Corrections to node-red-node-discovery (#380)

1- Ensure we stop advertising before creating a new advertiser if the object exists
2- Allow bool false to stop advertising
3- Documentation correction (state is in msg.payload, not in msg)

io/mdns/README.md

@@ -32,7 +32,7 @@ service discovery capability.
 
 `msg.payload` contains the service object on both arrival and leaving.
 
-`msg.state` contains boolean true or false depending if the service has arrived (true) or gone away (false)..
+`msg.payload.state` contains boolean true or false depending if the service has arrived (true) or gone away (false)..
 
 Within the `msg.payload` object the most interesting things are:
 
@@ -48,7 +48,7 @@ For a full list of official service types see [this list](http://www.dns-sd.org/
 
 Provides a Bonjour / Avahi / Zeroconf announcement node.
 
-If `msg.payload` is 0 - the announcement is stopped. Any other value starts the announcement process.
+If `msg.payload` is `false` - the announcement is stopped. Any other value starts the announcement process.
 
 The announcement can be customised by the msg if not configured in the edit panel.
 

io/mdns/mdns.html

@@ -18,7 +18,7 @@
 <script type="text/x-red" data-help-name="discovery">
     <p>Provides a Bonjour / Avahi / Zeroconf discovery node.</p>
     <p><code>msg.payload</code> contains the service object on both arrival and leaving.</p>
-    <p><code>msg.state</code> contains boolean <i>true</i> or <i>false</i> depending
+    <p><code>msg.payload.state</code> contains boolean <i>true</i> or <i>false</i> depending
     if the service has arrived (<i>true</i>) or gone away (<i>false</i>).</p>
     <p>Within the msg.payload object the most interesting things are:
     <ul><li>msg.payload.name</li>
@@ -73,7 +73,7 @@
 
 <script type="text/x-red" data-help-name="announce">
     <p>Provides a Bonjour / Avahi / Zeroconf announcement node.</p>
-    <p>If <code>msg.payload</code> is 0 - the announcement is stopped. Any other value starts the announcement process.</p>
+    <p>If <code>msg.payload</code> is <code>false</code> - the announcement is stopped. Any other value starts the announcement process.</p>
     <p>The announcement can be customised by the msg if not configured in the edit panel.</p>
     <p><ul>
         <li><code>msg.service</code> - For a full list of official service types see <i><a href="http://www.dns-sd.org/ServiceTypes.html" target="_new">this list</a></i>.</li>

io/mdns/mdns.js

@@ -65,8 +65,8 @@ module.exports = function(RED) {
         var node = this;
 
         this.on("input", function(msg) {
-            if ((msg.payload === 0) || (msg.payload === "0")) {
+            if (msg.payload == false) {
-                node.ad.stop();
+                if (node.ad) { node.ad.stop(); }
             }
             else {
                 var service = node.service || msg.service;
@@ -76,6 +76,7 @@ module.exports = function(RED) {
                     options.name = (node.name || msg.name).replace(/\%h/g, os.hostname());
                 }
                 if (node.txt || msg.txtRecord) { options.txtRecord = node.txt || msg.txtRecord }
+                if (node.ad) { node.ad.stop(); }
                 node.ad = mdns.createAdvertisement(service, port, options);
                 node.ad.start();
             }

io/mdns/package.json

@@ -1,6 +1,6 @@
 {
     "name"          : "node-red-node-discovery",
-    "version"       : "0.0.18",
+    "version"       : "0.0.19",
     "description"   : "A Node-RED node that uses Bonjour / Avahi to discover nearby services.",
     "dependencies"  : {
         "mdns"   : "~2.3.3"