From d9ff5e4ffa6de4b4c743988b235bcaf776c22cb0 Mon Sep 17 00:00:00 2001
From: Daniel Brahneborg <daniel@braxo.se>
Date: Mon, 24 Mar 2025 15:37:40 +0100
Subject: [PATCH] plugin smtputf8

---
 plugins/smtputf8/README.md   | 37 ++++++++++++++++++++++++++++++++++++
 plugins/smtputf8/smtputf8.pl | 15 +++++++++++++++
 2 files changed, 52 insertions(+)
 create mode 100644 plugins/smtputf8/README.md
 create mode 100644 plugins/smtputf8/smtputf8.pl

diff --git a/plugins/smtputf8/README.md b/plugins/smtputf8/README.md
new file mode 100644
index 0000000..4da711d
--- /dev/null
+++ b/plugins/smtputf8/README.md
@@ -0,0 +1,37 @@
+# Route some emails to a specific connector
+
+As of version 8.0.4, EMG supports internationalized email addresses, as specified by RFCs 6530 and 6531.
+The most important case is when the username part contains a non-ascii character, such as `åsa@example.se`.
+Such destinations can only be used with SMTP servers supporting the `SMTPUTF8` extension.
+If your default downstreams SMTP server supports that, you do not need to do anything.
+However, you may have a situation where your default SMTP server does not support this, but you have a secondary server that does.
+It may be more expensive, preventing it from being your primary server.
+In this case you can use the plugin here.
+
+## Usage
+
+Let's say you have two outgoing SMTP servers, named `smtp-out-primary` and `smtp-out-utf8`.
+You're using a routing file to route destinations containing the '@' character to `smtp-out-primary`:
+
+````
+>/.*@.*  smtp-out-primary
+````
+
+Now you tell EMG about this new plugin.
+
+````
+PLUGIN smtputf8 <
+LIBRARY=smtputf8.pl
+>
+````
+
+Next, let it redirect messages that require it.
+You do this by adding a new line before the existing one.
+
+````
+!smtputf8
+>/.*@.*  smtp-out-primary
+````
+
+If the destination address does not contain a '@' character, or the username contains only ascii characters, the plugin just returns 0 and let the rule(s) below make a decision.
+
diff --git a/plugins/smtputf8/smtputf8.pl b/plugins/smtputf8/smtputf8.pl
new file mode 100644
index 0000000..7c5e367
--- /dev/null
+++ b/plugins/smtputf8/smtputf8.pl
@@ -0,0 +1,15 @@
+sub route {
+	my ($request, $response) = @_;
+	my $sms = ${$request}{qe};
+	my $dest = $sms->{DESTADDR};
+	my @parts = split('@', $dest);
+	return 0 if (scalar @parts < 2);
+	foreach $ch (split //, $parts[0]) {
+		if (ord($ch) > 127) {
+			$response->{route} = 'smtp-out-utf8';
+			return 0;
+		}
+	}
+	return 0;
+}
+