Merge pull request #30 from chfritz/get_system_state

Implemented getSystemState and added example

Author: chris-smith

example_turtle.js

@@ -20,6 +20,11 @@ rosnodejs.initNode('/my_node', {
   services: ["turtlesim/TeleportRelative"]
 }).then((rosNode) => {
 
+  // get list of existing publishers, subscribers, and services
+  rosNode._node._masterApi.getSystemState("/my_node").then((data) => {
+    console.log("getSystemState, result", data, data.publishers[0]);
+  });
+
   // ---------------------------------------------------------
   // Service Call
 

lib/MasterApiClient.js

@@ -126,8 +126,23 @@ class MasterApiClient {
     throw new Error('NOT SUPPORTED');
   }
 
+  /** return an object containing all current publishers (by topic),
+      subscribers (by topic), and services (by name) */
   getSystemState(callerId) {
-    throw new Error('NOT SUPPORTED');
+    function toObject(memo, sublist) {
+      memo[sublist[0]] = sublist[1];
+      return memo;
+    }
+    let data = [callerId];
+    return new Promise((resolve, reject) => {
+      this._call('getSystemState', data, function(data) {
+        return resolve({
+          publishers: data[2][0].reduce(toObject, {}),
+          subscribers: data[2][1].reduce(toObject, {}),
+          services: data[2][2].reduce(toObject, {})
+        });
+      }, reject);
+    });
   }
 
   getUri(callerId) {