommendation
    > on how to handle "misplaced" attributes. There is currently a clause
    that
    > lumps "misplaced" attributes with missing or duplicate attributes.
    (section
    > 3.1.2.1.4.3)
    >
    > Pete
    >
    > By the way my email address has changed from Peter.Zehler@u... to
    > pzehler@c...
    >
    > Peter Zehler
    > XEROX
    > Xerox Architecture Center
    > Email: PZehler@c...
    > Voice: (716) 265-8755
    > FAX: (716) 265-8792
    > US Mail: Peter Zehler
    > Xerox Corp.
    > 800 Phillips Rd.
    > M/S 139-05A
    > Webster NY, 14580-9701



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