rfc2639.txt

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   of requests just before the Document Content and at the end of
   response, except for the Get-Jobs response, where it maybe there or
   before the first job attributes returned.  If an IPP object receives
   an unknown attribute group in these positions, it ignores the entire
   group, rather than returning an error, since that group may be a new
   group in a later minor version of the protocol that can be ignored.
   (If the new attribute group cannot be ignored without confusing the
   client, the major version number would have been increased in the





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   protocol document and in the request).  If the unknown group occurs
   in a different position, the IPP object REJECTS the request and
   RETURNS the 'client-error-bad-request' status code.

   Clients also ignore unknown attribute groups returned in a response.

   Note:  By validating that requests are in the proper form, IPP
   objects force clients to use the proper form which, in turn,
   increases the chances that customers will be able to use such clients
   from multiple vendors with IPP objects from other vendors.

2.2.1.4.3 Validate the presence of a single occurrence of required
          Operation attributes

   Client requests and IPP object responses contain Operation attributes
   that [RFC2566] Section 3 requires to be present.  Attributes within a
   group may be in any order, except for the ordering of target,
   charset, and natural languages attributes.  These attributes MUST be
   first, and MUST be supplied in the following order: charset, natural
   language, and then target. An IPP object verifies that the attributes
   that Section 4 requires to be supplied by the client have been
   supplied in the request (attributes without an * in the following
   tables).  An asterisk (*) indicates groups and Operation attributes
   that the client may omit in a request or an IPP object may omit in a
   response.

   If an IPP object receives a request with required attributes missing
   or repeated from a group or in the wrong position, the behavior of
   the IPP object is IMPLEMENTATION DEPENDENT.  Some of the possible
   implementations are:

      1.REJECTS the request and RETURNS the 'client-error-bad-request'
        status code

      2.accepts the request and uses the first occurrence of the
        attribute no matter where it is

      3.accepts the request and uses the last occurrence of the
        attribute no matter where it is

      4.accept the request and assume some default value for the missing
        attribute

   Therefore, client MUST send conforming requests, if they want to
   receive the same behavior from all IPP object implementations.  For
   example, it is an error for the "attributes-charset" or "attributes-
   natural-language" attribute to be omitted in any operation request,
   or for an Operation attribute to be supplied in a Job Template group



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   or a Job Template attribute to be supplied in an Operation Attribute
   group in a create request.  It is also an error to supply the
   "attributes-charset" attribute twice.

   Since these kinds of attribute errors are most likely to be detected
   by a client developer rather than by a customer, the IPP object NEED
   NOT return an indication of which attribute was in error in either
   the Unsupported Attributes group or the Status Message.  Also, the
   IPP object NEED NOT find all attribute errors before returning this
   error.

   The following tables list all the attributes for all the operations
   by attribute group in each request and each response.  The order of
   the groups is the order that the client supplies the groups as
   specified in [RFC2566] Section 3.  The order of the attributes within
   a group is arbitrary, except as noted for some of the special
   operation attributes (charset, natural language, and target).  The
   tables below use the following notation:

     R   indicates a REQUIRED attribute that an IPP object MUST support
     O   indicates an OPTIONAL attribute that an IPP object NEED NOT
               support
     *   indicates that a client MAY omit the attribute in a request
               and that an IPP object MAY omit the attribute in a
               response. The absence of an * means that a client MUST
               supply the attribute in a request and an IPP object MUST
               supply the attribute in a response.

                            Operation Requests

   The tables below show the attributes in their proper attribute groups
   for operation requests:

   Note: All operation requests contain "version-number", "operation-
   id", and "request-id" parameters.

   Print-Job Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             printer-uri (R)
             requesting-user-name (R*)
             job-name (R*)
             ipp-attribute-fidelity (R*)
             document-name (R*)
             document-format (R*)
             document-natural-language (O*)
             compression (O*)



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             job-k-octets (O*)
             job-impressions (O*)
             job-media-sheets (O*)
        Group 2: Job Template Attributes (R*)
             <Job Template attributes> (O*)
                  (see [RFC2566] Section 4.2)
        Group 3: Document Content (R)
             <document content>

   Validate-Job Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             printer-uri (R)
             requesting-user-name (R*)
             job-name (R*)
             ipp-attribute-fidelity (R*)
             document-name (R*)
             document-format (R*)
             document-natural-language (O*)
             compression (O*)
             job-k-octets (O*)
             job-impressions (O*)
             job-media-sheets (O*)
        Group 2: Job Template Attributes (R*)
             <Job Template attributes> (O*)
                  (see [RFC2566] Section 4.2)

   Create-Job Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             printer-uri (R)
             requesting-user-name (R*)
             job-name (R*)
             ipp-attribute-fidelity (R*)
             job-k-octets (O*)
             job-impressions (O*)
             job-media-sheets (O*)
        Group 2: Job Template Attributes (R*)
             <Job Template attributes> (O*) (see
                  (see [RFC2566] Section 4.2)

   Print-URI Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             printer-uri (R)



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             document-uri (R)
             requesting-user-name (R*)
             job-name (R*)
             ipp-attribute-fidelity (R*)
             document-name (R*)
             document-format (R*)
             document-natural-language (O*)
             compression (O*)
             job-k-octets (O*)
             job-impressions (O*)
             job-media-sheets (O*)
        Group 2: Job Template Attributes (R*)
             <Job Template attributes> (O*) (see
                  (see [RFC2566] Section 4.2)

   Send-Document Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             (printer-uri & job-id) | job-uri (R)
             last-document (R)
             requesting-user-name (R*)
             document-name (R*)
             document-format (R*)
             document-natural-language (O*)
             compression (O*)
        Group 2: Document Content (R*)
             <document content>

   Send-URI Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             (printer-uri & job-id) | job-uri (R)
             last-document (R)
             document-uri (R)
             requesting-user-name (R*)
             document-name (R*)
             document-format (R*)
             document-natural-language (O*)
             compression (O*)










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   Cancel-Job Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             (printer-uri & job-id) | job-uri (R)
             requesting-user-name (R*)
             message (O*)

   Get-Printer-Attributes Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             printer-uri (R)
             requesting-user-name (R*)
             requested-attributes (R*)
             document-format (R*)

   Get-Job-Attributes Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             (printer-uri & job-id) | job-uri (R)
             requesting-user-name (R*)
             requested-attributes (R*)

   Get-Jobs Request:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             printer-uri (R)
             requesting-user-name (R*)
             limit (R*)
             requested-attributes (R*)
             which-jobs (R*)
             my-jobs (R*)


                            Operation Responses

   The tables below show the response attributes in their proper
   attribute groups for responses.

   Note: All operation responses contain "version-number", "status-
   code", and "request-id" parameters.

   Print-Job Response:
   Print-URI Response:
   Create-Job Response:



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   Send-Document Response:
   Send-URI Response:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             status-message (O*)
        Group 2: Unsupported Attributes (R*) (see Note 3)
             <unsupported attributes> (R*)
        Group 3: Job Object Attributes(R*) (see Note 2)
             job-uri (R)
             job-id (R)
             job-state (R)
             job-state-reasons (O*)
             job-state-message (O*)
             number-of-intervening-jobs (O*)

   Validate-Job Response:
   Cancel-Job Response:
        Group 1: Operation Attributes (R)
             attributes-charset (R)
             attributes-natural-language (R)
             status-message (O*)
        Group 2: Unsupported Attributes (R*) (see Note 3)
             <unsupported attributes> (R*)

   Note 2 - the Job Object Attributes and Printer Object Attributes are
   returned only if the IPP object returns one of the success status
   codes.

   Note 3 - the Unsupported Attributes Group is present only if the
   client included some Operation and/or Job Template attributes or
   values that the Printer doesn't support whether a success or an error