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Calendars on the Internet

Topic Last Modified: 2006-06-11

New Internet standards enable you to send meeting requests to users who have various calendaring systems. The iCalendar specification (RFC 2445) defines the format of calendar information sent between calendar user agents. Calendar user agents (CUAs) are client programs such as Microsoft® Outlook®. You can use Collaboration Data Objects (CDO) to send calendar information to any CUAs that comply with the iCalendar specification.

CDO also creates a plain-text representation of calendar messages. When you send a meeting request or response to users who do not have an iCalendar-compliant e-mail client, they see the plain text version of the meeting, including the start and end times, location, subject, and meeting description.

Microsoft Exchange Server 2007 supports the iCalendar specification as an interchange format. Exchange 2007 automatically converts calendar information to the correct format for client programs including CDO, Outlook, and Schedule+.

iCalendar information is transported across the Internet formatted as a Multipurpose Internet Mail Extensions (MIME). The MIME body part containing iCalendar information has a content type of text/calendar. The following example shows a typical iCalendar meeting request:

X-Receiver: someone@example.com
X-Receiver: another@example.com
X-Sender: user12@exchange.example.com
thread-index: Ab76K9YbzaPyz4RUTJWwZL3wQ+HxyA==
Content-Class: urn:content-classes:calendarmessage
From: <user12@exchange.example.com>
Sender: <user12@exchange.example.com>
To: <someone@example.com>
Cc: <another@example.com>
Subject: Documentation Review Meeting
Date: Wed, 8 Sep 1999 11:56:19 -0700
Message-ID: <000201befa2b$d62c2e70$79b41eac@exchange.example.com>
MIME-Version: 1.0
Content-Type: multipart/alternative;
   boundary="----=_NextPart_000_0003_01BEF9F1.29D23870"
Content-Transfer-Encoding: 7bit
X-Mailer: Microsoft CDO for Exchange Server
X-MimeOLE: Produced By Microsoft MimeOLE V5.00.2919.5500

This is a multi-part message in MIME format.

------=_NextPart_000_0003_01BEF9F1.29D23870
Content-Type: text/plain;
   charset="us-ascii"
Content-Transfer-Encoding: 7bit

Type       : Single Meeting
Organizer  : MAILTO:user12@exchange.example.com
Start Time : 09/09/1999 10:00
End Time   : 09/09/1999 11:30
Time Zone  : Local time
Location   : Executive Conference Room

*~*~*~*~*~*~*~*~*~*


------=_NextPart_000_0003_01BEF9F1.29D23870
Content-Class: urn:content-classes:calendarmessage
Content-Type: text/calendar;
   method=REQUEST;
   charset="utf-8"
Content-Transfer-Encoding: 7bit

BEGIN:VCALENDAR
METHOD:REQUEST
PRODID:Microsoft CDO for Microsoft Exchange
VERSION:2.0
BEGIN:VEVENT
DTSTAMP:19990908T185620Z
DTSTART:19990909T100000
SUMMARY:Documentation Review Meeting
UID:{A6DEF157-DFCE-40F4-AC77-217563191E7B}
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE:MAILTO:someone@example.com
ATTENDEE;ROLE=OPT-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE:MAILTO:another@example.com
ORGANIZER;ROLE=REQ-PARTICIPANT;PARTSTAT=ACCEPTED;RSVP=TRUE:MAILTO:user12@exchange.example.com
LOCATION:Executive Conference Room
DTEND:19990909T113000
SEQUENCE:0
PRIORITY:5
CLASS:Personal
CREATED:19990908T185620Z
LAST-MODIFIED:19990908T185620Z
STATUS:CONFIRMED
TRANSP:OPAQUE
X-MICROSOFT-CDO-BUSYSTATUS:BUSY
X-MICROSOFT-CDO-INSTTYPE:0
END:VEVENT
END:VCALENDAR

------=_NextPart_000_0003_01BEF9F1.29D23870--

For more information about the iCalendar format, see RFC 2445.