On Thu, 5 Oct 2006, Eli wrote:
> I dunno - my personal opinion is that I'd prefer to have add_header function
> *just* like message did *IF* the point to using add_header is to ultimately
> abolish the use of "warn message = ...". However, if the actual intended
> use of add_header is to allow the unconditional addition of a header to a
> message, then perhaps calling "warn message = ..." depreciated behaviour
> should be revoked, and both methods kept for the future.
>
> Comments?
0. "add_header" was never meant as an exact drop-in for "message".
1. The use of "message" in "warn" is anomalous (I should have thought
about this more deeply when I overloaded its meaning). In all other
cases, "message" is used when access is denied. It seems best to keep it
for that function.
2. When it was adapted for "warn", "message" was assuming that it was
kind of like a pseudo- or soft deny, with the value being used only when
all the conditions were true. When I implemented add_header, which of
course applies to verbs other than "warn", I thought it simpler to make
it work like "set" and other modifiers (which have grown in number -
originally there was only "endpass", IIRC) and make it work "in line".
3. I don't think there is anything you could do with "message" that you
can't do with "add_header", is there? If you want it only to happen when
all the conditions are true, as "message" did, you just put it at the
end.
4. The manual contains this:
---------------------------------------------------------------------
The add_header modifier acts immediately it is encountered during the
processing of an ACL. Notice the difference between these two cases:
accept add_header = ADDED: some text
<some condition>
accept <some condition>
add_header = ADDED: some text
In the first case, the header line is always added, whether or not the
condition is true. In the second case, the header line is added only if
the condition is true. Multiple occurrences of add_header may occur in
the same ACL statement. All those that are encountered before a
condition fails are honoured.
---------------------------------------------------------------------
I hoped that that would make it clear how it works.
5. I think it's confusing to keep both methods indefinitely.
--
Philip Hazel University of Cambridge Computing Service
Get the Exim 4 book: http://www.uit.co.uk/exim-book
