301441 - Request for a better MIME multipart/alternative handler

Status: RESOLVED DUPLICATE of bug 505024

(Thunderbird :: Mail Window Front End, enhancement)

Description

[Eliot Lear]

User-Agent:       Mozilla/5.0 (Macintosh; U; PPC Mac OS X Mach-O; en-US; rv:1.7.9) Gecko/20050713 Firefox/1.0.5 (PowerBook)
Build Identifier: Thunderbird version 1.0.6 (20050716)

Currently Thunderbird processes multipart/alternative through the "Display
Message As" preference.  This works fine if the alternatives are simply html and
text.  However, Microsoft Exchange transmits iCal invites as
multipart/alternative (not altogether unreasonable) along with text/plain and
text/html.  Obviously Mozilla only knows the latter two, and there is no way to
register a third.


Reproducible: Always

Steps to Reproduce:
1. From OWA transmit an invite to a an email address
2. Open the address in Thunderbird

Actual Results:  
Note that you do not see attachments and that adding MIME handlers is useless.


Expected Results:  

It would be good if we were able to register a filter and an action to feed the
part into an appropriate processor (like iCal, Entourage, Evolution, or Mozilla
Calendar).

Comment 1

[David :Bienvenu]

Mike, does Lightning do this?

Comment 2

[Mike Shaver (:shaver emeritus)]

Do what, sorry?  Lightning can register a text/calendar handler, though it
doesn't currently, but it doesn't do anything with the multipart/alternative
handling.

It sounds like the request here is for improvements in the multipart/alternative
handling to give extensions or helper apps access to the non-text parts of the
alternative, which is a layer above where Lightning would get invoked.

Comment 3

[David :Bienvenu]

sorry to be vague - I meant display text/calendar parts. I'm not sure what our
multi-part alternative code does. It's supposed to display the "richest" part it
knows how to, and the sending program is supposed to order the parts in order of
increasing richness. In theory, if we think we know how to display text/calendar
parts, and that's the last alternative part, it should just work. But knowing
how to display text/calendar parts is required first. Knowing our mime code,
however, it probably has some hard-coded checks for text/html :-(

Comment 4

[Mike Shaver (:shaver emeritus)]

AFAIK, Thunderbird always had a text/calendar handler that just did nothing
interesting, until I took out the stub earlier in the 1.1 cycle.  I don't think
I've ever tested Lightning's text/calendar handler with multipart/alternative.

Comment 5

[David :Bienvenu]

the mimemalt.cpp code looks like it would do the right thing if it thought the
part was displayable:

http://lxr.mozilla.org/mozilla/source/mailnews/mime/src/mimemalt.cpp#222

but I don't know if the custom handlers fall into this code.

Comment 6

[Eliot Lear]

Thank you for your responses to my RFE.  Yes, the intent is that one should be
able to register an external handler for the richer content.  The example I have
is one that is very practical.  There are many calendar programs and a known
standard exchange format (VCAL).

My understanding of the mime code here is VERY VERY limited, so take the
following thoughts  with a grain of salt.

Presumably one would display in the UI the next less rich option that is
viewable (e.g., HTML or text).

One way to implement the feature would be to popup a dialog when you see a
format that is richer than Mozilla/T-Bird knows how to deal with.  This question
itself could be subject to a pref.  Once you have such a handler registered it
should go into mimeTypes.rdf and manipulated in the same way.

Comment 7

[Harald Alvestrand]

I need this too.
In general, being able to get to all the alternatives in multipart/alternative 
is a feature.

Comment 8

[zug_treno]

Related to/duplicate of Core bug 259480?

(In reply to comment #7)
> In general, being able to get to all the alternatives in multipart/alternative 
> is a feature.

See Core bug 130119.

Comment 9

[Eliot Lear]

Absolutely related.  If there is no reason for TB to have a different handler than Core, it would seem to be a duplicate of either or both of those two bugs.  I'll leave that to others to decide.

Comment 10

[Ludovic Hirlimann [:Usul]]

Eliot this might have been fixed by bug 351224. Could you take a few minutes and download the latest nightly ( http://ftp.mozilla.org/pub/mozilla.org/thunderbird/nightly/latest-comm-central/ ), backup your profile and test and let us know if this is fixed or not ?

Comment 11

[Jim Porter (:squib)]

Duping to the bug where I'm working on this (and which has test cases).