IPP Mail Archive: IPP> MOD - New attribute metadata proposal

IPP Mail Archive: IPP> MOD - New attribute metadata proposal

IPP> MOD - New attribute metadata proposal

From: McDonald, Ira (imcdonald@sharplabs.com)
Date: Thu Mar 16 2000 - 21:06:41 EST

  • Next message: Internet-Drafts@ietf.org: "IPP> I-D ACTION:draft-ietf-ipp-collection-02.txt"

    Hi folks, Thursday (16 March 2000)

    Per my action item from yesterday's IPP Telecon, I propose the following
    extensible mechanism for IPP clients to 'discover' metadata about the
    attributes supported by IPP server implementations.

    No new IPP operations are required and the mechanism may be used with
    any version of IPP (1.0, 1.1, etc.).

    The proposed mechanism is modelled on the use of metadata 'facts' in
    <draft-ietf-ftpext-mlst-10.txt>, February 2000, which defines the 'MLST'
    (file) and 'MLSD' (directory) machine-readable list command extensions
    to FTP.

    Define three new Printer object attributes which can be queried with
    the existing 'Get-Printer-Attributes' operation.

    ----------------------------------------------------------------------
    * printer-metadata-attributes-supported (1setOf text(MAX))

    This OPTIONAL Printer attribute specifies the set of metadata for all
    supported attributes for this Printer object.

    This attribute is encoded as a set of strings containing keyword/value
    metadata 'facts' about supported Printer object attributes.

    ----------------------------------------------------------------------
    job-metadata-attributes-supported (1setOf text(MAX))

    This OPTIONAL Printer attribute specifies the set of metadata for all
    supported attributes for Job objects which are contained by this Printer
    object.

    This attribute is encoded as a set of strings containing keyword/value
    metadata 'facts' about supported Job object attributes.

    ----------------------------------------------------------------------
    subscription-metadata-attributes-supported (1setOf text(MAX))
    job-metadata-attributes-supported (1setOf text(MAX))

    This OPTIONAL Printer attribute specifies the set of metadata for all
    supported attributes for Subscription objects which are contained by
    this Printer object.

    This attribute is encoded as a set of strings containing keyword/value
    metadata 'facts' about supported Subscription object attributes.

    ----------------------------------------------------------------------

    The metadata 'facts' are encoded according to the following ABNF (hope
    I got this right):

    metadata-entry = 1*( metadata-fact ";" )
    metadata-fact = metadata-factname "=" metadata-value
    metadata-factname = "name" / ; attribute name
                                            ; name defined in IPP
                          "syntax" / ; attribute syntax
                                            ; syntax defined in IPP
                          "minlen" / ; attribute minimum length
                          "maxlen" / ; attribute maximum length
                          "minint" / ; attribute minimum integer
                          "maxint" / ; attribute maximum integer
                          vendor-factname ; vendor unique factname
                          local-factname ; local unique factname
    vendor-factname = <vendor> "." metadata-token
    local-factname = "x" "." metadata-token
    metadata-token = 1*( token-char )
    metadata-value = 1*( token-char )
    token-char = ALPHA / DIGIT / "-"

    Every 'metadata-entry' string MUST begin with a 'name' fact and MAY
    contain zero or more other facts. Each 'syntax' fact MAY be followed by
    zero or more constraint facts 'minlen', 'maxlen', 'minint', or 'maxint'
    (which further constrain that 'syntax'). Multiple 'syntax' facts may be
    present in each 'metadata-entry' string.

    Comments?

    Cheers,
    - Ira McDonald (consulting architect at Sharp Labs America)
      High North Inc



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