Re: [Exim] Removing headers in ACLs

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Autor: Philip Hazel
Data:  
Para: Eli
CC: exim-users
Asunto: Re: [Exim] Removing headers in ACLs
On Tue, 13 Jan 2004, Eli wrote:

> I was just wondering if anyone can tell me why the ability to remove headers
> during the ACL processing stage doesn't exist (just wondering if it's
> currently impossible due to certain constraints!).
>
> It would seem to make some sense that if we're able to add headers at
> certain stages of the ACL stuff, that we could also remove them at that
> time.


Header lines that are "added" in ACLS are not in fact added; they are
remembered and added later. This is necessary for all ACLs before DATA,
because there is nothing to add them to at that point.

As far as I can recall, nobody has asked for the ability to remove
header lines at ACL time. I suppose it could operate by remembering
them, but there could be nasty complications when different ACLs are
adding and removing.

I suspect a re-implementation is needed, which maintains a list of
headers even before the message is received. This would probably behave
more in the way that users expect.

> I'm interested in this more in a source code programming sort of way, since
> if it's just that nobody has got around to adding this feature, I might try
> taking a stab at it :)


As always, I'll look at patches, but I think it needs a re-think to
tidy-up this area properly.

--
Philip Hazel            University of Cambridge Computing Service,
ph10@???      Cambridge, England. Phone: +44 1223 334714.
Get the Exim 4 book:    http://www.uit.co.uk/exim-book