From 6bc45d64266de82118164c6d590f2c9ba41fd013 Mon Sep 17 00:00:00 2001
From: rudolfkoenig <>
Date: Sat, 18 Aug 2018 14:54:09 +0000
Subject: [PATCH] 00_MQTT2_SERVER.pm: accept clients with empty clientId (Forum
 #90145)

git-svn-id: https://svn.fhem.de/fhem/trunk/fhem@17163 2b470e98-0d58-463d-a4d8-8e2adae1ed80
---
 FHEM/00_MQTT2_SERVER.pm | 13 +++++++------
 FHEM/10_MQTT2_DEVICE.pm |  2 +-
 2 files changed, 8 insertions(+), 7 deletions(-)

diff --git a/FHEM/00_MQTT2_SERVER.pm b/FHEM/00_MQTT2_SERVER.pm
index c0c74e160..b5937b3e6 100644
--- a/FHEM/00_MQTT2_SERVER.pm
+++ b/FHEM/00_MQTT2_SERVER.pm
@@ -221,11 +221,12 @@ MQTT2_SERVER_Read($@)
   my $cpt = $cptype{$cp};
   $hash->{lastMsgTime} = gettimeofday();
 
-  #my $pltxt = $pl;
-  #$pltxt =~ s/[^ -~]/./g;
-  #Log3 $sname, 5, "$pltxt";
+  # Lowlevel debugging
+  # my $pltxt = $pl;
+  # $pltxt =~ s/([^ -~])/"(".ord($1).")"/ge;
+  # Log3 $sname, 5, "$pltxt";
 
-  if(!$hash->{cid} && $cpt ne "CONNECT") {
+  if(!defined($hash->{cid}) && $cpt ne "CONNECT") {
     Log3 $sname, 2, "$cname $cpt before CONNECT, disconnecting";
     CommandDelete(undef, $cname);
     return MQTT2_SERVER_Read($hash, 1);
@@ -234,8 +235,8 @@ MQTT2_SERVER_Read($@)
   ####################################
   if($cpt eq "CONNECT") {
     ($hash->{protoTxt}, $off) = MQTT2_SERVER_getStr($pl, 0); # V3:MQIsdb V4:MQTT
-    $hash->{protoNum}  = unpack('C*', substr($pl, $off++, 1));
-    $hash->{cflags}    = unpack('C*', substr($pl, $off++, 1));
+    $hash->{protoNum}  = unpack('C*', substr($pl,$off++,1)); # 3 or 4
+    $hash->{cflags}    = unpack('C*', substr($pl,$off++,1));
     $hash->{keepalive} = unpack('n', substr($pl, $off, 2)); $off += 2;
     ($hash->{cid}, $off) = MQTT2_SERVER_getStr($pl, $off);
 
diff --git a/FHEM/10_MQTT2_DEVICE.pm b/FHEM/10_MQTT2_DEVICE.pm
index dce1c2aa1..300537c8b 100644
--- a/FHEM/10_MQTT2_DEVICE.pm
+++ b/FHEM/10_MQTT2_DEVICE.pm
@@ -126,7 +126,7 @@ MQTT2_DEVICE_Parse($$)
 
   # autocreate and expand readingList
   if($autocreate && !%fnd) {
-    return "" if($cid =~ m/mosqpub.*/);
+    return "" if($cid && $cid =~ m/mosqpub.*/);
     my $cidHash = $modules{MQTT2_DEVICE}{defptr}{cid}{$cid};
     my $nn = $cidHash ? $cidHash->{NAME} : "MQTT2_$cid";
     PrioQueue_add(sub{