The mailing list for listmasters using Sympa

[Olivier Salaün <address@concealed>]

Hi Brent,

I've just written a new chapter of the documentation on this topic : 
http://www.sympa.org/wiki/manual/message-handling#does_sympa_alter_messages

The only unexpected changes that might happen would be due to the use of 
MIME::Entity objects. We are aware that MIME::Entity for example don't 
respect original line size of messages.

If you note additional alterations, you can find out what was changed by 
1) using the --keepcopy sympa.pl option so that message is the spool are 
not removed and 2) adding a dump of the message in the code, just before 
it is sent to users.

Brent Emerson wrote:

> I work with a group of folks who've been hosting hundreds of lists on 
> Sympa for several years now, and when our users ask questions about 
> MIME parts being corrupted or changing in transit through Sympa, we 
> always had the answer "Sympa doesn't change anything about the content 
> of your messages, so don't blame Sympa."  Recently, however, we 
> noticed a message where a text/html part using quoted-printable 
> encoding was substantially different when processed through a 
> Sympa-hosted list compared with the version sent direct from the 
> sender.  The same thing happened to a base64-endoded image/gif part in 
> the same message.  Nothing else was altered about the message or its 
> MIME structure.
>
> In the quoted-printable encoding, Sympa seems to have changed line 
> breaks to make the lines a bit longer.  In the base64 encoding, Sympa 
> seems to have altered the original 76-character lines to 60-character 
> lines.  In both cases, the Sympa-altered text decodes to the same 
> destination HTML and image as the original text did, so it's not 
> necessarily breaking anything.  However, some message recipients have 
> complained that their clients are having problems with the 
> Sympa-processed messages and not the originals, so we're trying to 
> understand what Sympa is doing.
>
> So, my question: is Sympa supposed to be decoding and re-encoding 
> these MIME parts?  If not, any hints about how we can determine what's 
> going wrong?  If, on the other hand, Sympa is designed to decode and 
> re-encode, why?  Can we turn that behavior off so it just re-sends 
> these parts unmolested?
>
> We're using Sympa 5.1.2 with perl 5.8.8 and probably the latest 
> versions of all of Sympa's perl module dependencies.