Subject: [calsify] JSCalendar: plain text and HTML descriptions

From: Robert Stepanek <[email-masked]>
Date: Fri, 29 Jun 2018 11:38:02 +0200

For the next RFC draft we plan to  reduce the description and
htmlDescription properties to just a single description property. In
addition, we will introduce a new descriptionContentType property, that
defines the description MIME type. Several calendar services (including
FastMail) already see HTML text dumped into iCalendar plain text
DESCRIPTIONs and in JSCalendar we want to handle this better. However,
having two properties for descriptions shows to be an issue in practice,
as the contents get out of sync.
As a minimum the allowed values of the descriptionContenType property
(and consequently the description text format) should be text/plain and
text/html without parameters (charset MUST be utf-8).
In fact, we might want to allow any subtype of `text` MIME type, as RFC
2046 phrases this nicely:
   In the absence of appropriate interpretation software, it is
   reasonable to show subtypes of "text" to the user, while it is not
   reasonable to do so with most nontextual data. Such formatted textual
   data should be represented using subtypes of "text".
I remember at last CalConnect someone asking for allowing arbitrary MIME
types for descriptions, but I see the real risk of multipart or
application content-types getting dumped into the description. This
rather should go into an attachment.  Do you see any reasons to allow
anything else than text MIME types?
Cheers,
Robert