One document matched: draft-ietf-calsify-rfc2447bis-03.txt
Differences from draft-ietf-calsify-rfc2447bis-02.txt
INTERNET-DRAFT A. Melnikov
Document: draft-ietf-calsify-rfc2447bis-03.txt Editor
Intended status: Standard Track February 2007
Expires: August 2007
iCalendar Message-Based Interoperability Protocol
(iMIP)
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet
Engineering Task Force (IETF), its areas, and its
working groups. Note that other groups may also distribute
working documents as Internet-Drafts.
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."
The list of current Internet-Drafts can be accessed at
http://www.ietf.org/1id-abstracts.html
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html
A revised version of this draft document will be submitted to the RFC
editor as a Draft Standard for the Internet Community. Discussion
and suggestions for improvement are requested, and should be sent to
the CALSIFY Mailing list <ietf-calsify@osafoundation.org>.
Distribution of this document is unlimited.
Copyright Notice
Copyright (C) The IETF Trust (2007).
Abstract
This document, iCalendar Message-Based Interoperability Protocol
(iMIP), specifies a binding from the iCalendar Transport-independent
Interoperability Protocol (iTIP) to Internet email-based transports.
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Calendaring entries defined by the iCalendar Object Model (iCAL) are
composed using constructs from RFC 2822, RFC 2045, RFC 2046,
RFC 2047 and RFC 2049.
This document is a product of Calendaring and Scheduling Standards
Simplification (calsify) working group. More information about the
IETF CALSIFY working group activities can be found on the IETF web
site at <http://www.ietf.org/html.charters/calsify-charter.html>.
The issue tracker for the Calsify WG is located at:
<http://www.ofcourseimright.com/cgi-bin/roundup/calsify>
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Table of Contents
1 INTRODUCTION........................................................2
1.1 RELATED MEMOS ...................................................2
1.2 FORMATTING CONVENTIONS ..........................................3
1.3 TERMINOLOGY .....................................................4
2 MIME MESSAGE FORMAT BINDING.........................................4
2.1 MIME MEDIA TYPE .................................................4
2.2 SECURITY ........................................................4
2.2.1 Authorization ...............................................4
2.2.2 Authentication ..............................................5
2.2.3 Confidentiality .............................................5
2.3 [RFC-2822] ADDRESSES ............................................5
2.4 CONTENT TYPE ....................................................5
2.5 CONTENT-TRANSFER-ENCODING .......................................6
2.6 CONTENT-DISPOSITION .............................................6
3 SECURITY CONSIDERATIONS.............................................7
4 EXAMPLES............................................................8
4.1 SINGLE COMPONENT WITH AN ATTACH PROPERTY ........................8
4.2 USING MULTIPART ALTERNATIVE FOR LOW FIDELITY CLIENTS ............8
4.3 SINGLE COMPONENT WITH AN ATTACH PROPERTY AND INLINE ATTACHMENT ..9
4.4 MULTIPLE SIMILAR COMPONENTS ....................................10
4.5 MULTIPLE MIXED COMPONENTS ......................................11
4.6 DETAILED COMPONENTS WITH AN ATTACH PROPERTY ....................13
5 RECOMMENDED PRACTICES..............................................14
5.1 USE OF CONTENT AND MESSAGE IDS .................................14
6 REFERENCES.........................................................15
7 EDITOR'S ADDRESSES.................................................16
8 FULL COPYRIGHT STATEMENT...........................................XX
9 INTELLECTUAL PROPERTY..............................................XX
1 Introduction
This binding document provides the transport specific information
necessary to convey iCalendar Transport-independent Interoperability
Protocol (iTIP) [iTIP] over MIME as defined in [RFC-2822] and
[RFC-2045].
1.1 Related Memos
Implementers will need to be familiar with several other memos that,
along with this memo, form a framework for Internet calendaring and
scheduling standards.
This document, [iMIP], specifies an Internet email binding for iTIP.
[iCAL] - specifies a core specification of objects, data types,
properties and property parameters;
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[iTIP] - specifies an interoperability protocol for scheduling
between different implementations;
This memo does not attempt to repeat the specification of concepts or
definitions from these other memos. Where possible, references are
made to the memo that provides for the specification of these
concepts or definitions.
1.2 Formatting Conventions
The mechanisms defined in this memo are defined in prose. In order to
refer to elements of the calendaring and scheduling model, core
object or interoperability protocol defined in [iCAL] and [iTIP] some
formatting conventions have been used.
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC-2119].
Calendaring and scheduling roles are referred to in quoted-strings of
text with the first character of each word in upper case. For
example, "Organizer" refers to a role of a "Calendar User" within the
scheduling protocol defined by [iTIP].
Calendar components defined by [iCAL] are referred to with
capitalized, quoted-strings of text. All calendar components start
with the letter "V". For example, "VEVENT" refers to the event
calendar component, "VTODO" refers to the to-do calendar component
and "VJOURNAL" refers to the daily journal calendar component.
Scheduling methods defined by [iTIP] are referred to with
capitalized, quoted-strings of text. For example, "REQUEST" refers to
the method for requesting a scheduling calendar component be created
or modified, "REPLY" refers to the method a recipient of a request
uses to update their status with the "Organizer" of the calendar
component.
Properties defined by [iCAL] are referred to with capitalized,
quoted-strings of text, followed by the word "property". For example,
"ATTENDEE" property refers to the iCalendar property used to convey
the calendar address of a calendar user.
Property parameters defined by [iCAL] are referred to with lower
case, quoted-strings of text, followed by the word "parameter". For
example, "value" parameter refers to the iCalendar property parameter
used to override the default data type for a property value.
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1.3 Terminology
The email terms used in this memo are defined in [RFC-2822] and
[RFC-2045]. The calendaring and scheduling terms used in this memo
are defined in [iCAL] and [iTIP].
2 MIME Message Format Binding
This section defines the message binding to the MIME electronic mail
transport.
The sections below refer to the "originator" and the "respondent" of
an iMIP message. Typically, the originator is the "Organizer" of an
event. The respondent is an "Attendee" of the event.
The [RFC-2822] "Reply-To" header typically contains the email address
of the originator or respondent of an event. However, this cannot be
guaranteed as Mail User Agents (MUA) are not required to enforce iMIP
semantics.
2.1 MIME Media Type
A MIME entity containing content information formatted according to
this document will be referenced as a "text/calendar" content type.
It is assumed that this content type will be transported through a
MIME electronic mail transport.
2.2 Security
This section addresses several aspects of security including
Authentication, Authorization and Confidentiality. Authentication and
confidentiality can be achieved using [RFC-1847] that specifies the
Security Multiparts for MIME. This framework defines new content
types and subtypes of multipart: signed and encrypted. Each contains
two body parts: one for the protected data and another for the
control information necessary to remove the protection.
2.2.1 Authorization
In [iTIP] messages, only the "Organizer" is authorized to modify or
cancel calendar entries they organize. That is, spoof@xyz.example.net
is not allowed to modify or cancel a meeting that was organized by
a@example.com. Furthermore, only the respondent has the authorization
to indicate their status to the "Organizer". That is, the "Organizer"
must ignore an [iTIP] message from spoof@xyz.example.net that
declines a meeting invitation for b@example.com.
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Implementations of iMIP SHOULD verify the authenticity of the creator
of an iCalendar object before taking any action. The methods for
doing this are presented later in this document.
[RFC-1847] Message flow in iTIP supports someone working on behalf of
a "Calendar User" through use of the "sent-by" parameter that is
associated with the "ATTENDEE" and "ORGANIZER" properties. However,
there is no mechanism to verify whether or not a "Calendar User" has
authorized someone to work on their behalf. It is left to
implementations to provide mechanisms for the "Calendar Users" to
make that decision.
2.2.2 Authentication
Authentication can be performed using an implementation of [RFC-1847]
"multipart/signed" that supports public/private key certificates.
Authentication is possible only on messages that have been signed.
Authenticating an unsigned message may not be reliable.
2.2.3 Confidentiality
To ensure confidentiality using iMIP implementations should utilize
encryption compliant with [RFC-1847]. The protocol does not restrict
a "Calendar User Agent" (CUA) from forwarding iCalendar objects to
other users or agents.
2.3 [RFC-2822] Addresses
The calendar address specified within the "ATTENDEE" property in an
iCalendar object MUST be a fully qualified, [RFC-2822] address
specification for the corresponding "Organizer" or "Attendee" of the
"VEVENT" or "VTODO".
Because [iTIP] does not preclude "Attendees" from forwarding
"VEVENTS" or "VTODOS" to others, the [RFC-2822] "Sender" value may
not equal that of the "Organizer". Additionally, the "Organizer" or
"Attendee" cannot be reliably inferred by the [RFC-2822] "Sender" or
"Reply-to" values of an iMIP message. The relevant address MUST be
ascertained by opening the "text/calendar" MIME body part and
examining the "ATTENDEE" and "ORGANIZER" properties.
2.4 Content Type
A MIME body part containing content information that conforms to this
document MUST have an [RFC-2045] "Content-Type" value of
"text/calendar". The [RFC-2045] "Content-Type" header field MUST also
include the type parameter "method". The value MUST be the same as
the value of the "METHOD" calendar property within the iCalendar
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object.
Note 1: A MIME message containing multiple iCalendar objects with
different method values must be further encapsulated with a
"multipart/mixed" MIME entity. This will allow each of the iCalendar
objects to be encapsulated within their own "text/calendar" MIME
entity.
Note 2: A MIME body part of "text/calendar" "Content-Type" that lacks
the "method" parameter is not considered to be an iMIP body part and
thus is not subject to the requirements specified in this document.
Note that according to [iCAL] the default character set for iCalendar
objects is UTF-8 [UTF-8]. However the default character set for a
"text/*" MIME entity [RFC-2046] is US-ASCII. Thus a "charset"
parameter MUST be present if the iCalendar object contains characters
that are not part of the US-ASCII character set. [RFC-2046] discusses
the selection of an appropriate "charset" value.
The optional "component" parameter defines the iCalendar component
type contained within the iCalendar object.
The following is an example of this header field with a value that
indicates an event message.
Content-Type: text/calendar; method=request; charset=UTF-8;
component=vevent
The "text/calendar" content type allows for the scheduling message
type to be included in a MIME message with other content information
(i.e., "multipart/mixed") or included in a MIME message with a clear-
text, human-readable form of the scheduling message (i.e.,
"multipart/alternative").
In order to permit the information in the scheduling message to be
understood by MIME user agents (UA) that do not support the
"text/calendar" content type, scheduling messages SHOULD be sent with
an alternative, human-readable form of the information.
Note that "multiple/alternative" MUST NOT be used to represent two
slightly different iCalendar objects, for example two VEVENT with
alternative starting times.
CUA can use language and other parameters to pick a "text/calendar"
part if a "multipart/alternative" MIME message contains more than one
"text/calendar" part.
Any receiving UA compliant with this specification MUST be able to
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process "text/calendar" body parts enclosed within "multipart/*".
Note that a "multipart/mixed" MIME message can include multiple
"text/calendar" components. The receiving UA MUST be able to process
all of them.
2.5 Content-Transfer-Encoding
Unless iMIP message is transported over 8-bit clean transport (such
as SMTP [8BITMIME]), a transfer encoding such as quoted-printable or
base64 [RFC-2045] MUST be used for iCalendar objects containing any
characters that are not part of the US-ASCII character set.
<<Add examples of 8bit and quoted-printable>>
2.6 Content-Disposition
Implementations MAY include a "Content-Disposition" header field to
define a file name for an iCalendar object. However, the handling of
a MIME part MUST be based on its [RFC-2045] "Content-Type" and not on
the extension specified in the "Content-Disposition", as different
email malware is known to trick User Agents into misinterpreting
content of messages by specifying a file extension in the Content-
Disposition header field that doesn't correspond to the value of
Content-Type header field.
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3 Security Considerations
The security threats that applications must address when implementing
iTIP are detailed in [iTIP]. Two spoofing threats are identified:
Spoofing the "Organizer", and Spoofing an "Attendee". To address
these threats, the originator of an iCalendar object must be
authenticated by a recipient. Once authenticated, a determination can
be made as to whether or not the originator is authorized to perform
the requested operation. Compliant applications MUST support signing
and encrypting text/calendar attachments using a mechanism based on
Security Multiparts for MIME [RFC-1847] to facilitate the
authentication the originator of the iCalendar object.
Implementations MAY provide a means for users to disable signing and
encrypting. The steps are described below:
1. The iCalendar object MUST be signed by the "Organizer" sending an
update or the "Attendee" sending a reply.
2. Using the security mechanism compliant with [RFC-1847], determine
who signed the iCalendar object. This is the "signer". Note that the
signer is not necessarily the person sending an e-mail message since
an e-mail message can be forwarded.
3. Correlate the signer to an "ATTENDEE" property in the iCalendar
object. If the signer cannot be correlated to an "ATTENDEE" property,
ignore the message.
4. Determine whether or not the "ATTENDEE" is authorized to perform
the operation as defined by [iTIP]. If the conditions are not met,
ignore the message.
5. If all the above conditions are met, the message can be processed.
To address the confidentiality security threats, signed iMIP messages
SHOULD be encrypted by a mechanism based on Security Multiparts for
MIME [RFC-1847].
It is possible to receive iMIP messages sent by someone working on
behalf of another "Calendar User". This is determined by examining
the "sent-by" parameter in the relevant "ORGANIZER" or "ATTENDEE"
property. [iCAL] and [iTIP] provide no mechanism to verify that a
"Calendar User" has authorized someone else to work on their behalf.
To address this security issue, implementations MUST provide
mechanisms for the "Calendar Users" to make that decision before
applying changes from someone working on behalf of a "Calendar User".
A security consideration associated with use of Content-Disposition
header field is described in section 2.6.
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4 Examples
4.1 Single Component With An ATTACH Property
This minimal message shows how an iCalendar object references an
attachment. The attachment is accessible via its URL.
From: sman@netscape.example.com
To: stevesil@microsoft.example.com
Subject: Phone Conference
Mime-Version: 1.0
Content-Type: text/calendar; method=REQUEST; charset=US-ASCII
Content-Transfer-Encoding: 7bit
BEGIN:VCALENDAR
PRODID:-//ACME/DesktopCalendar//EN
METHOD:REQUEST
VERSION:2.0
BEGIN:VEVENT
ORGANIZER:mailto:sman@netscape.example.com
ATTENDEE;ROLE=CHAIR;ATTSTAT=ACCEPTED:mailto:sman@netscape.example.com
ATTENDEE;RSVP=YES:mailto:stevesil@microsoft.example.com
DTSTAMP:19970611T190000Z
DTSTART:19970701T210000Z
DTEND:19970701T230000Z
SUMMARY:Phone Conference
DESCRIPTION:Please review the attached document.
UID:calsvr.example.com-873970198738777
ATTACH:ftp://ftp.bar.example.com/pub/docs/foo.doc
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
4.2 Using Multipart Alternative for Low Fidelity Clients
This example shows how a client can emit a multipart message that
includes both a plain text version as well as the full iCalendar
object. Clients that do not support text/calendar will still be
capable of rendering the plain text representation.
From: foo1@example.com
To: foo2@example.com
Subject: Phone Conference
Mime-Version: 1.0
Content-Type: multipart/alternative;boundary="01BD3665.3AF0D360"
--01BD3665.3AF0D360
Content-Type: text/plain;charset=us-ascii
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Content-Transfer-Encoding: 7bit
This is an alternative representation of a TEXT/CALENDAR MIME Object
When: 7/1/1997 10:00AM PDT - 7/1/97 10:30AM PDT
Where:
Organizer: foo1@example.com
Summary: Phone Conference
--01BD3665.3AF0D360
Content-Type: text/calendar; method=REQUEST; charset=US-ASCII
Content-Transfer-Encoding: 7bit
BEGIN:VCALENDAR
PRODID:-//ACME/DesktopCalendar//EN
METHOD:REQUEST
VERSION:2.0
BEGIN:VEVENT
ORGANIZER:mailto:foo1@example.com
ATTENDEE;ROLE=CHAIR;ATTSTAT=ACCEPTED:mailto:foo1@example.com
ATTENDEE;RSVP=YES;TYPE=INDIVIDUAL:mailto:foo2@example.com
DTSTAMP:19970611T190000Z
DTSTART:19970701T170000Z
DTEND:19970701T173000Z
SUMMARY:Phone Conference
UID:calsvr.example.com-8739701987387771
SEQUENCE:0
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
--01BD3665.3AF0D360
4.3 Single Component With An ATTACH Property and Inline Attachment
This example shows how a message containing an iCalendar object
references an attached document. The reference is made using a
Content-id (CID). Thus, the iCalendar object and the document are
packaged in a multipart/related encapsulation.
From: foo1@example.com
To: foo2@example.com
Subject: Phone Conference
Mime-Version: 1.0
Content-Type: multipart/related; boundary="boundary-example-1"
--boundary-example-1
Content-Type: text/calendar; method=REQUEST; charset=US-ASCII
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Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="event.vcs"
BEGIN:VCALENDAR
PRODID:-//ACME/DesktopCalendar//EN
METHOD:REQUEST
VERSION:2.0
BEGIN:VEVENT
ORGANIZER:mailto:foo1@example.com
ATTENDEE;ROLE=CHAIR;ATTSTAT=ACCEPTED:mailto:foo1@example.com
ATTENDEE;RSVP=YES;TYPE=INDIVIDUAL:mailto:foo2@example.com
DTSTAMP:19970611T190000Z
DTSTART:19970701T180000Z
DTEND:19970701T183000Z
SUMMARY:Phone Conference
UID:calsvr.example.com-8739701987387771
ATTACH:cid:123456789@example.com
SEQUENCE:0
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
--boundary-example-1
Content-Type: application/msword; name="FieldReport.doc"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="FieldReport.doc"
Content-ID: <123456789@example.com>
0M8R4KGxGuEAAAAAAAAAAAAAAAAAAAAAPgADAP7/CQAGAAAAAAAAAAABAAAARAAAAAAA
AAAAEAAAQAAAAAEAAAD+////AAAAAEUAAAD/////////////////////////////////
...
--boundary-example-1--
4.4 Multiple Similar Components
Multiple iCalendar components of the same type can be included in the
iCalendar object when the METHOD is the same for each component.
From: foo1@example.com
To: foo2@example.com
Subject: Summer Company Holidays
Mime-Version: 1.0
Content-Type: text/calendar; method=PUBLISH; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="event.vcs"
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BEGIN:VCALENDAR
PRODID:-//ACME/DESKTOPCALENDAR//EN
METHOD:PUBLISH
VERSION:2.0
BEGIN:VEVENT
ORGANIZER:MAILTO:FOO1@EXAMPLE.COM
DTSTAMP:19970611T150000Z
DTSTART:19970701T150000Z
DTEND:19970701T230000Z
SUMMARY:Company Picnic
DESCRIPTION:Food and drink will be provided
UID:CALSVR.EXAMPLE.COM-873970198738777-1
SEQUENCE:0
STATUS:CONFIRMED
END:VEVENT
BEGIN:VEVENT
ORGANIZER:MAILTO:FOO1@EXAMPLE.COM
DTSTAMP:19970611T190000Z
DTSTART:19970715T150000Z
DTEND:19970715T230000Z
SUMMARY:Company Bowling Tournament
DESCRIPTION:We have 10 lanes reserved
UID:CALSVR.EXAMPLE.COM-873970198738777-2
SEQUENCE:0
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
4.5 Multiple Mixed Components
Different component types must be encapsulated in separate iCalendar
objects.
From: foo1@example.com
To: foo2@example.com
Subject: Phone Conference
Mime-Version: 1.0
Content-Type: multipart/mixed;boundary="--FEE3790DC7E35189CA67CE2C"
This is a multi-part message in MIME format.
----FEE3790DC7E35189CA67CE2C
Content-Type: text/calendar; method=REQUEST; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="event1.vcs"
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BEGIN:VCALENDAR
PRODID:-//ACME/DesktopCalendar//EN
METHOD:REQUEST
VERSION:2.0
BEGIN:VEVENT
ORGANIZER:mailto:foo1@example.com
ATTENDEE;ROLE=CHAIR;ATTSTAT=ACCEPTED:mailto:foo1@example.com
ATTENDEE;RSVP=YES;TYPE=INDIVIDUAL:mailto:foo2@example.com
DTSTAMP:19970611T190000Z
DTSTART:19970701T210000Z
DTEND:19970701T230000Z
SUMMARY:Phone Conference
DESCRIPTION:Discuss what happened at the last meeting
UID:calsvr.example.com-8739701987387772
SEQUENCE:0
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
----FEE3790DC7E35189CA67CE2C
Content-Type: text/calendar; method=REQUEST; charset=US-ASCII
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="todo1.vcs"
BEGIN:VCALENDAR
PRODID:-//ACME/DesktopCalendar//EN
METHOD:REQUEST
VERSION:2.0
BEGIN:VTODO
DUE:19970701T090000-0700
ORGANIZER:mailto:foo1@example.com
ATTENDEE;ROLE=CHAIR;ATTSTAT=ACCEPTED:mailto:foo1@example.com
ATTENDEE;RSVP=YES:mailto:foo2@example.com
SUMMARY:Phone Conference
DESCRIPTION:Discuss a new location for the company picnic
UID:calsvr.example.com-td-8739701987387773
SEQUENCE:0
STATUS:NEEDS ACTION
END:VEVENT
END:VCALENDAR
----FEE3790DC7E35189CA67CE2C
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4.6 Detailed Components With An ATTACH Property
This example shows the format of a message containing a group meeting
between three individuals. The multipart/related encapsulation is
used because the iCalendar object contains an ATTACH property that
uses a CID to reference the attachment.
From: foo1@example.com
MIME-Version: 1.0
To: foo2@example.com,foo3@example.com
Subject: REQUEST - Phone Conference
Content-Type: multipart/related;boundary="--FEE3790DC7E35189CA67CE2C"
----FEE3790DC7E35189CA67CE2C
Content-Type: multipart/alternative;
boundary="--00FEE3790DC7E35189CA67CE2C00"
----00FEE3790DC7E35189CA67CE2C00
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
When: 7/1/1997 10:00PM PDT- 7/1/97 10:30 PM PDT
Where:
Organizer: foo1@example.com
Summary: Let's discuss the attached document
----00FEE3790DC7E35189CA67CE2C00
Content-Type: text/calendar; method=REQUEST; charset=US-ASCII;
Component=vevent
Content-Transfer-Encoding: 7bit
Content-Disposition: attachment; filename="event.vcs"
BEGIN:VCALENDAR
PRODID:-//ACME/DesktopCalendar//EN
PROFILE:REQUEST
PROFILE-VERSION:1.0
VERSION:2.0
BEGIN:VEVENT
ORGANIZER:foo1@example.com
ATTENDEE;ROLE=CHAIR;ATTSTAT=ACCEPTED:foo1@example.com
ATTENDEE;RSVP=YES;TYPE=INDIVIDUAL:mailto:foo2@example.com
ATTENDEE;RSVP=YES;TYPE=INDIVIDUAL:mailto:foo3@example.com
DTSTAMP:19970611T190000Z
DTSTART:19970621T170000Z
DTEND:199706211T173000Z
SUMMARY:Let's discuss the attached document
UID:calsvr.example.com-873970198738777-8aa
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ATTACH:cid:calsvr.example.com-12345aaa
SEQUENCE:0
STATUS:CONFIRMED
END:VEVENT
END:VCALENDAR
----00FEE3790DC7E35189CA67CE2C00
----FEE3790DC7E35189CA67CE2C
Content-Type: application/msword; name="FieldReport.doc"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="FieldReport.doc"
Content-ID: <calsvr.example.com-12345aaa>
R0lGODdhTAQZAJEAAFVVVd3d3e4AAP///ywAAAAATAQZAAAC/5yPOSLhD6OctNqLs94Xq
AG4kiW5omm6sq27gvH8kzX9o1y+s73/g8MCofEovGITCoxKMbyCR16cNSq9YrNarfcrvd
riIH5LL5jE6rxc3G+v2cguf0uv2Oz+v38L7/DxgoOKjURnjIIbe3yNjo+AgZWYVIWWl5i
ZnJY6J
...
----FEE3790DC7E35189CA67CE2C
5 Recommended Practices
This section outlines a series of recommended practices when using a
messaging transport to exchange iCalendar objects.
5.1 Use of Content and Message IDs
The [iCAL] specification makes frequent use of the URI for data types
in properties such as "DESCRIPTION", "ATTACH", "CONTACT" and others.
Two forms of URIs are Message ID (MID) and Content ID (CID). These
are defined in [RFC-2392]. Although [RFC-2392] allows referencing
messages or MIME body parts in other MIME entities or stores, it is
strongly recommended that iMIP implementations include all referenced
messages and body parts in a single MIME entity. Simply put, if an
iCalendar object contains CID or MID references to other messages or
body parts, implementations should ensure that these messages and/or
body parts are transmitted with the iCalendar object. If they are not
there is no guarantee that the receiving CUA will have the access or
the authorization to view those objects.
Melnikov (Ed.) Standards Track FORMFEED[Page 16]
RFC 2447bis iMIP February 2007
6 IANA Considerations
Registration of text/calendar MIME Media Type is done in [iCal].
This document doesn't require any additional actions from IANA.
7 References
7.1 Normative References
[iCAL] Desruisseaux, B., (Ed.), "Internet Calendaring and
Scheduling Core Object Specification (iCalendar)", work in progress,
draft-ietf-calsify-rfc2445bis-XX.txt (Updated RFC 2445)
[iTIP] Daboo, C., "iCalendar Transport-Independent
Interoperability Protocol (iTIP)", work in progress, draft-ietf-
calsify-2446bis-XX.txt (Updates RFC 2446)
[RFC-2822] Resnick, P., "Internet Message Format", RFC 2822, April
2001.
[RFC-1847] Galvin, J., Murphy, S., Crocker, S. and N. Freed,
"Security Multiparts for MIME: Multipart/Signed and
Multipart/Encrypted", RFC 1847, October 1995.
[RFC-2045] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) - Part One: Format of Internet Message Bodies", RFC
2045, November 1996.
[RFC-2046] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) - Part Two: Media Types", RFC 2046, November 1996.
[RFC-2392] Levinson, E., "Content-ID and Message-ID Uniform Resource
Locators", RFC 2392, August 1998.
[RFC-2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
[UTF-8] Yergeau, F., "UTF-8, a transformation format of ISO 10646",
STD 63, RFC 3629, November 2003.
7.2 Informative References
[8BITMIME] Klensin, J., Freed, N., Rose, M., Stefferud, E., and D.
Crocker, "SMTP Service Extension for 8bit-MIMEtransport", RFC 1652,
July 1994.
[RFC-2047] Moore, K., "Multipurpose Internet Mail Extensions (MIME) -
Melnikov (Ed.) Standards Track FORMFEED[Page 17]
RFC 2447bis iMIP February 2007
Part Three: Message Header Extensions for Non-ASCII Text", RFC 2047,
November 1996.
[RFC-2049] Freed, N. and N. Borenstein, "Multipurpose Internet Mail
Extensions (MIME) Part Five: Conformance Criteria and Examples", RFC
2049, November 1996.
Melnikov (Ed.) Standards Track FORMFEED[Page 18]
RFC 2447bis iMIP February 2007
8 Editor's Addresses
The following address information is provided in a vCard v3.0,
Electronic Business Card, format.
BEGIN:VCARD
VERSION:3.0
N:Melnikov;Alexey
FN:Alexey Melnikov
ORG:Isode Ltd.
ADR;TYPE=WORK,POSTAL,PARCEL:;;5 Castle Business Village,
36 Station Road;Hampton;Middlesex;TW12 2BX;UK
EMAIL;TYPE=INTERNET:Alexey.Melnikov@isode.com
END:VCARD
Melnikov (Ed.) Standards Track FORMFEED[Page 19]
RFC 2447bis iMIP February 2007
9. Full Copyright Statement
Copyright (C) The IETF Trust (2007).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Acknowledgement
Funding for the RFC Editor function is provided by the IETF
Administrative Support Activity (IASA).
10. Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at ietf-
ipr@ietf.org.
Appendix A. Changes since RFC 2447.
Melnikov (Ed.) Standards Track FORMFEED[Page 20]
RFC 2447bis iMIP February 2007
Updated references. Split them into Normative and Informative.
Updated examples to use example.com/example.net domains.
Corrected usage of RFC 2119 language.
Clarified that charset=UTF-8 is required, unless the calendar can be
entirely represented in US-ASCII.
Clarified that 7-bit content transfer encodings should be used unless
the calendar object is known to be transferred over 8-bit clean
transport.
Clarified that file extension specified in the Content-Disposition
header field is not to be used to override the Content-Type MIME
type.
Disallow use of "multiple/alternative" for slightly different
representations of the same calendar.
<<TBD>>
Melnikov (Ed.) Standards Track FORMFEED[Page 21]
| PAFTECH AB 2003-2026 | 2026-04-24 09:08:22 |