[RFC][PATCH] Config.pm: Add support for mailing list information

[ebiederm@xmission.com (Eric W. Biederman)]

The world has turned since I first started following mailing lists and
to my surprise every mailling list that I am subscribed to properly
sets the "List-ID:" mailing list header.  So instead of doing
something clever and flexible I am adding support for looking up
public inbox mailing lists by their mailing list name.

That makes the work needed for each email trivial and easy to understand.
- Parse the "List-ID:" header.
- Lookup in the configuration which mailbox is connected to that
  "List-ID:"
- Deliver the mail to that mailbox.

To that end this change enhances PublicInbox to have an additional
mailbox configuration parameter "list" that holds the mailling list
name.

A method is added to the PublicInbox config object called
lookup_list that given a mailing list name will return
the PublicInbox in the configarion that is configured to
handle that mailing list.

Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
---

Some context.  I have my mailing list email coming in via imap, and I
have a script that looks at List-ID and delivers them to the appropriate
public-inbox.  I am hoping to get my script at least into the PublicInbox
scripts directory.

I have looked and see that you a watchheader directive that effectively
does the same thing that I am doing.  Even so, I think a mailing list
having one or more mailling list names is more fundamental.  A mailing
name is a well supported concept and it differs from an address
in that a mailing list name does not have an "@".

So as part of getting my small changes to your PublicInbox code
to support my email fetching script.  Do you mind the addition
of a mailing list name configuration parameter?

If you don't mind can we apply the patch below?  Do I need to tweak
public-inbox-watch to be able to use the list parameter?  I can't
really test it as my setup is quite different but I am willing to
work things through so that the code is harmonized and people
can benefit from each others improvements.

 lib/PublicInbox/Config.pm | 33 ++++++++++++++++++++++++++++++++-
 1 file changed, 32 insertions(+), 1 deletion(-)

diff --git a/lib/PublicInbox/Config.pm b/lib/PublicInbox/Config.pm
index 09f9179b085a..70bd88f51556 100644
--- a/lib/PublicInbox/Config.pm
+++ b/lib/PublicInbox/Config.pm
@@ -25,6 +25,7 @@ sub new {
 
 	# caches
 	$self->{-by_addr} ||= {};
+	$self->{-by_list} ||= {};
 	$self->{-by_name} ||= {};
 	$self->{-by_newsgroup} ||= {};
 	$self->{-no_obfuscate} ||= {};
@@ -84,6 +85,32 @@ sub lookup {
 	_fill($self, $pfx);
 }
 
+sub lookup_list {
+	my ($self, $list) = @_;
+	my $inbox = $self->{-by_list}->{$list};
+	return $inbox if $inbox;
+
+	my $pfx;
+
+	foreach my $k (keys %$self) {
+		$k =~ /\A(publicinbox\.[\w-]+)\.list\z/ or next;
+		my $v = $self->{$k};
+		if (ref($v) eq "ARRAY") {
+			foreach my $alias (@$v) {
+				($alias eq $list) or next;
+				$pfx = $1;
+				last;
+			}
+		} else {
+			($v eq $list) or next;
+			$pfx = $1;
+			last;
+		}
+	}
+	defined $pfx or return;
+	_fill($self, $pfx);
+}
+
 sub lookup_name ($$) {
 	my ($self, $name) = @_;
 	$self->{-by_name}->{$name} || _fill($self, "publicinbox.$name");
@@ -389,7 +416,7 @@ sub _fill {
 	}
 	# TODO: more arrays, we should support multi-value for
 	# more things to encourage decentralization
-	foreach my $k (qw(address altid nntpmirror coderepo hide)) {
+	foreach my $k (qw(address altid nntpmirror coderepo hide list)) {
 		if (defined(my $v = $self->{"$pfx.$k"})) {
 			$ibx->{$k} = _array($v);
 		}
@@ -412,6 +439,10 @@ sub _fill {
 		$self->{-by_addr}->{$lc_addr} = $ibx;
 		$self->{-no_obfuscate}->{$lc_addr} = 1;
 	}
+	foreach (@{$ibx->{list}}) {
+		my $list = $_;
+		$self->{-by_list}->{$list} = $ibx;
+	}
 	if (my $ng = $ibx->{newsgroup}) {
 		$self->{-by_newsgroup}->{$ng} = $ibx;
 	}
-- 
2.17.1