[Email-SIG] Generating zipped or gzipped attachment with email package?

[Stephen J. Turnbull]

Oleg Broytmann writes:
 > Skip wrote:

 > > Alas, then I lose the notion that the file is actually text/csv.  For
 > > example, how would Outlook or Thunderbird know to open such a file in Excel
 > > or OpenOffice Calc?
 > 
 >    I think it unzips and then guesses the filetype of the unzipped file.

Indeed.

 > Guessing is a widely deploying trick in software, alas.
 >    Web headers are better in this regard as there are separate
 > Content-Type and Content-Encoding headers.

No, they're not "better", except by accident of being able to deal
with binary data by default.  They suffer from the same problem that
only one transformation can be applied.  Of course this is usually
enough, but not always.