[Mailman-Developers] multipart/alternative

[Jim Cole]

On Mar 10, 2004, at 4:09 AM, Brad Knowles wrote:

>>  If I were to simply remove the call to 
>> collapse_multipart_alternatives,
>>  would that allow the multipart/alternative part to slip through
>>  unmolested? Does later processing code depend on 
>> multipart/alternative
>>  parts being collapsed?
>
> 	Why would you do this?  What do you have in multipart/alternative 
> that would require this kind of action?

In the particular case that I am looking at, there is both text/plain 
and text/html. Since text/plain happens to be the first non-empty part, 
it is saved and text/html is thrown away. I am trying to find a way to 
ensure that both parts make it through so that people who prefer html 
in their mail still have the ability to view it that way.

>>  Besides turning off filtering altogether, is there any other simple 
>> way
>>  to get Mailman to pass multipart/alternative as-is? Stripping
>>  alternatives is not likely to be acceptable for the environment to
>>  which we would be deploying.
>
> 	Yes.  Just list multipart/alternative as one of the formats to pass 
> unchanged.  Go to "Content Filtering", then add 
> "multipart/alternative" to the "pass_mime_types" field (the second big 
> one on the page).  Note that you have to have filtering turned on for 
> this to have any effect -- if you don't have filtering turned on (the 
> radio button at the top), then no filtering should be done.

If it were that easy, I wouldn't be bothering you ;) Assuming of course 
I didn't do something stupid. Our first step was to do exactly what you 
suggest. Under those conditions, the text/html portion is still 
stripped. Based on my first couple reads through the code, all but the 
first non-empty part of any multipart/alternative is stripped 
unconditionally (unless filtering is turned off altogether or the 
message is a digest). In the call to 'process', general filtering is 
performed, collapse_multipart_alternative is called unconditionally, 
and then a few last steps are executed to cleanup and repackage the 
message. Or at least that is the way it appears to me at the moment. As 
far as I can see, once you are in 'process' with filtering enabled, 
your alternatives get stripped automatically; list configuration does 
not appear to be relevant in this regard.

Jim