[ mailman-Bugs-1461279 ] Filtering content while allowing HTML messages impossible

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Bugs item #1461279, was opened at 2006-03-30 02:41
Message generated for change (Comment added) made by msapiro
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Category: None
Group: 2.1 (stable)
Status: Open
Resolution: None
Priority: 5
Submitted By: - (psy-q)
Assigned to: Nobody/Anonymous (nobody)
Summary: Filtering content while allowing HTML messages impossible

Initial Comment:
I hope this is a genuine bug. I'll use 2.1.7 in these    
examples, though I verified this behavior in 2.1.5    
also.    
    
I have a mailing list configured as such:    
    
filter_content = 1    
filter_mime_types = ''   
pass_mime_types = """multipart/mixed   
multipart/alternative   
text/plain   
text/html"""   
collapse_alternatives = 0   
convert_html_to_plaintext = 0   
filter_action = 2   
   
And yet all HTML messages are automatically stripped   
of HTML, have their attachments removed and are    
immediately posted to the list.   
  
The originals are sent as multipart/alternative with  
two attachments, one the text/plain rendition of the  
message and one the text/html original. It seems to 
be okay, user agents can render this message as 
intended. All that remains when delivered by Mailman 
is the text/plain bit, though. 
  
Shouldn't this list configuration let HTML mails  
through? I can't see a reason why Mailman should 
remove the HTML silently with these settings. 
 
If filter_content is turned off, sending HTML 
messages works. 
 
(I know it's not polite to send HTML messages through 
mailing lists, but some of my users insist.) 

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>Comment By: Mark Sapiro (msapiro)
Date: 2006-03-30 17:00

Message:
Logged In: YES 
user_id=1123998

You can't really compare 2.1.5 and 2.1.7 in this respect
since 2.1.5 doesn't have the collapse_alternatives setting
and always operates as if collapse_alternatives is true
(non-zero). I.e., 2.1.5 will always replace a
multipart/alternative part with just the first alternative.

Also, your "immediately posted" remark makes me think that
you think filter_action applies whenever content is filtered
in any way. This is not true. filter_action only applies
when the message is empty after filtering.

You also say "yet all HTML messages are automatically
stripped of HTML, have their attachments removed and ...". I
think you may or may not have a misconception here. With the
pass_mime_types settings you have given, no attachments of
any type other than text/plain or text/html should be left
in the message. The types multipart/alternative and
multipart/mixed only allow such messages/parts to be further
processed looking for allowable types. I.e, with these
settings a message or part of type multipart/related will be
filtered completely (nothing left) regardless of what it
contains, because multipart/related is not accepted.

On the other hand, a message or part of type multipart/mixed
will have it's sub-parts examined for allowable types
because multipart/mixed is allowed.

So the only issue is why are text/html parts being removed
in 2.1.7 from multipart/mixed and/or multipart/alternative
parts. This may or may not be a bug. Please attach full
copies of a message both before and after filtering
including all headers to this report, so we can see if there
is a bug or what the problem might be.

Note that your description of the multipart/alternative
messages and results is the only way Mailman 2.1.5 works so
there is no bug there. In 2.1.7 with collapse_alternatives =
0 and text/html in pass_mime_types, the html should remain
in the outgoing message, so there is clearly a problem here.


----------------------------------------------------------------------

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