1) Take a look at the specs at
http://info.cern.ch/hypertext/WWW/Protocols/HTTP/Object_Headers.html
They say the following about Content-Type:
"As defined in MIME..."
Now take a look at the MIME spec, rfc1521: about unknown
content-types:
When a mail reader encounters mail with an unknown Content-type
value, it should generally treat it as equivalent to
"application/octet-stream", as described later in this document.
So my conclusion is that the specs _do_ say how to handle the situation!
2) In my opinion a missing content-type is equivalent to an unknown
content-type. I think it is a very narrow solution to assume that
everything unknown is HTML (or plain text) - this does not comply
with the normal level of abstraction in HTTP. The right thing
for the client to do is to treat it as "application/octet-stream"
and then dump the whole thing to a local file for further processing.
-- cheers --
Henrik Frystyk