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Network Working Group                                        M. Douglass
Internet-Draft                                       Spherical Cow Group
Updates: 5545,5546 (if approved)                         August 24, 2016
Intended status: Standards Track
Expires: February 25, 2017


                Event Publishing Extensions to iCalendar
                draft-ietf-calext-eventpub-extensions-00

Abstract

   This specification introduces a number of new iCalendar properties
   which are of particular use for event publishers and in social
   networking.

   This specification also defines a new STRUCTURED-DATA property for
   iCalendar (RFC 5545) to allow for data that is directly pertinent to
   an event or task to be included with the calendar data.

Status of This Memo

   This Internet-Draft is submitted in full conformance with the
   provisions of BCP 78 and BCP 79.

   Internet-Drafts are working documents of the Internet Engineering
   Task Force (IETF).  Note that other groups may also distribute
   working documents as Internet-Drafts.  The list of current Internet-
   Drafts is at http://datatracker.ietf.org/drafts/current/.

   Internet-Drafts are draft documents valid for a maximum of six months
   and may be updated, replaced, or obsoleted by other documents at any
   time.  It is inappropriate to use Internet-Drafts as reference
   material or to cite them other than as "work in progress."

   This Internet-Draft will expire on February 25, 2017.

Copyright Notice

   Copyright (c) 2016 IETF Trust and the persons identified as the
   document authors.  All rights reserved.

   This document is subject to BCP 78 and the IETF Trust's Legal
   Provisions Relating to IETF Documents
   (http://trustee.ietf.org/license-info) in effect on the date of
   publication of this document.  Please review these documents
   carefully, as they describe your rights and restrictions with respect
   to this document.  Code Components extracted from this document must



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   include Simplified BSD License text as described in Section 4.e of
   the Trust Legal Provisions and are provided without warranty as
   described in the Simplified BSD License.

Table of Contents

   1.  Introduction  . . . . . . . . . . . . . . . . . . . . . . . .   2
     1.1.  Conventions Used in This Document . . . . . . . . . . . .   4
   2.  Typed References  . . . . . . . . . . . . . . . . . . . . . .   4
     2.1.  Use Cases . . . . . . . . . . . . . . . . . . . . . . . .   4
       2.1.1.  Piano Concert Performance . . . . . . . . . . . . . .   5
       2.1.2.  Itineraries . . . . . . . . . . . . . . . . . . . . .   5
   3.  Modifications to Calendar Components  . . . . . . . . . . . .   5
   4.  New Property Parameters . . . . . . . . . . . . . . . . . . .   6
     4.1.  Loctype . . . . . . . . . . . . . . . . . . . . . . . . .   6
     4.2.  Assoctype . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.3.  Restype . . . . . . . . . . . . . . . . . . . . . . . . .   7
     4.4.  Order . . . . . . . . . . . . . . . . . . . . . . . . . .   8
     4.5.  Schema  . . . . . . . . . . . . . . . . . . . . . . . . .   8
   5.  New Properties  . . . . . . . . . . . . . . . . . . . . . . .   9
     5.1.  Associate . . . . . . . . . . . . . . . . . . . . . . . .   9
     5.2.  Styled-Description  . . . . . . . . . . . . . . . . . . .  11
     5.3.  Structured-Location . . . . . . . . . . . . . . . . . . .  13
     5.4.  Structured-Resource . . . . . . . . . . . . . . . . . . .  14
     5.5.  Structured-Data . . . . . . . . . . . . . . . . . . . . .  16
   6.  Associate Types . . . . . . . . . . . . . . . . . . . . . . .  17
   7.  Extended examples . . . . . . . . . . . . . . . . . . . . . .  18
     7.1.  Example 1 . . . . . . . . . . . . . . . . . . . . . . . .  18
   8.  Security Considerations . . . . . . . . . . . . . . . . . . .  19
   9.  Privacy Considerations  . . . . . . . . . . . . . . . . . . .  19
   10. IANA Considerations . . . . . . . . . . . . . . . . . . . . .  19
     10.1.  Property Registrations . . . . . . . . . . . . . . . . .  20
     10.2.  Parameter Registrations  . . . . . . . . . . . . . . . .  20
     10.3.  Associate Type Registrations . . . . . . . . . . . . . .  20
   11. Acknowledgements  . . . . . . . . . . . . . . . . . . . . . .  21
   12. Normative References  . . . . . . . . . . . . . . . . . . . .  21
   Appendix A.  Open issues  . . . . . . . . . . . . . . . . . . . .  22
   Appendix B.  Change log . . . . . . . . . . . . . . . . . . . . .  22
   Author's Address  . . . . . . . . . . . . . . . . . . . . . . . .  24

1.  Introduction

   The currently existing iCalendar standard [RFC5545] lacks useful
   methods for referencing additional, external information relating to
   calendar components.

   This document defines a number of properties referencing such
   external information that can provide additional information about an



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   iCalendar component.  The intent is to allow interchange of such
   information between applications or systems (e.g., between clients,
   between client and server, and between servers).  Formats such as
   VCARD are likely to be most useful.

   A new property is also defined to support HTML descriptions.  Event
   publishers typically wish to provide more and better formatted
   information about the event.

   Additionally this specification defines a property to allow the
   inclusion of structured data within the iCalendar object itself.  The
   existing properties in iCalendar cover key elements of events and
   tasks such as start time, end time, location, summary, etc.  However,
   different types of events often have other specific "fields" that it
   is useful to include in the calendar data.  For example, an event
   representing an airline flight could include the airline, flight
   number, departure and arrival airport codes, check-in and gate-
   closing times etc.  As another example, a sporting event might
   contain information about the type of sport, the home and away teams,
   the league the teams are in, information about nearby parking, etc.

   Rather than define new iCalendar properties for the variety of event
   types that might occur, it would be better to leverage existing
   "schemas" for such data.  For example, schemas available at
   https://schema.org include different event types.  By using standard
   schemas, interoperability can be improved between calendar clients
   and non-calendaring systems that wish to generate or process the
   data.

   This specification defines a new "STRUCTURED-DATA" iCalendar property
   to allow for direct inclusion of ancillary data whose schema is
   defined elsewhere.  This property includes parameters to clearly
   identify the type of the schema being used so that clients can
   quickly and easily spot what is relevant within the calendar data and
   present that to users or process it within the calendaring system.

   iCalendar does support an "ATTACH" property which can be used to
   include documents or links to documents within the calendar data.
   However, that property does not allow data to be included as a "TEXT"
   value (a feature that "STRUCTURED-DATA" does allow), plus attachments
   are often treated as "opaque" data to be processed by some other
   system rather than the calendar client.  Thus the existing "ATTACH"
   property is not sufficient to cover the specific needs of inclusion
   of schema data.  Extending the "ATTACH" property to support a new
   value type would likely cause interoperability problems.  Thus a new
   property to support inclusion of schema data is warranted.





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1.1.  Conventions Used in This Document

   The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
   "SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
   "OPTIONAL" in this document are to be interpreted as described in
   [RFC2119].

2.  Typed References

   The properties defined here can all reference external meta-data
   which may be used by applications to provide enhanced value to users.
   By providing type information as parameters, clients and servers are
   able to discover interesting references and make use of them, perhaps
   for indexing or the presentation of additional related information
   for the user.

   These properties are designed to handle common use cases in event
   publication.  It is generally important to provide information about
   the organizers of such org.bedework.util.jms.events.  Sponsors wish
   to be referenced in a prominent manner.  In social calendaring it is
   often important to identify the active associates in the event, for
   example a school sports team, and the inactive associates, for
   example the parents.

   The [RFC5545] LOCATION property provides only an unstructured single
   text value for specifying the location where an event (or "TODO"
   item) will occur.  This is inadequate for use cases where structured
   location information (e.g. address, region, country, postal code) is
   required or preferred, and limits widespread adoption of iCalendar in
   those settings.

   Using STRUCTURED-LOCATION, information about a number of interesting
   locations can be communicated, for example, parking, restaurants and
   the venue.  Servers and clients can retrieve the objects when storing
   the event and use them to index by geographic location.

   When a calendar client receives a calendar component it can search
   the set of supplied properties looking for those of particular
   interest.  The TYPE and FMTTYPE parameters, if supplied, can be used
   to help the selection.

2.1.  Use Cases

   The main motivation for these properties has been event publication
   but there are opportunities for use elsewhere.  The following use
   cases will describe some possible scenarios.





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2.1.1.  Piano Concert Performance

   In putting together a concert there are many associates: piano tuner,
   performer, stage hands etc.  In addition there are sponsors and
   various contacts to be provided.  There will also be a number of
   related locations.  A number of events can be created, all of which
   relate to the performance in different ways.

   There may be an iTip meeting request for the piano tuner who will
   arrive before the performance.  Other members of staff may also
   receive meeting requests.

   An event can also be created for publication which will have an
   ASSOCIATE reference to the pianist providing vcard information about
   the performer.  This event would also hold information about parking,
   local subway stations and the venue itself.  In addition, there will
   be sponsorship information for sponsors of the event and perhaps paid
   sponsorship properties essentially advertising local establishments.

2.1.2.  Itineraries

   These properties also provide opportunities for the travel industry.
   When booking a flight the ASSOCIATE property can be used to provide
   references to businesses at the airports and to car hire businesses
   at the destination.

   The embedded location information can guide the traveller at the
   airport or to their final destination.  The contact information can
   provide detailed information about the booking agent, the airlines
   and car hire companies and the hotel.

3.  Modifications to Calendar Components

   The following changes to the syntax defined in iCalendar [RFC5545]
   are made here.  New elements are defined in subsequent sections.
















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   eventprop =/ *(
                 ;
                 ; The following are OPTIONAL,
                 ; and MAY occur more than once.
                 ;
                 styleddescription / strucloc / strucres / associate /
                 sdataprop
                 ;
                 )

   todoprop =/ *(
                ;
                ; The following are OPTIONAL,
                ; and MAY occur more than once.
                ;
                styleddescription / strucloc / strucres / associate /
                sdataprop
                ;
                )

   jourprop =/ *(
                ;
                ; The following are OPTIONAL,
                ; and MAY occur more than once.
                ;
                styleddescription / associate /
                sdataprop
                ;
                )

4.  New Property Parameters

   This specification makes use of the LABEL property parameter which is
   defined in [I-D.ietf-calext-extensions]

4.1.  Loctype

   Parameter name:  LOCTYPE

   Purpose:  To specify the type of location.

   Format Definition:

   This parameter is defined by the following notation:

     loctypeparam   = "LOCTYPE" "=" param-value





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   Description:  This parameter MAY be specified on STRUCTURED-LOCATION
      and provides a way to differentiate multiple properties.  For
      example, it allows event producers to provide location information
      for the venue and the parking.

      Values for this parameter are taken from the values defined in
      [RFC4589].  New location types SHOULD be registered in the manner
      laid down in that specification

4.2.  Assoctype

   Parameter name:  ASSOCTYPE

   Purpose:  To specify the type of associate.

   Format Definition:

   This parameter is defined by the following notation:

     assoctypeparam   = "ASSOCTYPE" "=" param-value

   Description:  This parameter MAY be specified on the ASSOCIATE
      property, and defines the type of association.  Allowable values
      are defined in Section 6.

4.3.  Restype

   Parameter name:  RESTYPE

   Purpose:  To specify the type of resource.

   Format Definition:

   This parameter is defined by the following notation:

     restypeparam   = "RESTYPE" "=" param-value

   Description:  This parameter MAY be specified on STRUCTURED-RESOURCE
      and provides a way to differentiate multiple properties.

      Values for this parameter are taken from the values defined in
      [todo].  New resource types SHOULD be registered in the manner
      laid down in that specification








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4.4.  Order

   Parameter name:  ORDER

   Purpose:  To define ordering for the associated property.

   Format Definition:

   This parameter is defined by the following notation:

  orderparam    = "ORDER" "=" integer ;Must be greater than or equal to 1

   Description:  The ORDER parameter is OPTIONAL and is used to indicate
      the relative ordering of the corresponding instance of a property.
      Its value MUST be an integer greater than or equal to 1 that
      quantifies the order.  Lower values correspond to a higher level
      of ordering, with 1 being the highest.

      When the parameter is absent, the default MUST be to interpret the
      property instance as being at the lowest level of ordering.

      Note that the value of this parameter is to be interpreted only in
      relation to values assigned to other corresponding instances of
      the same property in the same entity.  A given value, or the
      absence of a value, MUST NOT be interpreted on its own.

      This parameter MAY be applied to any property that allows multiple
      instances.

4.5.  Schema

   Parameter Name:  SCHEMA

   Purpose:  To specify the schema used for the content of a
      "STRUCTURED-DATA" property value.

   Format Definition:

   This parameter is defined by the following notation:

     schemaparam    = "SCHEMA" "=" DQUOTE uri DQUOTE

   Description:  This property parameter SHOULD be specified on
      "STRUCTURED-DATA" properties.  When present it provides
      identifying information about the nature of the content of the
      corresponding "STRUCTURED-DATA" property value.  This can be used
      to supplement the media type information provided by the "FMTTYPE"
      parameter on the corresponding property.



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   Example:

     STRUCTURED-DATA;FMTTYPE=application/ld+json;
      SCHEMA="https://schema.org/FlightReservation";
      ENCODING=BASE64;VALUE=BINARY:Zm9vYmFy

5.  New Properties

5.1.  Associate

   Property name:  ASSOCIATE

   Purpose:  This property provides a typed reference to external
      information about associates in an event or optionally a plain
      text typed value.

   Value type:  The default value type for this property is URI.  The
      value type can also be set to TEXT to indicate plain text content.

   Property Parameters:  Non-standard, label, assoctype, order or format
      type parameters can be specified on this property.

   Conformance:  This property MAY be specified in any iCalendar
      component.

   Description:  When used in a component the value of this property
      points to information about an event associate.  This is NOT an
      attendee in a scheduling sense and the ATTENDEE property may in
      fact be specified in addition.  Associates in events can be
      individuals or organizations, for example a soccer team, the
      spectators, or the musicians.

   Format Definition:


















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   This property is defined by the following notation:

     associate     = "ASSOCIATE" assocparam
                       (
                         (
                           ";" "VALUE" "=" "URI"
                           ":" uri
                         )  /
                         (
                           ";" "VALUE" "=" "TEXT"
                           ":" text
                         )
                       )
                       CRLF

     assocparam      = *(
                     ;
                     ; the following are OPTIONAL
                     ; but MUST NOT occur more than once
                     ;
                     (";" fmttypeparam) /
                     (";" labelparam) /
                     (";" orderparam) /
                     (";" assoctypeparam) /
                     ;
                     ; the following is OPTIONAL
                     ; and MAY occur more than once
                     ;
                     (";" other-param)
                     ;
                     )


   Note:  When the ORDER parameter is supplied it defines the ordering
      of ASSOCIATE properties with the same value for the TYPE
      parameter.

   Example:

   The following is an example of this property.  It points to a VCARD
   providing information on an event associate.

                    ASSOCIATE;ASSOCTYPE=PRINCIPAL_PERFORMER:
                      http://dir.example.com/vcard/aviolinist.vcf

   Example:





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   The following is an example referring to a VCARD providing
   information on the primary contact.

                    ASSOCIATE;FMTTYPE=text/vcard;
                      ASSOCTYPE=PRIMARY-CONTACT;LABEL=A contact:
                      http://dir.example.com/vcard/contacts/contact1.vcf

   Example:

   The following is an example of the property used to link to VCARD
   information on the event planner.

                    ASSOCIATE;FMTTYPE=text/vcard;
                      ASSOCTYPE=PLANNER-CONTACT;LABEL=ClownsIsUs:
                      http://dir.example.com/vcard/clowns-is-us.vcf

5.2.  Styled-Description

   Property name:  STYLED-DESCRIPTION

   Purpose:  This property provides for one or more rich-text
      descriptions to replace or augment that provided by the
      DESCRIPTION property.

   Value type:  There is no default value type for this property.  The
      value type can be set to URI or TEXT.  Other text-based value
      types can be used when defined in the future.  Clients MUST ignore
      any properties with value types they do not understand.

   Property Parameters:  IANA, non-standard, id, alternate text
      representation, and language property parameters can be specified
      on this property.

   Conformance:  The property can be specified multiple times in the
      "VEVENT", "VTODO", "VJOURNAL", or "VALARM" calendar components.

   Description:  This property is used in the "VEVENT" and "VTODO" to
      capture lengthy textual descriptions associated with the activity.
      This property is used in the "VJOURNAL" calendar component to
      capture one or more textual journal entries.  This property is
      used in the "VALARM" calendar component to capture the display
      text for a DISPLAY category of alarm, and to capture the body text
      for an EMAIL category of alarm.

      VALUE=TEXT is used to provide rich-text variants of the plain-text
      DESCRIPTION property.





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      VALUE=URI is used to provide a link to rich-text content which is
      expected to be displayed inline as part of the event.

      The intent of this property is limited to providing a styled and/
      or language specific version of the DESCRIPTION property.  The URL
      property should be used to link to websites or other related
      information.

      Applications MAY attempt to guess the media type of the resource
      via inspection of its content if and only if the media type of the
      resource is not given by the "FMTTYPE" parameter.  If the media
      type remains unknown, calendar applications SHOULD treat it as
      type "text/html".

      Multiple STYLED-DESCRIPTION properties may be used to provide
      different formats or different language variants.

   Format Definition:

   This property is defined by the following notation:

     styleddescription = "STYLED-DESCRIPTION" styleddescparam ":"
                       (
                         (
                           ";" "VALUE" "=" "URI"
                           ":" uri
                         )  /
                         (
                           ";" "VALUE" "=" "TEXT"
                           ":" text
                         )
                       )
                       CRLF

     styleddescparam   = *(
                     ;
                     ; The following are OPTIONAL,
                     ; but MUST NOT occur more than once.
                     ;
                     (";" altrepparam) / (";" languageparam) /
                     (";" fmttypeparam) /
                     ;
                     ; the following is OPTIONAL
                     ; and MAY occur more than once
                     ;
                     (";" other-param)





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   Example:

   The following is an example of this property.  It points to an html
   description.

          STYLED-DESCRIPTION;VALUE=URI:http://example.org/desc001.html

5.3.  Structured-Location

   Property name:  STRUCTURED-LOCATION

   Purpose:  This property provides a typed reference to external
      information about the location of an event or optionally a plain
      text typed value.

   Value type:  There is no default value type for this property.  The
      value type can be set to URI or TEXT.  Other text-based value
      types

   Property Parameters:  IANA, non-standard, label, loctype or format
      type parameters can be specified on this property.

   Conformance:  This property MAY be specified zero or more times in
      any iCalendar component.

   Description:  When used in a component the value of this property
      provides information about the event venue or of related services
      such as parking, dining, stations etc..

      When a LABEL parameter is supplied the language of the label must
      match that of the content and of the LANGUAGE parameter if
      present.

   Format Definition:

















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   This property is defined by the following notation:

     strucloc        = "STRUCTURED-LOCATION" struclocparam
                       (
                         (
                           ";" "VALUE" "=" "URI"
                           ":" uri
                         )  /
                         (
                           ";" "VALUE" "=" "TEXT"
                           ":" text
                         )
                       )
                       CRLF

     struclocparam   = *(
                     ;
                     ; the following are OPTIONAL
                     ; but MUST NOT occur more than once
                     ;
                     (";" fmttypeparam) /
                     (";" labelparam) /
                     (";" languageparam) /
                     (";" loctypeparam) /
                     ;
                     ; the following is OPTIONAL
                     ; and MAY occur more than once
                     ;
                     (";" other-param)
                     )


   Example:

   The following is an example of this property.  It points to a venue.

                    STRUCTURED-LOCATION;LABEL="The venue":
                      http://dir.example.com/venues/big-hall.vcf

5.4.  Structured-Resource

   Property name:  STRUCTURED-RESOURCE

   Purpose:  This property provides a typed reference to external
      information about a resource or optionally a plain text typed
      value.





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   Value type:  The default value type for this property is URI.  The
      value type can also be set to TEXT to indicate plain text content.

   Property Parameters:  IANA, non-standard, label, restype or format
      type parameters can be specified on this property.

   Conformance:  This property MAY be specified zero or more times in
      any iCalendar component.

   Description:  When used in a component the value of this property
      provides information about resources used for the event.

      When a LABEL parameter is supplied the language of the label must
      match that of the content and of the LANGUAGE parameter if
      present.

   Format Definition:

   This property is defined by the following notation:

     strucres       = "STRUCTURED-RESOURCE" strucresparam (":" uri)  /
                       (
                         ";" "VALUE" "=" "TEXT"
                         ":" text
                       )
                       CRLF

     strucresparam  = *(
                     ;
                     ; the following are OPTIONAL
                     ; but MUST NOT occur more than once
                     ;
                     (";" fmttypeparam) /
                     (";" labelparam) /
                     (";" languageparam) /
                     (";" restypeparam) /
                     ;
                     ; the following is OPTIONAL
                     ; and MAY occur more than once
                     ;
                     (";" other-param)
                     )


   Example:






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   The following is an example of this property.  It refers to a
   projector.

                    STRUCTURED-RESOURCE;restype="projector":
                      http://dir.example.com/projectors/3d.vcf

5.5.  Structured-Data

   Property Name:  STRUCTURED-DATA

   Purpose:  This property specifies ancillary data associated with the
      calendar component.

   Value Type:  TEXT

   Property Parameters:  IANA, non-standard, inline encoding, and value
      data type property parameters can be specified on this property.
      The format type and schema parameters can be specified on this
      property and are RECOMMENDED for text or inline binary encoded
      content information.

   Conformance:  This property can be specified multiple times in an
      iCalendar object.  Typically it would be used in "VEVENT",
      "VTODO", or "VJOURNAL" calendar components.

   Description:  This property is used to specify ancillary data in some
      structured format either directly (inline) as a "TEXT" or "BINARY"
      value, or as a link via a "URI" value.

   Format Definition:





















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   This property is defined by the following notation:

     sdataprop   = "STRUCTURED-DATA" sdataparam
                       (":" text) /
                       (
                         ";" "ENCODING" "=" "BASE64"
                         ";" "VALUE" "=" "BINARY"
                         ":" binary
                       ) /
                       (
                         ";" "VALUE" "=" "URI"
                         ":" uri
                       )
                       CRLF

     sdataparam  = *(
                      ;
                      ; The following is OPTIONAL for a URI value,
                      ; RECOMMENDED for a TEXT or BINARY value,
                      ; and MUST NOT occur more than once.
                      ;
                      (";" fmttypeparam) /
                      (";" schemaparam) /
                      ;
                      ; The following is OPTIONAL,
                      ; and MAY occur more than once.
                      ;
                      (";" other-param)
                      ;
                   )

   Example:  The following is an example of this property:

     STRUCTURED-DATA;FMTTYPE=application/ld+json;
      SCHEMA="https://schema.org/SportsEvent";
      VALUE=TEXT:{\n
        "@context": "http://schema.org"\,\n
        "@type": "SportsEvent"\,\n
        "homeTeam": "Pittsburgh Pirates"\,\n
        "awayTeam": "San Francisco Giants"\n
      }\n

6.  Associate Types

   This section describes types of association and provide registered
   values for the ASSOCIATE property ASSOCTYPE parameter.





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   ACTIVE:  An associate taking an active role - for example a team
      member.

   INACTIVE:  An associate taking an inactive part - for example an
      audience member.

   SPONSOR:  A sponsor of the event.  The ORDER parameter may be used
      with this associate type to define the relative order of multiple
      sponsors.

   CONTACT:  Contact information for the event.  The ORDER parameter may
      be used with this associate type to define the relative order of
      multiple contacts.

   BOOKING-CONTACT:  Contact information for reservations or payment

   EMERGENCY-CONTACT:  Contact in case of emergency

   PUBLICITY-CONTACT:  Contact for publicity

   PLANNER-CONTACT:  Contact for the event planner or organizer

   PERFORMER:  A performer - for example the soloist or the accompanist.
      The ORDER parameter may be used with this associate type to define
      the relative order of multiple sponsors.  For example, ORDER=1
      could define the principal performer or soloist.

   SPEAKER:  Speaker at an event

7.  Extended examples

   The following are some examples of the use of the properties defined
   in this specification.  They include additional properties defined in
   [I-D.ietf-calext-extensions] which includes IMAGE and LIVEFEED.

7.1.  Example 1















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   The following is an example of a VEVENT describing a concert.  It
   includes location information for the venue itself as well as
   references to parking and restaurants.

   BEGIN:VEVENT
   CREATED:20101116T145739Z
   DESCRIPTION: Piano Sonata No 3\n
    Piano Sonata No 30
   DTSTAMP:20101116T145739Z
   DTSTART;TZID=America/New_York:20110315T150000Z
   DTEND;TZID=America/New_York:20110315T163000Z
   LAST-MODIFIED:20101116T145739Z
   SUMMARY:Beethoven Piano Sonatas
   UID:123456
   STRUCTURED-LOCATION;LABEL="The venue":
    http://dir.example.com/venues/big-hall.vcf
   STRUCTURED-LOCATION;LABEL="The venue":
    http://dir.example.com/venues/parking.vcf
   ASSOCIATE;ASSOCTYPE=SPONSOR:http://example.com/sponsor.vcf
   ASSOCIATE;ASSOCTYPE=PERFORMER:
    http://www.example.com/people/johndoe.vcf
   END:VEVENT


8.  Security Considerations

   Applications using these properties need to be aware of the risks
   entailed in using the URIs provided as values.  See [RFC3986] for a
   discussion of the security considerations relating to URIs.

   Security considerations relating to the "ATTACH" property, as
   described in [RFC5545], are applicable to the "STRUCTURED-DATA"
   property.

9.  Privacy Considerations

   Properties with a "URI" value type can expose their users to privacy
   leaks as any network access of the URI data can be tracked.  Clients
   SHOULD NOT automatically download data referenced by the URI without
   explicit instruction from users.  This specification does not
   introduce any additional privacy concerns beyond those described in
   [RFC5545].

10.  IANA Considerations







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10.1.  Property Registrations

   This document defines the following new iCalendar properties to be
   added to the registry defined in Section 8.2.3 of [RFC5545]:

         +---------------------+---------+----------------------+
         | Property            | Status  | Reference            |
         +---------------------+---------+----------------------+
         | ASSOCIATE           | Current | RFCXXXX, Section 5.1 |
         | STRUCTURED-DATA     | Current | RFCXXXX, Section 5.5 |
         | STYLED-DESCRIPTION  | Current | RFCXXXX, Section 5.2 |
         | STRUCTURED-LOCATION | Current | RFCXXXX, Section 5.3 |
         | STRUCTURED-RESOURCE | Current | RFCXXXX, Section 5.4 |
         +---------------------+---------+----------------------+

10.2.  Parameter Registrations

   This document defines the following new iCalendar property parameters
   to be added to the registry defined in Section 8.2.4 of [RFC5545]:

          +--------------------+---------+----------------------+
          | Property Parameter | Status  | Reference            |
          +--------------------+---------+----------------------+
          | ASSOCTYPE          | Current | RFCXXXX, Section 4.2 |
          | LOCTYPE            | Current | RFCXXXX, Section 4.1 |
          | ORDER              | Current | RFCXXXX, Section 4.4 |
          | RESTYPE            | Current | RFCXXXX, Section 4.3 |
          | SCHEMA             | Current | RFCXXXX, Section 4.5 |
          +--------------------+---------+----------------------+

10.3.  Associate Type Registrations

   The following table has been used to initialize the associate types
   registry.

















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           +-------------------+---------+--------------------+
           | Associate Type    | Status  | Reference          |
           +-------------------+---------+--------------------+
           | ACTIVE            | Current | RFCXXXX, Section 6 |
           | INACTIVE          | Current | RFCXXXX, Section 6 |
           | SPONSOR           | Current | RFCXXXX, Section 6 |
           | CONTACT           | Current | RFCXXXX, Section 6 |
           | BOOKING-CONTACT   | Current | RFCXXXX, Section 6 |
           | EMERGENCY-CONTACT | Current | RFCXXXX, Section 6 |
           | PUBLICITY-CONTACT | Current | RFCXXXX, Section 6 |
           | PLANNER-CONTACT   | Current | RFCXXXX, Section 6 |
           | PERFORMER         | Current | RFCXXXX, Section 6 |
           | SPEAKER           | Current | RFCXXXX, Section 6 |
           +-------------------+---------+--------------------+

11.  Acknowledgements

   The author would like to thank Chuck Norris of eventful.com for his
   work which led to the development of this RFC.

   The author would also like to thank the members of the Calendaring
   and Scheduling Consortium Event Publication technical committee and
   the following individuals for contributing their ideas and support:

   Cyrus Daboo, John Haug, Dan Mendell, Scott Otis,

   The authors would also like to thank the Calendaring and Scheduling
   Consortium for advice with this specification.

12.  Normative References

   [I-D.ietf-calext-extensions]
              Daboo, C., "New Properties for iCalendar", draft-ietf-
              calext-extensions-05 (work in progress), August 2016.

   [RFC2119]  Bradner, S., "Key words for use in RFCs to Indicate
              Requirement Levels", BCP 14, RFC 2119,
              DOI 10.17487/RFC2119, March 1997,
              <http://www.rfc-editor.org/info/rfc2119>.

   [RFC2434]  Narten, T. and H. Alvestrand, "Guidelines for Writing an
              IANA Considerations Section in RFCs", RFC 2434,
              DOI 10.17487/RFC2434, October 1998,
              <http://www.rfc-editor.org/info/rfc2434>.

   [RFC3688]  Mealling, M., "The IETF XML Registry", BCP 81, RFC 3688,
              DOI 10.17487/RFC3688, January 2004,
              <http://www.rfc-editor.org/info/rfc3688>.



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   [RFC3986]  Berners-Lee, T., Fielding, R., and L. Masinter, "Uniform
              Resource Identifier (URI): Generic Syntax", STD 66,
              RFC 3986, DOI 10.17487/RFC3986, January 2005,
              <http://www.rfc-editor.org/info/rfc3986>.

   [RFC4589]  Schulzrinne, H. and H. Tschofenig, "Location Types
              Registry", RFC 4589, DOI 10.17487/RFC4589, July 2006,
              <http://www.rfc-editor.org/info/rfc4589>.

   [RFC5545]  Desruisseaux, B., Ed., "Internet Calendaring and
              Scheduling Core Object Specification (iCalendar)",
              RFC 5545, DOI 10.17487/RFC5545, September 2009,
              <http://www.rfc-editor.org/info/rfc5545>.

   [W3C.REC-xml-20060816]
              Bray, T., Paoli, J., Sperberg-McQueen, M., Maler, E., and
              F. Yergeau, "Extensible Markup Language (XML) 1.0 (Fourth
              Edition)", World Wide Web Consortium Recommendation REC-
              xml-20060816, August 2006,
              <http://www.w3.org/TR/2006/REC-xml-20060816>.

Appendix A.  Open issues

   restype values:  Need to determine what if any registry of resource
      types already exists and use that.

Appendix B.  Change log

   v05 2016-06-26 MD

   o  Fix up abnf

   o  change ref to ietf from daboo

   o  take out label spec - use Cyrus spec

   v05 2016-06-14 MD

   o  Remove GROUP and HASH. they can be dealt with elsewhere if desired

   o  Change ORDER to integer >= 1.

   o  Incorporate Structured-Data into this specification.

   v04 2014-02-01 MD

   o  Added updates attribute.




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   o  Minor typos.

   o  Resubmitted mostly to refresh the draft.

   v03 2013-03-06 MD

   o  Replace PARTICIPANT with ASSOCIATE plus related changes.

   o  Added section showing modifications to components.

   o  Replace ID with GROUP and modify HASH.

   o  Replace TITLE param with LABEL.

   o  Fixed STYLED-DESCRIPTION in various ways, correct example.

   v02 2012-11-02 MD

   o  Collapse sections with description of properties and the use cases
      into a section with sub-sections.

   o  New section to describe relating properties.

   o  Remove idref and upgrade hash to have the reference

   o  No default value types on properties..

   v01 2012-10-18 MD Many changes.

   o  SPONSOR and STRUCTURED-CONTACT are now in PARTICIPANT

   o  Add a STRUCTURED-RESOURCE property

   o  STYLED-DESCRIPTION to handle rich text

   o  Much more...

   2011-01-07

   o  Remove MEDIA - it's going in the Cyrus RFC

   o  Rename EXTENDED-... to STRUCTURED-...

   o  Add TYPE parameter to SPONSOR

   v00 2007-10-19 MD Initial version





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Author's Address

   Michael Douglass
   Spherical Cow Group
   226 3rd Street
   Troy, NY  12180
   USA

   Email: mdouglass@sphericalcowgroup.com
   URI:   http://sphericalcowgroup.com









































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