[IPP] [PWG5100.6] Issue #30: "overrides-supported": 'document-numbers' should be conditionally required depending on "multiple-document-jobs-supported" = 'true'

Mon May 9 11:03:05 UTC 2016

Smith,
My concern is that clients that implement page overrides will break.  The long standing specification explicitly states the printer must accept document number in a request.  I know there are some clients that do not ask the printer first to see if the page number or document number are permitted in the request.  The specification does not say that the printer must support the document object, and therefore "document-number" , in order to support page overrides.  It only says that the printer must support the document number in the request.  I would prefer to keep the requirements as specified not only to prevent client interoperability problems but also to keep the implementations simplified and not have to accommodate special case processing.  The simplified implementation would be true not only on the client side but the printer side as well.  I have no problem with the client checking to see if the "document-copies" is supported since the use of it is a corner condition.  I would also argue that by definition even a printer implementation that supports only single document jobs does implement a document object and its associated number.  It is just not exposed through the IPP protocol.  
Pete

Peter Zehler
Xerox Corp.
Global Development Group
800 Phillips Rd, 111-04A
Webster NY, 14580-9701
Email: Peter.Zehler at Xerox.com
Office: +1 (585) 265-8755
Fax: +1 (585) 422-0238
Mobile: +1 (585) 329-9508

-----Original Message-----
From: Kennedy, Smith (Wireless Architect) [mailto:smith.kennedy at hp.com] 
Sent: Friday, May 06, 2016 6:56 PM
To: Zehler, Peter <Peter.Zehler at xerox.com>
Cc: ipp at pwg.org
Subject: Re: [IPP] [PWG5100.6] Issue #30: "overrides-supported": 'document-numbers' should be conditionally required depending on "multiple-document-jobs-supported" = 'true'

Hi Pete,

Thanks for providing the background on this.  But it still seems a bit odd to me to require support for an attribute when the feature itself isn't supported.  As you say, if "document-numbers" is omitted, that is semantically equivalent to "all my documents" and on these products that is equivalent to "my first document" since it only supports one document per job.

Is your concern that there could be clients out there that would have their jobs rejected because they expect the printer to always support "document-numbers" and they don't?  There are certainly a lot of printers out there that do not support it.

Smith

/**
    Smith Kennedy
    Wireless Architect - Client Software - IPG-PPS
    Standards - IEEE ISTO PWG / Bluetooth SIG / Wi-Fi Alliance / NFC Forum / USB IF
    PWG Chair
    HP Inc.
*/

> On 2016-05-05, at 9:11 AM, Zehler, Peter <Peter.Zehler at xerox.com> wrote:
> 
> All,
> 
> If I remember correctly, the printer must accept the “document-numbers” in a client request even if the printer only supports single document jobs.  For a single document job, and a printer that supports either single or multiple document jobs,  the following attribute values in request containing an "overrides" attribute would all be equivalent:
> "document-numbers": '1: 2147483647', (i.e., all my documents)
> "document-numbers": '1: 1', (i.e., my first document)
> "document-numbers" omitted (i.e. all my documents)
> 
> The client may specify a subset of documents to which the override is applied.  The implication of not specifying is that the overrides applies to all.    The printer must accept and understand all of these.  A client specifying a document number that does not exist is ignored since the override applies only to the pages/documents/document-copies specified for the override.
> 
> I think it is simpler and cleaner to keep the primary specification of the override target (i.e., pages and document) mandatory for the printer to support in a request while the edge case (i.e., document-copies) remains optional.
> 
> Peter Zehler
> Xerox Corp.
> Global Development Group
> 800 Phillips Rd, 111-04A
> Webster NY, 14580-9701
> Email: Peter.Zehler at Xerox.com
> Office: +1 (585) 265-8755
> Fax: +1 (585) 422-0238
> Mobile: +1 (585) 329-9508
> 
> -----Original Message-----
> From: ipp [mailto:ipp-bounces at pwg.org] On Behalf Of smith.kennedy at hp.com
> Sent: Wednesday, May 04, 2016 4:27 PM
> To: ipp at pwg.org
> Subject: [IPP] [PWG5100.6] Issue #30: "overrides-supported": 'document-numbers' should be conditionally required depending on "multiple-document-jobs-supported" = 'true'
> 
> [Issue Unconfirmed]
> 
> PWG 5100.6-2004 section 4.1.7 says:
> 
>   This attribute MUST contain the keywords “pages” and “document-numbers” because
>   a Printer MUST support these attributes.
> 
> But the 'document-numbers' attribute should not be required unconditionally; it should be conditionally required depending on whether the Printer reports "multiple-document-jobs-supported" = 'true'.  If it doesn't support "multiple-document-jobs-supported" or reports "multiple-document-jobs-supported" = 'false' then 'document-numbers' should not be required.
> 
> Link: http://www.pwg.org/issues/30
> 
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