From 81c44c0172dbb56b6e36915a6f87cdcec132addb Mon Sep 17 00:00:00 2001
From: "Eric S. Raymond" <esr@thyrsus.com>
Date: Tue, 16 Apr 2013 07:57:59 -0400
Subject: [PATCH] Prevent actually sending an empty privmsg.

---
 irkerd     | 30 +++++++++++++++++-------------
 irkerd.xml |  7 ++++---
 2 files changed, 21 insertions(+), 16 deletions(-)

diff --git a/irkerd b/irkerd
index 3889cc7..cacd4bf 100755
--- a/irkerd
+++ b/irkerd
@@ -252,19 +252,23 @@ class Connection:
                     if channel not in self.channels_joined:
                         self.connection.join(channel)
                         self.irker.debug(1, "joining %s on %s." % (channel, self.servername))
-                    for segment in message.split("\n"):
-                        # Truncate the message if it's too long,
-                        # but we're working with characters here,
-                        # not bytes, so we could be off.
-                        # 500 = 512 - CRLF - 'PRIVMSG ' - ' :'
-                        maxlength = 500 - len(channel)
-                        if len(segment) > maxlength:
-                            segment = segment[:maxlength]
-                        try:
-                            self.connection.privmsg(channel, segment)
-                        except ValueError as err:
-                            self.irker.debug(1, "irclib rejected a message to %s on %s because: %s" % (channel, self.servername, str(err)))
-                        time.sleep(ANTI_FLOOD_DELAY)
+                    # An empty message might be used as a keepalive or
+                    # to join a channel for logging, so suppress the
+                    # privmsg send unless there is actual traffic.
+                    if message:
+                        for segment in message.split("\n"):
+                            # Truncate the message if it's too long,
+                            # but we're working with characters here,
+                            # not bytes, so we could be off.
+                            # 500 = 512 - CRLF - 'PRIVMSG ' - ' :'
+                            maxlength = 500 - len(channel)
+                            if len(segment) > maxlength:
+                                segment = segment[:maxlength]
+                            try:
+                                self.connection.privmsg(channel, segment)
+                            except ValueError as err:
+                                self.irker.debug(1, "irclib rejected a message to %s on %s because: %s" % (channel, self.servername, str(err)))
+                            time.sleep(ANTI_FLOOD_DELAY)
                     self.last_xmit = self.channels_joined[channel] = time.time()
                     self.irker.debug(1, "XMIT_TTL bump (%s transmission) at %s" % (self.servername, time.asctime()))
                     self.queue.task_done()
diff --git a/irkerd.xml b/irkerd.xml
index 345c053..6102245 100644
--- a/irkerd.xml
+++ b/irkerd.xml
@@ -57,10 +57,11 @@ colon, as shown in the third example; otherwise
 <application>irkerd</application> sends messages to the the default 6667 IRC
 port of each server.</para>
 
-<para>An empty message is legal and will cause 
+<para>An empty message is legal and will cause
 <application>irkerd</application> to join the target channels without
 actually emitting a message.  This may be useful for advertising that
-an instance is up and running.</para>
+an instance is up and running, or for joining a channel to log its
+traffic.</para>
 </refsect1>
 
 <refsect1 id='options'><title>OPTIONS</title>
@@ -78,7 +79,7 @@ consult the source code for details.</para></listitem>
 <term>-l</term>
 <listitem><para>Takes a following filename, logs traffic to that file.
 Each log line consists of three |-separated fields; a numeric
-timestamp in Unix time, the fqdn of the sending server, and the
+timestamp in Unix time, the FQDN of the sending server, and the
 message data.</para></listitem>
 </varlistentry>
 <varlistentry>
-- 
2.26.2