adding prototype getNodes to ROSLIB.Ros allowing to get list of available nodes

Author: barraq

src/core/Ros.js

@@ -232,6 +232,26 @@ ROSLIB.Ros.prototype.getServices = function(callback) {
   });
 };
 
+/**
+ * Retrieves list of active node names in ROS.
+ *
+ * @param callback - function with the following params:
+ *   * nodes - array of node names
+ */
+ROSLIB.Ros.prototype.getNodes = function(callback) {
+  var nodesClient = new ROSLIB.Service({
+    ros : this,
+    name : '/rosapi/nodes',
+    serviceType : 'rosapi/Nodes'
+  });
+
+  var request = new ROSLIB.ServiceRequest();
+
+  nodesClient.callService(request, function(result) {
+    callback(result.nodes);
+  });
+};
+
 /**
  * Retrieves list of param names from the ROS Parameter Server.
  *