HTML in iCal attachment

Question

Can an iCal attachment contain HTML in the description property? If so, what are the restrictions?

Answer 1

For anyone happening upon this page like I did and is looking to specifically have HTML content displayed for Outlook events, this can be done with the e-mail being multipart/alternative, e.g.

MIME-Version: 1.0
Content-Type: multipart/alternative; boundary="_CAL_B598a1969806776.58663423_B_"
To: "Your Name" 
From: "John Doe" 

--_CAL_B598a1969806776.58663423_B_
Content-Type: text/html; charset="iso - 8859 - 1"
Content-Transfer-Encoding: quoted-printable


Hello World
This is a calendar event test


--_CAL_B598a1969806776.58663423_B_
Content-Type: text/calendar; charset="utf - 8"; method=REQUEST
Content-Transfer-Encoding: base64
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--_CAL_B598a1969806776.58663423_B_--

In case you are wondering, that Base64 encoding translates to:

BEGIN:VCALENDAR
METHOD:REQUEST
PRODID:-//PHP//MeetingRequest//EN
VERSION:2.0
BEGIN:VEVENT
ORGANIZER;CN=John Doe:MAILTO:john.doe@example.com
ATTENDEE;ROLE=REQ-PARTICIPANT;PARTSTAT=NEEDS-ACTION;RSVP=TRUE;CN=Your Name:MAILTO:yourname@example.com
DESCRIPTION:Hello World Event
SUMMARY:Hello World Event
DTSTART:20170815T190000Z
DTEND:20170815T200000Z
UID:0123456789
CLASS:PUBLIC
PRIORITY:5
DTSTAMP:20170808T200457Z
TRANSP:OPAQUE
STATUS:CONFIRMED
SEQUENCE:0
LOCATION:123 Any Street
BEGIN:VALARM
ACTION:DISPLAY
DESCRIPTION:REMINDER
TRIGGER;RELATED=START:-PT15M
END:VALARM
END:VEVENT
END:VCALENDAR