[Tickets #12062] Re: Mime parser fails to parse multipart message

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Ticket URL: http://bugs.horde.org/ticket/12062
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  Ticket             | 12062
  Updated By         | Thomas Jarosch <thomas.jarosch at intra2net.com>
  Summary            | Mime parser fails to parse multipart message
  Queue              | Horde Framework Packages
  Version            | Git master
  Type               | Bug
  State              | Unconfirmed
  Priority           | 1. Low
  Milestone          |
  Patch              |
  Owners             |
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Thomas Jarosch <thomas.jarosch at intra2net.com> (2013-02-21 09:53) wrote:

>> Further debugging showed the Kolab object / email
>> in question is missing the
>>
>> "MIME-Version: 1.0"
>>
>> header field. Should the MIME parser be less strict about this?
>
> NO.  Without a MIME-Version header, it is NOT a MIME message.
>
> And it is not something we should ignore.  For example, IMAP servers  
> will treat a message as non-MIME in BODYSTRUCTURE (i.e. single  
> tex/plain ASCII part) without MIME-Version.

The initial Kolab parse code uses getStructure() which in turn uses  
Horde_Imap_Client::FETCH_STRUCTURE. At least the cyrus imap server  
sends back the full structure and is unimpressed by the missing  
MIME-Version header.

Peeking through the cyrus code, it just checks for "multipart" in the  
Content-Type header.

I've also looked at the dovecot code. It checks for the presence of  
the "Content-Type" header field if it doesn't find "MIME-Version".  
This behavior can be disabled by a flag but it is enabled by default  
(and there's no code to configure it by the user)
See also here:
http://www.dovecot.org/list/dovecot/2009-November/044311.html
"...but there were enough broken mails that I decided to make this  
optional in code (but
not by admin)"

What could go wrong if we do the same (to be more relaxed on parsing)?