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RFC 2639

 
 
 

Internet Printing Protocol/1.0: Implementer's Guide

Part 2 of 3, p. 26 to 50
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2.2.2 Suggested Additional Processing Steps for Operations that
      Create/Validate Jobs and Add Documents

   This section in combination with the previous section recommends the
   processing steps for the Print-Job, Validate-Job, Print-URI, Create-
   Job, Send-Document, and Send-URI operations that IPP objects SHOULD
   use.  These are the operations that create jobs, validate a Print-Job
   request, and add documents to a job.

2.2.2.1   Default "ipp-attribute-fidelity" if not supplied

   The Printer object checks to see if the client supplied an "ipp-
   attribute-fidelity" Operation attribute.  If the attribute is not
   supplied by the client, the IPP object assumes that the value is
   'false'.

2.2.2.2   Check that the Printer object is accepting jobs

   If the value of the Printer object's "printer-is-accepting-jobs" is
   'false', the Printer object REJECTS the request and RETURNS the
   'server-error-not-accepting-jobs' status code.

2.2.2.3   Validate the values of the Job Template attributes

   An IPP object validates the values of all Job Template attribute
   supplied by the client.  The IPP object performs the analogous
   syntactic validation checks of each Job Template attribute value that
   it performs for Operation attributes (see Section 2.2.1.5.):

      a)that the length of each value is correct for the attribute
        syntax tag supplied by the client according to [RFC2566] Section
        4.1.

      b)that the attribute syntax tag is correct for that attribute
        according to [RFC2566] Sections 4.2 to 4.4.

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      c)that multiple values are supplied only for multi-valued
        attributes, i.e., that are 1setOf  X according to [RFC2566]
        Sections 4.2 to 4.4.

   As in Section 2.2.1.5, if any of these syntactic checks fail, the IPP
   object REJECTS the request and RETURNS the 'client-error-bad-request'
   or 'client-error-request-value-too-long' status code as appropriate,
   independent of the value of the "ipp-attribute-fidelity".  Since such
   an error is most likely to be an error detected by a client
   developer, rather than by an end-user, the IPP object NEED NOT return
   an indication of which attribute had the error in either the
   Unsupported Attributes Group or the Status Message.  The description
   for each of these syntactic checks is explicitly expressed in the
   first IF statement in the following table.

   Each Job Template attribute MUST occur no more than once.  If an IPP
   Printer receives a create request with multiple occurrences of a Job
   Template attribute, it MAY:

      1.reject the operation and return the 'client-error-bad syntax'
        error status code

      2.accept the operation and use the first occurrence of the
        attribute

      3.accept the operation and use the last occurrence of the
        attribute

   depending on implementation.  Therefore, clients MUST NOT supply
   multiple occurrences of the same Job Template attribute in the Job
   Attributes group in the request.

2.2.3 Algorithm for job validation

   The process of validating a Job-Template attribute "xxx" against a
   Printer attribute "xxx-supported" can use the following validation
   algorithm (see section 3.2.1.2 in [RFC2566]).

   To validate the value U of Job-Template attribute "xxx" against the
   value V of Printer "xxx-supported", perform the following algorithm:

      1.If U is multi-valued, validate each value X of U by performing
        the algorithm in Table 3 with each value X. Each validation is
        separate from the standpoint of returning unsupported values.

        Example: If U is "finishings" that the client supplies with
        'staple', 'bind' values, then X takes on the successive values:
        'staple', then 'bind'

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      2.If V is multi-valued, validate X against each Z of V by
        performing the algorithm in Table 3 with each value Z.  If a
        value Z validates, the validation for the attribute value X
        succeeds. If it fails, the algorithm is applied to the next
        value Z of V. If there are no more values Z of V, validation
        fails.

        Example: If V is "sides-supported" with values: 'one-sided',
        'two-sided-long', and 'two-sided-short', then Z takes on the
        successive values: 'one-sided', 'two-sided-long', and
        'two-sided-short'.  If the client supplies "sides" with 'two-
        sided-long', the first comparison fails ('one-sided' is not
        equal to 'two-sided-long'), the second comparison succeeds
        ('two-sided-long' is equal to 'two-sided-long"), and the third
        comparison ('two-sided-short' with 'two-sided-long') is not even
        performed.

      3.If both U and V are single-valued, let X be U and Z be V and use
        the validation rules in Table 3.

            Table 3 - Rules for validating single values X against Z

     attribute    attribute       validated if:
     syntax of X  syntax of Z

     integer      rangeOfInteger  X is within the range of
                                   Z

     uri          uriScheme       the uri scheme in X is
                                   equal to Z

     any          boolean         the value of Z is TRUE

     any          any             X and Z are of the same
                                   type and are equal.

   If the value of the Printer object's "xxx-supported" attribute is '
   no-value' (because the system administrator hasn't configured a
   value), the check always fails.  If the check fails, the IPP object
   copies the attribute to the Unsupported Attributes response group
   with its unsupported value.  If the attribute contains more than one
   value, each value is checked and each unsupported value is separately
   copied, while supported values are not copied.  If an IPP object
   doesn't recognize/support a Job Template attribute, i.e., there is no
   corresponding Printer object "xxx-supported" attribute, the IPP
   object treats the attribute as an unknown or unsupported attribute
   (see the last row in the table below).

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   If some Job Template attributes are supported for some document
   formats and not for others or the values are different for different
   document formats, the IPP object SHOULD take that into account in
   this validation using the value of the "document-format" supplied by
   the client (or defaulted to the value of the Printer's "document-
   format-default" attribute, if not supplied by the client).  For
   example, if "number-up" is supported for the 'text/plain' document
   format, but not for the 'application/postscript' document format, the
   check SHOULD (though it NEED NOT) depend on the value of the
   "document-format" operation attribute.  See "document-format" in
   [RFC2566] section 3.2.1.1 and 3.2.5.1.

   Note: whether the request is accepted or rejected is determined by
   the value of the "ipp-attribute-fidelity" attribute in a subsequent
   step, so that all Job Template attribute supplied are examined and
   all unsupported attributes and/or values are copied to the
   Unsupported Attributes response group.

   job-priority (integer(1:100))

      IF NOT a single 'integer' value with a length equal to 4 octets,
         REJECT/RETURN 'client-error-bad-request'.
      IF NOT supplied by the client, use the value of the Printer
         object's "job-priority-default" attribute at job submission
         time.
      IF NOT in the range 1 to 100, inclusive, copy the attribute and
         the unsupported value to the Unsupported Attributes response
         group.
      Map the value to the nearest supported value in the range 1:100 as
         specified by the number of discrete values indicated by the
         value of the Printer's "job-priority-supported" attribute.  See
         the formula in [RFC2566] Section 4.2.1.

   job-hold-until (type3 keyword | name)

      IF NOT a single 'keyword' or 'name' value, REJECT/RETURN 'client-
         error-bad-request'.
      IF the value length is greater than 255 octets, REJECT/RETURN
         'client-error-request-value-too-long'.
      IF NOT supplied by the client, use the value of the Printer
         object's "job-hold-until" attribute at job submission time.
      IF NOT in the Printer object's "job-hold-until-supported"
         attribute, copy the attribute and the unsupported value to the
         Unsupported Attributes response group.

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   job-sheets (type3 keyword | name)

      IF NOT a single 'keyword' or 'name' value, REJECT/RETURN 'client-
         error-bad-request'.
      IF the value length is greater than 255 octets, REJECT/RETURN
         'client-error-request-value-too-long'.
      IF NOT in the Printer object's "job-sheets-supported" attribute,
         copy the attribute and the unsupported value to the Unsupported
         Attributes response group.

   multiple-document-handling (type2 keyword)

      IF NOT a single 'keyword' value, REJECT/RETURN 'client-error-bad-
         request'.
      IF the value length is greater than 255 octets, REJECT/RETURN
         'client-error-request-value-too-long'.
      IF NOT in the Printer object's "multiple-document-handling-
         supported" attribute, copy the attribute and the unsupported
         value to the Unsupported Attributes response group.

   copies (integer(1:MAX))

      IF NOT a single 'integer' value with a length equal to 4 octets,
      REJECT/RETURN 'client-error-bad-request'.
      IF NOT in range of the Printer object's "copies-supported"
         attribute copy the attribute and the unsupported value to the
         Unsupported
         Attributes response group.

   finishings (1setOf type2 enum)

      IF NOT an 'enum' value(s) each with a length equal to 4 octets,
         REJECT/RETURN 'client-error-bad-request'.
      IF NOT in the Printer object's "finishings-supported" attribute,
         copy the attribute and the unsupported value(s), but not any
         supported values, to the Unsupported Attributes response group.

   page-ranges (1setOf  rangeOfInteger(1:MAX))

      IF NOT a 'rangeOfInteger' value(s) each with a length equal to 8
         octets, REJECT/RETURN 'client-error-bad-request'.
      IF first value is greater than second value in any range, the
         ranges are not in ascending order, or ranges overlap,
         REJECT/RETURN 'client-error-bad-request'.
      IF the value of the Printer object's "page-ranges-supported"
         attribute is 'false', copy the attribute to the Unsupported
         Attributes response group and set the value to the "out-of-
         band" 'unsupported' value.

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   sides (type2 keyword)

      IF NOT a single 'keyword' value, REJECT/RETURN 'client-error-bad-
         request'.
      IF the value length is greater than 255 octets, REJECT/RETURN
         'client-error-request-value-too-long'.
      IF NOT in the Printer object's "sides-supported" attribute, copy
         the attribute and the unsupported value to the Unsupported
         Attributes response group.

   number-up (integer(1:MAX))

      IF NOT a single 'integer' value with a length equal to 4 octets,
      REJECT/RETURN 'client-error-bad-request'.
      IF NOT a value or in the range of one of the values of the Printer
         object's "number-up-supported" attribute, copy the attribute
         and value to the Unsupported Attribute response group.

   orientation-requested (type2 enum)

      IF NOT a single 'enum' value with a length equal to 4 octets,
      REJECT/RETURN 'client-error-bad-request'.
      IF NOT in the Printer object's "orientation-requested-supported"
         attribute, copy the attribute and the unsupported value to the
         Unsupported Attributes response group.

   media (type3 keyword | name)

      IF NOT a single 'keyword' or 'name' value, REJECT/RETURN 'client-
         error-bad-request'.
      IF the value length is greater than 255 octets, REJECT/RETURN
         'client-error-request-value-too-long'.
      IF NOT in the Printer object's "media-supported" attribute, copy
         the attribute and the unsupported value to the Unsupported
         Attributes response group.

   printer-resolution (resolution)

      IF NOT a single 'resolution' value with a length equal to 9
         octets,
      REJECT/RETURN 'client-error-bad-request'.
      IF NOT in the Printer object's "printer-resolution-supported"
         attribute, copy the attribute and the unsupported value to the
         Unsupported Attributes response group.

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   print-quality (type2 enum)

      IF NOT a single 'enum' value with a length equal to 4 octets,
      REJECT/RETURN 'client-error-bad-request'.
      IF NOT in the Printer object's "print-quality-supported"
         attribute, copy the attribute and the unsupported value to the
         Unsupported Attributes response group.

   unknown or unsupported attribute (i.e., there is no corresponding
   Printer object "xxx-supported" attribute)

      IF the attribute syntax supplied by the client is supported but
         the length is not legal for that attribute syntax,
      REJECT/RETURN 'client-error-bad-request' if the length of the
         attribute syntax is fixed or 'client-error-request-value-too-
         long' if the length of the attribute syntax is variable.
      ELSE copy the attribute and value to the Unsupported Attributes
         response group and change the attribute value to the "out-of-
         band" 'unsupported' value.  Any remaining Job Template
         Attributes are either unknown or unsupported Job Template
         attributes and are validated algorithmically according to their
         attribute syntax for proper length (see below).

         If the attribute syntax is supported AND the length check
         fails, the IPP object REJECTS the request and RETURNS the '
         client-error-bad-request' if the length of the attribute syntax
         is fixed or the 'client-error-request-value-too-long' status
         code if the length of the attribute syntax is variable.
         Otherwise, the IPP object copies the unsupported Job Template
         attribute to the Unsupported Attributes response group and
         changes the attribute value to the "out-of-band" 'unsupported'
         value.  The following table shows the length checks for all
         attribute syntaxes.  In the following table:  "<=" means less
         than or equal, "=" means equal to:

   Name              Octet length check for read-write attributes
   -----------       --------------------------------------------
   'textWithLanguage    <= 1023 AND 'naturalLanguage'  <= 63
   'textWithoutLanguage' <= 1023
   'nameWithLanguage'    <= 255 AND 'naturalLanguage'  <= 63
   'nameWithoutLanguage' <= 255
   'keyword'             <= 255
   'enum'                = 4
   'uri'                 <= 1023
   'uriScheme'           <= 63
   'charset'             <= 63
   'naturalLanguage'     <= 63
   'mimeMediaType'       <= 255

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   'octetString'         <= 1023
   'boolean'             = 1
   'integer'             = 4
   'rangeOfInteger'      = 8
   'dateTime'            = 11
   'resolution'          = 9
   '1setOf  X'

2.2.3.1   Check for conflicting Job Template attributes values

   Once all the Operation and Job Template attributes have been checked
   individually, the Printer object SHOULD check for any conflicting
   values among all the supported values supplied by the client.  For
   example, a Printer object might be able to staple and to print on
   transparencies, however due to physical stapling constraints, the
   Printer object might not be able to staple transparencies. The IPP
   object copies the supported attributes and their conflicting
   attribute values to the Unsupported Attributes response group.  The
   Printer object only copies over those attributes that the Printer
   object either ignores or substitutes in order to resolve the
   conflict, and it returns the original values which were supplied by
   the client.  For example suppose the client supplies "finishings"
   equals 'staple' and "media" equals 'transparency', but the Printer
   object does not support stapling transparencies.  If the Printer
   chooses to ignore the stapling request in order to resolve the
   conflict, the Printer objects returns "finishings" equal to 'staple'
   in the Unsupported Attributes response group.  If any attributes are
   multi-valued, only the conflicting values of the attributes are
   copied.

   Note: The decisions made to resolve the conflict (if there is a
   choice) is implementation dependent.

2.2.3.2   Decide whether to REJECT the request

   If there were any unsupported Job Template attributes or
   unsupported/conflicting Job Template attribute values and the client
   supplied the "ipp-attribute-fidelity" attribute with the 'true'
   value, the Printer object REJECTS the request and return the status
   code:

      (1) 'client-error-conflicting-attributes' status code, if there
          were any conflicts between attributes supplied by the client.
      (2) 'client-error-attributes-or-values-not-supported' status code,
          otherwise.

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   Note:  Unsupported Operation attributes or values that are returned
   do not affect the status returned in this step.  If the unsupported
   Operation attribute was a serious error, the above already rejected
   the request in a previous step.  If control gets to this step with
   unsupported Operation attributes being returned, they are not serious
   errors.

2.2.3.3   For the Validate-Job operation, RETURN one of the success
          status codes

   If the requested operation is the Validate-Job operation, the Printer
   object returns:

      (1) the "successful-ok" status code, if there are no unsupported
          or conflicting Job Template attributes or values.
      (2) the "successful-ok-conflicting-attributes, if there are any
          conflicting Job Template attribute or values.
      (3) the "successful-ok-ignored-or-substituted-attributes, if there
          are only unsupported Job Template attributes or values.

   Note:  Unsupported Operation attributes or values that are returned
   do not affect the status returned in this step.  If the unsupported
   Operation attribute was a serious error, the above already rejected
   the request in a previous step.  If control gets to this step with
   unsupported Operation attributes being returned, they are not serious
   errors.

2.2.3.4   Create the Job object with attributes to support

   If "ipp-attribute-fidelity" is set to 'false' (or it was not supplied
   by the client), the Printer object:

      (1) creates a Job object, assigns a unique value to the job's
          "job-uri" and "job-id" attributes, and initializes all of the
          job's other supported Job Description attributes.
      (2) removes all unsupported attributes from the Job object.
      (3) for each unsupported value, removes either the unsupported
          value or substitutes the unsupported attribute value with some
          supported value.  If an attribute has no values after removing
          unsupported values from it, the attribute is removed from the
          Job object (so that the normal default behavior at job
          processing time will take place for that attribute).
      (4) for each conflicting value, removes either the conflicting
          value or substitutes the conflicting attribute value with some
          other supported value.  If an attribute has no values after
          removing conflicting values from it, the attribute is removed
          from the Job object (so that the normal default behavior at
          job processing time will take place for that attribute).

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   If there were no attributes or values flagged as unsupported, or the
   value of 'ipp-attribute-fidelity" was 'false', the Printer object is
   able to accept the create request and create a new Job object.  If
   the "ipp-attribute-fidelity" attribute is set to 'true', the Job
   Template attributes that populate the new Job object are necessarily
   all the Job Template attributes supplied in the create request.  If
   the "ipp-attribute-fidelity" attribute is set to 'false', the Job
   Template attributes that populate the new Job object are all the
   client supplied Job Template attributes that are supported or that
   have value substitution.  Thus, some of the requested Job Template
   attributes may not appear in the Job object because the Printer
   object did not support those attributes.  The attributes that
   populate the Job object are persistently stored with the Job object
   for that Job.  A Get-Job-Attributes operation on that Job object will
   return only those attributes that are persistently stored with the
   Job object.

   Note: All Job Template attributes that are persistently stored with
   the Job object are intended to be "override values"; that is, they
   that take precedence over whatever other embedded instructions might
   be in the document data itself.  However, it is not possible for all
   Printer objects to realize the semantics of "override".  End users
   may query the Printer's "pdl-override-supported" attribute to
   determine if the Printer either attempts or does not attempt to
   override document data instructions with IPP attributes.

   There are some cases, where a Printer supports a Job Template
   attribute and has an associated default value set for that attribute.
   In the case where a client does not supply the corresponding
   attribute, the Printer does not use its default values to populate
   Job attributes when creating the new Job object; only Job Template
   attributes actually in the create request are used to populate the
   Job object. The Printer's default values are only used later at Job
   processing time if no other IPP attribute or instruction embedded in
   the document data is present.

   Note: If the default values associated with Job Template attributes
   that the client did not supply were to be used to populate the Job
   object, then these values would become "override values" rather than
   defaults.  If the Printer supports the 'attempted' value of the
   "pdl-override-supported" attribute, then these override values could
   replace values specified within the document data.  This is not the
   intent of the default value mechanism. A default value for an
   attribute is used only if the create request did not specify that
   attribute (or it was ignored when allowed by "ipp-attribute-fidelity"
   being 'false') and no value was provided within the content of the
   document data.

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   If the client does not supply a value for some Job Template
   attribute, and the Printer does not support that attribute, as far as
   IPP is concerned, the result of processing that Job (with respect to
   the missing attribute) is undefined.

2.2.3.5   Return one of the success status codes

   Once the Job object has been created, the Printer object accepts the
   request and returns to the client:

      (1) the 'successful-ok' status code, if there are no unsupported
          or conflicting Job Template attributes or values.
      (2) the 'successful-ok-conflicting-attributes' status code, if
          there are any conflicting Job Template attribute or values.
      (3) the 'successful-ok-ignored-or-substituted-attributes' status
          code, if there are only unsupported Job Template attributes or
          values.

   Note:  Unsupported Operation attributes or values that are returned
   do not affect the status returned in this step.  If the unsupported
   Operation attribute was a serious error, the above already rejected
   the request in a previous step.  If control gets to this step with
   unsupported Operation attributes being returned, they are not serious
   errors.

   The Printer object also returns Job status attributes that indicate
   the initial state of the Job ('pending', 'pending-held', '
   processing', etc.), etc.  See Print-Job Response, [RFC2566] section
   3.2.1.2.

2.2.3.6   Accept appended Document Content

   The Printer object accepts the appended Document Content data and
   either starts it printing, or spools it for later processing.

2.2.3.7   Scheduling and Starting to Process the Job

   The Printer object uses its own configuration and implementation
   specific algorithms for scheduling the Job in the correct processing
   order.  Once the Printer object begins processing the Job, the
   Printer changes the Job's state to 'processing'. If the Printer
   object supports PDL override (the "pdl-override-supported" attribute
   set to 'attempted'), the implementation does its best to see that IPP
   attributes take precedence over embedded instructions in the document
   data.

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2.2.3.8   Completing the Job

   The Printer object continues to process the Job until it can move the
   Job into the 'completed' state.  If an Cancel-Job operation is
   received, the implementation eventually moves the Job into the '
   canceled' state.  If the system encounters errors during processing
   that do not allow it to progress the Job into a completed state, the
   implementation halts all processing, cleans up any resources, and
   moves the Job into the 'aborted' state.

2.2.3.9   Destroying the Job after completion

   Once the Job moves to the 'completed', 'aborted', or 'canceled'
   state, it is an implementation decision as to when to destroy the Job
   object and release all associated resources.  Once the Job has been
   destroyed, the Printer would return either the "client-error-not-
   found" or "client-error-gone" status codes for operations directed at
   that Job.

   Note:  the Printer object SHOULD NOT re-use a "job-uri" or "job-id"
   value for a sufficiently long time after a job has been destroyed, so
   that stale references kept by clients are less likely to access the
   wrong (newer) job.

2.2.3.10  Interaction with "ipp-attribute-fidelity"

   Some Printer object implementations may support "ipp-attribute-
   fidelity" set to 'true' and "pdl-override-supported" set to '
   attempted' and yet still not be able to realize exactly what the
   client specifies in the create request.  This is due to legacy
   decisions and assumptions that have been made about the role of job
   instructions embedded within the document data and external job
   instructions that accompany the document data and how to handle
   conflicts between such instructions.  The inability to be 100%
   precise about how a given implementation will behave is also
   compounded by the fact that the two special attributes, "ipp-
   attribute-fidelity" and "pdl-override-supported", apply to the whole
   job rather than specific values for each attribute. For example, some
   implementations may be able to override almost all Job Template
   attributes except for "number-up".

2.3 Status codes returned by operation

   This section lists all status codes once in the first operation
   (Print-Job).  Then it lists the status codes that are different or
   specialized for subsequent operations under each operation.

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2.3.1 Printer Operations

2.3.1.1   Print-Job

   The Printer object MUST return one of the following "status-code"
   values for the indicated reason.  Whether all of the document data
   has been accepted or not before returning the success or error
   response depends on implementation.  See Section 14 for a more
   complete description of each status code.

   For the following success status codes, the Job object has been
   created and the "job-id", and "job-uri" assigned and returned in the
   response:

      successful-ok:  no request attributes were substituted or ignored.
      successful-ok-ignored-or-substituted-attributes:  some supplied
         (1) attributes were ignored or (2) unsupported attribute
         syntaxes or values were substituted with supported values or
         were ignored.  Unsupported attributes, attribute syntaxes, or
         values MUST be returned in the Unsupported Attributes group of
         the response.
      successful-ok-conflicting-attributes:  some supplied attribute
         values conflicted with the values of other supplied attributes
         and were either substituted or ignored.  Attributes or values
         which conflict with other attributes and have been substituted
         or ignored MUST be returned in the Unsupported Attributes group
         of the response as supplied by the client.

   [RFC2566] section 3.1.6 Operation Status Codes and Messages states:

         If the Printer object supports the "status-message" operation
         attribute, it SHOULD use the REQUIRED 'utf-8' charset to return
         a status message for the following error status codes (see
         section 14):  'client-error-bad-request', 'client-error-
         charset-not-supported', 'server-error-internal-error', '
         server-error-operation-not-supported', and 'server-error-
         version-not-supported'.  In this case, it MUST set the value of
         the "attributes-charset" operation attribute to 'utf-8' in the
         error response.

   For the following error status codes, no job is created and no "job-
   id" or "job-uri" is returned:

      client-error-bad-request:  The request syntax does not conform to
         the specification.

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      client-error-forbidden:  The request is being refused for
         authorization or authentication reasons.  The implementation
         security policy is to not reveal whether the failure is one of
         authentication or authorization.
      client-error-not-authenticated:  Either the request requires
         authentication information to be supplied or the authentication
         information is not sufficient for authorization.
      client-error-not-authorized:  The requester is not authorized to
         perform the request on the target object.
      client-error-not-possible:  The request cannot be carried out
         because of the state of the system.  See also 'server-error-
         not-accepting-jobs' status code which MUST take precedence if
         the Printer object's "printer-accepting-jobs" attribute is '
         false'.
      client-error-timeout:  not applicable.
      client-error-not-found:  the target object does not exist.
      client-error-gone:  the target object no longer exists and no
         forwarding address is known.
      client-error-request-entity-too-large:  the size of the request
         and/or print data exceeds the capacity of the IPP Printer to
         process it.
      client-error-request-value-too-long:  the size of request variable
         length attribute values, such as 'text' and 'name' attribute
         syntaxes, exceed the maximum length specified in [RFC2566] for
         the attribute and MUST be returned in the Unsupported
         Attributes Group.
      client-error-document-format-not-supported:  the document format
         supplied is not supported.  The "document-format" attribute
         with the unsupported value MUST be returned in the Unsupported
         Attributes Group.  This error SHOULD take precedence over any
         other 'xxx-not-supported' error, except 'client-error-charset-
         not-supported'.
      client-error-attributes-or-values-not-supported:  one or more
         supplied attributes, attribute syntaxes, or values are not
         supported and the client supplied the "ipp-attributes-fidelity"
         operation attribute with a 'true' value.  They MUST be returned
         in the Unsupported Attributes Group as explained below.
      client-error-uri-scheme-not-supported:  not applicable.
      client-error-charset-not-supported:  the charset supplied in the
         "attributes-charset" operation attribute is not supported.  The
         Printer's "configured-charset" MUST be returned in the response
         as the value of the "attributes-charset" operation attribute
         and used for any 'text' and 'name' attributes returned in the
         error response.  This error SHOULD take precedence over any
         other error, unless the request syntax is so bad that the
         client's supplied "attributes-charset" cannot be determined.

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      client-error-conflicting-attributes:  one or more supplied
         attribute va attribute values conflicted with each other and
         the client supplied the "ipp-attributes-fidelity" operation
         attribute with a 'true' value.  They MUST be returned in the
         Unsupported Attributes Group as explained below.
      server-error-internal-error:  an unexpected condition prevents the
         request from being fulfilled.
      server-error-operation-not-supported:  not applicable (since
         Print-Job is REQUIRED).
      server-error-service-unavailable:  the service is temporarily
         overloaded.
      server-error-version-not-supported:  the version in the request is
         not supported.  The "closest" version number supported MUST be
         returned in the response.
      server-error-device-error:  a device error occurred while
         receiving or spooling the request or document data or the IPP
         Printer object can only accept one job at a time.
      server-error-temporary-error:  a temporary error such as a buffer
         full write error, a memory overflow, or a disk full condition
         occurred while receiving the request and/or the document data.
      server-error-not-accepting-jobs:  the Printer object's "printer-
         is-not-accepting-jobs" attribute is 'false'.
      server-error-busy:  the Printer is too busy processing jobs to
         accept another job at this time.
      server-error-job-canceled:  the job has been canceled by an
         operator or the system while the client was transmitting the
         document data.

2.3.1.2   Print-URI

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to Print-URI with the following
   specializations and differences.  See Section 14 for a more complete
   description of each status code.

      server-error-uri-scheme-not-supported:  the URI scheme supplied in
         the "document-uri" operation attribute is not supported and is
         returned in the Unsupported Attributes group.

2.3.1.3   Validate-Job

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to Validate-Job.  See Section 14
   for a more complete description of each status code.

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2.3.1.4   Create-Job

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to Create-Job with the following
   specializations and differences.  See Section 14 for a more complete
   description of each status code.

      server-error-operation-not-supported:  the Create-Job operation is
         not supported.

2.3.1.5   Get-Printer-Attributes

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to the Get-Printer-Attributes
   operation with the following specializations and differences.   See
   Section 14 for a more complete description of each status code.

   For the following success status codes, the requested attributes are
   returned in Group 3 in the response:

      successful-ok:  no request attributes were substituted or ignored
         (same as Print-Job) and no requested attributes were
         unsupported.
      successful-ok-ignored-or-substituted-attributes:   same as Print-
         Job, except the "requested-attributes" operation attribute MAY,
         but NEED NOT, be returned with the unsupported values.
      successful-ok-conflicting-attributes:  same as Print-Job.

   For the error status codes, Group 3 is returned containing no
   attributes or is not returned at all:

      client-error-not-possible:  Same as Print-Job, in addition the
         Printer object is not accepting any requests.
      client-error-request-entity-too-large:  same as Print-job, except
         that no print data is involved.
      client-error-attributes-or-values-not-supported:  not applicable,
         since unsupported operation attributes MUST be ignored and '
         successful-ok-ignored-or-substituted-attributes' returned.
      client-error-conflicting-attributes:  same as Print-Job, except
         that "ipp-attribute-fidelity" is not involved.
      server-error-operation-not-supported:  not applicable (since Get-
         Printer-Attributes is REQUIRED).
      server-error-device-error:  same as Print-Job, except that no
         document data is involved.
      server-error-temporary-error:  same as Print-Job, except that no
         document data is involved.
      server-error-not-accepting-jobs:  not applicable.

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      server-error-busy:  same as Print-Job, except the IPP object is
         too busy to accept even query requests.
      server-error-job-canceled:  not applicable.

2.3.1.6   Get-Jobs

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to the Get-Jobs operation with the
   following specializations and differences.   See Section 14 for a
   more complete description of each status code.

   For the following success status codes, the requested attributes are
   returned in Group 3 in the response:

      successful-ok:  no request attributes were substituted or ignored
         (same as Print-Job) and no requested attributes were
         unsupported.
      successful-ok-ignored-or-substituted-attributes:   same as Print-
         Job, except the "requested-attributes" operation attribute MAY,
         but NEED NOT, be returned with the unsupported values.
      successful-ok-conflicting-attributes:  same as Print-Job.

   For any error status codes, Group 3 is returned containing no
   attributes or is not returned at all.  The following brief error
   status code descriptions contain unique information for use with
   Get-Jobs operation.  See section 14 for the other error status codes
   that apply uniformly to all operations:

      client-error-not-possible:  Same as Print-Job, in addition the
         Printer object is not accepting any requests.
      client-error-request-entity-too-large:  same as Print-job, except
         that no print data is involved.
      client-error-document-format-not-supported:  not applicable.
      client-error-attributes-or-values-not-supported:  not applicable,
         since unsupported operation attributes MUST be ignored and '
         successful-ok-ignored-or-substituted-attributes' returned.
      client-error-conflicting-attributes:  same as Print-Job, except
         that "ipp-attribute-fidelity" is not involved.
      server-error-operation-not-supported:  not applicable (since Get-
         Jobs is REQUIRED).
      server-error-device-error:  same as Print-Job, except that no
         document data is involved.
      server-error-temporary-error:  same as Print-Job, except that no
         document data is involved.
      server-error-not-accepting-jobs:  not applicable.
      server-error-job-canceled:  not applicable.

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2.3.2 Job Operations

2.3.2.1   Send-Document

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to the Get-Printer-Attributes
   operation with the following specializations and differences.   See
   Section 14 for a more complete description of each status code.

   For the following success status codes, the document has been added
   to the specified Job object and the job's "number-of-documents"
   attribute has been incremented:

      successful-ok:  no request attributes were substituted or ignored
         (same as Print-Job).
      successful-ok-ignored-or-substituted-attributes:  same as Print-
         Job.
      successful-ok-conflicting-attributes:  same as Print-Job.

   For the error status codes, no document has been added to the Job
   object and the job's "number-of-documents" attribute has not been
   incremented:

      client-error-not-possible: Same as Print-Job, except that the
         Printer's "printer-is-accepting-jobs" attribute is not
         involved, so that the client is able to finish submitting a
         multi-document job after this attribute has been set to 'true'.
         Another condition is that the state of the job precludes Send-
         Document, i.e., the job has already been closed out by the
         client.  However, if the IPP Printer closed out the job due to
         timeout, the 'client-error-timeout' error status SHOULD  be
         returned instead.
      client-error-timeout:  This request was sent after the Printer
         closed the job, because it has not received a Send-Document or
         Send-URI operation within the Printer's "multiple-operation-
         time-out" period.
      client-error-request-entity-too-large:  same as Print-Job.
      client-error-conflicting-attributes:  same as Print-Job, except
         that "ipp-attributes-fidelity" operation attribute is not
         involved.
      server-error-operation-not-supported:  the Send-Document request
         is not supported.
      server-error-not-accepting-jobs:  not applicable.
      server-error-job-canceled:  the job has been canceled by an
         operator or the system while the client was transmitting the
         data.

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2.3.2.2   Send-URI

   All of the Print-Job status code descriptions in Section 3.2.1.2
   Print-Job Response with the specializations described for Send-
   Document are applicable to Send-URI.  See Section 14 for a more
   complete description of each status code.

      server-error-uri-scheme-not-supported:  the URI scheme supplied in
         the "document-uri" operation attribute is not supported and the
         "document-uri" attribute MUST be returned in the Unsupported
         Attributes group.

2.3.2.3   Cancel-Job

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to Cancel-Job with the following
   specializations and differences.  See Section 14 for a more complete
   description of each status code.

   For the following success status codes, the Job object is being
   canceled or has been canceled:

      successful-ok:  no request attributes were substituted or ignored
         (same as Print-Job).
      successful-ok-ignored-or-substituted-attributes:   same as Print-
         Job.
      successful-ok-conflicting-attributes:  same as Print-Job.

   For any of the error status codes, the Job object has not been
   canceled or was previously canceled.

      client-error-not-possible:  The request cannot be carried out
         because of the state of the Job object ('completed', '
         canceled', or 'aborted') or the state of the system.
      client-error-not-found:  the target Printer and/or Job object does
         not exist.
      client-error-gone:  the target Printer and/or Job object no longer
         exists and no forwarding address is known.
      client-error-request-entity-too-large:  same as Print-Job, except
         no document data is involved.
      client-error-document-format-not-supported:  not applicable.
      client-error-attributes-or-values-not-supported:  not applicable,
         since unsupported operation attributes and values MUST be
         ignored.
      client-error-conflicting-attributes:  same as Print-Job, except
         that the Printer's "printer-is-accepting-jobs" attribute is not
         involved.

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      server-error-operation-not-supported:  not applicable (Cancel-Job
         is REQUIRED).
      server-error-device-error:  same as Print-Job, except no document
         data is involved.
      server-error-temporary-error:  same as Print-Job, except no
         document data is involved.
      server-error-not-accepting-jobs:  not applicable.
      server-error-job-canceled:  not applicable.

2.3.2.4   Get-Job-Attributes

   All of the Print-Job status codes described in Section 3.2.1.2
   Print-Job Response are applicable to Get-Job-Attributes with the
   following specializations and differences.  See Section 14 for a more
   complete description of each status code.

   For the following success status codes, the requested attributes are
   returned in Group 3 in the response:

      successful-ok:  no request attributes were substituted or ignored
         (same as Print-Job) and no requested attributes were
         unsupported.
      successful-ok-ignored-or-substituted-attributes:   same as Print-
         Job, except the "requested-attributes" operation attribute MAY,
         but NEED NOT, be returned with the unsupported values.
      successful-ok-conflicting-attributes:  same as Print-Job.

   For the error status codes, Group 3 is returned containing no
   attributes or is not returned at all.

      client-error-not-possible:  Same as Print-Job, in addition the
         Printer object is not accepting any requests.
      client-error-document-format-not-supported:  not applicable.
      client-error-attributes-or-values-not-supported:  not applicable.
      client-error-uri-scheme-not-supported:  not applicable.
      client-error-conflicting-attributes:  not applicable
      server-error-operation-not-supported:  not applicable (since Get-
         Job-Attributes is REQUIRED).
      server-error-device-error:  same as Print-Job, except no document
         data is involved.
      server-error-temporary-error:  sane as Print-Job, except no
         document data is involved.
      server-error-not-accepting-jobs:  not applicable.  server-error-
      job-canceled:  not applicable.

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2.4 Validate-Job

   The Validate-Job operation has been designed so that its
   implementation may be a part of the Print-Job operation.  Therefore,
   requiring Validate-Job is not a burden on implementers.  Also it is
   useful for client's to be able to count on its presence in all
   conformance implementations, so that the client can determine before
   sending a long document, whether the job will be accepted by the IPP
   Printer or not.

2.5 Case Sensitivity in URIs

   IPP client and server implementations must be aware of the diverse
   uppercase/lowercase nature of URIs.  RFC 2396 defines URL schemes and
   Host names as case insensitive but reminds us that the rest of the
   URL may well demonstrate case sensitivity.  When creating URL's for
   fields where the choice is completely arbitrary, it is probably best
   to select lower case.  However, this cannot be guaranteed and
   implementations MUST NOT rely on any fields being case-sensitive or
   case-insensitive in the URL beyond the URL scheme and host name
   fields.

   The reason that the IPP specification does not make any restrictions
   on URIs, is so that implementations of IPP may use off-the-shelf
   components that conform to the standards that define URIs, such as
   RFC 2396 and the HTTP/1.1 specifications [RFC2068].  See these
   specifications for rules of matching, comparison, and case-
   sensitivity.

   It is also recommended that System Administrators and implementations
   avoid creating URLs for different printers that differ only in their
   case.  For example, don't have Printer1 and printer1 as two different
   IPP Printers.

   The HTTP/1.1 specification [RFC2068] contains more details on
   comparing URLs.

2.6 Character Sets, natural languages, and internationalization

   This section discusses character set support, natural language
   support and internationalization.

2.6.1 Character set code conversion support

   IPP clients and IPP objects are REQUIRED to support UTF-8.  They MAY
   support additional charsets.  It is RECOMMENDED that an IPP object
   also support US-ASCII, since many clients support US-ASCII, and
   indicate that UTF-8 and US-ASCII are supported by populating the

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   Printer's "charset-supported" with 'utf-8' and 'us-ascii' values.  An
   IPP object is required to code covert with as little loss as possible
   between the charsets that it supports, as indicated in the Printer's
   "charsets-supported" attribute.

   How should the server handle the situation where the "attributes-
   charset" of the response itself is "us-ascii", but one or more
   attributes in that response is in the "utf-8" format?

   Example:  Consider a case where a client sends a Print-Job request
   with "utf-8" as the value of "attributes-charset" and with the "job-
   name" attribute supplied.  Later another client submits a Get-Job-
   Attribute or Get-Jobs request.  This second request contains the
   "attributes-charset" with value "us-ascii" and "requested-attributes"
   attribute with exactly one value "job-name".

   According to the RFC2566 document (section 3.1.4.2), the value of the
   "attributes-charset" for the response of the second request must be
   "us-ascii" since that is the charset specified in the request.  The
   "job-name" value, however, is in "utf-8" format.  Should the request
   be rejected even though both "utf-8" and "us-ascii" charsets are
   supported by the server? or should the "job-name" value be converted
   to "us-ascii" and return "successful-ok-conflicting-attributes"
   (0x0002) as the status code?

   Answer:  An IPP object that supports both utf-8 (REQUIRED) and us-
   ascii, the second paragraph of section 3.1.4.2 applies so that the
   IPP object MUST accept the request, perform code set conversion
   between these two charsets with "the highest fidelity possible" and
   return 'successful-ok', rather than a warning 'successful-ok-
   conflicting-attributes, or an error.  The printer will do the best it
   can to convert between each of the character sets that it supports--
   even if that means providing a string of question marks because none
   of the characters are representable in US ASCII.  If it can't perform
   such conversion, it MUST NOT advertise us-ascii as a value of its
   "attributes-charset-supported" and MUST reject any request that
   requests 'us-ascii'.

   One IPP object implementation strategy is to convert all request text
   and name values to a Unicode internal representation.  This is 16-bit
   and virtually universal.  Then convert to the specified operation
   attributes-charset on output.

   Also it would be smarter for a client to ask for 'utf-8', rather than
   'us-ascii' and throw away characters that it doesn't understand,
   rather than depending on the code conversion of the IPP object.

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2.6.2 What charset to return when an unsupported charset is requested?

   Section 3.1.4.1 Request Operation attributes was clarified in
   November 1998 as follows:

      All clients and IPP objects MUST support the 'utf-8' charset
      [RFC2044] and MAY support additional charsets provided that they
      are registered with IANA [IANA-CS].  If the Printer object does
      not support the client supplied charset value, the Printer object
      MUST reject the request, set the "attributes-charset" to 'utf-8'
      in the response, and return the 'client-error-charset-not-
      supported' status code and any 'text' or 'name' attributes using
      the 'utf-8' charset.

   Since the client and IPP object MUST support UTF-8, returning any
   text or name attributes in UTF-8 when the client requests a charset
   that is not supported should allow the client to display the text or
   name.

   Since such an error is a client error, rather than a user error, the
   client should check the status code first so that it can avoid
   displaying any other returned 'text' and 'name' attributes that are
   not in the charset requested.

   Furthermore, [RFC2566] section 14.1.4.14 client-error-charset-not-
   supported (0x040D) was clarified in November 1998 as follows:

      For any operation, if the IPP Printer does not support the charset
      supplied by the client in the "attributes-charset" operation
      attribute, the Printer MUST reject the operation and return this
      status and any 'text' or 'name' attributes using the 'utf-8'
      charset (see Section 3.1.4.1).

2.6.3 Natural Language Override (NLO)

   The 'text' and 'name' attributes each have two forms.  One has an
   implicit natural language, and the other has an explicit natural
   language.  The 'textWithoutLanguage' and 'textWithoutLanguage' are
   the two 'text' forms.  The 'nameWithoutLanguage" and '
   nameWithLanguage are the two 'name' forms.  If a receiver (IPP object
   or IPP client) supports an attribute with attribute syntax 'text', it
   MUST support both forms in a request and a response.  A sender (IPP
   client or IPP object) MAY send either form for any such attribute.
   When a sender sends a WithoutLanguage form, the implicit natural
   language is specified in the "attributes-natural-language" operation
   attribute which all senders MUST include in every request and
   response.

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   When a sender sends a WithLanguage form, it MAY be different from the
   implicit natural language supplied by the sender or it MAY be the
   same.  The receiver MUST treat either form equivalently.

   There is an implementation decision for senders, whether to always
   send the WithLanguage forms or use the WithoutLanguage form when the
   attribute's natural language is the same as the request or response.
   The former approach makes the sender implementation simpler.  The
   latter approach is more efficient on the wire and allows inter-
   working with non-conforming receivers that fail to support the
   WithLanguage forms.  As each approach have advantages, the choice is
   completely up to the implementer of the sender.

   Furthermore, when a client receives a 'text' or 'name' job attribute
   that it had previously supplied, that client MUST NOT expect to see
   the attribute in the same form, i.e., in the same WithoutLanguage or
   WithLanguage form as the client supplied when it created the job.
   The IPP object is free to transform the attribute from the
   WithLanguage form to the WithoutLanguage form and vice versa, as long
   as the natural language is preserved.  However, in order to meet this
   latter requirement, it is usually simpler for the IPP object
   implementation to store the natural language explicitly with the
   attribute value, i.e., to store using an internal representation that
   resembles the WithLanguage form.

   The IPP Printer MUST copy the natural language of a job, i.e., the
   value of the "attributes-natural-language" operation attribute
   supplied by the client in the create operation, to the Job object as
   a Job Description attribute, so that a client is able to query it.
   In returning a Get-Job-Attributes response, the IPP object MAY return
   one of three natural language values in the response's "attributes-
   natural-language" operation attribute: (1) that requested by the
   requester, (2) the natural language of the job, or (3) the configured
   natural language of the IPP Printer, if the requested language is not
   supported by the IPP Printer.

   This "attributes-natural-language" Job Description attribute is
   useful for an IPP object implementation that prints start sheets in
   the language of the user who submitted the job.  This same Job
   Description attribute is useful to a multi-lingual operator who has
   to communicate with different job submitters in different natural
   languages.  This same Job Description attribute is expected to be
   used in the future to generate notification messages in the natural
   language of the job submitter.

   Early drafts of [RFC2566] contained a job-level natural language
   override (NLO) for the Get-Jobs response.  A job-level (NLO) is an
   (unrequested) Job Attribute which then specified the implicit natural

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   language for any other WithoutLanguage job attributes returned in the
   response for that job.  Interoperability testing of early
   implementations showed that no one was implementing the job-level NLO
   in Get-Job responses.  So the job-level NLO was eliminated from the
   Get- Jobs response.  This simplification makes all requests and
   responses consistent in that the implicit natural language for any
   WithoutLanguage 'text' or 'name' form is always supplied in the
   request's or response's "attributes-natural-language" operation
   attribute.



(page 50 continued on part 3)

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