rfc2639.txt

<VC++网络游戏建摸与实现>源代码

Network Working Group                                        T. Hastings
Request for Comments: 2639                                     C. Manros
Category: Informational                                Xerox Corporation
                                                               July 1999


          Internet Printing Protocol/1.0: Implementer'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 (1999).  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).  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 [RFC2566]
   and the IPP Transport and Encoding [RFC2565] documents.  It is
   intended to help implementers understand IPP/1.0 and some of the
   considerations that may assist them in the design of their client
   and/or IPP object implementations.  For example, a typical order of
   processing requests is given, including error checking.  Motivation
   for some of the specification decisions is also included.

   The full 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/1.0: Model and Semantics [RFC2566]
     Internet Printing Protocol/1.0: Encoding and Transport [RFC2565]
     Mapping between LPD and IPP Protocols [RFC2569]

   The document, "Design Goals for an Internet Printing Protocol", takes
   a broad look at distributed printing functionality, and it enumerates
   real-life scenarios that help to clarify the features that need to be
   included in a printing protocol for the Internet.  It identifies
   requirements for three types of users: end users, operators, and





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   administrators.  The design goals document calls out a subset of end
   user requirements that are satisfied in IPP/1.0.  Operator and
   administrator requirements are out of scope for version 1.0.

   The document, "Rationale for the Structure and Model and Protocol for
   the Internet Printing Protocol", describes IPP from a high level
   view, defines a roadmap for the various documents that form the suite
   of IPP specifications, and gives background and rationale for the
   IETF working group's major decisions.

   The document, "Internet Printing Protocol/1.0: Model and Semantics",
   describes a simplified model with abstract objects, their attributes,
   and their operations.  The model introduces a Printer and a Job.  The
   Job supports multiple documents per Job.  The model document also
   addresses how security, internationalization, and directory issues
   are addressed.

   The document, "Internet Printing Protocol/1.0: Encoding and
   Transport", is a formal mapping of the abstract operations and
   attributes defined in the model document onto HTTP/1.1.  It also
   defines the encoding rules for a new Internet media type called
   "application/ipp".

   The document, "Mapping between LPD and IPP Protocols", gives some
   advice to implementers of gateways between IPP and LPD (Line Printer
   Daemon) implementations.

Table of Contents

  1  Introduction......................................................4
   1.1 Conformance language............................................4
   1.2 Other terminology...............................................5
  2  Model and Semantics...............................................5
   2.1 Summary of Operation Attributes.................................5
   2.2 Suggested Operation Processing Steps for IPP Objects ..........10
       2.2.1 Suggested Operation Processing Steps for all Operations..11
       2.2.1.1  Validate version number...............................11
       2.2.1.2  Validate operation identifier.........................11
       2.2.1.3  Validate the request identifier.......................11
       2.2.1.4  Validate attribute group and attribute presence and
                order.................................................12
       2.2.1.5  Validate the values of the REQUIRED Operation
                attributes............................................19
       2.2.1.6  Validate the values of the OPTIONAL Operation
                attributes............................................23
     2.2.2 Suggested Additional Processing Steps for Operations that
           Create/Validate Jobs and Add Documents.....................26
       2.2.2.1  Default "ipp-attribute-fidelity" if not supplied......26



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       2.2.2.2  Check that the Printer object is accepting jobs.......26
       2.2.2.3  Validate the values of the Job Template attributes....26
     2.2.3 Algorithm for job validation...............................27
       2.2.3.1  Check for conflicting Job Template attributes values..33
       2.2.3.2  Decide whether to REJECT the request..................33
       2.2.3.3  For the Validate-Job operation, RETURN one of the
                success status codes..................................34
       2.2.3.4  Create the Job object with attributes to support......34
       2.2.3.5  Return one of the success status codes................36
       2.2.3.6  Accept appended Document Content......................36
       2.2.3.7  Scheduling and Starting to Process the Job............36
       2.2.3.8  Completing the Job....................................37
       2.2.3.9  Destroying the Job after completion...................37
       2.2.3.10 Interaction with "ipp-attribute-fidelity".............37
   2.3 Status codes returned by operation ............................37
     2.3.1 Printer Operations.........................................38
       2.3.1.1  Print-Job.............................................38
       2.3.1.2  Print-URI.............................................40
       2.3.1.3  Validate-Job..........................................40
       2.3.1.4  Create-Job............................................41
       2.3.1.5  Get-Printer-Attributes................................41
       2.3.1.6  Get-Jobs..............................................42
     2.3.2 Job Operations.............................................43
       2.3.2.1  Send-Document.........................................43
       2.3.2.2  Send-URI..............................................44
       2.3.2.3  Cancel-Job............................................44
       2.3.2.4  Get-Job-Attributes....................................45
   2.4 Validate-Job...................................................46
   2.5 Case Sensitivity in URIs ......................................46
   2.6 Character Sets, natural languages, and internationalization....46
     2.6.1 Character set code conversion support .....................46
     2.6.2 What charset to return when an unsupported charset is
           requested?.................................................48
     2.6.3 Natural Language Override (NLO) ...........................48
   2.7 The "queued-job-count" Printer Description attribute...........50
     2.7.1 Why is "queued-job-count" RECOMMENDED?.....................50
     2.7.2 Is "queued-job-count" a good measure of how busy a printer
           is?........................................................50
   2.8 Sending empty attribute groups ................................50
   2.9 Returning unsupported attributes in Get-Xxxx responses ........51
   2.10 Returning job-state in Print-Job response ....................51
   2.11 Flow controlling the data portion of a Print-Job request .....52
   2.12 Multi-valued attributes ......................................53
   2.13 Querying jobs with IPP that were submitted using other job
        submission protocols .........................................53
   2.14 The 'none' value for empty sets ..............................54
   2.15 Get-Jobs, my-jobs='true', and 'requesting-user-name'?.........54




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   2.16 The "multiple-document-handling" Job Template attribute and
        support of multiple document jobs.............................54
  3  Encoding and Transport...........................................55
   3.1 General Headers................................................56
   3.2 Request  Headers...............................................57
   3.3 Response Headers...............................................58
   3.4 Entity  Headers................................................59
   3.5 Optional support for HTTP/1.0..................................60
   3.6 HTTP/1.1 Chunking..............................................60
     3.6.1 Disabling IPP Server Response Chunking.....................60
     3.6.2 Warning About the Support of Chunked Requests..............60
  4  References.......................................................61
   4.1 Authors' Addresses.............................................62
  5  Security Considerations..........................................62
  6  Notices..........................................................62
  Full Copyright Statement............................................65

1  Introduction

  This document contains information that supplements the IPP Model and
  Semantics [RFC2566] and the IPP Transport and Encoding [RFC2565]
  documents.  As such this information is not part of the formal
  specifications.  Instead information is presented to help implementers
  understand the specification, 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 [RFC2566] or
  [RFC2565], those documents take precedence over this document.

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 [RFC2566] and [RFC2565] documents require and
  allow, rather than specifying additional conformance requirements.
  These terms are defined in section 13 on conformance terminology in
  [RFC2566], most of which is taken from RFC 2119 [RFC2119].

  Implementers should read section 13 in [RFC2566] 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 [RFC2566] and
  [RFC2565].  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.



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1.2 Other terminology

  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.

2  Model and Semantics

  This section discusses various aspects of IPP/1.0 Model and Semantics
  [RFC2566].

2.1 Summary of Operation Attributes

  Legend for the following table:

      R indicates a REQUIRED operation or attribute for an
        implementation to support

      O indicates an OPTIONAL operation or attribute for an
        implementation to support






























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    Table 1.  Summary of operation attributes for Printer operations

                           Printer Operations

                         Requests                         Responses

     Operation           Print-   Pri  Crea Get-     Get- All
     Attributes          Job,     nt-  te-  Printer- Jobs Opera-
                         Validate URI  Job  Attribut      tions
                         -Job     (O)  (O)  es

     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-            R      R    R      R      R     R
     natural-language

     document-uri                   R

     job-id*

     job-uri*

     last-document

     printer-uri            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
     name







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