RFC3196 - Internet Printing Protocol/1.1: Implementors Guide

Network Working Group T. Hastings
Request for Comments: 3196 C. Manros
Obsoletes: 2639 P. Zehler
Category: Informational Xerox Corporation
C. Kugler
IBM Printing Systems Co
H. Holst
i-data Printing Systems
November 2001
Internet Printing Protocol/1.1: Implementor"s Guide
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2001). All Rights Reserved.
Abstract
This document is one of a set of documents, which together describe
all ASPects of a new Internet Printing Protocol (IPP).
Table of Contents
1 IntrodUCtion................................................... 4
1.1 Conformance language........................................ 5
1.2 Other terminology........................................... 6
1.3 Issues Raised from Interoperability Testing Events.......... 6
2 IPP Objects.................................................... 6
3 IPP Operations................................................. 7
3.1 Common Semantics............................................ 7
3.1.1 Summary of Operation Attributes............................ 8
3.1.2 Suggested Operation Processing Steps for IPP Objects....... 16
3.1.2.1 Suggested Operation Processing Steps for all Operations. 17
3.1.2.1.1 Validate version number............................... 18
3.1.2.1.2 Validate operation identifier......................... 20
3.1.2.1.3 Validate the request identifier....................... 20
3.1.2.1.4 Validate attribute group and attribute presence and
order................................................. 20
3.1.2.1.4.1 Validate the presence and order of attribute groups. 20
3.1.2.1.4.2 Ignore unknown attribute groups in the eXPected
position............................................ 21
3.1.2.1.4.3 Validate the presence of a single occurrence of
required Operation attributes....................... 21
3.1.2.1.5 Validate the values of the REQUIRED Operation
attributes............................................ 29
3.1.2.1.6 Validate the values of the OPTIONAL Operation
attributes............................................ 33
3.1.2.2 Suggested Additional Processing Steps for Operations
that Create/Validate Jobs and Add Documents............. 37
3.1.2.2.1 Default "ipp-attribute-fidelity" if not supplied...... 37
3.1.2.2.2 Check that the Printer object is accepting jobs....... 38
3.1.2.2.3 Validate the values of the Job Template attributes.... 38
3.1.2.3 Algorithm for job validation............................ 39
3.1.2.3.1 Check for conflicting Job Template attributes values.. 45
3.1.2.3.2 Decide whether to REJECT the request.................. 46
3.1.2.3.3 For the Validate-Job operation, RETURN one of the
success status codes.................................. 48
3.1.2.3.4 Create the Job object with attributes to support...... 48
3.1.2.3.5 Return one of the success status codes................ 50
3.1.2.3.6 Accept appended Document Content...................... 50
3.1.2.3.7 Scheduling and Starting to Process the Job............ 50
3.1.2.3.8 Completing the Job.................................... 50
3.1.2.3.9 Destroying the Job after completion................... 51
3.1.2.3.10 Interaction with "ipp-attribute-fidelity"............. 51
3.1.2.3.11 Character set code conversion support................. 51
3.1.2.3.12 What charset to return when an unsupported charset is
requested (Issue 1.19)?....... ....................... 52
3.1.2.3.13 Natural Language Override (NLO)....................... 53
3.1.3 Status codes returned by operation......................... 55
3.1.3.1 Printer Operations...................................... 55
3.1.3.1.1 Print-Job............................................. 55
3.1.3.1.2 Print-URI............................................. 58
3.1.3.1.3 Validate-Job.......................................... 58
3.1.3.1.4 Create-Job............................................ 58
3.1.3.1.5 Get-Printer-Attributes................................ 59
3.1.3.1.6 Get-Jobs.............................................. 60
3.1.3.1.7 Pause-Printer......................................... 61
3.1.3.1.8 Resume-Printer........................................ 62
3.1.3.1.8.1 What about Printers unable to change state due to
an error condition?................................. 63
3.1.3.1.8.2 How is "printer-state" handled on Resume-Printer?... 63
3.1.3.1.9 Purge-Printer......................................... 63
3.1.3.2 Job Operations.......................................... 64
3.1.3.2.1 Send-Document......................................... 64
3.1.3.2.2 Send-URI.............................................. 65
3.1.3.2.3 Cancel-Job............................................ 65
3.1.3.2.4 Get-Job-Attributes.................................... 67
3.1.3.2.5 Hold-Job.............................................. 68
3.1.3.2.6 Release-Job........................................... 69
3.1.3.2.7 Restart-Job........................................... 69
3.1.3.2.7.1 Can documents be added to a restarted job?.......... 69
3.1.4 Returning unsupported attributes in Get-Xxxx responses
(Issue 1.18)............................................... 70
3.1.5 Sending empty attribute groups............................. 70
3.2 Printer Operations.......................................... 71
3.2.1 Print-Job operation........................................ 71
3.2.1.1 Flow controlling the data portion of a Print-Job
request (Issue 1.22).................................... 71
3.2.1.2 Returning job-state in Print-Job response (Issue 1.30).. 71
3.2.2 Get-Printer-Attributes operation........................... 72
3.2.3 Get-Jobs operation......................................... 72
3.2.3.1 Get-Jobs, my-jobs="true", and "requesting-user-name"
(Issue 1.39)?.......................................... 72
3.2.3.2 Why is there a "limit" attribute in the Get-Jobs
operation?.............................................. 73
3.2.4 Create-Job operation....................................... 73
3.3 Job Operations.............................................. 74
3.3.1 Validate-Job............................................... 74
3.3.2 Restart-Job................................................ 74
4 Object Attributes.............................................. 74
4.1 Attribute Syntax"s.......................................... 74
4.1.1 The "none" value for empty sets (Issue 1.37)............... 74
4.1.2 Multi-valued attributes (Issue 1.31)....................... 75
4.1.3 Case Sensitivity in URIs (issue 1.6)....................... 75
4.1.4 Maximum length for xxxWithLanguage and xxxWithoutLanguage.. 76
4.2 Job Template Attributes..................................... 76
4.2.1 multiple-document-handling(type2 keyWord).................. 76
4.2.1.1 Support of multiple document jobs....................... 76
4.3 Job Description Attributes.................................. 76
4.3.1 Getting the date and time of day........................... 76
4.4 Printer Description Attributes.............................. 77
4.4.1 queued-job-count (integer(0:MAX)).......................... 77
4.4.1.1 Why is "queued-job-count" RECOMMENDED (Issue 1.14)?..... 77
4.4.1.2 Is "queued-job-count" a good measure of how busy a
printer is (Issue 1.15)?................................ 77
4.4.2 printer-current-time (dateTime)............................ 78
4.4.3 Printer-uri................................................ 78
4.5 Empty Jobs.................................................. 79
5 Directory Considerations....................................... 79
5.1 General Directory Schema Considerations..................... 79
5.2 IPP Printer with a DNS name................................. 79
6 Security Considerations........................................ 80
6.1 Querying jobs with IPP that were submitted using other job
submission protocols (Issue 1.32)........................... 80
7 Encoding and Transport......................................... 81
7.1 General Headers............................................. 83
7.2 Request Headers............................................ 84
7.3 Response Headers............................................ 86
7.4 Entity Headers............................................. 87
7.5 Optional support for HTTP/1.0............................... 88
7.6 HTTP/1.1 Chunking........................................... 88
7.6.1 Disabling IPP Server Response Chunking..................... 88
7.6.2 Warning About the Support of Chunked Requests.............. 88
8 References..................................................... 89
9 Authors" Addresses............................................. 91
10 Description of the Base IPP Documents.......................... 94
11 Full Copyright Statement....................................... 96
Tables
Table 1 - Summary of Printer operation attributes that sender MUST
supply ................................................. 8
Table 2 - Summary of Printer operation attributes that sender MAY
supply ................................................. 10
Table 3 - Summary of Job operation attributes that sender MUST
supply.................................................. 12
Table 4 - Summary of Job operation attributes that sender MAY
supply.................................................. 14
Table 5 - Printer operation response attributes................... 16
Table 6 - Examples of validating IPP version...................... 19
Table 7 - Rules for validating single values X against Z.......... 40
1. Introduction
IPP is an application level protocol that can be used for distributed
printing using Internet tools and technologies. This document
contains information that supplements the IPP Model and Semantics
[RFC2911] and the IPP Transport and Encoding [RFC2910] documents. It
is intended to help implementers understand IPP/1.1, as well as
IPP/1.0 [RFC2565, RFC2566], and some of the considerations that may
assist them in the design of their client and/or IPP object
implementation. For example, a typical order of processing requests
is given, including error checking. Motivation for some of the
specification decisions is also included.
This document obsoletes RFC2639 which was the Implementor"s Guide
for IPP/1.0. The IPP Implementor"s Guide (IIG) (this document)
contains information that supplements the IPP Model and Semantics
[RFC2911] and the IPP Transport and Encoding [RFC2910] documents.
This document is just one of a suite of documents that fully define
IPP. The base set of IPP documents includes:
Design Goals for an Internet Printing Protocol [RFC2567]
Rationale for the Structure and Model and Protocol for the
Internet Printing Protocol [RFC2568]
Internet Printing Protocol/1.1: Model and Semantics [RFC2911]
Internet Printing Protocol/1.1: Encoding and Transport [RFC2910]
Internet Printing Protocol/1.1: Implementor"s Guide (this
document)
Mapping between LPD and IPP Protocols [RFC2569]
See section 10 for a description of these base IPP documents. Anyone
reading these documents for the first time is strongly encouraged to
read the IPP documents in the above order.
As such the information in this document is not part of the formal
specification of IPP/1.1. Instead information is presented to help
implementers understand IPP/1.1, as well as IPP/1.0 [RFC2565,
RFC2566], including some of the motivation for decisions taken by the
committee in developing the specification. Some of the
implementation considerations are intended to help implementers
design their client and/or IPP object implementations. If there are
any contradictions between this document and [RFC2911] or [RFC2910],
those documents take precedence over this document.
Platform-specific implementation considerations will be included in
this guide as they become known.
Note: In order to help the reader of the IIG and the IPP Model and
Semantics document, the sections in this document parallel the
corresponding sections in the Model document and are numbered the
same for ease of cross reference. The sections that correspond to
the IPP Transport and Encoding are correspondingly offset.
1.1 Conformance language
Usually, this document does not contain the terminology MUST, MUST
NOT, MAY, NEED NOT, SHOULD, SHOULD NOT, REQUIRED, and OPTIONAL.
However, when those terms do appear in this document, their intent is
to repeat what the [RFC2911] and [RFC2910] documents require and
allow, rather than specifying additional conformance requirements.
These terms are defined in section 12 on conformance terminology in
[RFC2911], most of which is taken from RFC2119 [RFC2119].
Implementers should read section 12 (APPENDIX A) in [RFC2911] in
order to understand these capitalized words. The words MUST, MUST
NOT, and REQUIRED indicate what implementations are required to
support in a client or IPP object in order to be conformant to
[RFC2911] and [RFC2910]. MAY, NEED NOT, and OPTIONAL indicate was is
merely allowed as an implementer option. The verbs SHOULD and SHOULD
NOT indicate suggested behavior, but which is not required or
disallowed, respectively, in order to conform to the specification.
1.2 Other terminology
This document uses other terms, such as "attributes", "operation",
and "Printer" as defined in [RFC2911] section 12. In addition, the
term "sender" refers to the client that sends a request or an IPP
object that returns a response. The term "receiver" refers to the
IPP object that receives a request and to a client that receives a
response.
1.3 Issues Raised from Interoperability Testing Events
The IPP WG has conducted three open Interoperability Testing Events.
The first one was held in September 1998, the second one was held in
March 1999, and the third one was held in October 2000. See the
summary reports in:
FTP://ftp.pwg.org/pub/pwg/ipp/new_TES/
The issues raised from the first Interoperability Testing Event are
numbered 1.n in this document and have been incorporated into
"IPP/1.0 Model and Semantics" [RFC2566] and the "IPP/1.0 Encoding and
Transport" [RFC2565] documents. However, some of the discussion is
left here in the Implementor"s Guide to help understanding.
The issues raised from the second Interoperability Testing Event are
numbered 2.n in this document have been incorporated into "IPP/1.1
Model and Semantics" [RFC2911] and the "IPP/1.1 Encoding and
Transport" [RFC2910] documents. However, some of the discussion is
left here in the Implementor"s Guide to help understanding.
The issues raised from the third Interoperability Testing Event are
numbered 3.n in this document and are described in:
ftp://ftp.pwg.org/pub/pwg/ipp/Issues/Issues-raised-at-Bake-
Off3.pdf
ftp://ftp.pwg.org/pub/pwg/ipp/Issues/Issues-raised-at-Bake-
Off3.doc
ftp://ftp.pwg.org/pub/pwg/ipp/Issues/Issues-raised-at-Bake-
Off3.txt
2. IPP Objects
The term "client" in IPP is intended to mean any client that issues
IPP operation requests and accepts IPP operation responses, whether
it be a desktop or a server. In other words, the term "client" does
not just mean end-user clients, such as those associated with
desktops.
The term "IPP Printer" in IPP is intended to mean an object that
accepts IPP operation requests and returns IPP operation responses,
whether implemented in a server or a device. An IPP Printer object
MAY, if implemented in a server, turn around and forward received
jobs (and other requests) to other devices and print
servers/services, either using IPP or some other protocol.
3 IPP Operations
This section corresponds to Section 3 "IPP Operations" in the
IPP/1.1 Model and Semantics document [RFC2911].
3.1 Common Semantics
This section discusses semantics common to all operations.
3.1.1 Summary of Operation Attributes
Table 1 - Summary of Printer operation attributes that sender MUST
supply
Printer Operations
Requests Responses
Operation PJ, PU CJ GPA GJ PP, All
Attributes VJ (O) (O) (R) (R) RP, Operations
(R) PP
(O+)
Operation parameters--REQUIRED to be supplied by the sender:
operation-id R R R R R R
status-code R
request-id R R R R R R R
version-number R R R R R R R
Operation attributes--REQUIRED to be supplied by the sender:
attributes- R R R R R R R
charset
attributes- R R R R R R R
natural-
language
document-uri R
job-id*
job-uri*
Printer Operations
Requests Responses
Operation PJ, PU CJ GPA GJ PP, All
Attributes VJ (O) (O) (R) (R) RP, Operations
(R) PP
(O+)
last-document
printer-uri R R R R R R
Operation attributes--RECOMMENDED to be supplied by the
sender:
job-name R R R
requesting-user- R R R R R R
name
Legend:
PJ, VJ: Print-Job, Validate-Job
PU: Print-URI
CJ: Create-Job
GPA: Get-Printer-Attributes
GJ: Get-Jobs
PP, RP, PP: Pause-Printer, Resume-Printer, Purge-Printer
R indicates a REQUIRED operation that MUST be supported by the IPP
object (Printer or Job). For attributes, R indicates that the
attribute MUST be supported by the IPP object that supports the
associated operation.
O indicates an OPTIONAL operation or attribute that MAY be supported
by the IPP object (Printer or Job).
+ indicates that this is not an IPP/1.0 feature, but is only a part
of IPP/1.1 and future versions of IPP.
Table 2 - Summary of Printer operation attributes that sender MAY
supply
Printer Operations
Requests Respon-
ses
Operation Attributes PJ, PU CJ GPA GJ PP, All
VJ (O) (O) (R) (R) RP, Opera
(R) PP tions
(O+)
Operation attributes--OPTIONAL to be supplied by the sender:
status-message O
detailed-status- O
message
document-Access- O**
error
compression R R
document-format R R R
document-name O O
document-natural- O O
language
ipp-attribute- R R R
fidelity
job-impressions O O O
job-k-octets O O O
job-media-sheets O O O
Printer Operations
Requests Respon-
ses
Operation Attributes PJ, PU CJ GPA GJ PP, All
VJ (O) (O) (R) (R) RP, Opera
(R) PP tions
(O+)
limit R
message
my-jobs R
requested-attributes R R
which-jobs R
Legend:
PJ, VJ: Print-Job, Validate-Job
PU: Print-URI
CJ: Create-Job
GPA: Get-Printer-Attributes
GJ: Get-Jobs
PP, RP, PP: Pause-Printer, Resume-Printer, Purge-Printer
R indicates a REQUIRED operation that MUST be supported by the IPP
object (Printer or Job). For attributes, R indicates that the
attribute MUST be supported by the IPP object that supports the
associated operation.
O indicates an OPTIONAL operation or attribute that MAY be supported
by the IPP object (Printer or Job).
+ indicates that this is not an IPP/1.0 feature, but is only a part
of IPP/1.1 and future versions of IPP.
* "job-id" is REQUIRED only if used together with "printer-uri" to
identify the target job; otherwise, "job-uri" is REQUIRED.
** "document-access-error" applies to the Print-URI response only.
Table 3 - Summary of Job operation attributes that sender MUST supply
Job Operations
Requests Responses
Operation SD SU CJ GJA HJ All
Attributes (O) (O) (R) (R) RJ, RJ Opera-
(O+) tions
Operation parameters--REQUIRED to be supplied by the sender:
operation-id R R R R R
status-code R
request-id R R R R R R
version-number R R R R R R
Operation attributes--REQUIRED to be supplied by the sender:
attributes-charset R R R R R R
attributes-natural- R R R R R R
language
document-uri R
job-id* R R R R R
job-uri* R R R R R
last-document R R
printer-uri R R R R R
Operation attributes--RECOMMENDED to be supplied by the sender:
job-name
Job Operations
Requests Responses
Operation SD SU CJ GJA HJ All
Attributes (O) (O) (R) (R) RJ, RJ Opera-
(O+) tions
requesting-user- R R R R R
name
Legend:
SD: Send-Document
SU: Send-URI
CJ: Cancel-Job
GJA: Get-Job-Attributes
HJ, RJ, RJ: Hold-Job, Release-Job, Restart-Job
R indicates a REQUIRED operation that MUST be supported by the IPP
object (Printer or Job). For attributes, R indicates that the
attribute MUST be supported by the IPP object that supports the
associated operation.
O indicates an OPTIONAL operation or attribute that MAY be supported
by the IPP object (Printer or Job).
+ indicates that this is not an IPP/1.0 feature, but is only a part
of IPP/1.1 and future versions of IPP.
* "job-id" is REQUIRED only if used together with "printer-uri" to
identify the target job; otherwise, "job-uri" is REQUIRED.
Table 4 - Summary of Job operation attributes that sender MAY supply
Job Operations
Requests Responses
Operation SD SU CJ GJA HJ, SD All
Attributes (O) (O) (R) (R) RJ, (O) Opera-
RJ tions
(O+)
Operation attributes--OPTIONAL to be supplied by the sender:
status-message O
detailed-status- O
message
document-access- O**
error
compression R R
document-format R R
document-name O O
document-natural- O O
language
ipp-attribute-
fidelity
job-impressions
job-k-octets
job-media-sheets
Job Operations
Requests Responses
Operation SD SU CJ GJA HJ, SD All
Attributes (O) (O) (R) (R) RJ, (O) Opera-
RJ tions
(O+)
limit
message O O O
job-hold-until R
my-jobs
requested- R
attributes
which-jobs
Legend:
SD: Send-Document
SU: Send-URI
CJ: Cancel-Job
GJA: Get-Job-Attributes
HJ, RJ, RJ: Hold-Job, Release-Job, Restart-Job
R indicates a REQUIRED operation that MUST be supported by the IPP
object (Printer or Job). For attributes, R indicates that the
attribute MUST be supported by the IPP object that supports the
associated operation.
O indicates an OPTIONAL operation or attribute that MAY be supported
by the IPP object (Printer or Job).
+ indicates that this is not an IPP/1.0 feature, but is only a part
of IPP/1.1 and future versions of IPP.
* "job-id" is REQUIRED only if used together with "printer-uri" to
identify the target job; otherwise, "job-uri" is REQUIRED.
** "document-access-error" applies to the Send-URI operation only
Table 5 - Printer operation response attributes
Printer Operations
Response
Operation PJ (R) VJ (R) PU (O) CJ (O) GPA GJ (R) PP,
Attributes SD (O) SU (O) (R) RP, PP
(O+)
job-uri R R R
job-id R R R
job-state R R R
job-state- R+ R+ R+
reasons
number-of- O O O
intervening-
jobs
document- O
access-
error+
Legend:
PJ, SJ: Print-Job, Send-Document
VJ: Validate-Job
PU, SU: Print-URI, Send-URI
CJ: Create-Job
GPA: Get-Printer-Attributes
GJ: Get-Jobs
PP, RP, PP: Pause-Printer, Resume-Printer, Purge-Printer
R indicates a REQUIRED operation that MUST be supported by the IPP
object (Printer or Job). For attributes, R indicates that the
attribute MUST be supported by the IPP object that supports the
associated operation.
O indicates an OPTIONAL operation or attribute that MAY be supported
by the IPP object (Printer or Job).
3.1.2 Suggested Operation Processing Steps for IPP Objects
This section suggests the steps and error checks that an IPP object
MAY perform when processing requests and returning responses. An IPP
object MAY perform some or all of the error checks. However, some
implementations MAY choose to be more forgiving than the error checks
shown here, in order to be able to accept requests from non-
conforming clients. Not performing all of these error checks is a
so-called "forgiving" implementation. On the other hand, clients
that successfully submit requests to IPP objects that do perform all
the error checks will be more likely to be able to interoperate with
other IPP object implementations. Thus an implementer of an IPP
object needs to decide whether to be a "forgiving" or a "strict"
implementation. Therefore, the error status codes returned may
differ between implementations. Consequentially, client SHOULD NOT
expect exactly the error code processing described in this section.
When an IPP object receives a request, the IPP object either accepts
or rejects the request. In order to determine whether or not to
accept or reject the request, the IPP object SHOULD execute the
following steps. The order of the steps may be rearranged and/or
combined, including making one or multiple passes over the request.
A client MUST supply requests that would pass all of the error checks
indicated here in order to be a conforming client. Therefore, a
client SHOULD supply requests that are conforming, in order to avoid
being rejected by some IPP object implementations and/or riSKINg
different semantics by different implementations of forgiving
implementations. For example, a forgiving implementation that
accepts multiple occurrences of the same attribute, rather than
rejecting the request might use the first occurrences, while another
might use the last occurrence. Thus such a non-conforming client
would get different results from the two forgiving implementations.
In the following, processing continues step by step until a "RETURNS
the xxx status code ..." statement is encountered. Error returns are
indicated by the verb: "REJECTS". Since clients have difficulty
getting the status code before sending all of the document data in a
Print-Job request, clients SHOULD use the Validate-Job operation
before sending large documents to be printed, in order to validate
whether the IPP Printer will accept the job or not.
It is assumed that security authentication and authorization has
already taken place at a lower layer.
3.1.2.1 Suggested Operation Processing Steps for all Operations
This section is intended to apply to all operations. The next
section contains the additional steps for the Print-Job, Validate-
Job, Print-URI, Create-Job, Send-Document, and Send-URI operations
that create jobs, adds documents, and validates jobs.
IIG Sect # Flow IPP error status codes
---------- ---- ----------------------

v err
3.1.2.1.1 <Validate version> --> server-error-version-not-
supported
ok
v err
3.1.2.1.2 <Validate operation> --> server-error-operation-not-
supported
ok
v err
3.1.2.1.4.1- <Validate presence> --> client-error-bad-request
3.1.2.1.4.2 <of attributes>
ok
v err
3.1.2.1.4.3 <Validate presence> --> client-error-bad-request
<of operation attr>
ok
v err
3.1.2.1.5 <Validate values of> --> client-error-bad-request
<operation attrs> client-error-request-value-
too-long
<(length, tag, range,>
<multi-value)>
ok
v err
3.1.2.1.5 <Validate values> --> client-error-bad-request
<with supported values> client-error-charset-not-
supported
ok client-error-attributes-or-
values-
not-supported
v err
3.1.2.1.6 <Validate optionally> --> client-error-bad-request
<operation attr> client-error-natural-language-
not-supported
client-error-request-value-
too-long
client-error-attributes-or-
values-not-supported
3.1.2.1.1 Validate version number
Every request and every response contains the "version-number"
attribute. The value of this attribute is the major and minor
version number of the syntax and semantics that the client and IPP
object is using, respectively. The "version-number" attribute
remains in a fixed position across all future versions so that all
clients and IPP object that support future versions can determine
which version is being used. The IPP object checks to see if the
major version number supplied in the request is supported. If not,
the Printer object REJECTS the request and RETURNS the "server-
error-version-not-supported" status code in the response. The IPP
object returns in the "version-number" response attribute the major
and minor version for the error response. Thus the client can learn
at least one major and minor version that the IPP object supports.
The IPP object is encouraged to return the closest version number to
the one supplied by the client.
The checking of the minor version number is implementation dependent,
however if the client-supplied minor version is explicitly supported,
the IPP object MUST respond using that identical minor version
number. If the major version number matches, but the minor version
number does not, the Printer SHOULD accept and attempt to process the
request, or MAY reject the request and return the "server-error-
version-not-supported" status code. In all cases, the Printer MUST
return the nearest version number that it supports. For example,
suppose that an IPP/1.2 Printer supports versions "1.1" and "1.2".
The following responses are conforming:
Table 6 - Examples of validating IPP version
Client supplies Printer Accept Request? Printer returns
1.0 yes (SHOULD) 1.1
1.0 no (SHOULD NOT) 1.1
1.1 yes (MUST) 1.1
1.2 yes (MUST) 1.2
1.3 yes (SHOULD) 1.2
1.3 no (SHOULD NOT) 1.2
It is advantageous for Printers to support both IPP/1.1 and IPP/1.0,
so that they can interoperate with either client implementations.
Some implementations may allow an Administrator to explicitly disable
support for one or the other by setting the "ipp-versions-supported"
Printer description attribute.
Likewise, it is advantageous for clients to support both versions to
allow interoperability with new and legacy Printers.
3.1.2.1.2 Validate operation identifier
The Printer object checks to see if the "operation-id" attribute
supplied by the client is supported as indicated in the Printer
object"s "operations-supported" attribute. If not, the Printer
REJECTS the request and returns the "server-error-operation-not-
supported" status code in the response.
3.1.2.1.3 Validate the request identifier
The Printer object SHOULD NOT check to see if the "request-id"
attribute supplied by the client is in range: between 1 and 2**31 - 1
(inclusive), but copies all 32 bits.
Note: The "version-number", "operation-id", and the "request-id"
parameters are in fixed octet positions in the IPP/1.1 encoding. The
"version-number" parameter will be the same fixed octet position in
all versions of the protocol. These fields are validated before
proceeding with the rest of the validation.
3.1.2.1.4 Validate attribute group and attribute presence and order
The order of the following validation steps depends on
implementation.
3.1.2.1.4.1 Validate the presence and order of attribute groups
Client requests and IPP object responses contain attribute groups
that Section 3 requires to be present and in a specified order. An
IPP object verifies that the attribute groups are present and in the
correct order in requests supplied by clients (attribute groups
without an * in the following tables).
If an IPP object receives a request with (1) required attribute
groups missing, or (2) the attributes groups are out of order, or (3)
the groups are repeated, the IPP object REJECTS the request and
RETURNS the "client-error-bad-request" status code. For example, it
is an error for the Job Template Attributes group to occur before the
Operation Attributes group, for the Operation Attributes group to be
omitted, or for an attribute group to occur more than once, except in
the Get-Jobs response.
Since this kind of attribute group error is most likely to be an
error detected by a client developer rather than by a customer, the
IPP object NEED NOT return an indication of which attribute group was
in error in either the Unsupported Attributes group or the Status
Message. Also, the IPP object NEED NOT find all attribute group
errors before returning this error.
3.1.2.1.4.2 Ignore unknown attribute groups in the expected position
Future attribute groups may be added to the specification at the end
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
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.
3.1.2.1.4.3 Validate the presence of a single occurrence of required
Operation attributes
Client requests and IPP object responses contain Operation attributes
that [RFC2911] 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:
REJECTS the request and RETURNS the "client-error-bad-request"
status code
accepts the request and uses the first occurrence of the attribute
no matter where it is
accepts the request and uses the last occurrence of the attribute
no matter where it is
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
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 [RFC2911] 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 or operation that an IPP
object MUST support
O indicates an OPTIONAL attribute or operation 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.
+ indicates that this is not a IPP/1.0 operation, but is only
a part of IPP/1.1 and future versions of IPP.
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 (R):
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 (R*)
job-k-octets (O*)
job-impressions (O*)
job-media-sheets (O*)
Group 2: Job Template Attributes (R*)
<Job Template attributes> (O*)
(see [RFC2911] Section 4.2)
Group 3: Document Content (R)
<document content>
Validate-Job Request (R):
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 (R*)
job-k-octets (O*)
job-impressions (O*)
job-media-sheets (O*)
Group 2: Job Template Attributes (R*)
<Job Template attributes> (O*)
(see [RFC2911] Section 4.2)
Print-URI Request (O):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
printer-uri (R)
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 (R*)
job-k-octets (O*)
job-impressions (O*)
job-media-sheets (O*)
Group 2: Job Template Attributes (R*)
<Job Template attributes> (O*) (see
(see [RFC2911] Section 4.2)
Create-Job Request (O):
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 [RFC2911] Section 4.2)
Get-Printer-Attributes Request (R):
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-Jobs Request (R):
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*)
Send-Document Request (O):
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 (R*)
Group 2: Document Content (R*)
<document content>
Send-URI Request (O):
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 (R*)
Cancel-Job Request (R):
Release-Job Request (O+):
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-Job-Attributes Request (R):
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*)
Pause-Printer Request (O+):
Resume-Printer Request (O+):
Purge-Printer Request (O+):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
printer-uri (R)
requesting-user-name (R*)
Hold-Job Request (O+):
Restart-Job Request (O+):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
(printer-uri & job-id) job-uri (R)
requesting-user-name (R*)
job-hold-until (R*)
message (O*)
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 (R):
Create-Job Response (O):
Send-Document Response (O):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
Group 2: Unsupported Attributes (R*) (see Note 3)
n <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* R+)
job-state-message (O*)
number-of-intervening-jobs (O*)
Validate-Job Response (R):
Cancel-Job Response (R):
Hold-Job Response (O+):
Release-Job Response (O+):
Restart-Job Response (O+):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
Group 2: Unsupported Attributes (R*) (see Note 3)
<unsupported attributes> (R*)
Print-URI Response (O):
Send-URI Response (O):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
document-access-error (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* R+)
job-state-message (O*)
number-of-intervening-jobs (O*)
Get-Printer-Attributes Response (R):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
Group 2: Unsupported Attributes (R*) (see Note 4)
<unsupported attributes> (R*)
Group 3: Printer Object Attributes(R*) (see Note 2)
<requested attributes> (R*)
Get-Jobs Response (R):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
Group 2: Unsupported Attributes (R*) (see Note 4)
<unsupported attributes> (R*)
Group 3: Job Object Attributes(R*) (see Note 2, 5)
<requested attributes> (R*)
Get-Job-Attributes Response (R):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
Group 2: Unsupported Attributes (R*) (see Note 4)
<unsupported attributes> (R*)
Group 3: Job Object Attributes(R*) (see Note 2)
<requested attributes> (R*)
Pause-Printer Response (O+):
Resume-Printer Response (O+):
Purge-Printer Response (O+):
Group 1: Operation Attributes (R)
attributes-charset (R)
attributes-natural-language (R)
status-message (O*)
detailed-status-message (O*)
Group 2: Unsupported Attributes (R*) (see Note 4)
<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
return.
Note 4 - the Unsupported Attributes Group is present only if the
client included some Operation attributes that the Printer doesn"t
support whether a success or an error return.
Note 5: for the Get-Jobs operation the response contains a separate
Job Object Attributes group 3 to N containing requested-attributes
for each job object in the response.
3.1.2.1.5 Validate the values of the REQUIRED Operation attributes
An IPP object validates the values supplied by the client of the
REQUIRED Operation attribute that the IPP object MUST support. The
next section specifies the validation of the values of the OPTIONAL
Operation attributes that IPP objects MAY support.
The IPP object performs the following syntactic validation checks of
each Operation attribute value:
a) that the length of each Operation attribute value is correct
for the attribute syntax tag supplied by the client according
to [RFC2911] Section 4.1,
b) that the attribute syntax tag is correct for that Operation
attribute according to [RFC2911] Section 3,
c) that the value is in the range specified for that Operation
attribute according to [RFC2911] Section 3,
d) that multiple values are supplied by the client only for
operation attributes that are multi-valued, i.e., that are
1setOf X according to [RFC2911] Section 3.
If any of these checks fail, the IPP object REJECTS the request and
RETURNS the "client-error-bad-request" or the "client-error-request-
value-too-long" status code. 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.
In addition, the IPP object checks each Operation attribute value
against some Printer object attribute or some hard-coded value if
there is no "xxx-supported" Printer object attribute defined. If its
value is not among those supported or is not in the range supported,
then the IPP object REJECTS the request and RETURNS the error status
code indicated in the table by the second IF statement. 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.
-----------------------------------------------
attributes-charset (charset)
IF NOT a single non-empty "charset" value, REJECT/RETURN "client-
error-bad-request".
IF the value length is greater than 63 octets, REJECT/RETURN
"client-error-request-value-too-long".
IF NOT in the Printer object"s "charset-supported" attribute,
REJECT/RETURN "client-error-charset-not-supported".
attributes-natural-language(naturalLanguage)
IF NOT a single non-empty "naturalLanguage" value, REJECT/RETURN
"client-error-bad-request".
IF the value length is greater than 63 octets, REJECT/RETURN
"client-error-request-value-too-long".
ACCEPT the request even if not a member of the set in the Printer
object"s "generated-natural-language-supported" attribute. If the
supplied value is not a member of the Printer object"s
"generated-natural-language-supported" attribute, use the Printer
object"s "natural-language- configured" value.
requesting-user-name
IF NOT a single "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 the IPP object can oBTain a better-authenticated name, use it
instead.
job-name(name)
IF NOT a single "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, the Printer object creates a name
from the document-name or document-uri.
document-name (name)
IF NOT a single "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".
ipp-attribute-fidelity (boolean)
IF NEITHER a single "true" NOR a single "false" "boolean" value,
REJECT/RETURN "client-error-bad-request".
IF the value length is NOT equal to 1 octet, REJECT/RETURN
"client-error-request-value-too-long"
IF NOT supplied by the client, the IPP object assumes the value
"false".
document-format (mimeMediaType)
IF NOT a single non-empty "mimeMediaType" 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 "document-format-supported"
attribute, REJECT/RETURN "client-error-document-format-not-
supported"
IF NOT supplied by the client, the IPP object assumes the value of
the Printer object"s "document-format-default" attribute.
document-uri (uri)
IF NOT a single non-empty "uri" value, REJECT/RETURN "client-
error-bad-request".
IF the value length is greater than 1023 octets, REJECT/RETURN
"client-error-request-value-too-long".
IF the URI syntax is not valid, REJECT/RETURN "client-error-bad-
request".
If the client-supplied URI scheme is not supported, i.e., the
value is not in the Printer object"s referenced-uri-scheme-
supported" attribute, the Printer object MUST reject the request
and return the "client-error-uri-scheme-not-supported" status
code. The Printer object MAY check to see if the document exists
and is accessible. If the document is not found or is not
accessible, REJECT/RETURN "client-error-not found".
last-document (boolean)
IF NEITHER a single "true" NOR a single "false" "boolean" value,
REJECT/RETURN "client-error-bad-request".
IF the value length is NOT equal to 1 octet, REJECT/RETURN
"client-error-request-value-too-long"
job-id (integer(1:MAX))
IF NOT an single "integer" value equal to 4 octets AND in the
range 1 to MAX, REJECT/RETURN "client-error-bad-request".
IF NOT a job-id of an existing Job object, REJECT/RETURN "client-
error-not-found" or "client-error-gone" status code, if keep track
of recently deleted jobs.
requested-attributes (1setOf keyword)
IF NOT one or more "keyword" values, REJECT/RETURN "client-
error-bad-request".
IF the value length is greater than 255 octets, REJECT/RETURN
"client-error-request-value-too-long".
Ignore unsupported values, which are the keyword names of
unsupported attributes. Don"t bother to copy such requested
(unsupported) attributes to the Unsupported Attribute response
group since the response will not return them.
which-jobs (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 NEITHER "completed" NOR "not-completed", copy the attribute and
the unsupported value to the Unsupported Attributes response group
and REJECT/RETURN "client-error-attributes-or-values-not-
supported".
Note: a Printer still supports the "completed" value even if it
keeps no completed/canceled/aborted jobs: by returning no jobs
when so queried.
IF NOT supplied by the client, the IPP object assumes the "not-
completed" value.
my-jobs (boolean)
IF NEITHER a single "true" NOR a single "false" "boolean" value,
REJECT/RETURN "client-error-bad-request".
IF the value length is NOT equal to 1 octet, REJECT/RETURN
"client-error-request-value-too-long"
IF NOT supplied by the client, the IPP object assumes the "false"
value.
limit (integer(1:MAX))
IF NOT a single "integer" value equal to 4 octets AND in the range
1 to MAX, REJECT/RETURN "client-error-bad-request".
IF NOT supplied by the client, the IPP object returns all jobs, no
matter how many.
-----------------------------------------------
3.1.2.1.6 Validate the values of the OPTIONAL Operation attributes
OPTIONAL Operation attributes are those that an IPP object MAY
support. An IPP object validates the values of the OPTIONAL
attributes supplied by the client. The IPP object performs the same
syntactic validation checks for each OPTIONAL attribute value as in
Section 3.1.2.1.5. As in Section 3.1.2.1.5, if any fail, the IPP
object REJECTS the request and RETURNS the "client-error-bad-request"
or the "client-error-request-value-too-long" status code.
In addition, the IPP object checks each Operation attribute value
against some Printer attribute or some hard-coded value if there is
no "xxx-supported" Printer attribute defined. If its value is not
among those supported or is not in the range supported, then the IPP
object REJECTS the request and RETURNS the error status code
indicated in the table. 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 IPP object doesn"t recognize/support an attribute, the IPP
object treats the attribute as an unknown or unsupported attribute
(see the last row in the table below).
-----------------------------------------------
document-natural-language (naturalLanguage)
IF NOT a single non-empty "naturalLanguage" value, REJECT/RETURN
"client-error-bad-request".
IF the value length is greater than 63 octets, REJECT/RETURN
"client-error-request-value-too-long".
IF NOT a value that the Printer object supports in document
formats, (no corresponding "xxx-supported" Printer attribute),
REJECT/RETURN "client-error-natural-language-not-supported".
compression (type3 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 "compression-supported" attribute,
REJECT/RETURN "client-error-compression-not-supported".
Note to IPP/1.0 implementers: Support for the "compression"
attribute was optional in IPP/1.0 and was changed to REQUIRED in
IPP/1.1. However, an IPP/1.0 object SHOULD at least check for the
"compression" attribute being present and reject the create
request, if they don"t support "compression". Not checking is a
bug, since the data will be unintelligible.
job-k-octets (integer(0:MAX))
IF NOT a single "integer" value equal to 4 octets, REJECT/RETURN
"client-error-bad-request".
IF NOT in the range of the Printer object"s "job-k-octets-
supported" attribute, copy the attribute and the unsupported value
to the Unsupported Attributes response group and REJECT/RETURN
"client-error-attributes-or-values-not-supported".
job-impressions (integer(0:MAX))
IF NOT a single "integer" value equal to 4 octets, REJECT/RETURN
"client-error-bad-request".
IF NOT in the range of the Printer object"s "job-impressions-
supported" attribute, copy the attribute and the unsupported value
to the Unsupported Attributes response group and REJECT/RETURN
"client-error-attributes-or-values-not-supported".
job-media-sheets (integer(0:MAX))
IF NOT a single "integer" value equal to 4 octets, REJECT/RETURN
"client-error-bad-request".
IF NOT in the range of the Printer object"s "job-media-sheets-
supported" attribute, copy the attribute and the unsupported value
to the Unsupported Attributes response group and REJECT/RETURN
"client-error-attributes-or-values-not-supported".
message (text(127))
IF NOT a single "text" value, REJECT/RETURN "client-error-bad-
request".
IF the value length is greater than 127 octets, REJECT/RETURN
"client-error-request-value-too-long".
unknown or unsupported 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-request-value-too-long".
ELSE copy the attribute and value to the Unsupported Attributes
response group and change the attribute value to the "out-of-band"
"unsupported" value, but otherwise ignore the attribute.
Note: Future Operation attributes may be added to the protocol
specification that may occur anywhere in the specified group. When
the operation is otherwise successful, the IPP object returns the
"successful-ok-ignored-or-substituted-attributes" status code.
Ignoring unsupported Operation attributes in all operations is
analogous to the handling of unsupported Job Template attributes in
the create and Validate-Job operations when the client supplies the
"ipp-attribute-fidelity" Operation attribute with the "false" value.
This last rule is so that we can add OPTIONAL Operation attributes to
future versions of IPP so that older clients can inter-work with new
IPP objects and newer clients can inter-work with older IPP objects.
(If the new attribute cannot be ignored without performing
unexpectedly, the major version number would have been increased in
the protocol document and in the request). This rule for Operation
attributes is independent of the value of the "ipp-attribute-
fidelity" attribute. For example, if an IPP object doesn"t support
the OPTIONAL "job-k-octets" attribute", the IPP object treats "job-
k-octets" as an unknown attribute and only checks the length for the
"integer" attribute syntax supplied by the client. If it is not four
octets, the IPP object REJECTS the request and RETURNS the "client-
error-bad-request" status code, else the IPP object copies the
attribute to the Unsupported Attribute response group, setting the
value to the "out-of-band" "unsupported" value, but otherwise ignores
the attribute.
3.1.2.2 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.
IIG Sect # Flow IPP error status codes
---------- ---- ----------------------

v No
3.1.2.2.1 <ipp-attribute-fidelity> ------------------+
<supplied?>
Yes
ipp-attribute-fidelity = no
<------------------------------+
v No
3.1.2.2.2 <Printer is> --> server-error-not-accepting-jobs
<accepting jobs?>
Yes
v err
3.1.2.3 <Validate values of> --> client-error-bad-request
<Job template attributes> client-error-request-value-too-
long
<(length, tag, range,>
<multi-value)>
ok
v err
3.1.2.3 <Validate values with> --> client-error-bad-request
<supported values> client-error-attributes-or-
values-not-supported
v err
3.1.2.3.1 <Any conflicting> --> client-error-conflicting-
attributes
<Job Template attr values> client-error-attributes-or-
values-not-supported
v
3.1.2.2.1 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".
3.1.2.2.2 Check that the Printer object is accepting jobs
If the value of the Printer objects "printer-is-accepting-jobs" is
"false", the Printer object REJECTS the request and RETURNS the
"server-error-not-accepting-jobs" status code.
3.1.2.2.3 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 3.1.2.1.5.):
a) that the length of each value is correct for the attribute
synta