The Extensible Markup Language (XML) Configuration Access Protocol (XCAP)
RFC 4825

Network Working Group                                       J. Rosenberg
Request for Comments: 4825                                         Cisco
Category: Standards Track                                       May 2007

                 The Extensible Markup Language (XML)
                  Configuration Access Protocol (XCAP)

Status of This Memo

   This document specifies an Internet standards track protocol for the
   Internet community, and requests discussion and suggestions for
   improvements.  Please refer to the current edition of the "Internet
   Official Protocol Standards" (STD 1) for the standardization state
   and status of this protocol.  Distribution of this memo is unlimited.

Copyright Notice

   Copyright (C) The IETF Trust (2007).

Abstract

   This specification defines the Extensible Markup Language (XML)
   Configuration Access Protocol (XCAP).  XCAP allows a client to read,
   write, and modify application configuration data stored in XML format
   on a server.  XCAP maps XML document sub-trees and element attributes
   to HTTP URIs, so that these components can be directly accessed by
   HTTP.

Rosenberg                   Standards Track                     [Page 1]
RFC 4825                          XCAP                          May 2007

Table of Contents

   1.  Introduction . . . . . . . . . . . . . . . . . . . . . . . . .  4
   2.  Overview of Operation  . . . . . . . . . . . . . . . . . . . .  5
   3.  Terminology  . . . . . . . . . . . . . . . . . . . . . . . . .  5
   4.  Definitions  . . . . . . . . . . . . . . . . . . . . . . . . .  6
   5.  Application Usages . . . . . . . . . . . . . . . . . . . . . .  7
     5.1.  Application Unique ID (AUID) . . . . . . . . . . . . . . .  7
     5.2.  Default Document Namespace . . . . . . . . . . . . . . . .  8
     5.3.  Data Validation  . . . . . . . . . . . . . . . . . . . . .  9
     5.4.  Data Semantics . . . . . . . . . . . . . . . . . . . . . . 10
     5.5.  Naming Conventions . . . . . . . . . . . . . . . . . . . . 11
     5.6.  Resource Interdependencies . . . . . . . . . . . . . . . . 11
     5.7.  Authorization Policies . . . . . . . . . . . . . . . . . . 12
     5.8.  Data Extensibility . . . . . . . . . . . . . . . . . . . . 12
     5.9.  Documenting Application Usages . . . . . . . . . . . . . . 13
     5.10. Guidelines for Creating Application Usages . . . . . . . . 13
   6.  URI Construction . . . . . . . . . . . . . . . . . . . . . . . 15
     6.1.  XCAP Root  . . . . . . . . . . . . . . . . . . . . . . . . 15
     6.2.  Document Selector  . . . . . . . . . . . . . . . . . . . . 16
     6.3.  Node Selector  . . . . . . . . . . . . . . . . . . . . . . 18
     6.4.  Namespace Bindings for the Selector  . . . . . . . . . . . 23
   7.  Client Operations  . . . . . . . . . . . . . . . . . . . . . . 24
     7.1.  Create or Replace a Document . . . . . . . . . . . . . . . 26
     7.2.  Delete a Document  . . . . . . . . . . . . . . . . . . . . 26
     7.3.  Fetch a Document . . . . . . . . . . . . . . . . . . . . . 26
     7.4.  Create or Replace an Element . . . . . . . . . . . . . . . 26
     7.5.  Delete an Element  . . . . . . . . . . . . . . . . . . . . 29
     7.6.  Fetch an Element . . . . . . . . . . . . . . . . . . . . . 30
     7.7.  Create or Replace an Attribute . . . . . . . . . . . . . . 30
     7.8.  Delete an Attribute  . . . . . . . . . . . . . . . . . . . 31
     7.9.  Fetch an Attribute . . . . . . . . . . . . . . . . . . . . 31
     7.10. Fetch Namespace Bindings . . . . . . . . . . . . . . . . . 32
     7.11. Conditional Operations . . . . . . . . . . . . . . . . . . 32
   8.  Server Behavior  . . . . . . . . . . . . . . . . . . . . . . . 34
     8.1.  POST Handling  . . . . . . . . . . . . . . . . . . . . . . 35
     8.2.  PUT Handling . . . . . . . . . . . . . . . . . . . . . . . 35
       8.2.1.  Locating the Parent  . . . . . . . . . . . . . . . . . 35
       8.2.2.  Verifying Document Content . . . . . . . . . . . . . . 36
       8.2.3.  Creation . . . . . . . . . . . . . . . . . . . . . . . 37
       8.2.4.  Replacement  . . . . . . . . . . . . . . . . . . . . . 41
       8.2.5.  Validation . . . . . . . . . . . . . . . . . . . . . . 42
       8.2.6.  Conditional Processing . . . . . . . . . . . . . . . . 43
       8.2.7.  Resource Interdependencies . . . . . . . . . . . . . . 44
     8.3.  GET Handling . . . . . . . . . . . . . . . . . . . . . . . 44
     8.4.  DELETE Handling  . . . . . . . . . . . . . . . . . . . . . 45
     8.5.  Managing Etags . . . . . . . . . . . . . . . . . . . . . . 46
   9.  Cache Control  . . . . . . . . . . . . . . . . . . . . . . . . 47

Rosenberg                   Standards Track                     [Page 2]
RFC 4825                          XCAP                          May 2007