Hello Phil,
Phil Pennock <exim-users@???> (Mo 13 Jul 2009 15:51:45 CEST):
> On 2009-07-13 at 15:03 +0200, Heiko Schlittermann wrote:
> > Heiko Schlittermann <hs@???> (Mo 13 Jul 2009 14:00:26 CEST):
> > > Hello,
> > >
> > > I'd like to use something like:
> > >
> > > transport:
> > > driver = ....
> > > headers_remove = NX-Spam.*
> > >
> >
> > Hm. Something like
> >
> > transport:
> > ...
> > headers_remove = <\n ${filter \
> > {<\n ${map{<\n$message_headers_raw} {${extract{1}{:}{$item}}}}} \
> > {match{$item}{(?i:^X-)}}}
>
> The ${map{<\n$message_headers_raw} {${extract{1}{:}{$item}}}} takes no
> account of continuation lines.
Thank you for your response. I missed the fact, that $message_headers*
just contains the RFC2822 header part of the message, _unaltered_.
> This is somewhat more accurate:
> ${map{<\n${filter{<\n$message_headers_raw}{match{$item}{^(?i:[a-z_-]+\s*:)}}}} {${extract{1}{:}{$item}}}}
> but still prone to false-positives; the problem is more visible if you
> do:
> ${map{<\n$message_headers_raw} {[$item]}}
> and see that the leading tabs on the follow-on lines have been lost as
> part of whitespace folding.
>
> This shouldn't have false positives but leaves you with some extra
> whitespace in the form of blank lines:
> ${sg{$message_headers_raw}{\N(?m)(?:^\s|\s*:).*$\N}{}}
Now I implented it like this:
MESSAGE_HEADERS = \
# replace "\n" with the default list separator ":" and
# and lowercase everything
${lc:${sg\
# fix continuation lines and extract the header names
# replace every "\n" followed by a number of whitespaces
# with a single whitespace
{${map\
{ <\n ${sg {$message_headers_raw}{\N\n\s+\N}{ }} }\
{${extract{1}{:}{$item}}}\
}\
}\
{\N\n\N}\
{:}\
}}
Later in the ACL (I did it in the ACL because we have several
processing policies and it seems more straight forward to me to do it
there.)
acl_check_data:
warn set acl_m_headers_remove \
= ${filter {MESSAGE_HEADERS}{match{$item}{\N^x-(?:ius|hh)\N}}}
log_message = DEBUG-X: $acl_m_headers_remove
...
And all transports look similar to this one:
lmtp:
driver = smtp
...
headers_remove = $acl_m_headers_remove
(Would be great to have the counterpart of add_header in the ACL ...)
> So this gets you all the actual headers:
> ${filter{<\n${sg{$message_headers_raw}{\N(?m)(?:^\s|\s*:).*$\N}{}}}{!eq{$item}{}}}
~~
Thank you for
this. Didn't know it. But now I found the reference in perlre(1).
Thanks and
best regards from Dresden/Germany
Heiko Schlittermann
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