Mail structure (Re: Extra Header field)

Joon Radley joon at radleys.co.za
Mon Jul 12 17:27:54 CEST 2004


Hi David,

  

> -----Original Message-----
> From: kolab-format-bounces at kolab.org 
> [mailto:kolab-format-bounces at kolab.org] On Behalf Of David Faure
> Sent: Monday, July 12, 2004 4:52 PM
> To: kolab-format at kolab.org
> Subject: Mail structure (Re: Extra Header field)
> 
> On Monday 12 July 2004 16:27, Joon Radley wrote:
> > 1) The Kolab XML format is encapsulated in a multipart/alternative 
> > content type as follows:
> > 
> > Content-type: multipart/alternative; boundary="STUPID-123456"
> > 
> > --STUPID-123456
> > Content-type: text/plain; charset="us-ascii"
> > 
> > This is a Kolab Groupware object. To view this object you 
> will need a 
> > email client that can understand the Kolab Groupware format. For a 
> > list of such email clients please visit 
> > http:://www.kolab.org/kolab-clients.html
> > 
> > --STUPID-123456
> > Content-type: application/x-vnd.kolab.note
> > Content-Transport-Encoding: base64
> > 
> > AABBDNNDKIJSGHGSHTUHAK==
> > 
> > --STUPID-123456--
> 
> This looks quite good. A much needed clarification, and an 
> easy way to implement the missing plain text.
>  
> > 2) When there are attachments associated with the object 
> the message 
> > is encapsulated in a multipart/mixed content type with the 
> > multipart/alternative encapsulation described in 1 as the 
> first body 
> > part in the multipart.
> 
> This needs clarification. There are two ways to read this.
> Are you thinking of
> 2a)
>   multipart/alternative
>       text/plain
>       multipart/mixed
>            application/x-vnd.kolab.note
>            some_other_attachment
> 
> or 2b)
>   multipart/mixed
>       multipart/alternative
>            text/plain
>            application/x-vnd.kolab.note
>       some_other_attachment
> 
> Karl Heinz mentionned that 2a) might not be legal? (needs to 
> be checked) But in any case 2b) looks very inconsistent... 

2a) is illegal.

Ok the full mail in case 2

MIME-Version: 1.0
Content-type: multipart/mixed; boundary="MIXED-123456"
Subject: "Kolab Groupware Object"

--MIXED-123456
Content-type: multipart/alternative; boundary="STUPID-123456"

--STUPID-123456
Content-type: text/plain; charset="us-ascii"

This is a Kolab Groupware object. To view this object you 
will need a email client that can understand the Kolab Groupware 
format. For a list of such email clients please visit 
http:://www.kolab.org/kolab-clients.html

--STUPID-123456
Content-type: application/x-vnd.kolab.note
Content-Transport-Encoding: base64
 
AABBDNNDKIJSGHGSHTUHAK==
 
--STUPID-123456--

--MIXED-123456

... a attachment ...

--MIXED-123456

... another attachment ...

--MIXED-123456--

> The parsing when looking for the XML would have to really 
> take both cases into account, and the code for adding an 
> attachment would have to restructure the whole thing....
> It would be much better and cleaner to have a single 
> structure that works for both cases.
> In case multipart/alternative (which I don't know much about) 
> is a problem, why not use multipart/mixed
>    text/plain
>    application/x-vnd.kolab.note
>    some_other_attachment
> ?   
> Most mail clients will show the first text/plain attachment, no?

The mixed/alternate is used for when you want the offer the email client a
option of what to display. A non-compliant client will see that it only
understands text/plain and will display this. A compliant client will
display the application/x-vnd.kolab.note.

Best Regards

Joon Radley
Radley Network Technologies CC
Cell: +27 (0)83 368 8557
Fax: +27 (0)12 998 4346
E-mail: joon at radleys.co.za




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