Re: "body" extension

On Mon, 2002-06-17 at 09:16, Nigel Swinson wrote:
> The most common usage seems to be as an attachment blocker.  And they have
> to implement this by using all sorts of fancy regexes which very quickly
> become a fairly sizable performance problem.  Which is what they are
> beginning to moan about just now.  There are also folks trying to do some
> spam filtering and then as a very early stage virus filter before the new
> virus definitions are out.
> 
> To reduce the performance burden we were thinking of implementing :matches
> for the x_body given that it is all they really need for their attachment
> blocker, and then also implementing a mime test that I was hoping we'd all
> design together so that we could get a standard for the syntax.  Glad to see
> this discussion coming up now :o)

:matches can (and will) get fooled about what does and doesn't match--a
message describing the symptoms, or a email of a Sieve filter that
matches the offending messages, will probably trigger the filter.

Although it's a lot easier to implement O(n) :matches than O(n)
:regex...

I'm definitely in favor of trying to provide MIME filtering capabilities
(i.e., mimepart :filename :matches "*.vbs in particular, but also types,
etc.).  Doing this with x_body can cause problems and false positives. 
There are real horror stories to this.

> I really like the idea of having arguments such as :raw or :mime that allow
> implementations to "build up" the extension by just supporting :raw then
> adding :mime and so forth.  Perhaps we should have arguments that describe