[imp] attachment MIME types

Graeme Wood Graeme.Wood at ed.ac.uk
Thu Jan 11 06:45:51 PST 2007

On Thu, 11 Jan 2007, Liam Hoekenga wrote:

>>> Anyhoo.  What I'd like to know is how an attachment's MIME type is 
>>> determined when composing mail in IMP.  I think I asked a similar question 
>>> about a year ago (where excel files were getting identified as word files 
>>> despite their .xls extension) and was told that the user's browser 
>>> determined the MIME type of the attached file.  Is that indeed the case?
>> Yes. And if it can't, i.e. is sending the attachment with a mime type of 
>> application/octet-stream, then we use MIME_Magic on the server to determine 
>> the mime type.
> Does anyone have information on how to change / correct the MIME types that 
> browsers assign to files?  (Various browsers / various platforms?)  We've 
> been asked about it here at UMich, and I think this would be useful 
> information for the User FAQ.

I just disable the browser detected mime type and use the mime-magic code 
in the Horde library, as I've found that if IE uploads a file which is 
held open by an application e.g. Word, then the mime type supplied by IE 
is wrong. I'm pretty sure this has been discussed on this list in the 

Graeme Wood                                 Email: Graeme.Wood at ed.ac.uk
Unix Systems Support                        Phone: +44 131 650 5003
The University of Edinburgh                 Fax:   +44 131 650 6552

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