IPP Mail Archive: Re: IPP> 4 significant proposed increases

Re: IPP> 4 significant proposed increases in conforman ce requirem ents for the IPP Document object spec

From: Mike Sweet (mike@easysw.com)
Date: Sun Apr 20 2003 - 17:18:24 EDT

  • Next message: Hastings, Tom N: "IPP> 1 more significant proposed conformance change to the IPP Documen t object spec"

    McDonald, Ira wrote:
    > ...
    > Is there any practical reason why PSI can't just require stricter
    > requirements than the basic IPP mapping? It seems idiotic to
    > require print-by-reference for IPP whose goals are different than
    > PSI.
    >
    >
    > <ira> _my_ goal is full-bandwidth application gateways between
    > IPP and PSI. Everywhere that IPP doesn't have a feature at all
    > (the out-of-band push in PSI's AddDocumentByPush) or has made a
    > feature optional (PSI's AddDocumentByReference), the gateway will
    > fail entirely.
    >
    > Note, PSI _is_ sending (over a TLS-secured channel) whatever
    > username and password or certificate necessary to do the SMTP,
    > IMAP, HTTPS, or whatever connection for the AddDocumentByReference,
    > from the client embedded in the PSI Print Service or Target Device.

    I will repeat this if it wasn't obvious from my example - passing
    authentication info does not solve the print-by-reference problem.
    Cookies, host-based access control, and other implementation-
    specific issues on the remote server end are not handled, and that
    means that print-by-reference stops working.

    While I understand that we cannot guarantee that every URI using
    a supported scheme can be printed, I do not see the point of
    requiring print-by-reference when we *know* that many common use
    cases will fail.

    > If this is security nightmare for IPP, then the same applies to
    > PSI - why is it so hard if the Print Service simply impersonates
    > the end user? (I know this can't work if the end user's TLS

    Because the print service cannot always impersonate the end-user.

    > ...
    > <ira> Well, print by reference is the main design center of PSI, so
    > if it will hurt adoption of IPP Document objects, then it will
    > equally hurt PSI adoption. Do you think PSI is in trouble??
    > </ira>

    I personally never saw the point of PSI, even for things like web
    pads. XHTML-Print + IPP is enough to support printing of web pages
    directly without print-by-reference (client can send a copy of the
    web page and images, which it already has in memory...), and PDF
    and other common web formats are well supported the same way. 

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

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