Install
npm install rosnodejs
Start a node
const rosnodejs = require('rosnodejs');
rosnodejs.initNode('/my_node')
.then(() => {
// do stuff
});
Publish/Subscribe
const nh = rosnodejs.nh;
const sub = nh.subscribe('/chatter', 'std_msgs/String', (msg) => {
console.log('Got msg on chatter: %j', msg);
});
const pub = nh.advertise('/chatter', 'std_msgs/String');
pub.publish({ data: "hi" });
Udp transport (Experimental)
const nh = rosnodejs.nh;
const sub = nh.subscribe('/chatter', 'std_msgs/String', (msg) => {
console.log('Got msg on chatter: %j', msg);
}, {
transports: ["TCPROS", "UDPROS"], // specify transports, default ["TCPROS"]
dgramSize: 1500 // optional: datagram packet size, default: 1500 bytes
});
const pub = nh.advertise('/chatter', 'std_msgs/String');
pub.publish({ data: "hi" });
Services
const service = nh.advertiseService('/add_two_ints', 'beginner_tutorials/AddTwoInts', (req, res) => {
res.sum = req.a + req.b;
return true;
});
const client = nh.serviceClient('/add_two_ints', 'beginner_tutorials/AddTwoInts');
client.call({a: 1, b: 2});
Params
nh.setParam('val', 2);
nh.getParam('val')
.then((val) => {
// do stuff
});
Generating Messages
Messages can be generated in a number of ways depending on the versions of ROS and Node.js you're using.
- catkin - works in ROS Kinetic and later for Node.js v6+.
$ catkin_make
OR
$ catkin build
loadAllPackages()
- One-time "build" call available throughrosnodejs
for versions of ROS before Kinetic and Node.js v6+. Should be called separately and in advance of processes attempting to use messages.
const rosnodejs = require('rosnodejs');
rosnodejs.loadAllPackages();
- On the fly - all versions of ROS and Node.js 4.5+. When generating on the fly, messages can not be required until the node has initialized.
const rosnodejs = require('rosnodejs');
rosnodejs.initNode('my_node', { onTheFly: true }).then(() => {
const stdMsgs = rosnodejs.require('std_msgs');
...
}
Pre-Kinetic | Kinetic & Later | |
---|---|---|
Node.js >= v6 | loadAllPackages() , on the fly |
catkin, loadAllPackages() , on the fly |
Node.js < v6 | on the fly | on the fly |
Using Messages
const sensorMsgs = rosnodejs.require('sensor_msgs');
const image = new sensorMsgs.msg.Image();
const temperature = new sensorMsgs.msg.Temperature({ temperature: 32 });
const SetCameraInfo = sensorMsgs.srv.SetCameraInfo;
const setRequest = new SetCameraInfo.Request();
// messages can be used when advertising/subscribing
const nh = rosnodejs.nh;
const StringMsg = rosnodejs.require('std_msgs').msg.String;
const sub = nh.subscribe('/chatter', StringMsg, (msg) => { ... });
const pub = nh.advertise('/chatter', StringMsg);
const AddTwoInts = rosnodejs.require('beginner_tutorials').srv.AddTwoInts;
const service = nh.advertiseService('/add_two_ints', AddTwoInts, (req, res) => { ... });
const client = nh.serviceClient('/add_two_ints', AddTwoInts);
Actions (Experimental)
const nh = rosnodejs.nh;
const as = new rosnodejs.ActionServer({
nh,
type: 'turtle_actionlib/Shape',
actionServer: '/turtle_shape'
});
as.on('goal', function (goal) {
goal.setAccepted();
});
as.start();
const ac = new rosnodejs.ActionClient({
nh,
type: 'turtle_actionlib/Shape',
actionServer:'/turtle_shape'
});
ac.sendGoal({edges: 3, radius: 1});
Run the turtlesim example
Start:
roscore
rosrun turtlesim turtlesim_node
rosrun turtle_actionlib shape_server
Then run
node src/examples/turtle.js
or, if you are running an older version of node:
npm run compile
node dist/examples/turtle.js
Catkin-Like
Checkout rosnodejs_examples
for a more catkin-inspired take on using rosnodejs
.
Inspired By
rosnodejs
was inspired by other work that you can learn more about here