Add basic announce capability to mdns node.

io/mdns/README.md

@@ -4,6 +4,8 @@ node-red-node-discover
 A <a href="http://nodered.org" target="_new">Node-RED</a> node that uses Bonjour
  / Avahi to discover local network services such as iTunes libraries, printers, etc.
 
+Now also supports announcing new services.
+
 Prerequisites
 -------------
 
@@ -11,19 +13,21 @@ please read the [install instructions](https://www.npmjs.com/package/mdns) for t
 
 For Debian / Ubuntu this requires installing
 
-    sudo apt-get install libavahi-compat-libdnssd-dev
+        sudo apt-get install libavahi-compat-libdnssd-dev
 
 Install
 -------
 
-Run the following command in the root directory of your Node-RED install
+Run the following command in the root directory of your Node-RED install, usually `~/.node-red`
 
-    npm install node-red-node-discovery
+        npm install node-red-node-discovery
 
 Usage
 -----
 
-Uses a javascript implenetation of mdns ( mdns-js ) to provide a Bonjour / Avahi
+### Discovery
+
+Uses an implemetation of mdns to provide a Bonjour / Avahi
 service discovery capability.
 
 **msg.payload** contains the service object on both arrival and leaving.
@@ -40,4 +44,19 @@ Within the msg.payload object the most interesting things are:
 
 For a full list of official service types see [this list](http://www.dns-sd.org/ServiceTypes.html" target="_new).
 
-**Note**: When Node-RED starts you will get a big WARNING message about the Bonjour compatability layer... this is just a warning so don't worry.
+###Announce
+
+Provides a Bonjour / Avahi / Zeroconf announcement node.
+
+If **msg.payload** is 0 - 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.
+
+ - **msg.service** - For a full list of official service types see <a href="http://www.dns-sd.org/ServiceTypes.html" target="_new">this list</a>.
+ - **msg.port** - the tcp or udp port to use.
+ - **msg.name** - the short description name of the service. If you use %h in the name, it will be replaced by the machine hostname.
+ - **msg.txtRecord** - a set of comma separated name:value pairs
+
+###Note:
+
+When Node-RED starts you will get a big WARNING message about the Bonjour compatability layer... this is just a warning so don't worry.