Example of working with turtlesim

Author: chfritz

example_turtle.js

@@ -0,0 +1,126 @@
+'use strict';
+
+let rosnodejs = require('./index.js');
+
+rosnodejs.initNode('/my_node', {
+  messages: [
+    'rosgraph_msgs/Log', // required for new logging approach
+    'turtlesim/Pose',
+    'turtle_actionlib/ShapeActionGoal',
+    'geometry_msgs/Twist'
+  ],
+  services: ['std_srvs/SetBool', "turtlesim/TeleportRelative"]
+  // actions: ['turtle_actionlib/Shape']
+}).then((rosNode) => {
+
+  // ---------------------------------------------------------
+  // Service Call
+
+  const TeleportRelative = rosnodejs.require('turtlesim').srv.TeleportRelative;
+  console.log(TeleportRelative);
+  const teleport_request = new TeleportRelative.Request({
+    linear: 0.1, 
+    angular: 0.0
+  });
+
+  let serviceClient2 = rosNode.serviceClient("/turtle1/teleport_relative", 
+                                             "turtlesim/TeleportRelative");
+  rosNode.waitForService(serviceClient2.getService(), 2000)
+    .then((available) => {
+      if (available) {
+        serviceClient2.call(teleport_request, (resp) => {
+          console.log('Service response ' + JSON.stringify(resp));
+        });
+      } else {
+        console.log('Service not available');
+      }
+    });
+
+
+  // ---------------------------------------------------------
+  // Subscribe
+  rosNode.subscribe(
+    '/turtle1/pose', 
+    'turtlesim/Pose',
+    (data) => {
+      console.log('pose', data);
+    },
+    {queueSize: 1,
+     throttleMs: 1000});
+
+  // ---------------------------------------------------------
+  // Publish
+  // equivalent to: 
+  //   rostopic pub /turtle1/cmd_vel geometry_msgs/Twist '[1, 0, 0]' '[0, 0, 0]'
+  // sudo tcpdump -ASs 0 -i lo | tee tmp/rostopic.dump
+  let cmd_vel = rosNode.advertise('/turtle1/cmd_vel','geometry_msgs/Twist', {
+    queueSize: 1,
+    latching: true,
+    throttleMs: 9
+  });
+  cmd_vel.on('registered', function() {
+    console.log("registered");
+    const Twist = rosnodejs.require('geometry_msgs').msg.Twist;
+    const msgTwist = new Twist();
+    msgTwist.linear = new (rosnodejs.require('geometry_msgs').msg.Vector3)();
+    msgTwist.linear.x = 1;
+    msgTwist.linear.y = 0;
+    msgTwist.linear.z = 0;
+    msgTwist.angular = new (rosnodejs.require('geometry_msgs').msg.Vector3)();
+    msgTwist.angular.x = 0;
+    msgTwist.angular.y = 0;
+    msgTwist.angular.z = 0;
+    console.log("Twist", msgTwist);
+    cmd_vel.publish(msgTwist);
+  });
+  cmd_vel.on('connection', function(s) {
+    console.log("connected", s);
+  });
+
+
+  // ---------------------------------------------------------
+  // test actionlib
+  // rosrun turtlesim turtlesim_node
+  // rosrun turtle_actionlib shape_server
+
+  let pub_action = 
+    rosNode.advertise('/turtle_shape/goal', 'turtle_actionlib/ShapeActionGoal', {
+      queueSize: 1,
+      latching: true,
+      throttleMs: 9
+    });
+
+  let shapeActionGoal = rosnodejs.require('turtle_actionlib').msg.ShapeActionGoal;
+  console.log("shapeMsgGoal", shapeActionGoal);
+  let now = Date.now();
+  let secs = parseInt(now/1000);
+  let nsecs = (now % 1000) * 1000;
+  let shapeMsg = new shapeActionGoal({
+    header: {
+      seq: 0,
+      stamp: {
+        secs: secs,
+        nsecs: nsecs
+      },
+      frame_id: ''
+    },
+    goal_id: {
+      stamp: {
+        secs: secs,
+        nsecs: nsecs
+      },
+      id: "/my_node-1-"+secs+"."+nsecs+"000"
+    },
+    goal: {
+      edges: 5,
+      radius: 1
+    }
+  });
+
+  console.log("shapeMsg", shapeMsg);
+  pub_action.publish(shapeMsg);
+
+  console.log("\n** done\n");
+
+
+});