ActionClient: export it and added cancel

- Added getActionClient to Rosnodejs (previously the action client wasn't exported in any way)

- ActionClient: added "cancel" function

Author: chfritz

example_turtle.js

@@ -7,8 +7,6 @@
 'use strict';
 
 let rosnodejs = require('./index.js');
-const ActionClient = require('./lib/ActionClient.js');
-
 rosnodejs.initNode('/my_node', {onTheFly: true}).then((rosNode) => {
 
   // get list of existing publishers, subscribers, and services
@@ -77,7 +75,7 @@ rosnodejs.initNode('/my_node', {onTheFly: true}).then((rosNode) => {
   // wait two seconds for previous example to complete
   setTimeout(function() {
       let shapeActionGoal = rosnodejs.require('turtle_actionlib').msg.ShapeActionGoal;
-      let ac = new ActionClient({
+      let ac = rosnodejs.getActionClient({
           type: "turtle_actionlib/ShapeAction",
           actionServer: "/turtle_shape"
         });
@@ -87,6 +85,9 @@ rosnodejs.initNode('/my_node', {onTheFly: true}).then((rosNode) => {
               radius: 1
             }
           }));
+      setTimeout(function() {
+          ac.cancel();
+      }, 1000);
     }, 2000);
 
   // ---------------------------------------------------------

index.js

@@ -29,6 +29,7 @@ const LogFormatter = require('./utils/log/LogFormatter.js');
 const RosNode = require('./lib/RosNode.js');
 const NodeHandle = require('./lib/NodeHandle.js');
 const Logging = require('./lib/Logging.js');
+const ActionClient = require('./lib/ActionClient.js');
 
 msgUtils.findMessageFiles();
 
@@ -216,6 +217,29 @@ let Rosnodejs = {
       console: ConsoleLogStream,
       ros:     RosLogStream
     }
+  },
+
+
+  //------------------------------------------------------------------
+  // ActionLib
+  //------------------------------------------------------------------
+
+  /**
+    Get an action client for a given type and action server.
+
+    Example:
+      let ac = rosNode.getActionClient({
+        type: "turtle_actionlib/ShapeAction",
+        actionServer: "/turtle_shape"
+      });
+      let shapeActionGoal =
+        rosnodejs.require('turtle_actionlib').msg.ShapeActionGoal;
+      ac.sendGoal(new shapeActionGoal({
+        goal: { edges: 3,  radius: 1 } }));
+   */
+  getActionClient(options) {
+    options.rosnodejs = Rosnodejs;
+    return new ActionClient(options);
   }
 }
 

lib/ActionClient.js

@@ -17,7 +17,6 @@
 
 'use strict';
 
-const rosnodejs = require('../index.js');
 const timeUtils = require('../utils/time_utils.js');
 let EventEmitter = require('events');
 
@@ -29,28 +28,29 @@ class ActionClient extends EventEmitter {
 
     this._actionServer = options.actionServer;
 
-    const nh = rosnodejs.nh;
+    this._rosnodejs = options.rosnodejs;
+    const nh = this._rosnodejs.getNodeHandle();
 
     // FIXME: support user options for these parameters
-    this._goalPub = nh.advertise(this._actionServer + '/goal', 
+    this._goalPub = nh.advertise(this._actionServer + '/goal',
                                  this._actionType + 'Goal',
                                  { queueSize: 1, latching: true });
 
-    this._cancelPub = nh.advertise(this._actionServer + '/cancel', 
+    this._cancelPub = nh.advertise(this._actionServer + '/cancel',
                                    'actionlib_msgs/GoalID',
                                    { queueSize: 1, latching: true });
 
-    this._statusSub = nh.subscribe(this._actionServer + '/status', 
+    this._statusSub = nh.subscribe(this._actionServer + '/status',
                                    'actionlib_msgs/GoalStatusArray',
                                    (msg) => { this._handleStatus(msg); },
                                    { queueSize: 1 } );
 
-    this._feedbackSub = nh.subscribe(this._actionServer + '/feedback', 
+    this._feedbackSub = nh.subscribe(this._actionServer + '/feedback',
                                      this._actionType + 'Feedback',
                                      (msg) => { this._handleFeedback(msg); },
                                      { queueSize: 1 } );
 
-    this._statusSub = nh.subscribe(this._actionServer + '/result', 
+    this._statusSub = nh.subscribe(this._actionServer + '/result',
                                    this._actionType + 'Result',
                                    (msg) => { this._handleResult(msg); },
                                    { queueSize: 1 } );
@@ -97,6 +97,19 @@ class ActionClient extends EventEmitter {
     this._goals[goalId] = goal;
 
     this._goalPub.publish(goal);
+    return goal;
+  }
+
+  /** Cancel the given goal. If none is given, send an empty goal message,
+  i.e. cancel all goals. See 
+  http://wiki.ros.org/actionlib/DetailedDescription#The_Messages
+  */
+  cancel(goal) {
+    if (!goal) {
+      let GoalID = this._rosnodejs.require('actionlib_msgs').msg.GoalID;
+      goal = new GoalID();
+    }
+    this._cancelPub.publish(goal);
   }
 
   _generateGoalId() {