[Mod_gzip] "mod_gzip_send_vary=Yes" disables caching on IE? (1.3.26.1a)

[Todd Vierling]

On Sun, 8 Dec 2002, Todd Vierling wrote:

: header("Content-Encoding: identity");
: header("Vary: Content-Encoding");
: header("Expires: Mon, 08 Dec 2003 00:00:00 GMT");
: echo "Hi";
:
: ?  See the "identity", uncompressed, encoding.

Er, I actually misspoke; this should have been:

header("Content-Encoding: identity");
header("Vary: Accept-Encoding");
header("Expires: Mon, 08 Dec 2003 00:00:00 GMT");
echo "Hi";

As was pointed out, it's based on request headers, not response headers.
The idea here is not to use "Vary: *" which can cause issues, but rather to
provide an explicit Content-Encoding that could trigger a different code
path in IE.  (As opposed to a missing Content-Encoding header altogether.)

I've noted that other artifacts happen in IE if Vary: is sent, including
improper caching of image data for screen display (try right-click-and-save
on an image if Vary: is sent).

-- 
-- Todd Vierling <tv@pobox.com>