IPP Mail Archive: RE: IPP> Document Object Spec Comments...

RE: IPP> Document Object Spec Comments... [Validate-Job for each document vs. Create-Document/Send-Data]

From: McDonald, Ira (imcdonald@sharplabs.com)
Date: Sun May 04 2003 - 16:50:16 EDT

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    Hi folks,

    PSI and IPP are NOT equivalent in their operations and
    semantics here!

    PSI defines basic AddDocumentByValue (read IPP 'Send-Document')
    and AddDocumentByReference (read IPP 'Send-URI').

    PSI also defines AddDocumentByPush (not really equivalent to
    IPP 'Create-Document'), which MUST be promptly followed by
    PushDocumentDocumentDelivered (after the data has been pushed
    _out_of_band_ to one of the server offered push URI that were
    sent back in the AddDocumentByPush response message).

    PSI does NOT define a 'Send-Data' inband operation. This is
    an IPP artifact. And IPP does not define an equivalent to
    PushDocumentDataDelivered (unfortunately).

    Note that security is NOT an issue for AddDocumentByPush or
    AddDocumentByReference because in both cases PSI REQUIRES support
    only of 'http:' schemed URLs (no credentials required, typically).

    Cheers,
    - Ira McDonald
      High North Inc

    -----------------------------
    Michael Sweet wrote:

    I personally don't think that Create-Job and Send-Data are necessary,
    and as presently defined they open up a serious (and obvious)
    security hole WRT DoS attacks. While we cannot provide absolute
    protection against such attacks, we *can* provide the necessary hooks
    so that implementations can provide controls/limits/algorithms and
    properly handle DoS cases.

    <th>
    Let's see if the PSI folks have a compelling use case for Create-Document,
    Send-Data.

    Let's see whether others find the two use cases that I cited to be useful
    enough to warrant the added complexity of Create-Document and Sent-Data.
    </th>



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